JP6577875B2 - Inner wall surface structure of flow path and heat exchange system - Google Patents
Inner wall surface structure of flow path and heat exchange system Download PDFInfo
- Publication number
- JP6577875B2 JP6577875B2 JP2016004394A JP2016004394A JP6577875B2 JP 6577875 B2 JP6577875 B2 JP 6577875B2 JP 2016004394 A JP2016004394 A JP 2016004394A JP 2016004394 A JP2016004394 A JP 2016004394A JP 6577875 B2 JP6577875 B2 JP 6577875B2
- Authority
- JP
- Japan
- Prior art keywords
- flow path
- wall surface
- riblets
- wavy
- wavy riblets
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Description
本発明は、流路の内壁面構造及び熱交換システムに関する。 The present invention relates to an inner wall surface structure of a flow path and a heat exchange system.
流路を流れる流体と流路の内壁面との間の摩擦抵抗を低減することを目的として、流路の長さ方向に延びる複数のリブレット（微細な凹凸）を流路の内壁面に設ける技術が知られている（例えば、特許文献１〜５参照）。 A technique for providing a plurality of riblets (fine irregularities) on the inner wall surface of the flow channel extending in the length direction of the flow channel for the purpose of reducing the frictional resistance between the fluid flowing through the flow channel and the inner wall surface of the flow channel Is known (see, for example, Patent Documents 1 to 5).
つまり、特許文献１には、流体用流入管の内面に、流体の流入方向に延びる複数のリブレットを有するシートを貼り付けることにより、流体の摩擦抵抗を低減させる技術が記載されている。 That is, Patent Document 1 describes a technique for reducing the frictional resistance of a fluid by attaching a sheet having a plurality of riblets extending in the fluid inflow direction to the inner surface of the fluid inflow pipe.
また、特許文献２には、リブレット付フィルムを航走体の船殻材に貼り付けることにより、航走体の流体抵抗と自己放射雑音レベルの低減を同時に実現する技術が記載されている。 Patent Document 2 describes a technology that simultaneously realizes reduction of the fluid resistance and the self-radiated noise level of the navigation body by attaching a film with riblets to the hull material of the navigation body.
また、特許文献３には、流体が流れる第一流路と、相変化する冷媒が流れる第二流路とを備える熱交換器において、第二流路の内壁に複数のリブレットを設けることにより、第二流路の抵抗低減効果と表面積拡大による伝熱促進効果を両立させる技術が記載されている。 Further, in Patent Document 3, in a heat exchanger including a first flow path through which a fluid flows and a second flow path through which a phase-change refrigerant flows, a plurality of riblets are provided on the inner wall of the second flow path. A technique for achieving both the resistance reduction effect of the two flow paths and the heat transfer enhancement effect by expanding the surface area is described.
また、特許文献４には、石炭層内のメタンガスを極低温に冷却し液化するガス液化装置において、熱交換を行う冷媒管の内壁にリブレットを付加することにより、主流方向の渦の発生を抑制して流体抵抗を低減させつつ、主流方向と垂直な方向の渦を誘起して伝熱効果を高める技術が記載されている。 Further, in Patent Document 4, in a gas liquefaction apparatus that cools and liquefies methane gas in a coal bed, the generation of vortices in the mainstream direction is suppressed by adding riblets to the inner wall of a refrigerant pipe that performs heat exchange. Thus, a technique is described in which a fluid resistance is reduced and a vortex in a direction perpendicular to the main flow direction is induced to enhance the heat transfer effect.
また、特許文献５には、物体の表面にジグザグ状又は曲線状のリブレットを配列させることで、流体の進行方向を左右に周期的に変えつつ流動させることで、乱流渦の発生と成長を阻害し、摩擦抵抗を低減させる技術が記載されている。 In addition, Patent Document 5 describes the generation and growth of turbulent vortices by arranging zigzag or curvilinear riblets on the surface of an object and causing the fluid to flow while periodically changing the direction of movement from side to side. Techniques for inhibiting and reducing frictional resistance are described.
また、特許文献６〜１０にも、上記と同様に、リブレットを用いる技術が記載されている。 Also, Patent Documents 6 to 10 describe a technique using a riblet as described above.
上述のリブレットを用いた従来の技術は、いずれも抵抗低減を第一の目的としているため、リブレットの形状及びサイズは、抵抗低減に有効となるように最適化されている。例えば、特許文献３、４に記載の技術では、抵抗低減と伝熱促進の両立を目的としているが、あくまでも抵抗低減用のリブレットを流用し、表面積拡大による伝熱促進を期待する程度である。したがって、それらのリブレットの形状は、伝熱促進に最適化されたものではなく、伝熱促進に対して必ずしも有効に作用するわけではない。 Since all of the conventional techniques using the above-described riblets have a primary purpose of reducing resistance, the shape and size of the riblets are optimized so as to be effective in reducing resistance. For example, the techniques described in Patent Documents 3 and 4 aim to achieve both resistance reduction and heat transfer promotion, but to the extent that resistance reduction riblets are used to the extent that heat transfer promotion is expected by expanding the surface area. Therefore, the shape of those riblets is not optimized for heat transfer promotion, and does not necessarily act effectively for heat transfer promotion.
加えて、一般に、流れ（抵抗）と熱（伝熱）にはアナロジーが成り立つことが知られており、抵抗低減した場合には伝熱性能も低下する。すなわち、従来の技術のように、単一のストレート形状のリブレットの使用において、抵抗を下げながら表面積の拡大効果による伝熱促進を達成できる可能性は低い。 In addition, it is generally known that an analogy is established between flow (resistance) and heat (heat transfer), and when the resistance is reduced, the heat transfer performance is also lowered. That is, unlike the prior art, in the use of a single straight riblet, it is unlikely that the heat transfer enhancement by the effect of expanding the surface area can be achieved while reducing the resistance.
本発明は、上記事情に鑑みてなされたものであって、伝熱量を維持又は向上させながら通水抵抗を低減できるようにすることを目的とする。 This invention is made | formed in view of the said situation, Comprising: It aims at enabling water resistance to be reduced, maintaining or improving the amount of heat transfer.
第一態様に係る流路の内壁面構造は、流体が流れる流路の内壁面に形成されると共に前記流路の長さ方向に延びる蛇行形状とされた複数の波状リブレットを有し、前記流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、前記流路における熱伝達率比であるＨＴＲを式（１）で表した場合に、前記流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の波状リブレットの波長及び振幅が設定されている。
The inner wall surface structure of the flow channel according to the first aspect includes a plurality of wavy riblets formed on the inner wall surface of the flow channel through which fluid flows and having a meandering shape extending in the length direction of the flow channel. The Nusselt number in the flow path when the inner wall surface of the road is a smooth surface is Nu flat, and the Nusselt number in the flow path when the plurality of corrugated riblets are formed on the inner wall surface of the flow path is Nu riblet. When the HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by Equation (1), the wavelength and amplitude of the plurality of wavy riblets are such that the heat transfer coefficient ratio in the flow path is HTR> 1. Is set.
第二態様に係る流路の内壁面構造は、流体が流れる流路の内壁面に形成されると共に前記流路の長さ方向に延びる蛇行形状とされた複数の波状リブレットを有し、前記流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、前記流路における熱伝達率比であるＨＴＲを式（１）で表し、前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（２）で表した場合に、前記流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の波状リブレットの進入角βが設定されている。
The inner wall surface structure of the flow channel according to the second aspect includes a plurality of wavy riblets formed on the inner wall surface of the flow channel through which fluid flows and having a meandering shape extending in the length direction of the flow channel. The Nusselt number in the flow path when the inner wall surface of the road is a smooth surface is Nu flat, and the Nusselt number in the flow path when the plurality of corrugated riblets are formed on the inner wall surface of the flow path is Nu riblet. HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1), and the amplitude of the plurality of wavy riblets is a and the wavelength is λ, and β, which is the angle of approach of the plurality of wavy riblets, is expressed by equation (2). ), The approach angle β of the plurality of wavy riblets is set so that the heat transfer coefficient ratio in the flow path is HTR> 1.
第三態様に係る流路の内壁面構造は、流体が流れる流路の内壁面に形成されると共に前記流路の長さ方向に延びる蛇行形状とされた複数の波状リブレットを有し、前記流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、前記流路における熱伝達率比であるＨＴＲを式（１）で表し、前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、前記流路における抵抗比であるＤＲを式（２）で表し、性能向上比であるｅを式（３）で表し、前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（４）で表した場合に、前記流路における性能向上比がｅ＞１となるように、前記複数の波状リブレットの進入角βが設定されている。
The inner wall surface structure of the flow channel according to the third aspect includes a plurality of wavy riblets formed on the inner wall surface of the flow channel through which fluid flows and having a meandering shape extending in the length direction of the flow channel. The Nusselt number in the flow path when the inner wall surface of the road is a smooth surface is Nu flat, and the Nusselt number in the flow path when the plurality of corrugated riblets are formed on the inner wall surface of the flow path is Nu riblet. HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1), and when the inner wall surface of the flow path is a smooth surface, the resistance coefficient in the flow path is Cf flat, and the inner wall surface of the flow path When the plurality of corrugated riblets are formed on the channel, the resistance coefficient in the channel is Cf rivet , the resistance ratio DR in the channel is expressed by Formula (2), and the performance improvement ratio e is expressed by Formula (3) ) When the amplitude of the plurality of wavy riblets is a, the wavelength is λ, and β, which is the angle of entry of the plurality of wavy riblets, is expressed by equation (4), the performance improvement ratio in the flow path is e> 1. Further, an approach angle β of the plurality of wavy riblets is set.
第四態様に係る熱交換システムは、流体が流れる第一流路と、前記第一流路の内壁面に形成されると共に前記第一流路の長さ方向に延びる蛇行形状とされた複数の第一波状リブレットとを有する流路部材と、前記第一流路と連通する第二流路と、前記第二流路の内壁面に形成されると共に前記第二流路の長さ方向に延びる蛇行形状とされ前記複数の第一波状リブレットよりも波長が短く振幅が大きい複数の第二波状リブレットとを有する熱交換器と、を備える。 The heat exchange system according to the fourth aspect includes a first flow path in which a fluid flows, and a plurality of first wavy shapes that are formed on the inner wall surface of the first flow path and meander in the length direction of the first flow path. A flow path member having a riblet; a second flow path communicating with the first flow path; and a meandering shape formed on an inner wall surface of the second flow path and extending in a length direction of the second flow path. A heat exchanger having a plurality of second corrugated riblets having a shorter wavelength and a larger amplitude than the plurality of first corrugated riblets.
第五態様に係る熱交換システムは、第四態様に係る熱交換システムにおいて、流体が流れる流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、前記流路における熱伝達率比であるＨＴＲを式（１）で表し、前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、前記流路における抵抗比であるＤＲを式（２）で表した場合に、前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長及び振幅が設定され、前記第二流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の第二波状リブレットの波長及び振幅が設定されている。
The heat exchange system according to the fifth aspect is the heat exchange system according to the fourth aspect , wherein the Nusselt number in the flow path when the inner wall surface of the flow path through which the fluid flows is a smooth surface is Nu flat . In the case where a plurality of corrugated riblets are formed on the inner wall surface, the Nusselt number in the flow path is Nu rivet, and the HTR which is the heat transfer coefficient ratio in the flow path is expressed by Equation (1). The resistance coefficient in the flow path in the case of a smooth surface is Cf flat, and the resistance coefficient in the flow path when the plurality of corrugated riblets are formed on the inner wall surface of the flow path is Cf ribbon , When the DR which is the resistance ratio is expressed by the formula (2), the wavelengths and amplitudes of the plurality of first wavy riblets are set so that the resistance ratio in the first flow path is DR <1, The wavelengths and amplitudes of the plurality of second wavy riblets are set so that the heat transfer coefficient ratio in the second flow path is HTR> 1.
第六態様に係る熱交換システムは、第四態様に係る熱交換システムにおいて、流体が流れる流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、前記流路における熱伝達率比であるＨＴＲを式（１）で表し、前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、前記流路における抵抗比であるＤＲを式（２）で表し、性能向上比であるｅを式（３）で表した場合に、前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長及び振幅が設定され、前記第二流路における性能向上比がｅ＞１となるように、前記複数の第二波状リブレットの波長及び振幅が設定されている。
The heat exchange system according to the sixth aspect is the heat exchange system according to the fourth aspect , wherein the Nusselt number in the flow path when the inner wall surface of the flow path through which the fluid flows is a smooth surface is Nu flat . In the case where a plurality of corrugated riblets are formed on the inner wall surface, the Nusselt number in the flow path is Nu rivet, and the HTR which is the heat transfer coefficient ratio in the flow path is expressed by Equation (1). The resistance coefficient in the flow path in the case of a smooth surface is Cf flat, and the resistance coefficient in the flow path when the plurality of corrugated riblets are formed on the inner wall surface of the flow path is Cf ribbon , When the resistance ratio DR is expressed by Equation (2) and the performance improvement ratio e is expressed by Equation (3), the resistance ratio in the first flow path is such that DR <1. Wave The wavelength and amplitude of the plurality of second wavy riblets are set so that the wavelength and amplitude of the riblet are set, and the performance improvement ratio in the second flow path is e> 1.
第七態様に係る熱交換システムは、第四態様に係る熱交換システムにおいて、流体が流れる流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、前記流路における熱伝達率比であるＨＴＲを式（１）で表し、前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、前記流路における抵抗比であるＤＲを式（２）で表し、前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（３）で表した場合に、前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長ａ及び振幅λが設定され、前記第二流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の第二波状リブレットの進入角βが設定されている。
The heat exchange system according to the seventh aspect is the heat exchange system according to the fourth aspect , wherein the Nusselt number in the flow path when the inner wall surface of the flow path through which the fluid flows is a smooth surface is Nu flat . In the case where a plurality of corrugated riblets are formed on the inner wall surface, the Nusselt number in the flow path is Nu rivet, and the HTR which is the heat transfer coefficient ratio in the flow path is expressed by Equation (1). The resistance coefficient in the flow path in the case of a smooth surface is Cf flat, and the resistance coefficient in the flow path when the plurality of corrugated riblets are formed on the inner wall surface of the flow path is Cf ribbon , The resistance ratio DR is expressed by equation (2), the amplitude of the plurality of wavy riblets is a, the wavelength is λ, and β, which is the angle of approach of the plurality of wavy riblets, is expressed by equation (3). In addition, the wavelength a and the amplitude λ of the plurality of first wavy riblets are set so that the resistance ratio in the first flow path is DR <1, and the heat transfer coefficient ratio in the second flow path is HTR> 1. Thus, an approach angle β of the plurality of second wavy riblets is set.
第八態様に係る熱交換システムは、第四態様に係る熱交換システムにおいて、流体が流れる流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、前記流路における熱伝達率比であるＨＴＲを式（１）で表し、前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、前記流路における抵抗比であるＤＲを式（２）で表し、性能向上比であるｅを式（３）で表し、前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（４）で表した場合に、前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長ａ及び振幅λが設定され、前記第二流路における性能向上比がｅ＞１となるように、前記複数の第二波状リブレットの進入角βが設定されている。
The heat exchange system according to the eighth aspect is the heat exchange system according to the fourth aspect , wherein the Nusselt number in the flow path when the inner wall surface of the flow path through which the fluid flows is a smooth surface is Nu flat . In the case where a plurality of corrugated riblets are formed on the inner wall surface, the Nusselt number in the flow path is Nu rivet, and the HTR which is the heat transfer coefficient ratio in the flow path is expressed by Equation (1). The resistance coefficient in the flow path in the case of a smooth surface is Cf flat, and the resistance coefficient in the flow path when the plurality of corrugated riblets are formed on the inner wall surface of the flow path is Cf ribbon , DR, which is a resistance ratio, is expressed by equation (2), e, which is a performance improvement ratio, is expressed by equation (3), and the amplitude of the plurality of waved riblets is a and the wavelength is λ, and the plurality of waved riblets. When β, which is an approach angle, is expressed by Equation (4), the wavelength a and the amplitude λ of the plurality of first wavy riblets are set so that the resistance ratio in the first flow path is DR <1, The approach angle β of the plurality of second wavy riblets is set so that the performance improvement ratio in the second flow path is e> 1.
本発明によれば、伝熱量を維持又は向上させながら通水抵抗を低減できる。 According to the present invention, the water flow resistance can be reduced while maintaining or improving the amount of heat transfer.
以下、本発明の一実施形態について説明する。 Hereinafter, an embodiment of the present invention will be described.
（流路の内壁面構造）
最初に、本発明で対象とする波状リブレットについて、その形状と抵抗・伝熱特性を述べる。
(Inner wall surface structure of the flow path)
First, the shape and resistance / heat transfer characteristics of the corrugated riblet targeted in the present invention will be described.
図１に波状リブレットを有する流路の内壁面構造１０の概略図を示す。流路の内壁面構造１０が適用された流路１２の内壁面には、流路１２の長さ方向に延びる蛇行形状とされた複数の波状リブレット１４が形成されている。図２は、波状リブレット１４を模式的に示した縦断面図、図３は、波状リブレット１４を模式的に示した平面図である。 FIG. 1 shows a schematic view of an inner wall surface structure 10 of a flow path having corrugated riblets. On the inner wall surface of the flow channel 12 to which the inner wall surface structure 10 of the flow channel is applied, a plurality of wavy riblets 14 having a meandering shape extending in the length direction of the flow channel 12 are formed. FIG. 2 is a longitudinal sectional view schematically showing the corrugated riblet 14, and FIG. 3 is a plan view schematically showing the corrugated riblet 14.
図２において、αは、断面三角形状に形成された波状リブレット１４の頂角、ｈは、波状リブレット１４の高さを示している。また、図３において、βは、波状リブレット１４の進入角、ａは、波状リブレット１４の振幅（片振幅）を示している。 In FIG. 2, α is the apex angle of the wave-like riblet 14 having a triangular cross section, and h is the height of the wave-like riblet 14. In FIG. 3, β indicates an approach angle of the waved riblet 14, and a indicates an amplitude (single amplitude) of the waved riblet 14.
一般に、リブレット（微細な凹凸）は、流れの方向と溝の方向とが一致したストレートタイプのものが広く知られているが、本発明で扱うリブレットは、x、y、z方向をそれぞれ主流、壁垂直、幅方向としたとき、x−z面内で溝が正弦波状に蛇行した波状リブレットである。 In general, a straight type in which the flow direction and the groove direction coincide with each other is widely known as the riblet (fine irregularities), but the riblet handled in the present invention has a mainstream and a wall in the x, y, and z directions, respectively. When the vertical direction and the width direction are set, the wavy riblet in which the groove meanders in a sine wave shape in the xz plane.
波状リブレットについては、既往研究にて抵抗低減効果が調べられており、波長λ+≒1000、あるいはλ+≒1000かつ進入角β（=2πa/λ）5.7°付近（aは振幅）が最も効果的であることが報告されている[参考文献1，2を参照]（上付き”+”は壁面摩擦速度と動粘性係数による無次元化を表す）。ただし、伝熱性能との関係については調べられておらず、不明である。 As for the wavy riblet, the resistance reduction effect has been investigated in past studies, and the wavelength λ + ≈1000 or λ + ≈1000 and the approach angle β (= 2πa / λ) near 5.7 ° (a is the amplitude) is the most effective [Refer to References 1 and 2] (The superscript “+” indicates non-dimensionalization by wall friction velocity and kinematic viscosity coefficient). However, the relationship with the heat transfer performance has not been investigated and is unknown.
そこで、数値シミュレーションにより波状リブレットの抵抗と伝熱特性を調べた結果を図４に示す（流路半幅と壁面摩擦速度に基づく摩擦レイノルズ数は180（平均流速と流路高さに基づくバルクレイノルズ数は約5500）、プラントル数は6.7）。リブレットのy−z断面形状は、頂角（α）60°の三角形状であり、溝高さh+は9とする。 Therefore, the results of investigating the resistance and heat transfer characteristics of the corrugated riblet by numerical simulation are shown in FIG. Is approximately 5500) and Prandtl number is 6.7). The riblet has a y-z cross-sectional shape of a triangular shape having an apex angle (α) of 60 °, and a groove height h + of 9.
ここでは、波状リブレットの設置による効果を、平板流路（内壁面が平滑面である流路）に対する抵抗の変化（抵抗比DR）と熱伝達率の変化（熱伝達率比HTR）で表す。抵抗比DR、熱伝達比HTRは、次式でそれぞれ表される。 Here, the effect of the installation of the corrugated riblet is expressed by a change in resistance (resistance ratio DR) and a change in heat transfer coefficient (heat transfer coefficient ratio HTR) with respect to a flat plate flow path (flow path whose inner wall surface is a smooth surface). The resistance ratio DR and the heat transfer ratio HTR are expressed by the following equations, respectively.
CfとNuはそれぞれ抵抗係数とヌセルト数である。流路の内壁面が平滑面である場合の該流路におけるヌセルト数は、Ｎｕｆｌａｔであり、流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数は、Ｎｕｒｉｂｌｅｔである。また、流路の内壁面が平滑面である場合の該流路における抵抗係数は、Ｃｆｆｌａｔであり、流路の内壁面に複数の波状リブレットが形成された場合の該流路における抵抗係数は、Ｃｆｒｉｂｌｅｔである。同図には参考のため、同じ断面形状を有するストレート状のリブレットの結果（図中の＊印）もあわせて示す。 Cf and Nu are the resistance coefficient and the Nusselt number, respectively. The Nusselt number in the channel when the inner wall surface of the channel is a smooth surface is Nu flat , and the Nusselt number in the channel when a plurality of corrugated riblets are formed on the inner wall surface of the channel is Nu It is a rivet . In addition, the resistance coefficient in the flow path when the inner wall surface of the flow path is a smooth surface is Cf flat , and the resistance coefficient in the flow path when a plurality of corrugated riblets are formed on the inner wall surface of the flow path is , Cf bundle . For reference, the results of straight riblets having the same cross-sectional shape (* mark in the figure) are also shown in the figure.
図４より、長波長の波状リブレットは抵抗低減に有効であり、既往研究でも報告されているように、ストレート状のリブレットを大きく上回る抵抗低減効果が得られる。特に、λ+≧1100において抵抗低減率は最大となる（この傾向は上の既往研究と概ね一致する）。 From FIG. 4, long-wave corrugated riblets are effective in reducing resistance, and as reported in previous studies, a resistance-reducing effect far exceeding that of straight riblets is obtained. In particular, the resistance reduction ratio in lambda + ≧ 1100 is maximized (this trend generally consistent with previous studies above).
一方、短波長・大振幅の波状リブレットは伝熱促進に対して有効である。今回の条件では、「a+=18,λ+＜283」の組み合わせ、あるいは、「a+=36,λ+＜565」の組み合わせで平板流路以上の伝熱性能（HTR＞1）が得られる。図５に、HTRと波状リブレットの進入角（β）の関係を示す。進入角（β）は、次式で表される。ａは波状リブレットの振幅、λは波状リブレットの波長である（図３参照）。 On the other hand, short-wavelength / large-amplitude corrugated riblets are effective in promoting heat transfer. Under these conditions, the combination of “a + = 18, λ + <283” or “a + = 36, λ + <565” provides heat transfer performance (HTR> 1) that exceeds that of flat plate channels. It is done. FIG. 5 shows the relationship between the HTR and the approach angle (β) of the wavy riblet. The approach angle (β) is expressed by the following equation. a is the amplitude of the wave-like riblet, and λ is the wavelength of the wave-like riblet (see FIG. 3).
上記の振幅と波長の組み合わせはいずれもβ≒39°である。また、図５より、HTR＞1を満たす波状リブレットの進入角はβ＞25°であると判断できる。 All of the above combinations of amplitude and wavelength are β≈39 °. Further, from FIG. 5, it can be determined that the approach angle of the wavy riblet satisfying HTR> 1 is β> 25 °.
図６に、性能向上率eと進入角βの関係を示す。ここで、eは平板流路に対する熱伝達率の変化（熱伝達率比HTR）と抵抗の変化（抵抗比DR）の比である。性能向上比eは、次式で表される。 FIG. 6 shows the relationship between the performance improvement rate e and the approach angle β. Here, e is the ratio of the change in heat transfer coefficient (heat transfer coefficient ratio HTR) to the flat plate flow path and the change in resistance (resistance ratio DR). The performance improvement ratio e is expressed by the following equation.
図６より、β＞15°の条件においてe＞1となることがわかる。図５との比較により、15°＜β＜25°の波状リブレットはHTR＜1であり、熱伝達率が平板流路の値を上回らないが、e＞1であることにより、伝熱量を確保するために流量を上げたとしても抵抗はそれほど増大せず、伝熱促進側に有利に作用する。 FIG. 6 shows that e> 1 under the condition of β> 15 °. By comparison with Fig. 5, the corrugated riblet of 15 ° <β <25 ° has HTR <1, and the heat transfer rate does not exceed the value of the flat plate channel, but e> 1 ensures heat transfer. Therefore, even if the flow rate is increased, the resistance does not increase so much, and acts favorably on the heat transfer promoting side.
波状リブレットを設置した場合には、壁近傍の流れが波状の溝により幅方向に偏向され、なおかつそれは周期的に変化する。この周期的な幅方向の流れが、乱流渦の発生と成長を阻害し、通水抵抗の低減をもたらすことが報告さている[参考文献1参照]。 When corrugated riblets are installed, the flow in the vicinity of the wall is deflected in the width direction by the corrugated grooves, and it changes periodically. It has been reported that this periodic flow in the width direction inhibits the generation and growth of turbulent vortices and leads to a reduction in water flow resistance [see Reference 1].
短波長・大振幅の波状リブレットにおいても同様の渦構造の抑制効果が生じるが、一方で蛇行した波状リブレットに流れが衝突することにより、通水抵抗が増大する。それと同時に、波状リブレットへの流れの衝突によって熱伝達率も増大し、その伝熱促進効果は短波長・大振幅のものほど顕著に現れる。 The same effect of suppressing the vortex structure also occurs in the short-wavelength / large-amplitude corrugated riblet. On the other hand, when the flow collides with the meandering corrugated riblet, the water resistance increases. At the same time, the heat transfer coefficient also increases due to the collision of the flow with the wavy riblet, and the effect of promoting heat transfer becomes more pronounced with short wavelength and large amplitude.
以上のように、波状リブレットでは波長や振幅によって抵抗・伝熱特性が大きく変化し、これらを制御することで抵抗と伝熱性能を制御できることが新たに分かった。また、抵抗が低減した長波長の波状リブレットでは伝熱性能も低下、抵抗が増大した短波長・大振幅の波状リブレットでは伝熱性能も増大し、（他の多くの抵抗低減技術と同じように）単一形状の波状リブレットだけで伝熱量を維持（もしくは向上）しながら抵抗低減を達成することは困難である。 As described above, it has been newly found that the resistance and heat transfer characteristics of the wavy riblet change greatly depending on the wavelength and amplitude, and the resistance and heat transfer performance can be controlled by controlling these. In addition, long-wave corrugated riblets with reduced resistance also reduce heat transfer performance, and short-wavelength, large-amplitude corrugated riblets with increased resistance also increase heat transfer performance (as in many other resistance reduction technologies). ) It is difficult to achieve resistance reduction while maintaining (or improving) the amount of heat transfer with only a single-shaped corrugated riblet.
すなわち、長波長の波状リブレットを例えば熱交換器の伝熱管内壁に使った場合、抵抗を下げることができる一方で熱伝達率も低下し、熱交換器に要求される伝熱性能を確保することができない。一方、短波長・大振幅の波状リブレットを使った場合には、熱伝達率が上がるが、抵抗も増大し、通水抵抗の低減は達成できない。 That is, when long-wave corrugated riblets are used, for example, on the heat transfer tube inner wall of a heat exchanger, the resistance can be lowered while the heat transfer rate is also lowered to ensure the heat transfer performance required for the heat exchanger. I can't. On the other hand, when a wavelet riblet having a short wavelength and a large amplitude is used, the heat transfer rate is increased, but the resistance is also increased, and the reduction of water flow resistance cannot be achieved.
（エンジン冷却システム）
そこで、以下では熱交換システムに有用な波状リブレットの利用方法を提案する。熱交換システムの冷却系の一例として、図７に示す自動車用のエンジン冷却システム２０を対象に考える。
(Engine cooling system)
Therefore, in the following, we propose a method of using corrugated riblets useful for heat exchange systems. As an example of the cooling system of the heat exchange system, consider the engine cooling system 20 for an automobile shown in FIG.
エンジン冷却システム２０（熱交換システムの一例）は、エンジン２２を一定温度に保つためのものであり、エンジン２２で発生した燃焼熱は冷却液を介して車両前方に設置されたラジエータ２４（熱交換器の一例）で放熱される。したがって、ラジエータ２４の内部の伝熱管４０では、ある所定の伝熱量を確保する必要があるが、燃費効率の観点から、それと同時に冷却液の抵抗を下げることも望まれる。 The engine cooling system 20 (an example of a heat exchange system) is for keeping the engine 22 at a constant temperature, and the combustion heat generated in the engine 22 is a radiator 24 (heat exchange) installed in front of the vehicle via a coolant. Heat). Therefore, in the heat transfer tube 40 inside the radiator 24, it is necessary to ensure a certain heat transfer amount, but from the viewpoint of fuel efficiency, it is also desired to reduce the resistance of the coolant at the same time.
一方、エンジン２２とラジエータ２４の間には、冷却液を循環させるための配管３０が存在する。配管３０は、冷却液を輸送することが目的であるから、伝熱性能に対する要求性能は存在しない（エンジンルームの熱害を防ぐ点では、むしろ熱伝達率が下がったほうが望ましい）。 On the other hand, a piping 30 for circulating the coolant exists between the engine 22 and the radiator 24. Since the piping 30 is intended to transport the coolant, there is no required performance for heat transfer performance (in order to prevent heat damage in the engine room, it is desirable that the heat transfer rate is rather lowered).
そこで、図４のような波状リブレットの特性を利用して、冷却系の場所と目的に応じて波状リブレットの形状を使い分けることを提案する。 Therefore, it is proposed to use the corrugated riblet according to the location and purpose of the cooling system by utilizing the characteristics of the corrugated riblet as shown in FIG.
すなわち、伝熱性能を考慮する必要のない配管３０（流路部材の一例）では、抵抗低減に有効な（伝熱性能も下がる）長波長の波状リブレットを利用する。つまり、図８に示すように、配管３０は、冷却液が流れる第一流路３２と、第一流路３２の内壁面に形成されると共に第一流路３２の長さ方向に延びる蛇行形状とされた複数の第一波状リブレット３４とを有する。この複数の第一波状リブレット３４は、第一流路３２における抵抗比がＤＲ＜１となるように、波長及び振幅が設定される。 That is, in the pipe 30 (an example of the flow path member) that does not need to consider the heat transfer performance, a long-wave corrugated riblet that is effective in reducing the resistance (which also reduces the heat transfer performance) is used. That is, as shown in FIG. 8, the pipe 30 has a first flow path 32 through which the coolant flows and a meandering shape that is formed on the inner wall surface of the first flow path 32 and extends in the length direction of the first flow path 32. A plurality of first wavy riblets 34. The plurality of first wavy riblets 34 are set in wavelength and amplitude so that the resistance ratio in the first flow path 32 is DR <1.
一方、伝熱量（放熱量）を確保しなければならない伝熱管４０では、伝熱促進に有効な短波長・大振幅の波状リブレットを利用する。つまり、図９に示すように、伝熱管４０は、上述の第一流路と連通する第二流路４２と、第二流路４２の内壁面に形成されると共に第二流路４２の長さ方向に延びる蛇行形状とされた複数の第二波状リブレット４４とを有する。複数の第二波状リブレット４４は、上述の配管３０に形成された複数の第一波状リブレット３４（図８参照）よりも波長が短く振幅が大きい、すなわち、進入角βが大きいリブレットである。 On the other hand, in the heat transfer tube 40 in which a heat transfer amount (heat release amount) must be ensured, a short-wavelength, large-amplitude wave riblet effective for heat transfer is used. That is, as shown in FIG. 9, the heat transfer tube 40 is formed on the second channel 42 communicating with the first channel and the inner wall surface of the second channel 42 and the length of the second channel 42. A plurality of second wavy riblets 44 having a meandering shape extending in the direction. The plurality of second corrugated riblets 44 are riblets having a shorter wavelength and a larger amplitude than the plurality of first corrugated riblets 34 (see FIG. 8) formed in the pipe 30 described above, that is, a large approach angle β.
この複数の第二波状リブレット４４は、第二流路４２における熱伝達率比がＨＴＲ＞１となるように、波長及び振幅が設定されるか、第二流路４２における熱伝達率比がＨＴＲ＞１となるように、進入角βが設定されるか、第二流路４２における性能向上比がｅ＞１となるように、進入角βが設定される。この伝熱管４０の内壁面には、本発明の流路の内壁面構造が適用されている。 The plurality of second wavy riblets 44 are set in wavelength and amplitude so that the heat transfer coefficient ratio in the second flow path 42 is HTR> 1, or the heat transfer coefficient ratio in the second flow path 42 is HTR. The approach angle β is set so that> 1 or the performance improvement ratio in the second flow path 42 is e> 1. The inner wall surface structure of the flow path of the present invention is applied to the inner wall surface of the heat transfer tube 40.
このエンジン冷却システム２０では、伝熱管４０により伝熱促進した分だけ流量を下げる。この流量の低下は、エンジン冷却システム２０に設けられたウォータポンプの回転数を下げることにより可能である。 In the engine cooling system 20, the flow rate is reduced by the amount of heat transfer promoted by the heat transfer tube 40. This reduction in the flow rate is possible by lowering the rotational speed of a water pump provided in the engine cooling system 20.
（作用効果）
これらの波状リブレットの使い分けにより、次に挙げる作用効果が期待できる。
（１）伝熱管４０の伝熱性能は維持（もしくは向上）しながら、流量低減によって、システム全体の抵抗を下げることが可能となる。
（２）配管３０では、流量低減の効果に加えて、長波長の第一波状リブレット３４による摩擦抵抗低減効果が重畳され、より高い抵抗低減効果が得られる。
（３）配管３０に用いる長波長の第一波状リブレット３４は熱伝達率が低いことから、配管３０における熱輸送中の放熱量が少なく、熱害の低減にもつながる。
（４）いずれの波状リブレットも従来の伝熱促進技術に比べて微細であることから、例えばロウ付けや溶接等による配管３０や伝熱管４０の組み付け工程においては、接合面積を十分に確保でき、組付不良の発生割合を少なくできることが期待できる。
(Function and effect)
The following effects can be expected by properly using these wavy riblets.
(1) While maintaining (or improving) the heat transfer performance of the heat transfer tube 40, it is possible to reduce the resistance of the entire system by reducing the flow rate.
(2) In the pipe 30, in addition to the effect of reducing the flow rate, the frictional resistance reduction effect by the long-wavelength first wave riblet 34 is superimposed, and a higher resistance reduction effect is obtained.
(3) Since the long-wavelength first wavy riblet 34 used for the pipe 30 has a low heat transfer coefficient, the amount of heat dissipated during heat transport in the pipe 30 is small, leading to a reduction in heat damage.
(4) Since any corrugated riblet is finer than the conventional heat transfer promotion technology, for example, in the assembly process of the pipe 30 and the heat transfer pipe 40 by brazing, welding, etc., a sufficient bonding area can be secured, It can be expected that the rate of occurrence of defective assembly can be reduced.
この波状リブレットの使い分けによってシステム全体で得られる効果を試算する。ここでは、エンジン側の冷却部分（ウォータージャケット）を除いたラジエータ冷却系を対象とし、伝熱管の内壁には最も伝熱促進したa+=36,λ+=283の波状リブレット、配管の内壁には最も抵抗が低減したa+=18,λ+=1696の波状リブレットを適用する。 The effect that can be obtained in the entire system by properly using the wavy riblets is estimated. Here, the radiator cooling system excluding the cooling part (water jacket) on the engine side is the target, and the inner wall of the heat transfer tube has a wave-like riblet with a + = 36, λ + = 283 that promotes the most heat transfer, and the inner wall of the pipe is a + = 18 the least resistance is reduced, applying the wavy riblets of lambda + = 1696.
試算に際し、冷却系全体の抵抗の約半分がラジエータの抵抗であり、さらにラジエータの抵抗の半分が伝熱管の抵抗とした。また、曲りや絞りによる波状リブレットの性能低下は生じないものとした。試算結果を図１０に示す。 In the trial calculation, about half of the resistance of the entire cooling system was the resistance of the radiator, and half of the resistance of the radiator was the resistance of the heat transfer tube. In addition, the performance of the wavy riblet is not deteriorated due to bending or drawing. The trial calculation results are shown in FIG.
全体の抵抗に対して、伝熱管で約8％、配管では25％抵抗が低減され、全体として約33％の抵抗低減効果が得られることがわかる。前記の仮定があるため、実際に得られる効果はこれより低下すると考えられるが、本結果は第一次近似的な簡易試算として、本発明の有用性を示すものである。 It can be seen that the resistance is reduced by about 8% for the heat transfer tube and 25% for the piping, and the overall resistance is reduced by about 33%. Although the above-mentioned assumptions are present, the actual effect is considered to be lower than this, but this result shows the usefulness of the present invention as a first-order approximate simple calculation.
[参考文献1] Peet, Y. and Sagault, P., “The theoretical prediction of turbulent skin friction on geometrically complex surfaces”, Physics of Fluids, Vol. 21, No. 105105 (2009), pp.1-17.
[参考文献2] 山田，岡林，淺井, “波状リブレットによる抵抗低減効果改善メカニズムの解明に関する数値解析”, 第27回数値流体力学シンポジウム, (2013), B06-4.
[Reference 1] Peet, Y. and Sagault, P., “The theoretical prediction of turbulent skin friction on geometrically complex surfaces”, Physics of Fluids, Vol. 21, No. 105105 (2009), pp.1-17.
[Reference 2] Yamada, Okabayashi, Sakurai, “Numerical analysis on elucidation of improvement mechanism of resistance reduction effect by wavy riblet”, 27th Symposium on Fluid Dynamics, (2013), B06-4.
（変形例）
なお、上記実施形態では、伝熱管について説明したが、本発明の流路の内壁面構造は、伝熱管以外の部材に適用されても良い。
(Modification)
In addition, although the heat transfer tube was demonstrated in the said embodiment, the inner wall surface structure of the flow path of this invention may be applied to members other than a heat transfer tube.
つまり、図１に示される流路の内壁面構造１０が伝熱管以外の部材に適用された場合において、流路１２における熱伝達率比がＨＴＲ＞１となるように、複数の波状リブレット１４の波長及び振幅が設定されるか、流路１２における熱伝達率比がＨＴＲ＞１となるように、複数の波状リブレット１４の進入角βが設定されるか、流路１２における性能向上比がｅ＞１となるように、複数の波状リブレット１４の進入角βが設定されても良い。 That is, when the inner wall surface structure 10 of the flow path shown in FIG. 1 is applied to a member other than the heat transfer tube, the plurality of wavy riblets 14 are arranged so that the heat transfer coefficient ratio in the flow path 12 becomes HTR> 1. The wavelength and amplitude are set, the entrance angle β of the plurality of wavy riblets 14 is set so that the heat transfer coefficient ratio in the flow path 12 is HTR> 1, or the performance improvement ratio in the flow path 12 is e The approach angle β of the plurality of wavy riblets 14 may be set so that> 1.
また、上記実施形態では、熱交換システムの一例として、エンジン冷却システムについて説明したが、本発明は、エンジン冷却システム以外の熱交換システムに適用されても良い。 Moreover, although the engine cooling system has been described as an example of the heat exchange system in the above embodiment, the present invention may be applied to a heat exchange system other than the engine cooling system.
また、上記実施形態では、流体の一例として、液体が用いられる場合について説明したが、本発明は、気体が用いられるシステムに適用されても良い。 Moreover, although the case where a liquid was used as an example of the fluid has been described in the above embodiment, the present invention may be applied to a system in which a gas is used.
以上、本発明の一実施形態について説明したが、本発明は、上記に限定されるものでなく、上記以外にも、その主旨を逸脱しない範囲内において種々変形して実施可能であることは勿論である。 Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and other various modifications can be made without departing from the spirit of the present invention. It is.
１０ 流路の内壁面構造
１２ 流路
１４ 波状リブレット
２０ エンジン冷却システム
２２ エンジン
２４ ラジエータ
３０ 配管
３２ 第一流路
３４ 第一波状リブレット
４０ 伝熱管
４２ 第二流路
４４ 第二波状リブレット
DESCRIPTION OF SYMBOLS 10 Inner wall surface structure 12 Flow path 14 Corrugated riblet 20 Engine cooling system 22 Engine 24 Radiator 30 Pipe 32 First flow path 34 First corrugated riblet 40 Heat transfer tube 42 Second flow path 44 Second corrugated riblet
Claims (8)
前記流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、
前記流路における熱伝達率比であるＨＴＲを式（１）で表した場合に、
前記流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の波状リブレットの波長及び振幅が設定されている、
流路の内壁面構造。 A plurality of wavy riblets formed on the inner wall surface of the flow path through which the fluid flows and extending in the length direction of the flow path , meandering in the groove width direction and suppressing the generation of turbulent vortices in the flow path Having wavy riblets
When the inner wall surface of the channel is a smooth surface, the Nusselt number in the channel is Nu flat .
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the Nusselt number in the flow path is Nu riblet ,
When the HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1),
The wavelength and amplitude of the plurality of wavy riblets are set so that the heat transfer coefficient ratio in the flow path is HTR> 1.
The inner wall structure of the flow path.
前記流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、
前記流路における熱伝達率比であるＨＴＲを式（１）で表し、
前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（２）で表した場合に、
前記流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の波状リブレットの進入角βが設定されている、
流路の内壁面構造。 A plurality of corrugated riblets extending in the longitudinal direction of the flow path is formed into the inner wall surface of the flow path through which fluid flows, a plurality of suppressing the occurrence of turbulent eddies in the flow path with meandering groove width direction Having wavy riblets
When the inner wall surface of the channel is a smooth surface, the Nusselt number in the channel is Nu flat .
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the Nusselt number in the flow path is Nu riblet ,
HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1),
When the amplitude of the plurality of wavy riblets is a, the wavelength is λ, and β, which is an angle of approach of the plurality of wavy riblets, is expressed by Equation (2),
The approach angle β of the plurality of wavy riblets is set such that the heat transfer coefficient ratio in the flow path is HTR> 1.
The inner wall structure of the flow path.
前記流路の内壁面が平滑面である場合の該流路におけるヌセルト数をＮｕｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、
前記流路における熱伝達率比であるＨＴＲを式（１）で表し、
前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、
前記流路における抵抗比であるＤＲを式（２）で表し、
性能向上比であるｅを式（３）で表し、
前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（４）で表した場合に、
前記流路における性能向上比がｅ＞１となるように、前記複数の波状リブレットの進入角βが設定されている、
流路の内壁面構造。 A plurality of wavy riblets formed on the inner wall surface of the flow path through which the fluid flows and extending in the length direction of the flow path , meandering in the groove width direction and suppressing the generation of turbulent vortices in the flow path Having wavy riblets
When the inner wall surface of the channel is a smooth surface, the Nusselt number in the channel is Nu flat .
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the Nusselt number in the flow path is Nu riblet
HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1),
The resistance coefficient of the flow path when the inner wall surface of the flow path is a smooth surface and Cf flat,
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the resistance coefficient in the flow path is Cf bundle ,
DR, which is a resistance ratio in the flow path, is expressed by Equation (2),
The performance improvement ratio e is expressed by the equation (3),
When the amplitude of the plurality of wavy riblets is a, the wavelength is λ, and β, which is an angle of approach of the plurality of wavy riblets, is expressed by Equation (4),
The approach angle β of the plurality of wavy riblets is set so that the performance improvement ratio in the flow path is e> 1.
The inner wall structure of the flow path.
前記第一流路と連通する第二流路と、前記第二流路の内壁面に形成されると共に前記第二流路の長さ方向に延びる複数の第二波状リブレットであって、溝幅方向に蛇行しており、前記複数の第一波状リブレットよりも波長が短く振幅が大きい複数の第二波状リブレットとを有する熱交換器と、
を備える熱交換システム。 A plurality of first wavy riblets formed on an inner wall surface of the first flow path and extending in a length direction of the first flow path, wherein the first flow paths meander in the groove width direction. A flow path member having wavy riblets;
A plurality of second wavy riblets formed on the inner wall surface of the second flow path and extending in the length direction of the second flow path, the second flow path communicating with the first flow path, and in the groove width direction A heat exchanger having a plurality of second wavy riblets having a shorter wavelength and a larger amplitude than the plurality of first wavy riblets,
A heat exchange system comprising.
前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、
前記流路における熱伝達率比であるＨＴＲを式（１）で表し、
前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、
前記流路における抵抗比であるＤＲを式（２）で表した場合に、
前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長及び振幅が設定され、
前記第二流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の第二波状リブレットの波長及び振幅が設定されている、
請求項４に記載の熱交換システム。 When the inner wall surface of the flow path through which the fluid flows is a smooth surface, the Nusselt number in the flow path is Nu flat .
The number of Nusselts in the flow path when a plurality of wavy riblets are formed on the inner wall surface of the flow path is Nu rivet ,
HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1),
When the inner wall surface of the flow path is a smooth surface, the resistance coefficient in the flow path is Cf flat .
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the resistance coefficient in the flow path is Cf bundle ,
When DR, which is a resistance ratio in the flow path, is expressed by equation (2),
The wavelength and amplitude of the plurality of first wavy riblets are set so that the resistance ratio in the first flow path is DR <1.
The wavelength and amplitude of the plurality of second wavy riblets are set so that the heat transfer coefficient ratio in the second flow path is HTR> 1.
The heat exchange system according to claim 4.
前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、
前記流路における熱伝達率比であるＨＴＲを式（１）で表し、
前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、
前記流路における抵抗比であるＤＲを式（２）で表し、
性能向上比であるｅを式（３）で表した場合に、
前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長及び振幅が設定され、
前記第二流路における性能向上比がｅ＞１となるように、前記複数の第二波状リブレットの波長及び振幅が設定されている、
請求項４に記載の熱交換システム。 When the inner wall surface of the flow path through which the fluid flows is a smooth surface, the Nusselt number in the flow path is Nu flat .
The number of Nusselts in the flow path when a plurality of wavy riblets are formed on the inner wall surface of the flow path is Nu rivet ,
HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1),
The resistance coefficient of the flow path when the inner wall surface of the flow path is a smooth surface and Cf flat,
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the resistance coefficient in the flow path is Cf bundle ,
DR, which is a resistance ratio in the flow path, is expressed by Equation (2),
When e, which is a performance improvement ratio, is expressed by equation (3),
The wavelength and amplitude of the plurality of first wavy riblets are set so that the resistance ratio in the first flow path is DR <1.
The wavelength and amplitude of the plurality of second wavy riblets are set so that the performance improvement ratio in the second flow path is e> 1.
The heat exchange system according to claim 4.
前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、
前記流路における熱伝達率比であるＨＴＲを式（１）で表し、
前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、
前記流路における抵抗比であるＤＲを式（２）で表し、
前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（３）で表した場合に、
前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長ａ及び振幅λが設定され、
前記第二流路における熱伝達率比がＨＴＲ＞１となるように、前記複数の第二波状リブレットの進入角βが設定されている、
請求項４に記載の熱交換システム。 When the inner wall surface of the flow path through which the fluid flows is a smooth surface, the Nusselt number in the flow path is Nu flat .
The number of Nusselts in the flow path when a plurality of wavy riblets are formed on the inner wall surface of the flow path is Nu rivet ,
HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1),
When the inner wall surface of the flow path is a smooth surface, the resistance coefficient in the flow path is Cf flat .
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the resistance coefficient in the flow path is Cf bundle ,
DR, which is a resistance ratio in the flow path, is expressed by Equation (2),
When the amplitude of the plurality of corrugated riblets is a, the wavelength is λ, and β that is the angle of approach of the plurality of corrugated riblets is expressed by Equation (3),
The wavelength a and the amplitude λ of the plurality of first wavy riblets are set so that the resistance ratio in the first flow path is DR <1.
The entrance angle β of the plurality of second wavy riblets is set so that the heat transfer coefficient ratio in the second flow path is HTR> 1.
The heat exchange system according to claim 4.
前記流路の内壁面に複数の波状リブレットが形成された場合の該流路におけるヌセルト数をＮｕｒｉｂｌｅｔとし、
前記流路における熱伝達率比であるＨＴＲを式（１）で表し、
前記流路の内壁面が平滑面である場合の該流路における抵抗係数をＣｆｆｌａｔとし、
前記流路の内壁面に前記複数の波状リブレットが形成された場合の該流路における抵抗係数をＣｆｒｉｂｌｅｔとし、
前記流路における抵抗比であるＤＲを式（２）で表し、
性能向上比であるｅを式（３）で表し、
前記複数の波状リブレットの振幅をａ、波長をλとして、前記複数の波状リブレットの進入角であるβを式（４）で表した場合に、
前記第一流路における抵抗比がＤＲ＜１となるように、前記複数の第一波状リブレットの波長ａ及び振幅λが設定され、
前記第二流路における性能向上比がｅ＞１となるように、前記複数の第二波状リブレットの進入角βが設定されている、
請求項４に記載の熱交換システム。 When the inner wall surface of the flow path through which the fluid flows is a smooth surface, the Nusselt number in the flow path is Nu flat .
The Nusselt number in the flow path in the case where a plurality of wavy riblets on the inner wall surface of the flow path is formed as a Nu Riblet,
HTR, which is the heat transfer coefficient ratio in the flow path, is expressed by equation (1),
When the inner wall surface of the flow path is a smooth surface, the resistance coefficient in the flow path is Cf flat .
When the plurality of wavy riblets are formed on the inner wall surface of the flow path, the resistance coefficient in the flow path is Cf bundle ,
DR, which is a resistance ratio in the flow path, is expressed by Equation (2),
The performance improvement ratio e is expressed by the equation (3),
When the amplitude of the plurality of wavy riblets is a, the wavelength is λ, and β, which is an angle of approach of the plurality of wavy riblets, is expressed by Equation (4),
The wavelength a and the amplitude λ of the plurality of first wavy riblets are set so that the resistance ratio in the first flow path is DR <1.
The approach angle β of the plurality of second wavy riblets is set so that the performance improvement ratio in the second flow path is e> 1.
The heat exchange system according to claim 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016004394A JP6577875B2 (en) | 2016-01-13 | 2016-01-13 | Inner wall surface structure of flow path and heat exchange system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016004394A JP6577875B2 (en) | 2016-01-13 | 2016-01-13 | Inner wall surface structure of flow path and heat exchange system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2017125640A JP2017125640A (en) | 2017-07-20 |
| JP6577875B2 true JP6577875B2 (en) | 2019-09-18 |
Family
ID=59363875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2016004394A Expired - Fee Related JP6577875B2 (en) | 2016-01-13 | 2016-01-13 | Inner wall surface structure of flow path and heat exchange system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6577875B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2025069247A1 (en) * | 2023-09-27 | 2025-04-03 | 株式会社ニコン | Sheet member, film member, moving body, blade member, windmill, and affixing method |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5485461A (en) * | 1977-12-21 | 1979-07-07 | Furukawa Metals Co | Insideegrooved heat transfer tube |
| JPS56100297A (en) * | 1980-01-16 | 1981-08-12 | Hitachi Ltd | Device for working shape of heat exchanger pipe and its inner groove |
| JPS62194195A (en) * | 1986-02-19 | 1987-08-26 | Nishiyodo Kuuchiyouki Kk | Heat transfer tube equipped with internal surface fin |
| JPH0194783U (en) * | 1987-12-10 | 1989-06-22 | ||
| JPH0631326Y2 (en) * | 1989-11-22 | 1994-08-22 | 東洋ラジエーター株式会社 | Tube for heat exchanger |
| JPH0717906Y2 (en) * | 1990-11-07 | 1995-04-26 | 積水化学工業株式会社 | Pipe fitting |
| JPH0914882A (en) * | 1995-06-23 | 1997-01-17 | Matsushita Refrig Co Ltd | Heat transfer tube |
| JP2000097211A (en) * | 1998-09-21 | 2000-04-04 | Fuminori Okamoto | Fluid inflow pipe |
| JP4824190B2 (en) * | 2001-03-07 | 2011-11-30 | 独立行政法人日本原子力研究開発機構 | Turbulent friction resistance reduction surface |
| JP2002310575A (en) * | 2001-04-12 | 2002-10-23 | Shimizu Reiki:Kk | Heat exchanger for cooling brine |
| JP2003056995A (en) * | 2001-08-20 | 2003-02-26 | Komatsu Electronics Inc | Heat exchanger |
| JP3772216B2 (en) * | 2003-05-28 | 2006-05-10 | 防衛庁技術研究本部長 | Multi-layered material for hull and its method for simultaneously reducing fluid resistance and self-radiated noise level of navigation vehicle |
| JP2005083741A (en) * | 2003-09-05 | 2005-03-31 | Lg Electronics Inc | Air conditioner having heat exchanger and refrigerant switching means |
| CN100451531C (en) * | 2005-03-25 | 2009-01-14 | 清华大学 | Water heater heat exchange tube |
| JP4756585B2 (en) * | 2005-09-09 | 2011-08-24 | 臼井国際産業株式会社 | Heat exchanger tube for heat exchanger |
| JP4911153B2 (en) * | 2008-09-30 | 2012-04-04 | 株式会社富士通ゼネラル | Heat exchanger |
| JP2012233652A (en) * | 2011-05-06 | 2012-11-29 | Shigemitsu Kurano | Gas liquefaction device, conduit pipe with riblets and spiral type cooling unit, and method for liquefying gas and method for cooling gas |
| FR2987107B1 (en) * | 2012-02-17 | 2020-04-17 | Universite D'aix Marseille | CONDUIT CONSTITUTING A HEAT EXCHANGER AND HEAT EXCHANGER COMPRISING SUCH A CONDUIT |
-
2016
- 2016-01-13 JP JP2016004394A patent/JP6577875B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2017125640A (en) | 2017-07-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Ghani et al. | Heat transfer augmentation in a microchannel heat sink with sinusoidal cavities and rectangular ribs | |
| CN101517345B (en) | heat exchanger | |
| Amrutkar et al. | Automotive radiator performance–Review | |
| CN106716041B (en) | Corrugated fins for heat exchangers | |
| JP5009249B2 (en) | Cooler | |
| Jamshidmofid et al. | Efficacy of a novel graphene quantum dots nanofluid in a microchannel heat exchanger | |
| Kim et al. | Numerical studies of heat transfer enhancement by cross-cut flow control in wavy fin heat exchangers | |
| Sahoo et al. | Energy and exergy comparisons of water based optimum brines as coolants for rectangular fin automotive radiator | |
| JPWO2016043340A6 (en) | Corrugated fin for heat exchanger | |
| CN104583708A (en) | heat exchanger | |
| JP6577875B2 (en) | Inner wall surface structure of flow path and heat exchange system | |
| Najim | Heat Transfer Enhancement Inside a Duct Using Turbulators, Vortex Generators, and Baffles | |
| JP5946651B2 (en) | Heat exchanger | |
| WO2015049737A1 (en) | Heat-radiating system | |
| Kumar et al. | Performance of an automotive car radiator operated with nanofluid-based coolant | |
| US20160252311A1 (en) | Wavy Fin Structure and Flat Tube Heat Exchanger Having the Same | |
| JP6559507B2 (en) | Corrugated fin heat exchanger core | |
| EBRAHIMNIA et al. | Convective heat transfer of nanofluids flows through an isothermally heated curved pipe | |
| JP6102424B2 (en) | Cooling structure | |
| JP2015174519A (en) | Vehicle lower part structure | |
| KR20120011481A (en) | Heat Exchanger for Exhaust Gas Heat Recovery | |
| JP2018048790A (en) | Heat transfer surface structure and heat transfer device | |
| CN115004362A (en) | Cooling structure and radiator | |
| CN104406424A (en) | Tube fin type cooler based on temperature of thermal medium | |
| JP2009079795A (en) | Heat exchanger |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20171130 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20180830 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20180904 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20181102 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20190219 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20190422 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20190422 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20190806 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20190823 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6577875 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |