SU1364994A1 - Static pressure transducer - Google Patents

Abstract

This invention relates to a technique for measuring pressure in fluids. The purpose of the invention is to expand the field of application of a static pressure nozzle by eliminating its sensitivity to dynamic pressure in any direction in a solid angle of 30 °. The receiver consists of a spherical head 1, the spherical part 2 of which, with the angle of solution d, is directed to the flow and is covered with evenly openings. Circumference 4 separates the part covered with holes from the part with a solid surface. A spider 5 is attached to the spherical head 1. A static pressure nozzle is placed in the flow. By varying the opening angle (i), the pressure transmitted to the transducer makes the static pressure in the flow greater or less. Experimentally, the value of a corresponding to the static pressure in the flow is selected; it is 105-1.5. To ensure the required density of the coating of the orifices of the sphere facing the flow, the diameter of the holes is O, O ID, where D is the diameter of the hollow sphere. 3 il. i (L

Description

00 od

 co; o

1

one

The invention relates to techniques and pressure measurements in fluids, in particular to the measurement of static pressure in turbulent flows.

The aim of the invention is to reduce the field of application of a static pressure nozzle by eliminating

its sensitivity to dynamic pressure corresponding to static pressure

head in all directions in a solid angle of 30 °.

Figure 1 shows a static pressure receiver, in an enlarged

in the stream, and its value is - 10510,5 °.

When the axis of the nozzle is rotated to the direction of flow, when the holder understands a part of the surface of the sphere, it covers position b (corresponds to the angle of the holes, general view; in Fig.2 - turn 30, Fig.2), the part with the curve

The pressure distribution is replaced by part of the d curve. Due to the fact that the pressure on the surface of the sphere is between the distribution of pressure, depicted in a more pronounced way using a coordinate system with

the abscissa axis is transformed into circles of +80 - 100 and (-80) - (-180)

X, and the Y axis is normal to the surface of the sphere; in FIG. 3, view A in FIG.

The receiver consists of a spherical

heads 1, the spherical part 2 of which is 25 pressures on the surface of the sphere. The next one with an angle of solution направ is directed onwards, when the axis is turned the nozzle into the flow and is evenly covered with a hole — any plane at an angle of no more than 130

the pressure transmitted to the transducer is equal to the static pressure in

mi 3 (fig.Z). Circumference 4 separates the part covered with holes from the part with a solid surface. A spherical 5, which is a hollow tube with a diameter O, ID, is soldered to a spherical 30 stream, the head in its rear part.

The device works as follows.

A static pressure nozzle is placed in the flow. If the holder

All dimensions of a spherical packing are defined by its diameter D, the change interval of which is determined by the range of the constant Reynolds number

sa Fe - VD / l) from 10 to 2-10. From here we get

occupies position a, then the pressure distribution is symmetrical about the axis of the PID nozzle and in the sector with an opening angle of + 44 ° there is an excess of pressure over the static, and in a spherical layer lying between 144 ° and ± s angles, the pressure on the surface is less than the static one.

Any section of a sphere along a large circle parallel to the axis of the nozzle separates a whole series of holes intersected by the section plane and transmitting pressure from its surface into the internal cavity of the sphere. A flow mode is established inside the sphere, corresponding to compensation of areas of high and low pressure relative to static pressure, as a result of which a pressure equal to static pressure is established at the inlet to the channel going to the pressure transducer. pressure in flow.

1364994

By varying the opening angle, the pressure transmitted to the transducer makes the static pressure in the flow greater or less.

The accuracy of the static pressure measurement is determined by the accuracy of the angle selection. Thus, experimentally, the angle o / is chosen, which is constant all the time, the equivalence of the parts of the pressure curve c and d is obtained from the point of view of compensating for the areas of above and below

flow

All dimensions of a spherical packing are defined by its diameter D, the change interval of which is determined by the range of the constant Reynolds number

sa Fe - VD / l) from 10 to 2-10. From here we get

D

g

ten

With the nozzle diameter selected, the oncoming flow velocity range is determined accordingly.

jj D

0 v

g °

For example, for air (V 0.15 cm / s) with a nozzle diameter D 4 cm, we have 0.38 m / s i V 65 m / s, and for water (ii 1, 002-1 Vc) with a diameter DI cm

Oh, 1 m / s V 20 m / s.

To ensure that the density of the holes of the part of the sphere facing the flow is necessary for the first time, while maintaining sufficient structural strength, the diameter of the holes is equal to, 01 D, and the distance between the centers of the holes is 1 2 d. When this

the total area of the holes is 22% of the total area of the part of the sphere covered with the holes, which ensures the strength of the nozzle over the entire working speed range. At the same time, any plane passing through the center of the sphere and the direction of the flow intersects on its surface an average of 72 holes, which ensures mutual compensation of areas with excess and lack of pressure on the surface of the sphere relative to the static pressure in the flow.

The device allows one to measure static pressures in flows that randomly change their direction. N. Gun'ko 6602/38

Fc22

Compiled by G. Belousov Tehred M. Khodanych

Proofreader L.Pi

Circulation 847 Subscription

VNISHI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

with respect to the probe.

to axis measured

Claims (1)

Invention Formula A static pressure receiver containing nozzles in the form of a hollow sphere in which receiving holes are made, similar to the fact that, in order to expand the field of application, the receiving holes are evenly distributed in the wall of the spherical sector of the hollow sphere with an angle of / 105, while the diameter the receiving holes and the wall thickness of the sphere are equal to 0.01 D, where D is the diameter of the hollow sphere of the nozzle. R O, 02D fpUf. 5 Proofreader L.Pilipenko