RU2282801C2 - Cooling device operation method and cooling device - Google Patents

Abstract

FIELD: cooling equipment, particularly that using vortex effect.

SUBSTANCE: method involves supplying direct flow in cold receiving means in several steps through serially connected vortex tubes. Each next vortex tube inlet is connected to cold nipple of previous vortex tube. Cold nipple of each next step is fastened to cold receiving means inlet. Energy separation chambers of vortex tubes are cooled with reverse flow leaving cold receiving means. The reverse flow successively passes through cooling cavities of energy separation chambers in reverse order so that cooling cavity of energy separation chamber at previous stage is cooled with reverse flow leaving cooling cavity of energy separation chamber of next stage.

EFFECT: simplified structure and increased efficiency.

6 cl, 12 dwg

Description

The invention relates to the field of creating refrigeration equipment that uses the properties of a rotating gas stream.

A known method of operation of a refrigeration device, comprising a sequential (step) flow of direct flow through several (two or more) vortex tubes in such a way that the working (input) stream of the vortex tube of each subsequent stage is the cold stream of the previous stage [1, p. 111], moreover, the cold stream of the last stage is fed into the cold receiver (refrigerator) for use.

This method is implemented in a refrigeration device containing several series (stepwise) connected vortex tubes in such a way that the inlet pipe of each subsequent stage is connected to the cold pipe of the previous stage [1, p.112, Fig. 6.14], and the cold pipe of the last stage is connected to the entrance of the refrigerator.

The known device uses two-line uncooled vortex tubes with low cooling capacity, and, moreover, their hot flows are released into the atmosphere. In addition, the thermodynamic efficiency of such a device is small due to the fact that the hot flows of the subsequent vortex tubes [1, p.112, Fig. 6.14] are cooled down below the inlet temperature T _о , and therefore, cold is emitted from the device, i.e. in such a device, there is a large under-recovery, to reduce which a massive and expensive recuperative heat exchanger must be introduced into the design, which will assume the entire heat transfer function, however, in the presence of highly efficient heat-exchange surfaces in uncooled vortex tubes.

If in the scheme depicted in [1, p. 112, Fig. 6.14], ΔТ _х for the first vortex tube can be about ≈50 °, then at Т _вх-0 = + 20 ° С its Т _х-0 = -30 ° C. But as practice shows, when cold gas is introduced into the vortex tube, ΔТ _х and ΔТ _g sharply decrease. For example, when a gas is fed into the second pipe with T _in-1 = -30 ° C, its hot end begins to give out not warm but cold gas, for example, T _g-1 = -24 ° C, i.e. ΔТ _g-1 = only 6 ° (see table).

Table
Experimental data for blowing a vortex tube with cold air T _in (° C) T _x (° C) / ΔT _x T _g (° C) / ΔT _g -10 -28/18 -2/8 -twenty -35/15 -13/7 -thirty -41/11 -24/6 -35 -45/10 -30/5

That is, in this case, even with a two-stage circuit, a large amount of cold will be emitted through the hot branch pipe, which is a significant drawback, for which correction it is necessary to introduce massive and expensive recuperative heat exchangers that capture and return this cold, which is also a significant drawback.

The technical result of the proposed technical solution is to reduce these disadvantages.

In terms of the method, the technical result is achieved by cooling all the energy separation chambers of sequentially (stepwise) connected vortex tubes. As a cooling medium, you can use tap or circulating water, chilled gas, arctic cold atmospheric air, a gas stream leaving the hot end of a two-stream vortex tube, as well as the return flow of a cold receiver, etc.

The latter option, especially combined with the previous ones, is most preferable.

In this case, the cooling of the energy separation chambers of the vortex tubes connected in series is carried out by the reverse flow leaving the cold receiver, sequentially passed in the reverse order through the cooling cavities of the vortex tube energy separation chambers, i.e. so that the cooling stream of the previous stage is the cooling stream of the next stage.

In terms of the device, the technical result is achieved in that the energy separation chamber of each series-connected vortex tube is enclosed in a separate sealed housing forming a cooling cavity through which the cooling medium (water, cold gas, etc.) is passed. For use as a cooling medium, a cooled return stream leaving the cold receiver, the cooling cavities of the energy separation chambers are connected in series in the reverse order, i.e. so that the inlet of the cooling cavity of the previous stage is connected to the outlet of the cooling cavity of the next stage, and the inlet of the cooling cavity of the last stage is connected to the outlet of the cold receiver (refrigerator), i.e. In addition to the direct flow passing through the inlet nozzles of the vortex tubes, they organize a reverse flow passing through the cooling cavities of the energy separation chambers.

The result is a complete design of coolers or even liquefiers. In this case, it becomes possible to reduce the heat transfer area of expensive recuperative heat exchangers or even to exclude them from the design. This simplifies and reduces the cost of construction.

In addition, due to the cooling of the energy separation chambers of the vortex tubes, it becomes possible to efficiently use simpler single-flow vortex tubes. As a result, the cooling capacity of the device is increased and the need for the emission of hot streams into the atmosphere is eliminated. This allows you to apply the proposed method for cooling valuable or dangerous gases.

Figure 1-a presents the simplest version of a two-stage refrigeration device.

Such a device consists of two sequentially (stepwise) connected single-threaded pipes 1 and 2, as well as a cold receiver 3.

The first vortex tube, which is the first (previous) stage ➀, contains an inlet pipe 4, a cold pipe 5 and a conical energy separation chamber 6. The energy separation chamber is enclosed in a sealed casing (housing) 7, forming a cooling cavity 8, which has an input 9 and output 10 branch pipes.

Another vortex tube, which is the second (subsequent) stage ➁, also contains an inlet pipe 11, a cold pipe 12 and a conical energy separation chamber 13. The energy separation chamber 13 is enclosed in a sealed housing (casing) 14, which forms a cooling cavity 15, which has an inlet 16 and output 17 nozzles.

The input 11 of the next stage ➁ (vortex tube 2) is connected to the cold pipe 5 of the previous stage ➀ (first vortex pipe), and the cold pipe of the last stage, in this case stage ➁, is connected to the input 18 of the cooler 3.

It turns out that the cooling cavities of the vortex tubes are connected in series so that the input 9 of the cooling cavity 8 of the previous stage ➀ is connected to the output 17 of the cooling cavity 14 of the next stage ➁, and the input 16 of the cooling cavity 15 of the next (last) stage ➁ is connected to the output 19 of the cold receiver 3 .

The cold receiver consists of a housing 3, input 18 and output 19 pipes. The inlet pipe 18 of the cold receiver is connected to the cold pipe 12 of the second vortex tube. The outlet pipe 19 of the cold receiver is connected to the inlet pipe 16 of the cooling cavity 15 of the subsequent stage ➁.

The outlet pipe 10 of the cooling cavity 8 of the previous stage ➀ is connected to the outlet 20 from the refrigeration device.

The considered device works as follows. Compressed gas is fed to the inlet 4 of the first vortex tube, inside which it is unwound, throttled, expanded and separated into zones with significantly different temperatures. A zone of elevated temperatures is located along the inner wall of the conical energy separation chambers (6 and 13). Along the axis of these chambers and in cold pipes (5 and 12) is a zone of low temperatures.

Therefore, cold gas flows from the cold pipe 5 of the first vortex tube to the inlet 11 of the second vortex tube 2, which is further cooled in the second vortex tube and enters the inlet 18 of the cold receiver 3.

The exhaust gas having a low temperature exits the cold receiver 3 and, through the nozzles 19 and 16, enters the cooling cavity 15, cools the outer surface of the energy separation chamber 13. Thus, thermal energy is taken through the wall of the energy separation chamber 13 from the rotating hot gas stream inside this camera. As a result, the temperature of the stream exiting the pipe 12 decreases and the temperature in the cold receiver gradually decreases.

Similarly, the stream exiting the pipe 17 cools the energy separation chamber 6 and cools the stream exiting the pipe 5 of the first vortex tube. As a result, there is a general decrease in the temperature of the gas leaving the cold nozzle 12 of the second vortex tube, and in the cold receiver 3, which smoothly reduces the temperature of the flow passing through the elements 19-16-15-17-9-8.

It is known that in the energy separation chamber the rotational gas flow has a pronounced turbulent character, therefore, a very highly efficient heat transfer between the gas stream and the inner metal (heat-conducting) wall of the chamber is realized [2, p. 74]. The efficiency of such heat transfer sometimes exceeds the efficiency of heat transfer in a conventional heat exchanger by an order of magnitude. This makes it possible to use the wall of the vortex tube energy separation chamber as a heat exchanger.

If you build a similar scheme of a refrigeration device without the use of vortex tubes, but on heat exchangers and conventional pneumatic throttles, then such an equivalent circuit may have the form (Fig.1-b). The numbering of equivalent elements in this diagram is the same as in figure 1-a:

1 - pneumatic throttle of the first stage;

2 - pneumatic throttle of the second stage;

3 - cold receiver;

6 - direct flow of the heat exchanger of the first stage;

8 - return flow of the heat exchanger of the first stage;

13 - direct flow of the heat exchanger of the second stage;

15 - return flow of the heat exchanger of the second stage.

When comparing these identical circuits, you can see that the device shown in Fig.1-a is much simpler and cheaper than its equivalent, shown in Fig.1-b.

If the heat transfer rate in the successively connected cooling chambers 8 and 15 is insufficient, for example, due to the absence of fins on the outer surface of the energy exchange chambers 6 and 13, and cold gas is still supplied to output 20, then input 4 of the first stage ➀ is necessary connect through a recuperative heat exchanger 21, which will provide a return of cold (figure 2) - off-design mode of operation.

In this case, the entrance to the vortex tube of the first stage is connected to the entrance to the device, and the exit from the cooling cavity of the energy separation chamber of the first stage is connected to the exit from the device, and they are connected through a regenerative heat exchanger.

It is possible to use not only single-flow (Fig. 1 ... 2), but also dual-flow cooled vortex tubes (Fig. 3, 4, 5, 6 ...). The use of two-stream vortex tubes allows for cooling not only to use the usual choke effect (i.e., in essence, an uncooled single-stream vortex tube is no different from a conventional pneumatic choke), but also to remove part of the thermal energy from the system through the wall of the energy exchange chamber, and through the hot pipe. In addition, there is no need to discharge a hot stream into the atmosphere. To do this, the hot pipe of one or all of the two-flow vortex tubes are connected to the return flow channel.

The following options are possible here (using the two-stage design as an example):

- Figures 3 and 4. The first stage ➀ consists of a two-stream vortex cooled vortex tube, which, in contrast to the single-stream vortex tube (Fig. 2), has a hot pipe 22 connected through a tee-mixer 23 with an outlet pipe 20. In this design, the application heat exchanger 21 (figure 3) is not always necessary (figure 4);

5 and 6. The second stage ➁ consists of a two-stream vortex cooled vortex tube, which, unlike a single-stream vortex tube, has a hot pipe 24 connected through a tee-mixer 25 to the inlet pipe 9 of the cooling cavity 8 of the first vortex pipe. Depending on the thermodynamic task, such a device can be equipped with an additional heat exchanger 26 (Fig.6), having a direct 27 and return 28 channels. In this case, through the direct channel 27 of the heat exchanger 26, the cold pipe 5 of the first vortex tube and the inlet 11 of the second vortex tube are connected, and through the return channel 28 of the heat exchanger 26, the outlet 17 of the cooling cavity 14 of the second vortex tube is connected to the input 9 of the cooling cavity 8 of the second vortex tube. In this case, a stream leaving the hot nozzle 24 of the second vortex tube is introduced into the return stream 28 through the tee-mixer 25, and such a stream can be introduced either after the heat exchanger (through the tee 25) or before the heat exchanger (such a possible connection is shown in dashed in Fig. 6 29);

- Figures 7, 8 and 9. Both stages ➀ and ➁ are made in the form of two-stream vortex cooled vortex tubes having hot nozzles 22 and 24.

Options are also possible here:

- the refrigeration device is built only on cooled dual-stream vortex tubes (Fig.7) - without heat exchangers. The streams leaving the hot nozzles 22 and 24 are introduced into the return flow through the tees-mixers 23 and 25;

- the refrigeration device is constructed using heat exchangers 21 and 26 (Figs. 8, 9 and 10), while this can be either one heat exchanger 21 (Fig. 8) or 26 (Fig. 9), or two heat exchangers 21 and 26 (Fig. 10).

It turns out that the steps can be interconnected through a regenerative heat exchanger.

Due to the fact that the energy exchange chambers 6 and 13, together with the cooling cavities 8 and 14, intensively implement the heat exchange process between the forward and reverse flows, the required heat exchange area for the heat exchangers 21 and 26 introduced into the design sharply decreases (Figs. 2, 3, 5, 6 , 8 ... 10). In fact, they only perform the function of a compensator for under-recovery of a highly efficient heat exchanger “cooled vortex tube”, combining the functions of a pneumatic throttle and a heat exchanger. With proper calculation, with proper design and careful manufacture, the considered design is quite functional even without recuperative heat exchangers, the function of which is performed by cooled vortex tubes.

The working scheme of a refrigeration device can be built not only from two, but also from a larger number of vortex tubes (steps) connected in series. 11 shows a diagram of such a three-stage ➀-➁-➂ refrigeration device constructed of three single-flow vortex tubes.

In addition, in the process of starting the refrigeration device, sometimes it becomes necessary to adjust (adjust) the flow area of the final choke. The best thing for this purpose is not a vortex tube, which is difficult to regulate, but an easily adjustable needle valve (pneumatic throttle). For this, the cold branch pipe of the last stage, for example stage ➁, is connected to the inlet of the cold receiver through an air throttle 30 (Fig. 12).

Thus, the essence of the invention in terms of the method lies in the fact that the cooling of the energy separation chambers of the vortex tubes, in which the working stream of each subsequent stage is the cold stream of the previous stage, is carried out by the reverse stream leaving the cold receiver, sequentially passed in the reverse order through the cooling cavities of the energy separation chambers vortex tubes i.e. so that the cooling stream of the energy separation chamber of the previous stage is the stream exiting the cooling cavity of the energy separation chamber of the next stage.

And the essence of the invention in terms of the device lies in the fact that the cooling cavities of the energy separation chambers of the series-connected vortex tubes are also connected in series, and this connection is made in such a way that the inlet of the cooling cavity of the previous stage is connected to the output of the next stage, and the entrance of the cooling cavity of the energy separation chamber of the last steps connected to the outlet of the cold receiver.

In this case, the entrance to the vortex tube of the first stage is connected to the entrance to the device, and the exit from the cooling cavity of the energy separation chamber of the first stage is connected to the exit from the device, and they are connected through a recuperative heat exchanger, and the stages are interconnected via a recuperative heat exchanger.

In addition, the hot branch pipe of the two-stream vortex tube is connected to the return flow channel, and the cold branch pipe of the vortex tube of the last stage is connected to the inlet of the cold receiver through a pneumatic throttle.

As a result, the proposed method and device can simplify the design and increase its effectiveness.

Information sources

1. Merkulov A.P. Vortex effect and its application in technology. M.: Mechanical Engineering, 1969.

2. Suslov A.D., Ivanov A.V., Murashkin A.V., Chizhikov Yu.V. Vortex devices. M .: Engineering. 1985.

Claims (6)

1. The method of operation of the refrigeration device, comprising a sequential (step) supply of a gas stream through several vortex tubes in such a way that the working (input) stream of the vortex tube of each subsequent stage is the cold stream of the previous stage, and the cold stream of the last stage is supplied to the cooler for use, while cooling the chambers of the energy separation of the vortex tubes, characterized in that the cooling chambers of the energy separation of the vortex tubes is produced by a reverse flow exiting the cold receiving IC, sequentially passed in reverse order through the cooling cavities of the vortex tube energy separation chambers, i.e. so that the cooling stream of the energy separation chamber of the previous stage is the stream exiting the cooling cavity of the energy separation chamber of the next stage. 2. A refrigeration device comprising vortex tubes connected in series so that the inlet of each subsequent stage is connected to the cold pipe of the previous stage, the cold pipe of the last stage connected to the inlet of the cold receiver, and each energy separation chamber of all the vortex pipes is enclosed in a sealed enclosure forming a cooling cavity characterized in that the cooling cavities of the chambers of the energy separation of the vortex tubes are connected in series, while such a connection is made in such a way that the inlet of the cooling cavity of the previous stage is connected to the outlet of the next stage, and the inlet of the cooling cavity of the energy separation chamber of the last stage is connected to the outlet of the cold receiver. 3. The refrigeration device according to claim 2, characterized in that the entrance to the vortex tube of the first stage is connected to the entrance to the device, and the outlet from the cooling cavity of the energy separation chamber of the first stage is connected to the exit from the device, and they are connected through a regenerative heat exchanger. 4. The refrigeration device according to claim 2, characterized in that the steps are interconnected via a recuperative heat exchanger. 5. The refrigeration device according to claim 2, characterized in that the hot pipe of the two-flow vortex tube is connected to the return flow channel. 6. The refrigeration device according to claim 2, characterized in that the cold branch pipe of the vortex tube of the last stage is connected to the inlet of the cold receiver through a pneumatic throttle.

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