CN107607582A - Test platform and test method for two-phase heat exchange experiment of shell-and-tube heat exchanger - Google Patents

Abstract

The invention discloses a two-phase heat exchange experiment test platform of a shell-and-tube heat exchanger, which comprises a boiler, wherein the boiler is respectively connected with a compressed air heater and a hot water heater, the hot water heater is connected with a hot water distributor, the compressed air heater and the hot water distributor are both connected with a mixer, the mixer is connected with an experiment element, the experiment element is sequentially connected with a cooling water tank, a cooling tower and a cooling water distributor, the cooling water distributor is further connected with the experiment element to form a loop, and the experiment element is further sequentially connected with a separator, a hot water tank and a hot water heater; the heat exchanger thermal performance and flow resistance characteristic test is completed by taking air and water as working media, passing a mixture of hot water and air through a shell side and introducing cooling water into a tube side. A test platform is built to complete the two-phase experiment of the shell-and-tube heat exchanger, the operation is convenient, the adjustment is flexible, and the heat exchange efficiency can be researched in many aspects by changing the flow velocity of hot water and cooling water, the content of non-condensable gas and the circulation space of a medium.

Description

Two-phase heat exchange experimental test platform and test method for shell and tube heat exchanger

technical field

The invention belongs to the technical field of heat exchanger testing, and in particular relates to a test platform and a test method for a two-phase heat exchange experiment of a shell-and-tube heat exchanger.

Background technique

With the development of modern science and technology, including computer technology, communication technology, sensor technology, modern control theory, etc., modern detection technology has gradually matured. The brand-new testing technology has the advantages of high precision, high real-time performance, friendly interface, and easy operation. It is widely used in actual production and laboratory research; in recent years, with the continuous improvement of industrial production for the accuracy of heat exchangers, the development and research of heat exchanger performance test platforms have developed rapidly.

Contents of the invention

Purpose of the invention: The present invention provides a two-phase heat exchange experimental test platform and test method for a shell-and-tube heat exchanger to solve the problems in the prior art.

Technical solution: In order to achieve the above object, the present invention adopts the following technical solutions:

A shell-and-tube heat exchanger two-phase heat exchange experimental test platform, including a boiler 5, the boiler 5 is respectively connected to a compressed air heater 4 and a hot water heater 6, and the hot water heater 6 is connected to a hot water separator 7, the compressed air heater 4 and the hot water separator 7 are all connected to the mixer 8, and the mixer 8 is connected to the experimental element 11, and the experimental element 11 is connected to the cooling water tank 12, the cooling tower 13 and the cooling water tank in turn. Moisture water dispenser 14, cooling water dispenser 14 is connected to experimental element 11 again to form a circuit, and described experimental element 11 is also connected to separator 10, hot water tank 9 and hot water heater 6 in sequence;

The compressed air heater 4 is also connected to an air storage tank 3, and the air storage tank 3 is connected to an air dryer 2 and an air compressor 1 in sequence;

The separator 10 is also provided with an exhaust device.

Further, the compressed air heater 4 and the hot water heater 6 are respectively provided with steam traps.

Further, the air dryer 2 and the air storage tank 3, the boiler 5 and the compressed air heater 4, the boiler 5 and the hot water heater 6, the mixer 8 and the experimental element 11, the experimental element 11 and the separator 10, the cooling A ball valve is provided between the tower 13 and the cooling water tank 14; a one-way valve is provided between the experimental element 11 and the cooling water tank 12; a cooling tower circulation pump is also provided on the cooling tower 13.

Further, two sets of ball valves, two water pumps with different flow ranges and two one-way valves are connected in parallel between the hot water tank 9 and the hot water heater 6; the hot water heater 6 is also provided with a hot water circulation pump.

Further, two groups of regulating valves with different opening ranges, two flow meters and two ball valves are connected in parallel between the compressed air heater 4 and the mixer 8, and a ball valve and a check valve are connected in series.

Further, two sets of regulating valves with different opening ranges, two flow meters and two ball valves are connected in parallel between the hot water separator 7 and the mixer 8, and a check valve is connected in series.

Further, two sets of ball valves, two pumps with different flow ranges and two one-way valves are connected in parallel between the cooling water tank 12 and the cooling tower 13, and a ball valve is connected in series; There are two groups of regulating valves with different opening ranges, two flow meters and two ball valves connected in parallel between 11, and a check valve and a ball valve in series.

Further, the gas storage tank 3, the hot water tank 9 and the cooling water tank 12 are all provided with a temperature measuring port and a pressure measuring port; .

Further, the regulating valves are all connected to the pneumatic valve port of the air storage tank 3 .

A two-phase heat transfer experimental test method for a shell-and-tube heat exchanger, including a compressed air system, a steam system, a cooling water system, and a test system, including the following steps: start the air compressor 1 and the air dryer 2, and adjust the air supply pressure , a part of which supplies air to the regulating valve, and the other part enters the experimental element 11 through the compressed air heater 4 to the mixer 8 . Start the cooling tower 13 and the cooling tower circulation pump, the cooling water passes through the cooling water tank 14 and then to the experimental element 11; start the hot water circulation pump, the hot water enters the hot water heater 6 from the hot water tank 9, and then divides the water through the hot water The device 7 enters the mixer 8 along with the pipeline to mix with the air, and finally enters the experimental element 11; finally starts the boiler 5, and the steam enters the hot water heater 6 and the compressed air heater 4 to heat the water and air, and the steam condenses into water , discharged from the steam trap; after the flow, temperature and pressure are stabilized, start data collection, after the heat exchange in the tube is completed, the hot water is sent to the separator 10 and then returns to the hot water tank 9, and the cooling water returns to the cooling water tank 12, Let the air out.

Beneficial effects: the invention uses air and water as the working medium, the mixture of hot water and air passes through the shell side, and the cooling water flows into the tube side, so as to complete the thermal performance and flow resistance characteristic test of the heat exchanger. Build a test platform to complete the two-phase experiment of the shell-and-tube heat exchanger. It is easy to operate and flexible to adjust. It can conduct various researches on the heat exchange efficiency by changing the flow rate of hot water and cooling water, the content of non-condensable gas and the circulation space of the medium. .

In the two-phase heat transfer experiment, keep the flow rate of hot water constant, and change the flow rate of air to obtain the influence of air content on the two-phase heat transfer coefficient and frictional pressure drop, and find out the mass air content ratio of the shell-and-tube heat exchanger The relationship between the shell-side heat transfer coefficient and frictional pressure drop; because the trace gas content can enhance the disturbance of the fluid and promote the effect of heat transfer, the performance coefficient of the heat exchanger will increase, but to a certain extent, the growth rate of the pressure drop is greater than that of the heat exchanger. The increase of thermal coefficient will reduce the coefficient of performance. This experiment can find out the air content rate that makes the heat exchanger reach the maximum coefficient of performance under specific working conditions, which is of great significance for strengthening the heat transfer on the shell side. Keeping the gas content constant, by changing the flow rate of hot water, the influence of hot water flow rate on the two-phase heat transfer coefficient and friction pressure drop is obtained, and the relationship between the hot water flow rate and the shell-side heat transfer coefficient of the shell-and-tube heat exchanger, The relationship between the frictional pressure drop; keeping the flow rate of the gas-liquid mixture constant, by changing the flow rate of the cooling water, find out the relationship between the change of the flow rate of the cooling water and the heat transfer coefficient in the tube bundle.

Since cooling water, hot water and compressed air are equipped with two water pumps with different flow ranges and a parallel flow path with two start-up regulating valves with different opening ranges, the range of working conditions available for adjustment is very wide and can be adapted to various A shell-and-tube heat exchanger with different rated working conditions and different ranges can also provide experimental research on two-phase heat transfer with a large range of gas fraction changes.

In addition, this experiment can be carried out in the monitoring room through the temperature, pressure and flow measured by various thermometers, pressure gauges and flowmeters, the water level of the cooling water tank and hot water tank, and the switching conditions of the boiler, cooling tower and various circulating water pumps. Display, save and process relevant data in real time, so as to find and deal with problems in the system in time. In addition, the system can directly adjust the opening of each pneumatic valve in the monitoring room to achieve the purpose of adjusting flow and changing working conditions. The operation is flexible, simple, safe and reliable.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Figure 2 is a simplified diagram of Figure 1;

Among them: 1-air compressor, 2-air dryer, 3-air storage tank, 4-compressed air heater, 5-boiler, 6-hot water heater, 7-hot water separator, 8-mixer , 9-hot water tank, 10-separator, 11-experimental element, 12-cooling water tank, 13-cooling tower, 14-cooling water water dispenser.

detailed description

Below in conjunction with embodiment the present invention will be further described.

As shown in Fig. 1, a kind of shell-and-tube heat exchanger two-phase heat exchange experiment test platform comprises boiler 5, and described boiler 5 is connected with compressed air heater 4 and hot water heater 6 respectively, and described hot water heater 6 is connected to the hot water separator 7, the compressed air heater 4 and the hot water separator 7 are both connected to the mixer 8, the mixer 8 is connected to the experimental component 11, and the experimental component 11 is connected to the cooling water tank 12 in turn , cooling tower 13 and cooling water water dispenser 14, cooling water water dispenser 14 connects experimental element 11 again to form a circuit, and described experimental element 11 also connects separator 10, hot water tank 9 and hot water heater 6 successively;

The compressed air heater 4 is also connected to an air storage tank 3, and the air storage tank 3 is connected with an air dryer 2 and an air compressor 1 in turn; the air compressor 1 is a screw air compressor;

The separator 10 is also provided with an exhaust device.

Steam traps are also arranged on the compressed air heater 4 and the hot water heater 6 respectively.

The air dryer 2 and the air storage tank 3, the boiler 5 and the compressed air heater 4, the boiler 5 and the hot water heater 6, the mixer 8 and the experimental element 11, the experimental element 11 and the separator 10, the cooling tower 13 and Ball valves are provided between the cooling water tanks 14; a one-way valve is provided between the experimental element 11 and the cooling water tank 12; and a cooling tower circulation pump is also provided on the cooling tower 13. The boiler 5 is an electric steam boiler.

Two sets of ball valves, two water pumps with different flow ranges and two check valves are connected in parallel between the hot water tank 9 and the hot water heater 6; the hot water heater 6 is also provided with a hot water circulation pump.

Two groups of regulating valves with different opening ranges, two flowmeters and two ball valves are connected in parallel between the compressed air heater 4 and the mixer 8, and a ball valve and a check valve are connected in series.

Two groups of regulating valves with different opening ranges, two flow meters and two ball valves are connected in parallel between the hot water separator 7 and the mixer 8, and a check valve is connected in series.

Between the cooling water tank 12 and the cooling tower 13, two groups of ball valves, two different water pumps and two check valves are connected in parallel, and a ball valve is connected in series; between the cooling water water tank 14 and the experimental element 11 There are two sets of regulating valves with different opening ranges, two flowmeters and two ball valves connected in parallel, and one check valve and one ball valve connected in series.

The air storage tank 3 , the hot water tank 9 and the cooling water tank 12 are all provided with a temperature measuring port and a pressure measuring port; the inlet and outlet pipes of the experimental component 11 are all provided with a temperature measuring port and a pressure measuring port.

The regulating valves are all connected to the pneumatic valve ports of the air storage tank 3 . Pneumatic regulating valve can meet the requirements of more accurate and convenient adjustment of the flow of air from the air storage tank, hot water from the water tank, and cold water from the cooling tower.

The flows of the two water pumps connected in parallel between the cooling water tank 12 and the cooling tower 13 are respectively 6 m ³ /h and 50 m ³ /h, and the flow rates of the two water pumps connected in parallel between the hot water tank 9 and the hot water heater 6 The flow rates are 6 m ³ /h and 50 m ³ /h respectively, and the opening ranges of the two regulating valves connected in parallel between the cooling water water tank 14 and the experimental element 11 are 0.6-6 m ³ /h and 6-60 m ³ /h, the opening ranges of the two regulating valves connected in parallel between the hot water separator 7 and the mixer 8 are 1-10m ^{3 /h and 5-50m 3 /} h respectively, the compressed air heater 4 and the mixing The opening ranges of the two regulating valves connected in parallel between the device 8 are 10-80 m ³ /h and 30-210 m ³ /h respectively.

The air compressor and air dryer can smoothly send the dry and stable pressure air into the gas-liquid mixer to mix with the steam after being metered and heated by steam. And along with the piping system to the shell and tube heat exchanger, it is separated and then emptied.

The cooling tower has the maximum cooling water required by the water cooling section and the maximum cooling water of other equipment in the system. And the corresponding cooling water pump can meet the functions of cooling water delivery and circulation.

A two-phase heat transfer experimental test method for a shell-and-tube heat exchanger, including a compressed air system, a steam system, a cooling water system and a test system, including the following steps: start the screw air compressor 1 and the air dryer 2, adjust the air supply Part of the pressure is supplied to the regulating valve, and the other part enters the shell side of the shell-and-tube heat exchanger of the experimental element 11 through the compressed air heater 4 to the mixer 8 . Start the cooling tower 13 and the cooling tower circulating pump, and the cooling water passes through the cooling water tank 14 and then into the shell-and-tube heat exchanger tube of the experimental element 11; start the hot water circulating pump, and the hot water enters the hot water heater from the hot water tank 9 6. After the hot water separator 7 enters the mixer 8 and mixes with the air through the pipeline, it finally enters the experimental element 11; finally starts the electric steam boiler 5, and the steam enters the hot water heater 6 and the compressed air heater 4. The water and air are heated, the steam condenses into water, and is discharged from the steam trap; after the flow, temperature, and pressure are stabilized, data collection starts, and after the heat exchange in the pipe is completed, the hot water is sent to the separator 10 and then returned to the hot water tank 9 , the cooling water returns to the cooling water tank 12, and the air is vented.

1. During the two-phase heat transfer experiment, keep the flow of hot water constant, and change the flow of non-condensable gas air to obtain the relationship between pressure drop, mass gas fraction and heat flux.

2. During the two-phase heat exchange experiment, keep the non-condensable gas content constant, and find out the relationship between the change of the hot water and cooling water flow, the heat transfer coefficient of the heat exchanger and the pressure drop by changing the flow rate of hot water and cooling water.

3. During the two-phase heat exchange experiment, keep the flow rate of each medium constant, and compare the influence of the qualitative temperature on the heat transfer coefficient of the heat exchanger by changing the qualitative temperature of dry air or hot water.

4. In the two-phase experiment, keep the above measured values unchanged, and compare the influence of the structure on the heat transfer coefficient and pressure drop by changing the structure of the heat exchanger, such as changing the arrangement of the tube bundles and adding baffles.

5. In the two-phase experiment, the effect on the convective heat transfer coefficient and pressure drop is compared by changing the flow space of the medium, that is, the tube side and the shell side.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also possible. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A two-phase heat exchange experimental test platform for shell-and-tube heat exchangers, characterized in that: it includes a boiler (5), and the boiler (5) is connected to a compressed air heater (4) and a hot water heater (6) respectively. ), the hot water heater (6) is connected to the hot water separator (7), the compressed air heater (4) and the hot water separator (7) are both connected to the mixer (8), and the mixing The device (8) is connected to the experimental component (11), and the experimental component (11) is connected to the cooling water tank (12), the cooling tower (13) and the cooling water dispenser (14) in turn, and the cooling water dispenser (14) is connected to The experimental element (11) forms a loop, and the experimental element (11) is also sequentially connected to the separator (10), the hot water tank (9) and the hot water heater (6); The compressed air heater (4) is also connected to an air storage tank (3), and the air storage tank (3) is sequentially connected to an air dryer (2) and an air compressor (1); An exhaust device is also provided on the separator (10). 2. The shell-and-tube heat exchanger two-phase heat exchange experimental test platform according to claim 1, characterized in that: the compressed air heater (4) and the hot water heater (6) are respectively provided with hydrophobic device. 3. The shell-and-tube heat exchanger two-phase heat exchange experimental test platform according to claim 1, characterized in that: the air dryer (2), the air storage tank (3), the boiler (5) and the compressed air Heater (4), boiler (5) and hot water heater (6), mixer (8) and experimental element (11), experimental element (11) and separator (10), cooling tower (13) and cooling Ball valves are provided between the water tanks (14); a check valve is provided between the experimental element (11) and the cooling water tank (12); a cooling tower circulation pump is also provided on the cooling tower (13) . 4. The shell-and-tube heat exchanger two-phase heat exchange experimental test platform according to claim 1, characterized in that two sets of ball valves are connected in parallel between the hot water tank (9) and the hot water heater (6) , two water pumps with different flow ranges and two one-way valves; the hot water heater (6) is also provided with a hot water circulation pump. 5. The shell-and-tube heat exchanger two-phase heat exchange experimental test platform according to claim 1, characterized in that: there are two sets of openings connected in parallel between the compressed air heater (4) and the mixer (8) Regulating valves with different ranges, two flow meters and two ball valves, and a ball valve and a check valve in series. 6. The shell-and-tube heat exchanger two-phase heat exchange experimental test platform according to claim 1, characterized in that: there are two sets of splitters connected in parallel between the hot water separator (7) and the mixer (8). Regulating valves with different temperature ranges, two flowmeters and two ball valves, and a check valve in series. 7. The shell-and-tube heat exchanger two-phase heat exchange experimental test platform according to claim 1, characterized in that: between the cooling water tank (12) and the cooling tower (13), there are two sets of ball valves, two Two water pumps with different flow ranges, two one-way valves, and a ball valve in series; two sets of regulating valves with different opening ranges and two sets of control valves with different opening ranges are connected in parallel between the cooling water water dispenser (14) and the experimental element (11). A flowmeter and two ball valves, and a check valve and a ball valve in series. 8. The shell-and-tube heat exchanger two-phase heat exchange experimental test platform according to claim 1, characterized in that: the gas storage tank (3), the hot water tank (9) and the cooling water tank (12) are Both are provided with a temperature measuring port and a pressure measuring port; the inlet and outlet pipes of the experimental element (11) are all provided with a temperature measuring port and a pressure measuring port. 9. The test platform for two-phase heat exchange experiments of shell-and-tube heat exchangers according to claim 1, characterized in that: the regulating valves are all connected to the pneumatic valve port of the gas storage tank (3). 10. A two-phase heat transfer experimental test method for a shell-and-tube heat exchanger, including a compressed air system, a steam system, a cooling water system and a test system, characterized in that it includes the following steps: starting the air compressor (1) and Dryer (2), adjust the air supply pressure, one part supplies air to the regulating valve, and the other part passes through the compressed air heater (4) to the mixer (8) and enters the experimental element (11); start the cooling tower (13) and Cooling tower circulation pump, the cooling water passes through the cooling water tank (14) and then to the experimental element (11); start the hot water circulation pump, the hot water enters the hot water heater (6) from the hot water tank (9), and then goes through the heating The moisture water tank (7) enters the mixer (8) along with the pipeline and mixes with the air, and finally enters the experimental element (11); finally starts the boiler (5), and the steam enters the hot water heater (6) and the compressed air heater (4) Heat water and air, steam condenses into water, and discharges from the steam trap; after the flow, temperature, and pressure are stabilized, start data collection, and after the heat exchange in the tube is completed, hot water is sent to the separator (10) Get back to the hot water tank (9) again, the cooling water gets back to the cooling water tank (12), and the air is vented.