Test platform and method for heat transfer characteristics of falling film boiling of non-azeotropic refrigerant for liquid hydrogen

Abstract

The application belongs to the technical field of hydrogen liquefaction, and provides a test platform and method for falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen, which comprises a gas filling system, a pre-cooling circulation system, a cryogenic circulation system and a falling film boiling test platform; the outlet and the inlet of the gas filling system are connected with the inlet and the outlet of the falling film boiling test platform through pipelines; the pipeline between the outlet of the gas filling system and the inlet of the falling film boiling test platform passes through the pre-cooling circulation system and the cryogenic circulation system; the pre-cooling circulation system and the cryogenic circulation system provide temperature conditions for hydrogen liquefaction; the real situation under the pre-cooling and cryogenic circulation systems is comprehensively considered; accurate measurement of temperature and pressure is realized; reliable data basis is provided for evaluation and optimization of the flow and heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen; and the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen can be fully understood.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen liquefaction, and particularly relates to a test platform and method for falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen. BACKGROUND

[0002] Hydrogen storage and transportation is a key technology for hydrogen energy utilization. Compared with gaseous hydrogen storage and transportation, liquid hydrogen storage and transportation has the advantages of high hydrogen storage density per unit volume, high purity and high transportation efficiency, facilitating large-scale hydrogen transportation and utilization. However, in terms of liquid hydrogen production capacity, the civil liquid hydrogen production capacity is insufficient, and there is great development space in the future. It is urgent to carry out research work in the field of liquid hydrogen storage and transportation. The phase change heat transfer process of low-temperature working medium in the hydrogen liquefaction process occurs inside the main low-temperature heat exchanger. In order to achieve a breakthrough in hydrogen liquefaction technology, related scientific problems must be solved.

[0003] The inventors found that at present, there are many studies on the phase change heat transfer of raw gas and refrigerant in the temperature zone of natural gas liquefaction, but the related scientific problems of falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen have not been fully understood. The existing test platform for hydrogen liquefaction system does not comprehensively consider the real situation under the deep cooling and pre-cooling circulation system, which leads to the inability to accurately measure the temperature zone and pressure data under the action of non-azeotropic refrigerant, thereby affecting the evaluation and optimization of the flow and heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen. SUMMARY

[0004] In order to solve the above problems, the application provides a test platform and method for falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen, which comprehensively considers the real situation under the deep cooling and pre-cooling circulation system, realizes accurate measurement of temperature and pressure, and provides reliable data basis for evaluation and optimization of the flow and heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen.

[0005] In order to achieve the above purpose, in a first aspect, the application provides a test platform for falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen, which adopts the following technical scheme:

[0006] A test platform for falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen, comprising a gas filling system, a pre-cooling circulation system, a deep cooling circulation system and a falling film boiling test platform;

[0007] The outlet and inlet of the gas filling system are connected with the inlet and outlet of the falling film boiling test platform through pipelines, respectively. The pipeline between the outlet of the gas filling system and the inlet of the falling film boiling test platform passes through the pre-cooling circulation system and the deep cooling circulation system, and the pre-cooling circulation system and the deep cooling circulation system provide temperature conditions for hydrogen liquefaction;

[0008] The temperature pressure sensor is arranged at the outlet and the inlet of the falling film boiling test platform to measure the temperature and pressure.

[0009] Further, the gas filling system comprises a second gasifier connected with the outlet of the falling film boiling test platform through a pipeline, a sixth buffer tank connected with the second gasifier through a pipeline, a third mass flow meter connected with the sixth buffer tank through a pipeline, a third compressor connected with the third mass flow meter through a pipeline, a third water cooler connected with the third compressor through a pipeline, a fifth buffer tank connected with the third water cooler through a pipeline, and a first heating temperature controller connected with the fifth buffer tank through a pipeline.

[0010] Further, the sixth buffer tank is connected with a hydrogen cylinder, a neon cylinder and a helium cylinder through pipelines.

[0011] Further, the pipeline between the fifth buffer tank and the first heating temperature controller passes through the pre-cooling circulation system and the cryogenic circulation system.

[0012] Further, the pre-cooling circulation system comprises a pre-cooling primary heat exchanger and a pre-cooling secondary heat exchanger.

[0013] Further, the pre-cooling primary heat exchanger is connected with a second buffer tank through a pipeline, the second buffer tank is connected with a first mass flow meter through a pipeline, the first mass flow meter is connected with a first compressor through a pipeline, the first compressor is connected with a first water cooler through a pipeline, the first water cooler is connected with a first buffer tank through a pipeline, and the first buffer tank is connected with the pre-cooling primary heat exchanger through a pipeline.

[0014] Further, a first throttling valve is arranged on the pipeline between the pre-cooling primary heat exchanger and the second buffer tank.

[0015] Further, the pre-cooling secondary heat exchanger is connected with a first gasifier through a pipeline, the first gasifier is connected with a fourth buffer tank through a pipeline, the fourth buffer tank is connected with a second mass flow meter through a pipeline, the second mass flow meter is connected with a second compressor through a pipeline, the second compressor is connected with a second water cooler through a pipeline, the second water cooler is connected with a third buffer tank through a pipeline, the third buffer tank is connected with the pre-cooling primary heat exchanger through a pipeline, and the pre-cooling primary heat exchanger is connected with the pre-cooling secondary heat exchanger through a pipeline.

[0016] Further, a second throttling valve is arranged on the pipeline between the pre-cooling secondary heat exchanger and the first gasifier.

[0017] In order to achieve the above-mentioned purpose, the second aspect, the application further provides a test method for the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen.

[0018] A test method for the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen adopts the test platform for the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen as described in the first aspect, and comprises that the pre-cooling circulation system and the cryogenic circulation system provide temperature conditions for hydrogen liquefaction; temperature and pressure sensors are arranged at the outlet and the inlet of the falling film boiling test platform to realize temperature and pressure measurement.

[0019] Compared with the prior art, the application has the beneficial effects that:

[0020] 1. The outlet and the inlet of the gas filling system are respectively connected with the inlet and the outlet of the falling film boiling test platform through pipelines; the pipeline between the outlet of the gas filling system and the inlet of the falling film boiling test platform passes through the pre-cooling circulation system and the cryogenic circulation system, the pre-cooling circulation system and the cryogenic circulation system provide temperature conditions for hydrogen liquefaction, the real situation under the cryogenic and pre-cooling circulation systems is comprehensively considered, accurate temperature and pressure measurement is realized, reliable data basis is provided for evaluation and optimization of the flow and heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen, and the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen can be fully understood;

[0021] 2. The test platform has the advantages of compactness, energy saving and stable operation, and can realize the test of the non-azeotropic refrigerant heat and mass coupled transfer mechanism of the complex multi-component and liquid hydrogen temperature zone in the hydrogen liquefaction process, and provide a basis for revealing the influence law of the non-azeotropic component migration on the bubble / liquid film / liquid drop morphology size parameter and movement behavior. BRIEF DESCRIPTION OF DRAWINGS

[0022] The drawings constituting a part of this embodiment are used to provide further understanding of this embodiment, the schematic embodiment of this embodiment and the description thereof are used to explain this embodiment, and do not constitute improper limitation on this embodiment.

[0023] Figure 1 It is a structural schematic diagram of the first embodiment of the application;

[0024] Figure 2 It is a structural schematic diagram of the second embodiment of the application;

[0025] 1, first buffer tank; 2, first water cooler; 3, first compressor; 4, first mass flow meter; 5, second buffer tank; 6, pre-cooling primary heat exchanger; 7, third buffer tank; 8, second water cooler; 9, second compressor; 10, second mass flow meter; 11, fourth buffer tank; 12, first vaporizer; 13, pre-cooling secondary heat exchanger; 14, first throttling valve; 15, second throttling valve; 16, first regulating valve; 17, fifth buffer tank; 18, third water cooler; 19, third compressor; 20, third mass flow meter; 21, stop valve; 22, hydrogen regulating valve; 23, neon regulating valve; 24, helium regulating valve; 25, total regulating valve; 26, sixth buffer tank; 27, hydrogen cylinder; 28, neon cylinder; 29, helium cylinder; 30, second vaporizer; 31, liquid nitrogen pre-cooler; 32, freon pre-cooler; 33, fourth compressor; 34, third vaporizer; 35, cryogenic heat exchanger; 36, cryogenic expander; 37, cryogenic throttling valve; 38, first temperature and pressure sensor; 39, second temperature and pressure sensor; 40, first differential pressure sensor; 41, third temperature and pressure sensor; 42, first falling film boiling test section; 43, first high-speed video camera; 44, second regulating valve; 45, first computer; 46, liquid nitrogen tank; 47, liquid nitrogen heat exchanger; 48, liquid nitrogen regulating valve; 49, nitrogen regulating valve; 50, first freon regulating valve; 51, second freon regulating valve; 52, freon refrigerator; 53, freon heat exchanger; 54, third regulating valve; 55, fourth temperature and pressure sensor; 56, fourth regulating valve; 57, second high-speed video camera; 58, second differential pressure sensor; 59, second falling film boiling test section; 60, seventh buffer tank; 61, fifth regulating valve; 62, fourth water cooler; 63, fifth compressor; 64, sixth regulating valve; 65, fourth mass flow meter; 66, eighth buffer tank; 67, regulating valve group; 68, methane tank; 69, ethane tank; 70, ethylene tank; 71, propane tank; 72, propylene tank; 73, butane tank; 74, nitrogen tank; 75, hydrogen tank; 76, helium tank; 77, fourth vaporizer; 78, second high-speed video camera; 79, second differential pressure sensor; 80, fifth temperature and pressure sensor; 81, second falling film boiling test section; 82, bypass stop valve. DETAILED DESCRIPTION

[0026] The application will be further described below in connection with the drawings and examples.

[0027] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0028] Example 1:

[0029] For the liquid hydrogen non-azeotropic refrigerant falling film boiling heat transfer characteristics research problem, and the existing research hydrogen liquefaction system test platform does not consider the real situation including the deep cooling and pre-cooling cycle system, resulting in the temperature and pressure data cannot be accurately measured under the action of non-azeotropic refrigerant, etc. Figure 1 As shown in FIG. 1, the embodiment provides a test platform for liquid hydrogen non-azeotropic refrigerant falling film boiling heat transfer characteristics, including a gas filling system, a pre-cooling cycle system, a deep cooling cycle system and a falling film boiling test platform 42;

[0030] The outlet and inlet of the gas filling system are connected with the inlet and outlet of the falling film boiling test platform 42 through pipelines respectively; the pipeline between the outlet of the gas filling system and the inlet of the falling film boiling test platform 42 passes through the pre-cooling cycle system and the deep cooling cycle system, and the pre-cooling cycle system and the deep cooling cycle system provide temperature conditions for hydrogen liquefaction;

[0031] The outlet and inlet of the falling film boiling test platform 42 are both provided with temperature and pressure sensors to realize temperature and pressure measurement.

[0032] Specifically, the pipeline between the outlet of the gas filling system and the inlet of the falling film boiling test platform 42 passes through the pre-cooling cycle system and the deep cooling cycle system, and the pre-cooling cycle system and the deep cooling cycle system provide temperature conditions for hydrogen liquefaction, which can realize the temperature (-190-265℃) conditions of the deep cooling cycle refrigerant in the hydrogen liquefaction process, comprehensively consider the real situation including the deep cooling and pre-cooling cycle system, realize the accurate measurement of temperature and pressure, provide reliable data basis for evaluating and optimizing the flow and heat transfer characteristics of the liquid hydrogen non-azeotropic refrigerant, and fully understand the liquid hydrogen non-azeotropic refrigerant falling film boiling heat transfer characteristics.

[0033] Optionally, the falling film boiling test platform 42 is realized by existing equipment, for example, the upper part of the falling film boiling test platform 42 is a distributor, and the lower part is a test circular pipe, the non-azeotropic refrigerant is uniformly dropped through the distributor and falls on the test circular pipe to realize the falling film boiling heat transfer process; the test platform shell is made of transparent material, which is matched with a high-speed camera to study the micro flow and heat transfer process of the internal fluid.

[0034] Optionally, the gas filling system comprises a second gasifier 30 connected to the outlet of the falling film boiling test platform 42 through a pipeline, a sixth buffer tank 26 connected to the second gasifier 30 through a pipeline, a third mass flow meter 20 connected to the sixth buffer tank 26 through a pipeline, a third compressor 19 connected to the third mass flow meter 20 through a pipeline, a third water cooler 18 connected to the third compressor 19 through a pipeline, a fifth buffer tank 17 connected to the third water cooler 18 through a pipeline, and a first heating and temperature controller 43 connected to the fifth buffer tank 17 through a pipeline, and the first heating and temperature controller 43 is connected to the inlet of the falling film boiling test platform 42 through a pipeline.

[0035] A second regulating valve 45 is arranged on the pipeline between the falling film boiling test platform 42 and the second gasifier 30; a first temperature and pressure sensor 38 is arranged at the inlet of the first heating and temperature controller 43; a second temperature and pressure sensor 39 and a third temperature and pressure sensor 41 are arranged at the inlet and outlet of the falling film boiling test platform 42, respectively; a first differential pressure sensor is further arranged on the falling film boiling test platform 42, specifically, two test point interfaces of the differential pressure sensor are connected to the fluid inlet and outlet of the platform, respectively, so as to test the pressure difference between the inlet and outlet of the test platform; a first high-speed camera 44 is further arranged at the third temperature and pressure sensor 41, specifically, the high-speed camera is directed to the falling film boiling test platform, the test platform shell is made of transparent material, the high-speed camera dynamically records the falling film boiling process inside the test platform, captures the falling film flow pattern, and micro-flow parameters such as droplets / bubbles, and realizes micro-experimental research on falling film boiling; the first temperature and pressure sensor 38, the second temperature and pressure sensor 39, the third temperature and pressure sensor 41, and the first high-speed camera 44 are connected to a first computer 46.

[0036] The sixth buffer tank 26 is connected to a hydrogen cylinder 27, a neon cylinder 28, and a helium cylinder 29 through a pipeline, and corresponding, a stop valve 21, a hydrogen regulating valve 22, a neon regulating valve 23, a helium regulating valve 24, and a total regulating valve 25 are arranged.

[0037] The pipeline between the fifth buffer tank 17 and the first heating and temperature controller 43 passes through the pre-cooling circulation system and the cryogenic circulation system; a first regulating valve 16 is arranged on the pipeline between the pre-cooling circulation system and the cryogenic circulation system. Optionally, the cryogenic circulation system can be a cryogenic heat exchanger 35, such as a helium cryogenic circulation system.

[0038] In this embodiment, the precooling circulation system includes a first-stage precooling heat exchanger 6 and a second-stage precooling heat exchanger 13. Specifically, the first-stage precooling heat exchanger 6 is connected to a second buffer tank 5 via a pipeline, the second buffer tank 5 is connected to a first mass flow meter 4 via a pipeline, the first mass flow meter 4 is connected to a first compressor 3 via a pipeline, the first compressor 3 is connected to a first water cooler 2 via a pipeline, the first water cooler 2 is connected to a first buffer tank 1 via a pipeline, and the first buffer tank 1 is connected to the first-stage precooling heat exchanger 6 via a pipeline; a first throttling valve 14 is installed on the pipeline between the first-stage precooling heat exchanger 6 and the second buffer tank 5. The precooling secondary heat exchanger 13 is connected to a first vaporizer 12 via a pipeline. The first vaporizer 12 is connected to a fourth buffer tank 11 via a pipeline. The fourth buffer tank 11 is connected to a second mass flow meter 10 via a pipeline. The second mass flow meter 10 is connected to a second compressor 9 via a pipeline. The second compressor 9 is connected to a second water cooler 8 via a pipeline. The second water cooler 8 is connected to a third buffer tank 7 via a pipeline. The third buffer tank 7 is connected to the precooling primary heat exchanger 6 via a pipeline. The precooling primary heat exchanger 6 is connected to the precooling secondary heat exchanger 13 via a pipeline. A second throttle valve 15 is installed on the pipeline between the precooling secondary heat exchanger 13 and the first vaporizer 12.

[0039] This embodiment refers to the deep cooling and precooling cycles in a real hydrogen liquefaction system, and constructs an experimental test device with corresponding temperature range, pressure and flow rate. By changing the composition of different refrigerants, the flow and heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen can be evaluated and optimized.

[0040] Example 2:

[0041] like Figure 2 As shown, this embodiment provides a test platform for the falling film boiling heat transfer characteristics of liquid hydrogen using a non-azeotropic refrigerant, including a liquid nitrogen tank 47, a liquid nitrogen heat exchanger 48, a liquid nitrogen regulating valve 49, a nitrogen regulating valve 50, a first Freon regulating valve 51, a second Freon regulating valve 52, a Freon refrigerator 53, a Freon heat exchanger 54, a third regulating valve 55, a fourth temperature and pressure sensor 56, a fourth regulating valve 57, a second heating thermostat 58, a second computer 59, a seventh buffer tank 60, and a fifth regulating valve. 61. Fourth water cooler; 62. Fifth compressor; 63. Sixth regulating valve; 64. Fourth mass flow meter; 65. Eighth buffer tank; 66. Regulating valve assembly; 67. Methane tank; 68. Ethane tank; 69. Ethylene tank; 70. Propane tank; 71. Propylene tank; 72. Butane tank; 73. Nitrogen tank; 74. Hydrogen tank; 75. Helium tank; 76. Fourth vaporizer; 77. Second high-speed camera; 78. Second differential pressure sensor; 79. Fifth temperature and pressure sensor; 80. Second falling film boiling test section; 81. and bypass shut-off valve; 82.

[0042] The main difference between the test platform in Example 1 and the test platform in this example is that in the gas filling system of this example, a methane tank 68, an ethane tank 69, an ethylene tank 70, a propane tank 71, a propylene tank 72, a butane tank 73, a nitrogen tank 74, a hydrogen tank 75, and a helium tank 76 are arranged; in the cold circulation system, a liquid nitrogen heat exchanger 48 and a freon heat exchanger 54 are arranged, so that the temperature (25 to -190℃) condition of the pre-cooling circulating refrigerant in the hydrogen liquefaction process can be realized; and a bypass is arranged at the second falling film boiling test section 81, and a bypass stop valve 82 is arranged on the bypass.

[0043] Example 3

[0044] The test method for the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen in this example uses the test platform for the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen as described in Example 1, which includes that the pre-cooling circulation system and the cryogenic circulation system provide temperature conditions for hydrogen liquefaction; and temperature and pressure sensors are arranged at the outlet and the inlet of the falling film boiling test platform to realize temperature and pressure measurement.

[0045] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A test platform for the falling film boiling heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen, characterized in that, The gas filling system, the pre-cooling circulation system, the deep cooling circulation system and the falling film boiling test platform are included. The outlet and the inlet of the gas filling system are connected with the inlet and the outlet of the falling film boiling test platform through pipelines respectively; the pipeline between the outlet of the gas filling system and the inlet of the falling film boiling test platform passes through the pre-cooling circulation system and the deep cooling circulation system, and the pre-cooling circulation system and the deep cooling circulation system provide temperature conditions for hydrogen liquefaction. Temperature and pressure sensors are arranged at the outlet and the inlet of the falling film boiling test platform to realize temperature and pressure measurement. The gas filling system includes a second vaporizer connected with the outlet of the falling film boiling test platform through a pipeline, a sixth buffer tank connected with the second vaporizer through a pipeline, a third mass flow meter connected with the sixth buffer tank through a pipeline, a third compressor connected with the third mass flow meter through a pipeline, a third water cooler connected with the third compressor through a pipeline, a fifth buffer tank connected with the third water cooler through a pipeline, and a first heating temperature controller connected with the fifth buffer tank through a pipeline, and the first heating temperature controller is connected with the inlet of the falling film boiling test platform through a pipeline. The pipeline between the fifth buffer tank and the first heating temperature controller passes through the pre-cooling circulation system and the deep cooling circulation system.

2. The test platform for the falling film boiling heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen according to claim 1, characterized in that, The sixth buffer tank is connected with a hydrogen cylinder, a neon cylinder and a helium cylinder through pipelines.

3. The test platform for the falling film boiling heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen according to claim 1, characterized in that, The pre-cooling circulation system includes a pre-cooling first-stage heat exchanger and a pre-cooling second-stage heat exchanger.

4. The test platform for the falling film boiling heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen according to claim 3, characterized in that, The pre-cooling first-stage heat exchanger is connected with a second buffer tank through a pipeline, the second buffer tank is connected with a first mass flow meter through a pipeline, the first mass flow meter is connected with a first compressor through a pipeline, the first compressor is connected with a first water cooler through a pipeline, the first water cooler is connected with a first buffer tank through a pipeline, and the first buffer tank is connected with the pre-cooling first-stage heat exchanger through a pipeline.

5. The test platform for the falling film boiling heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen according to claim 4, characterized in that, A first throttle valve is arranged on the pipeline between the pre-cooling first-stage heat exchanger and the second buffer tank.

6. The test platform for the falling film boiling heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen according to claim 3, characterized in that, The pre-cooling second-stage heat exchanger is connected with a first vaporizer through a pipeline, the first vaporizer is connected with a fourth buffer tank through a pipeline, the fourth buffer tank is connected with a second mass flow meter through a pipeline, the second mass flow meter is connected with a second compressor through a pipeline, the second compressor is connected with a second water cooler through a pipeline, the second water cooler is connected with a third buffer tank through a pipeline, the third buffer tank is connected with the pre-cooling first-stage heat exchanger through a pipeline, and the pre-cooling first-stage heat exchanger is connected with the pre-cooling second-stage heat exchanger through a pipeline.

7. The test platform for the falling film boiling heat transfer characteristics of non-azeotropic refrigerants for liquid hydrogen according to claim 6, characterized in that, A second throttle valve is arranged on the pipeline between the pre-cooling second-stage heat exchanger and the first vaporizer.

8. A test method for falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen, characterized by, The test platform for testing the falling film boiling heat exchange characteristics of the non-azeotropic refrigerant for liquid hydrogen adopts any one of the test platforms in claims 1-7, and the pre-cooling circulation system and the deep cooling circulation system provide temperature conditions for hydrogen liquefaction; temperature and pressure sensors are arranged at the outlet and the inlet of the falling film boiling test platform to realize temperature and pressure measurement.

Images