Heat exchanger performance evaluation method under multi-phase condition

A technology of heat exchangers and evaluation methods, applied in indirect heat exchangers, heat exchanger types, heat storage equipment, etc. problems, to overcome the large difference in heat transfer coefficients, a wide range of applications, and the effect of optimal design

Active Publication Date: 2021-06-25
HEFEI GENERAL MACHINERY RES INST
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  • Application Information

AI Technical Summary

Problems solved by technology

The calculation formula of the total heat transfer coefficient is based on the heat transfer film coefficient of the cold and hot side surfaces and the thermal resistance of the dirt. For the heat transfer between single-phase fluids, such as liquid-liquid heat transfer and gas-gas heat transfer, the existing technology The calculation formula of the total heat transfer coefficient can directly reflect the heat transfer performance of the heat exchanger, but for the heat exchanger with phase change, such as the heat transfer process under the condition of evaporation or condensation, due to the There is a large gap between the surface heat transfer film coefficients of the pure gas phase and the pure gas phase, and the calculation method of the total heat transfer coefficient of the prior art cannot accurately evaluate the heat transfer performance of the heat exchanger

Method used

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  • Heat exchanger performance evaluation method under multi-phase condition
  • Heat exchanger performance evaluation method under multi-phase condition
  • Heat exchanger performance evaluation method under multi-phase condition

Examples

Experimental program
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Effect test

Embodiment 1

[0044] In a shell-and-tube condensing heat exchanger, a unilateral condensation phase transition occurs during the pure countercurrent heat exchange process. The mixture mainly composed of propane is used as the hot fluid to go through the shell side, and water is used as the cold fluid to go through the tube side. When the hot fluid is imported, it is in the state of full gas. After exchanging heat with the cold fluid, the temperature drops, gradually condenses, and finally becomes liquid. The cold fluid does not undergo a phase change during the entire heat exchange process and is always in a liquid state.

[0045] S1. Segmentation

[0046] The thermometer measures the inlet temperature T of the thermal fluid H1 is 104°C, the outlet temperature T H4The temperature is 30°C, the inlet pressure is 3.2MPa, and the mass flow rate m of the thermal fluid is 10000kg / h. According to the physical property data of the substance, it is calculated that the thermal fluid starts to appea...

Embodiment 2

[0080] A vertical double-sided phase change heat exchanger for propylene evaporation and ethylene condensation. Propylene is a cold fluid that evaporates upward through the tube side, and ethylene is a hot fluid that condenses downward through the shell side.

[0081] S1. Segmentation

[0082] The ethylene inlet temperature T measured by the thermometer H1 -10°C, outlet temperature T H6 The temperature is -37.5℃, the inlet pressure is 1.56MPa, and the mass flow rate m of the thermal fluid is 275000kg / h. According to the thermophysical parameters of ethylene, it is determined that its corresponding dew point temperature and bubble point temperature are both -35.7°C at 1.56MPa, ignoring the pressure loss along the way. Propylene inlet temperature T measured by thermometer C1 -45°C, outlet temperature T C6The temperature is -15.2℃, the inlet pressure is 0.05MPa, and the mass flow rate m of the thermal fluid is 230000kg / h. According to the thermophysical parameters of propyle...

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Abstract

The invention belongs to the technical field of heat exchanger heat transfer performance evaluation, and particularly relates to a heat exchanger performance evaluation method under a multi-phase condition. According to the evaluation method, regions are divided by taking phase change positions of cold and hot fluids in a heat exchanger as boundaries, heat transfer coefficients Ki in the regions are respectively calculated so as to calculate a heat exchange area Ai, and an apparent heat transfer coefficient K of the heat exchanger based on weighted averaging of the heat exchange area Ai is obtained; and by comparing the apparent heat transfer coefficients K of different heat exchangers containing multiple phase states, the performance of different heat exchangers containing multiple phase states is determined. The weighted averaging is carried out based on the heat exchange area, so that the overall heat transfer performance of the phase change heat exchanger can be accurately reflected, the problems that in the prior art, heat transfer coefficients of different sections of the phase change heat exchanger are large in difference and cannot be accurately evaluated are solved, and an important basis is provided for optimal design and heat transfer performance evaluation of the phase change heat exchanger.

Description

technical field [0001] The invention belongs to the technical field of heat transfer performance evaluation of heat exchangers, and in particular relates to a performance evaluation method of heat exchangers under multiphase conditions. Background technique [0002] Heat transfer performance is one of the main indicators to measure the performance of a heat exchanger. The heat transfer coefficient can intuitively reflect the ability of heat exchange between cold fluid and hot fluid. The calculation formula of the total heat transfer coefficient is based on the heat transfer film coefficient of the cold and hot side surfaces and the thermal resistance of the dirt. For the heat transfer between single-phase fluids, such as liquid-liquid heat transfer and gas-gas heat transfer, the existing technology The calculation formula of the total heat transfer coefficient can directly reflect the heat transfer performance of the heat exchanger, but for the heat exchanger with phase chan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F28D20/02
CPCF28D20/028Y02E60/14
Inventor 陈永东李雪王严冬程沛吴晓红于改革夏春杰
Owner HEFEI GENERAL MACHINERY RES INST
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