Heat exchanger performance evaluation method under multi-phase condition

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...

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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

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