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Modelling heat transfer in the evaporators of heating-cooling energy systems taking into account nonstationarity of the boiling process

DOI: 10.17586/1606-4313-2022-21-4-52-59
UDC 621.56

Modelling heat transfer in the evaporators of heating-cooling energy systems taking into account nonstationarity of the boiling process

Apitsyna O.S., Aleksandr A. Malyshev, Andrei V. Zaitsev, Olga S. Malinina, Ignatiev Vitaly E.

For citation: Apitsyna O.S., Malyshev A.A., Zaitsev A.V., Malinina O.S., Ignatiev V.E. Modelling heat transfer in the evaporators of heating-cooling energy systems taking into account nonstationarity of the boiling process. Journal of International Academy of Refrigeration. 2022. No 4. p. 52-59. DOI: 10.17586/1606-4313-2022-21-4-52-59

Abstract
The relevance of the research is due to the improvements of techniques for calculation heat transfer processes in the heating-cooling energy systems, which result from implementing cutting-edge solutions in apparatus engineering. Upon analyzing and comparing common calculation techniques, it has been established that the divergence of their results exceeds500%, mainly due to the usingflow parameters of phases by their authors. Analysis of mathematical models for liquid boiling in the channels demonstrated their having been mainly oriented at energy industry conditions, which does not take into account the peculiarities of cryogenic engineering. In the paper, we consider a heat-hydrodynamic model for refrigerant boiling process of in the channels of various hydraulic diameters. In the model proposed, the equations for steam volume fraction are used as an empirical base. Among balance equations, we consider the equation of material and heat balance as well as heat-transfer equation that describes heat transfer form boiling refrigerant to the environment. The system of the equations at every time interval is solved iteratively by the method of finite approximations with a specialized FORTRAN-oriented program. The adequacy of the model is demonstrated by comparing the calculation results obtained from the program and the experimental data on the air-cooler test.

Keywords: heat transfer, boiling in channels, mathematical modeling of heat-hydrodynamic parameters, real quality of vapor, balance equations and heat-transfer

All references

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