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In the present comment, the results of recently published by Li Shu and Yonglin Ju "Numerical Study on the Condensation Characteristics of Various Refrigerants Outside a Horizontal Plain Tube at Low Temperatures" in International Journal of Thermal Sciences 2022 are discussed. It is shown that one of the conclusions of the work that "at low saturation temperatures, the periodic-averaged heat transfer coefficient in the numerical simulation is lower than that calculated with Nusselt's equation, especially at large wall subcooling", is not supported by the results of simulation performed by the author of this comment. [ABSTRACT FROM AUTHOR]

The present paper describes a numerical study of heat and mass transfer processes in a metal hydride reactor for hydrogen purification with aluminium foam. A numerical simulation was done with the help of the mathematical model, which had been used previously for a numerical simulation of heat and mass transfer processes in different types of metal hydride reactors during sorption/desorption processes. The results illustrate that the major factors that reduce the rate of sorption, and consequently the efficiency of the system, are increasing the temperature of the reactor and the pressure drop, which is due to filtering the mixture through a metal hydride bed with low permeability. It is shown that the use of aluminium foam allows us to realise a more effective system for hydrogen purification from impurities, compared to a case without aluminium foam, while the volumetric capacity of the system is reduced slightly (9%). Increasing pressure at the reactor inlet also increases the efficiency of the system. [ABSTRACT FROM AUTHOR]