Heat transfer in helium-xenon mixture flowing in straight and twisted tubes with square cross-section

The article considers heat transfer in a flow of helium-xenon mixture in straight and twisted tubes with square cross sections. The main attention is paid to the heat transfer at large Reynolds numbers for tubes with small effective diameter. Such flows are often found in compact heat exchangers, assemblies of heat-generating elements, and energy-separating devices. CFD simulation data serve to analyze the influence of the cross-section shape and the twist step of the tube on hydraulic resistance and heat transfer. Various methods of generalization of heat exchange data are analyzed, taking into account the effect of gas compressibility on the flow acceleration in the tube and dissipative effects on the equilibrium wall temperature. (paper)