Nusselt number correlation for turbulent heat transfer of helium–xenon gas mixtures

Abstract A gas-cooled nuclear reactor combined with a Brayton cycle shows promise as technology for high-power space power systems. Generally, helium–xenon gas mixture molecular weight of 14.5–40.0 g/mol is adopted the working fluid to reduce mass and volume turbomachinery. The Prandtl number mixtures this recommended mixing ratio may be low 0.2. As convective heat transfer closely related number, different correlations are often needed fluids various numbers. Previous studies have established medium–high numbers (such air water) extremely low-Prandtl liquid metals); however, these cannot directly such without verification. This study initially assessed applicability existing Nusselt correlations, finding that selected unsuitable mixtures. To establish more general correlation, theoretical derivation was conducted using turbulent boundary layer theory. Numerical simulations were carried out Ansys Fluent. Based on simulated results, parameters in derived correlation determined. It found calculations new good agreement experimental data, verifying its effect variable properties also analyzed, modified temperature established. conditions study, numerical error property-variable almost within 10%.