Numerical analysis for two-dimensional transient heat transfer from a flat plate at one-side of a duct containing pressurized He II Original Research Article

A numerical analysis of two-dimensional transient heat transfer produced by step heat inputs to a flat plate located at one end of a rectangular duct containing pressurized He II was performed. The computer code, SUPER-2D, that is the two-dimensional heat transfer code for He II developed by Tatsumoto et al. based on the two fluid model and the theory of the mutual friction was used for the calculation. The time lag from the application of the step heat input to the occurrence of the λ transition, which is called a lifetime, was obtained for various values of step heat flux for bulk liquid temperatures ranging from 1.8 to 2.0 K. The calculations were made for three rectangular ducts having different cross-sectional area. The ratios of the cross-sectional area of the duct to the heated surface area, Ad/Ah, were 1.0, 1.6 and 2.0. Effect of the Ad/Ah on the lifetime was clarified. The solutions agreed with the experimental data by Shiotsu et al. for the ducts with the same structures and the corresponding conditions. It was confirmed that the computer code, SUPER-2D, can describe transient heat transport in He II as well as steady-state one .