Comparison of Modeling Predictions and Experimental Data for He II Flow in Porous Materials

Abstract

The predictions of a numerical model for the flow of He II are compared with published experimental data. The purpose is to show that the model correctly predicts the flow in narrow channels and porous materials. The model is based on the most widely accepted one-dimensional equations for He II that include the Gorter-Mellink mutual friction term. The results show that the equations and associated parameters, which have been verified in wide channels, lead to agreement for uniform channels as small as 0.3 µm. The bulk value of the Gorter-Mellink parameter is adequate to model all the data. Simulation does show, however, that the internal structure of porous materials is very important in determining the flow. A procedure is described to probe the internal structure using He II flow measurements. Numerical modeling is shown to be sufficiently reliable so that it can be used to design He II systems. This can eliminate much of the costly and time consuming experimental trial and error testing.