Wall Effect on Fluid Flow and Heat Tranfser of Glass Beads Filled Cylinder in Non-Darcy Regime

Abstract

The wall effect is phenomenon that porosity near the wall is larger than internal space porosity, in other words, porosity inside the porous media packed channel is not uniform. In this paper, using the experiment method, the wall effect in porous medium packed channel is studied, flow resistance and convection heat transfer correlations under wall effect in porous media packed channel are proposed. In the experimental range of flow experiments, the relationship between the modified friction factor and modified Reynolds number is a power function, the change of coefficient A and B expose the effect of wall on the resistance characteristics of the porous medium packed channel, and through experiments we know that the porosity is an important influencing parameter for the resistance characteristics of porous media packed channel. In this paper we use the Wilson Plot Method to process the heat transfer experimental data, and summarize a heat transfer law with wall effect in porous medium packed channel. Indeed, the confining wall can affect the resistance characteristics and convection heat transfer of porous medium packed channel because the porosity distribution in porous medium packed channel is uneven. From the variation of the average porosity we can see that, when diameter ratio D/d is less than 10, the confining wall effect is very obvious, when diameter ratio D/d is less than 40 but larger than 10, it is weak, when diameter ratio D/d is larger than 40, the effect is negligible. Through the analysis of the experimental data and curve fitting, we get the experimental correlations of flow resistance and convective heat transfer in porous media packed channel. The proposed experimental correlations are compared with those existed in literature. This paper provides experimental evidence for further study on resistance characteristics and convection heat transfer rules under confining wall effect in porous medium packed channel in future.