Numerical Simulation Of Heat And Moisture Transfer Under High Temperature Based On FLUENT

Reference the previous two-dimensional axisymmetric model concept,thispaper establish the mode which regard the temperature gradient, soil waterpotential,and gravity as the driving force to drive heat and moisture migration.Themodel is suitable for the high-temperature heat and moisture migration. In theory, themigration of moisture is subdivided into migration under a temperature gradient andthe migration under the soil water potential, the migration of energy is also dividedinto thermal migration with thermal conductivity and thermal migration with themigration of liquid water.Summarize the empirical formula of previous heat and moisture migrationmodel, we have obtained the empirical formula of hydraulic conductivity coefficientsuch as water conductivity coefficient under temperature gradient, vaporconductivity coefficient under temperature gradient, and water conductivitycoefficient under the soil water potential.In this paper, on the cylindrical heat and moisture migration test bench, we havecompleted the low moisture content (volumetric moisture content3.5%) in soil high-temperature(80℃) heat and moisture migration experiment.The paper useexperimental results to verify the two-dimensional axisymmetrical heat and moisturetransfer model, and found that the temperature and humidity field changing trend isconsistent with the reality, the key phenomenon is obvious, it proves that thenumerical values are similar to high temperature heat and moisture transfer beforethe accuracy of that mechanism. This confirms that the speculation is correct before.In the initial volumetric moisture content of8%(80℃heat removal)conditions, this paper compares the results of the calculations of the model withpure heat conduction model, and found that the heat and moisture migration is notconducive to the heat removal of heat source.The paper select different initialvolumetric moisture conditions and different heat rejection temperature conditions tocalculated and contrast the moisture and temperature field by the new model. For theinitial moisture content of the unsaturated soil which is less than15%, the higher theinitial volumetric moisture content is, the faster the remove heat rate of thecorresponded drastic change stage. But the effect is gradually reduced in the slowlyvarying stage.The higher the temperature of the heat source is, the faster reduce ofthe remove heat rate.