A numerical study for the prediction of turbulent mixing factor in thermal storage tanks

The transient behavior of thermal stratification in storage systems were investigated numerically. An efficient computer code based on Chapeau-Galerkin integral formulation is developed. The validation of the present scheme is verified against published experimental and finite difference results. The predictions are adequately simulate the published data. The present results showed that the turbulent mixing (or eddy conductivity) factor caused by hydrodynamic disturbances at the inlet and outlet ports of storage tank plays an important role in the performance of thermal stratification storage tanks. The eddy conductivity factor is included in the model to yield good agreement with experimental data. Further, the variation of this factor is expressed in a decreasing exponential function in terms of Reynolds and Richardson numbers. The effect of nodal grid size on the computed results is also investigated. It is found to have negligible effect on the temperature profiles al moderate grid size. (C) 1997 Published by Elsevier Science Ltd.