Mohamed Abd El Fatah Mohamed Teamah
numerical simulation for double diffusive mixed convection with aidingopposing flow in vertical tubes
the present study is concerned with the mixed convection in a vertical tube underrnthe combined buoyancy effects of thermalmass diffusion. double-diffusive convectivernflow in a vertical tube with upwarddownward flow is studied numerically. the flowrnlaminarunder steady state condition are considered .the transport equations forrncontinuity, momentum, energymass transfer are solved. the numerical procedurernadopted in this analysis yields consistent performance over a wide range of parameters,rnrichardson number, ri, (10-2  ri  10) aspect ratio, ar, 2.5  ar  20 buoyancyrnratio,n,(-10<n<10)lewis number ,le,(0.1le100). the numerical results arernreported for the effect of the parameters on the iso-contours of temperature, andrnconcentration. the predicted results for both localaverage nusseltsherwoodrnnumbers are presented for various parametric conditions. this study was done for constantrngrashof number, gr=105prandtl number, pr=0.71.