COMPUTATION OF FLOW AND HEAT-TRANSFER AROUND A VERTICAL DISCRETE PROTRUDING HEATER USING AN OPERATOR-SPLITTING ALGORITHM

Steady mixed convection around a heated block placed in a vertical cha nnel is numerically studied. The block aspect ratio is taken as 1 / 3. The following range of parameters has been considered: 200 less than or equal to Re less than or equal to 1000 and Gr = 0 and 10(5). The go verning equations have been solved using an operator-splitting techniq ue. This method splits the equations into advection, diffusion, and so urce terms and solves each component in an implicit time-marching sche me as accurately as possible. are results obtained using this method h ave been compared with those obtained using the second upwind procedur e for the advection terms. The overall distribution of the local flow quantities around the heater is seen to be quite similar for the two m ethods. However, the average Nusselt number computed using the two met hods has significant differences. The operator-splitting method shows that the mixed convection Nusselt number can fall below that of the fo rced convection value for a certain range of parameters. A comparison of CPU times also shows the operator-splitting method to be superior t o upwinding.