ANALYSIS OF THE VALIDITY OF A CONSTANT SURFACE HEAT FLUX MODEL FOR THE CASE OF BLOCKS SUBMITTED TO UNIFORM VOLUMETRIC HEAT GENERATION AND PERIODICALLY MOUNTED ON THE LOWER WALL OF A HORIZONTAL CHANNEL

摘要

The validity of the heat flux redistribution method is examined in the case of heating blocks submitted to a volumetric heat generation, and periodically mounted on the lower wall of a horizontal channel by considering two models. In the first model (model 1), the blocks generate uniform volumetric heat dissipation, while in the second (model 2), the blocks release a uniform heat flux at their peripheral surface. The latter model was adopted in many previous works, but its validity has never been discussed. Hence, the objective of this study is to examine the combined effects of the thermal conductivity ratio of the solid blocks and the fluid (0:1 ≤ k* = k_s/k_a ≤ 200), the Rayleigh number(10~4≤Ra≤10~7), and the relative height of the blocks (1/8≤B≤1/2) on the validity of the model with constant surface heat flux by using criteria based on local and mean heat transfer characteristics.