LAMINAR DEVELOPING FLOW AND HEAT-TRANSFER BETWEEN A SERIES OF PARALLEL PLATES WITH SURFACE MOUNTED DISCRETE HEAT-SOURCES

Laminar developing flow (DF) and heat transfer between a series of con ducting parallel plates (substrate) with surface mounted heat generati ng blocks were numerically studied with consideration given to flow of air (Pr = 0.7). These channels resemble cooling passages of electroni c equipment. A single channel subjected to a repeated condition in the transverse direction was isolated as a computational domain. The gove rning equations were solved by a finite volume technique. The results of the DF problem were compared with the corresponding periodically fu lly developed flow (PDF) problem results and used to establish entry l ength. Thermal entry length decreased with an increase in substrate co nductivity. Thermal performance of channels was characterized in terms of thermal resistance per unit length of the channel. To separate the effects of self heating and upstream heating for each module, thermal resistance based on the channel inlet temperature (R(o)) and module i nlet bulk temperature (R(m)) was defined. These thermal resistances we re correlated with the independent parameters such as the Reynolds num ber (Re), substrate thickness (t/w), block height (h/w), block spacing (s/w), channel height (d/w), and thermal conductivity ratio of the so lid to fluid (K-s/K-f). The thermal resistance was found to decrease w ith an increase in Reynolds number, block spacing and substrate conduc tivity. The thermal resistance increased with an increase in the area of bypass flow (1 - h/d), substrate thickness (t/w) and block height ( h/w).