Mixed convection from multiple-layered boards with thermally periodic boundary conditions

Abstract

This paper considers the conjugate analysis of mixed convection heat transfer to minimize the maximum temperature at the chip arising from the uniform heat flux sources mounted on a conducting plate. The primary motivation for this work is to delineate the physical importance of the thermal periodicity between Printed-Circuit-Boards consisting of repeated layers on the flow field and heat transfer characteristics. Finite-difference numerical solutions have been obtained for air and water over a range of Reynolds numbers (100 ≤ Re ≤ 1500) and Grashof numbers ($0 ≤ Gr ≤ 5 × 10^5$) : this leads the mixed convection parameter, defined by $Gr/Re^2$, to be varied over a broad range, covering both the pure forced convection, the natural convection dominated regimes, and the mixed convection regime in-between. The heat transfer characteristics are presented for two cases, that of a horizontal plate and the vertical plate. For a smaller Pellet number, the thermal boundary layers from the two plates in the channel mix and the plate is an adiabatic wall which has nearly constant wall temperature only in further downstream region from the last block therefore, the adiabatic wall assumption cannot be employed to simulate a practical cooling modules, which consists of multiple-layered boards.