Fitting the flow regime in the internal structure of heat transfer systems

This paper explores the idea of selecting the flow regime in the internal structure of heat transfer systems in order to maximize their global performance under global constraints. In fluid distribution networks, we show that the pumping power requirement can be reduced by dividing a turbulent stream into several smaller laminar streams when the surfaces of the pipes are sufficiently rough. We also exemplify that for the packaging of heat-generating plates, in the range of Bejan number between 109 and 1011, spacing can be adjusted to obtain either the laminar or the turbulent regime for maximizing the heat transfer rate density. Scale analysis is used to evaluate the performance of the systems under study.