Dendritic constructal heat exchanger with small-scale crossflows and larger-scales counterflows

摘要

This paper describes the constructal route to the conceptual design of a two-stream heat exchanger with maximal heat transfer rate per unit volume. The flow structure has multiple scales. The smallest(elemental) scale consists of parallel-plates channels the length of which matches the thermal entrance length of the small stream that flow through the channel. This features has two advantages: it eliminates the longitudinal temperature increase(flow thermal resis- tance) that would occur in fully developed laminar flow, and it doubles the heat transfer coefficient associated with fully developed laminar flow.