Vascularized svelte (compact) flow architectures
In this paper we describe a new concept for vascularizing the flow architectures of compact devices. Vascularization is achieved by using tree-shaped (dendritic) flow passages on both sides of the heat transfer surface. For each side, we propose to use an architecture that consists of trees that alternate with upside down trees. By evaluating the fluid flow performance we show that dendritic vascularization is superior to the use of parallel microchannels when the tree structures have four or more levels of bifurcation. The local pressure losses that occur at the multiple junctions of each tree structure become negligible when the svelteness of the architecture (Sv) exceeds the order of 10. The svelteness is a global geometric property defined as the external length scale of the architecture divided by the internal length scale (the total flow volume raised to the power 1/3). The combination of fluid architectures and solid constitute a "smart" composite material: the fluids that bathe the volume can be used to provide multiple functions, such as self-healing, self-cooling, and variable transport properties. For example, when placed in counterflow, the vascularized hot and cold sides of the surface are a compact heat exchanger. The article shows under what conditions the tree vascularization offers greater flow access than parallel single-scale channels oriented perpendicularly to the parallel lines. Copyright © 2007 by ASME.
