Enhanced flow uniformity in parallel mini-channels with pin-finned inlet header

Abstract

A key challenge concerning the design of mini-channel heat sinks pertains to minimization of flow maldistribution in parallel channels. Although this challenge has spurred several research efforts towards exercising control over flow resistance within parallel channels to enhance flow uniformity, some practical issues associated with fabrication and implementation, as well as the possibility of a high pressure drop render the efforts less useful. The present study concerns development of a strategy that utilizes staggered pin-fin arrays in the inlet header of mini-channel heat sinks with the aim of achieving uniform flow distribution within parallel channels without increasing total pressure drop. Two different header shapes, trapezoidal and rectangular, have been considered, and ten different pin-fin arrangements for each type of header have been designed to numerically investigate flow uniformity within channels. The three-dimensional computational domain included the entire heat sink consisting of inlet/outlet connection tubes, inlet/outlet headers, and twenty parallel rectangular mini-channels—each measuring 3 mm in hydraulic diameter and equidistantly spaced with a 2-mm solid-wall spacing. It has been demonstrated that compared to baseline inlet headers, best pin-fin arrangements obtained for both trapezoidal and rectangular inlet headers yield significant improvement in flow uniformity within channels along with uniform temperature distribution over the heat sink base with minimal influence on the pumping power requirement.