Design of a collector shape for uniform flow distribution in microchannels

Abstract

The focus of this study is the design of a collector with the objective of achieving uniform flow in multiple parallel microchannels. This objective is achieved by understanding the limitations of current designs and a novel design is proposed, which is further carefully optimized. The existing collector shape considered is U-type, which is investigated numerically. The creation of a stagnation zone, growth of a boundary layer along the collector wall and low/high velocity zones in the collector are identified as the prime causes of flow maldistribution. A novel design, a dumbbell shape collector, is proposed to overcome the limitations of the earlier designs. The dumbbell shape is evaluated quantitatively and is found to perform better than all existing shapes. This dumbbell shape collector provides a uniform flow distribution with less than 0.4% relative difference from the average flow rate in different channels, which is substantially better than existing collectors with 2.3% relative difference from the average flow rate for Rech = 32. The uniformity is further confirmed using micro-particle image velocimetry measurements. The dumbbell shape collector is generalized and optimized to cater to heat sinks of different dimensions and to broaden its applicability in both micro and macro dimensions.

Mixing characteristics for the single and air‐water two‐phase flows in miniaturized parallel multichannel‐based devices

“…The tortuosity is represented by τ(À). Tortuosity is one of the predominant variables for the flow across a packed geometry (randomly filled with the uniformly shaped particles) can be estimated by Equation (19). 40 τ…”

“…Chein and Chen 18 investigated flow distributions in five geometric header configurations and concluded that the U and V‐type header produced more uniform flow. Siddique et al 19 did a numerical investigation to improve the flow distribution by utilizing a U‐type header. It was found that the presence of sharp corners, which act as the stagnation areas of a rectangular header, was the main reason for nonuniform flow distribution.…”

Effect of Outlet Plenum Volume During Flow Boiling Inside Plain Parallel Microchannel

“…The copper block is inserted inside a Teflon block on which inlet and outlet plenum are machined as illustrated in exploded view of test section in figure 1. The plenum is fabricated in the dumbbell shape having the same depth as the microchannel depth which ensures an equal single-phase flow distribution in the channels [9]. A transparent polycarbonate cover (12 mm thick) is fixed on the top of the Teflon copper block.…”

Numerical Study of Perturbators Influence on Heat Transfer and Investigation of Collector Performance for a Micro-Combined Heat and Power System Application

“…The microchannel entrance length effects, as well as flow maldistributions [15] play an essential role in CHE performance. Studies made on different type of collectors' shapes showed that the creation of a stagnation zone, the growth of a boundary layer along the collector wall and low/high-velocity zones in the collector are the prime causes of flow maldistribution [16]. The partition foil thickness strongly influenced the CHE thermal effectiveness by affecting the axial conduction [17].…”