Experimental investigation of header shape and inlet configuration on flow maldistribution in microchannel

• Effect of header and flow inlet on flow uniformity was studied experimentally.
• At low flow rates, flow is more uniform with trapezoidal and triangular headers.
• At higher flow rates, flow is more uniform with rectangular header.
• Higher the flower rate more uniform the flow distribution is.

A detailed experimental investigation has been carried out to analyze the flow maldistribution in a microchannel heat sink by using deionized water as the coolant in an aluminum microchannel heat sink with 25 numbers of rectangular microchannels of hydraulic diameter 763 μm, for Reynolds number range of 200–650. The prime focus of this experimental study is to find the suitable combination of header shape and flow inlet configuration to minimize the flow maldistribution effect. Experiments have been carried out with three types of header shapes rectangular, trapezoidal and triangular and two types of inlet configurations viz. vertical flow inlet configuration and inline flow inlet configuration. It is found that vertical flow inlet configuration gives less maldistribution than inline flow inlet configuration. Trapezoidal and triangular headers give less flow maldistribution at low flow rate while rectangular header gives less flow maldistribution at higher flow rates. As the flow rate increases maldistribution decreases. In general, it is found that flow distribution in the microchannel significantly depends on flow inlet configuration, header shape and flow rate.