The effects of the Reynolds number and width ratio on the flow distribution in manifolds of liquid cooling modules for electronic packaging

A uniform coolant distribution in the manifold of a liquid cooling module is necessary to eliminate local hot spots in electronic packaging. A numerical study was conducted to determine the effects of the Reynolds number and width ratio D_c/D_d (defined as the ratio of the combining header width to the dividing header width) on the coolant distribution in a parallel flow manifold. Of the four width ratios (0.5, 1.0, 2.0, and 4.0), the maximum channel flow rate to the minimum channel flow rate was 1.2. Regardless of the width ratio, the flow distribution is strongly dependent on the Reynolds number. It is concluded that a proper combination of the Reynolds number, D_c/D_d, and the area ratio, AR, is required to produce a uniform flow distribution in a manifold.