Numerical simulation of heat transfer cooling down by water in microgap structure

Abstract

With the increase of power density in chip, the electronic products have to face the challenge of heat dissipation technology. For the heat transfer of microgap, the fluid flows through the pathway which has a large ratio between the width and depth in the cross-section and a small ratio between the length and width in the top view. The rectangular microgap was built before modeling and Fluent software was applied to simulate and analyze the temperature field. The input heat flux was 8.3 × 104 w/m2, the water flow rate was 0.32 m/s, and the inlet water temperature was 300 K. Some conclusions had been drawn as following. The temperature distribution was symmetrical to the Z axis. The temperature gradient took a radial pattern from the model center to edges. The isotherm in microgap had a “U” shape, which indicated that the water flowing in center had a better capability for heat transfer. The isotherms presented the regular onion shape of wall temperature while the microgap depth varied from 0.05 mm to 0.7 mm. Each isotherm onion diagram had a tip at the right and a bottom at the left to correspond with the water flowing path from inlet to outlet. The center of wall had been cooled down more efficiently and the low temperature region was distributed along the water flowing path. When the depth increases to be 0.9 mm and 1.1 mm, the isotherm curves were so flat that the onion shape had been disappeared. This could be contributed to the large microgap depth reduce the water flow rate. The wall temperature curve had an ascending fluctuation with the increasing of microgap depth.