Thermal Test Apparatus for Mini Heat Sinks

Demands for more powerful and smaller electronic devices have increased the energy dissipation requirements. Accurate determination of the thermal performance of small sized heat sinks is necessary for innovation within the heat dissipation sector. This study designed, developed, and tested an apparatus for determining the thermal performance of mini heat sinks (MHS). The test apparatus consisted of a wind tunnel, fan, heater, heater block, five temperature sensors, air velocity sensor, and a data acquisition system. A robust dataset was created by testing the heater without a MHS and testing two different MHS materials of polycarbonate (PC) and aluminum (AL) and having 16 to 21 repeat tests. Linear and polynomial approximations for the temperature profile were explored. For the steady state tests, the mean and 90% confidence interval were calculated to determine statistically significant differences. The temperature gradient at the interface, rate of heat transfer, and the thermal resistances from the polynomial fit had higher variation than the linear fit. The experimentally determined heater surface temperature had a 90% confidence interval of ±0.3 to ±0.7°C. The 90% confidence intervals for the thermal resistances were 1.0 to 1.5 K/W for linear and 2.3 to 6.0 K/W for polynomial. Statistically significant differences for the temperature gradient at the interface, rate of heat transfer, and thermal resistances between the bare, PC, and AL were found. Due to heat losses, the linear fit had greater precision, but the polynomial fit had greater accuracy.