An Experimental Study of a Single-Device Jet Impingement Cooler With Phase Change Using HFE-7100 and a Vapor Extraction Manifold

Abstract

There is substantial ongoing research into jet impingement cooling with phase change for high heat flux electronics applications. Higher heat transfer coefficients can be achieved through coolant phase change, although the proper evacuation of the resulting two-phase flow is important as it can affect the overall heat transfer performance of the cooler. In prior work, the accumulation of vapor in a multi-device cooler during the two-phase heat transfer process was shown to cause a build-up of pressure inside the cooler. This increase in pressure is logically related to the position of the cooler inlet and outlet ports with respect to the internal cooling geometry. Such pressure increases lead to an increase in the saturation temperature of the coolant and additional concerns regarding fluid containment. The present study describes a novel two-phase single-device cooler with HFE-7100 as the coolant, where the design allows for efficient removal of vapor from the test-section via a sloped outlet manifold. The performance of the cooler was evaluated using smooth and finned copper heat spreaders. To assess the effectiveness of the vapor extraction manifold, a comparison is made with the performance of a related multi-device cooler. Experimental results show that the single-device design reduces pressure build-up inside the cooler by an order of magnitude from 59 kPa to 7 kPa. A 36% increase in the effective heat transfer coefficient (∼19,000 W/m2K) at 50 W/cm2) was also achieved using the new single-device design with the smooth heat spreader when compared to the multi-device cooler. Additionally, by enhancing the heat spreader surface area with fins, the effective heat transfer coefficient was further boosted to 23,000 W/m2K.