Thermal Investigations of Hemispherical Shell Vapor Chamber Heat Sink

Abstract

In the current study, a hemispherical shell vapor chamber (HSVC) was proposed and manufactured. A unique system of the HSVC consists of a very short evaporator space and a large condenser area with an inner and outer surface. The HSVC has a bottom surface that can be easily attached to the heat source and its radius varies from 0.045 m (near the bottom surface) to 0.078 m at the top with a curved side. An entirely new design of the integrated section of the large condenser with the evaporator section was verified using a new but simple concept. The current hemispherical shell vapor chamber (HSVC) was made from stainless steel. The current HSVC was specified with an outer/inner diameter of 78/70 mm at the top, a depth of 47 mm in the inner surface area, a total height of 60 mm, 30 mm at the bottom of the inner center, and a diameter of 45 mm on the surface of the outer bottom area. Three different models were manufactured and tested to verify which HSVC reached a high thermal performance. The effects of various operation parameters such as the filled volume ratio, heat load, coolant flow velocity, orientation, and so forth, were investigated experimentally. The experimental results showed that the optimum charge amount in terms of temperature difference is 20–30% of the charging ratio, and the condenser area has a direct effect on the thermal performance. Moreover, a one-dimensional thermal resistance model was tested to predict and simulate the thermal performance of the current system associated with various empirical correlations. Furthermore, the CFD (Computational Fluid Dynamics) model can simulate a lot of detailed flow behavior inside the HSVC. Both simulation methods can predict the thermal performance of the HSVC, and they can help to design the system with a focus on the optimum configuration of the design target for any application.