Experimental Study And Numerical Simulation On Cooling Of Micro-electronic Chips

With the fast development of the micro-electronic technology, the demand for high performance cooling technology has resulted in higher power densities as well as demand of chip cooling. Thus, it is very important to explore the micro-electronic cooling technology.Two kinds of cooling technology have been studied in this paper. One is the impingement jet cooling, which generates a high heat transfer rate by impinging vertically and quickly on surface with water; another is the vacuum cooling, which generates cooling effect by evaporating with vacuuming. Both of the cooling technology, which are used in many engineering applications, have a widely outlook of application in micro-electronic chip cooling. This paper includes 3 works as following:1.In this paper, a confined and submerged jet impingement device has been designed. In order to study enhanced heat transfer for micro-electronic chip cooling, a real jet impingement experimental system has been established. For the further study of heat transfer on jet impingement, numerical simulation has been conducted with FLUENT by establishing a 3-D mathematical model for the impingement device. The results of experimental study and numerical simulation indicate that as jet velocity increases, temperature of jet decreases, average heat transfer coefficient on impingement surface increases while the surface temperature decreases; as nozzle-to-surface distance increases, surface temperature and average heat transfer coefficient remain constant; as nozzle diameter increases while others remain constant, average heat transfer coefficient increases and its distribution becomes more uniform; as nozzle diameter decreases, while the jet flow mass remains constant, average heat transfer coefficient increases. The simulation results are in good agreement with the experimental test.2.Another jet impingement device combined with rectangle micro-channel has been designed to conduct experimental study and numerical simulation of enhanced heat transfer for micro-electronic chip cooling. It is concluded that this kind of device has higher heat transfer rate compared to formerly device, and the smaller the section dimension of rectangle channel is, the better the heat transfer performance is.3.The investigation of vacuum cooling for micro-electronic chip is conducted in this paper. A mathematical model of vacuum cooling process is developed to deduce a function of temperature evolution with time. An experimental study of vacuum cooling for microelectronic chip is carried out. The results show that it is feasible to cool microelectronic chip by vacuum pumping. Enhancing the heat conduction coefficient of evaporator bottom, reducing thermal resistance between water and evaporator bottom, and using fins can improve the heat transfer rate and reduce the chip surface temperature.