Performance Analysis And Optimization Of Microchannel Heat Sink Used For Chips With High Heat Fluxe In Micro/nano Satellite

The rapid development of aerospace technology accelerates the miniatu-rization of the volume and mass of artificial satellites. Meanwhile, the great progress of micro-electromechanical systems (MEMS) objectively makes the density of chips'function bigger and bigger. The small internal electronic equipments show some different thermal features under the special outer space circumstance which has higher vacuum, stronger radiation and lower gravity than the ordinary environment does. Taking into account the particular characteristic feature of the condition in which Micro/Nano satellites work and the increasing demand that is required for the thermal control in the future tasks, this thesis focuses on a new active thermal control method called MEMS-based cooling system using micro-channel heat sink.First, based on the lumped parameter method, the thermodynamic models of micro-channel heat sink and radiator are constructed, so is the overall single-phase fluid loop system driven by micro-pumps which is applied to the Micro/Nano satellites. Then the influence on the thermal control system of Micro/Nano satellites by the external thermal environment is studied, and the research about the thermal response of electron devices is performed by numerical simulation and calculation. There are several micro-valves in the loop system which can accommodate to the rate of liquid flow through the heat sink and radiator so as to precisely keep the temperature at the right level of stability. All of these are realized by the combination of expert intelligent systems (EIS) and classical PID control law.Second, in order to maximize the advantage of heat dissipation of the heat sink, the geometric parameter of rectangular micro-channel is optimized accord-ing to the fluid-flow continuum model which is based on the Navier-Stokes equations. The boundary conditions are also defined in the hydraulics and ther-modynamics fields. The optimization theory details as follows: trial points are primarily selected through a four-level full factorial design, the objective function values are gained by numerical simulation and calculation which is accomplished via a kind of CFD software. A surrogate model is then constructed by the response surface approximation (RSA) method, and the optimal design point which generates the least overall thermal resistance is searched by genetic algorithm.Last, this thesis also focuses on the effects of the inlet/outlet arrangement on the fluid flow and heat transfer inside the heat sink. Four models having different inlet/outlet arrangements are established via ICEPAK which is a kind of popular electronic equipments thermal design software. Suppose all of the materials have constant thermo-physical properties, numerical study could be simplified and solved by the finite volume method by means of FLUENT. The resultant ?ow ?elds and temperature distributions inside the heat sink are discussed. Finally, the best model is selected after investigating into some especial micro-channels in each one.