| Summary: | 博士 === 國立清華大學 === 動力機械工程學系 === 92 === Electronic devices have been mainly relying on passive heat exchangers to transfer heat away for preventing catastrophic thermal problems in the past. Nowadays, passive heat exchangers no longer provide ample cooling efforts due to stringent spatial limitations of high power-density systems. In this dissertation, a novel heat exchanger system, based upon magneto-hydrodynamic theory for pumping electrically conducting coolant, has been studied and experimentally verified in details. Governing equations of electrically conducting fluid driven by the Lorentz forces were first derived by assuming steady state, incompressible and fully developed laminar flow conditions. Then, numerical simulations were conducted via the explicit finite-difference method to evaluate the performance of the heat exchanger. Finally, an experimental apparatus was built for measuring the coolant flow-velocity and the total cooling capacity. Nominal flow velocity of 1.09×10-1 m/s at 3 Ampere of electric current was observed while the magnetic flux density was maintained at 0.41 Tesla. The experimental results concluded that the heat exchanger could provide equivalent cooling power of 1 Watt per 1 micro Watt of input electric power; hence, this high efficiency magneto-hydrodynamic cooling system is very promising for the cooling applications in future power electronic products.
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