| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 98 === The heat flux on electronic devices is significantly increasing in various industrial areas such as automobile and computer. A compact heat exchanger consisting of microchannel is a powerful technique for thermal management in electronic devices. In particular, using boiling heat transfer technique in mini- and microchannels has a great potential for use in portable electronic devices because of its large overall heat transfer coefficient.
The focus of this thesis is to study phenomena of thermal bubbles in microchannel. The thermal bubbles are generated by using a micro heater fabricated inside the microchannel by using MEMS technology. In the experiments, flow visualization technique is used to investigate phenomena of thermal bubbles including bubble nucleation, bubble growth, bubble movement and their related flow patterns under different flow rate and heat flux conditions. Experimental results reveal four different flow patterns including no boiling situation, single bubble formation, intermittent bubble formation and multi-bubble formation. When intermittent bubble phenomenon occurs, it is found that the channel will be filled with thermal bubbles, and the flow rate will stop or become unstable.
|
|---|
