Experimental And Numerical Study On Fractal Tree-like Microchannels

With the rapid development of electronic technology, biomedical technology,aerospace technology, micro products and systems such as micro-biochip, micro-reactor,and micro fuel cell has widely attracted experts and scholars to study. Micro-systemapplications require more reliable materials and sophisticated manufacture; moreover, itchallenges current cooling system with its much higher mass flow rate compared to thetraditional system. In this study, microchannels, applied in the cooling system for MEMSwas analyzed.In combination of numerical and experimental methods, this study focused on thestructure parameters’ influence on the fluid flow, heat transfer and overall performance inmicrochannels. And the pressure difference between the inlet and outlet of microchannels,the average heat transfer coefficient and COP were employed in this study to evaluatemicrochannels. Furthermore, microchannels with straight structure and serpentine structurewere compared with fractal tree-like microchannels. The Reynolds number in the presentstudy was from0to1600. By analysis of experimental results and simulation data, therelationship between structure parameters and the channels’ performance was obtained.The results shows that compared with straight microchannels and serpentinemicrochannels, fractal tree like microchannels are better in heat transfer, fluid flow andCOP generally. Besides, structure parameters including channels branch numbers, aspectratio and partial structure significantly has an influence on the fluid flow, heat transfer andCOP in the microchannels. In other words, with more complex structure, the difference ofpressure between the channel inlet and the channel outlet is bigger, at the same time, theheat transfer between the channel and the fluid is better. At this circumstance, an optimizedstructure with circle design in the fractal and turn area was proposed and analyzed.