作者：张培新，黄璐路，吕亮亮，孙雪茹（新疆理工学院机电工程学院，新疆 阿克苏 843000）
Abstract: [Objective] Currently, the research on the flow characteristics of fluid in microchannels is not very mature, and further research is needed to optimize the heating characteristics of conventional electronic devices using microchannel structured heat exchangers. [Method] In this study, a microchannel radiator with a gradually decreasing and gradually expanding throttling flow pattern was designed and fabricated, using liquid water as the experimental flow medium. The power device was provided by a diaphragm metering pump. A copper rod was used to simulate common heat sources in real life. By changing the sliding handwheel of the diaphragm metering pump, the flow rate of the working medium entering the gradually decreasing and gradually expanding throttling flow pattern microchannel was adjusted. [Result] 1) The working medium is a simple single-phase convective heat transfer at the inlet of the channel, with a lower heat transfer coefficient, making the temperature relatively high. When the working medium passes through a cavitation structure, due to the reduced cross-sectional area, the flow rate of the working medium increases and the pressure decreases, resulting in two-phase heat transfer of cavitation bubbles at the sudden expansion interface. 2) As the accumulation of inlet flow gradually exceeds the accumulation of outlet flow, the pressure difference between the inlet and outlet ends continuously increases. 3) The periodic fluctuation of inlet and outlet pressure in a stable state is related to the periodic fluctuation of the flow provided by the metering pump. 4) When experimental fluids with different constant temperatures pass through the microchannel, as time delays, more and more heat is input, and the temperature of the heating rod becomes higher and higher. The microchannel inlet temperature has a linear relationship with the input heat. 5) The Reynolds number of the fluid flowing in the microchannel and the channel resistance coefficient to the fluid show a decreasing rule. Within an acceptable error range, when the experimental medium is in the laminar flow stage, the error between the friction resistance coefficient and the theoretical simulation relationship simulation results is relatively small.
Keywords: heat dissipation performance; experimental simulation; flow heat transfer