微小通道换热器内流动沸腾换热与压降特性

An experimental study was performed to measure the flow boiling heat transfer and pressure drop characteristics of R141b in a microchannel (1.91 mm×2.55 mm) heat exchanger, and the effect of mass flow rate (9.8∼16.3 kg·m⁻²·s⁻¹), saturation pressure (138 kPa, 164 kPa, 236 kPa), and heat flow flux (2.2∼20 W·cm⁻²) on heat transfer coefficient and friction pressure drop were analyzed. The results show that with the raising heat flux, the frictional pressure drop increases but the heat transfer coefficient increases firstly and then decreases. With the raising saturation temperature, the frictional pressure drop decreases but the heat transfer coefficient increases; With the raising the mass flow rate, frictional pressure drop increases, and the heat transfer coefficient changes significantly with the mass flow rate in the high dryness area. The experimental results are compared with the existing boiling heat transfer correlation and the prediction results of homogeneous pressure drop model.