Test of Cross-Section Shape of Air-Liquid Interface in Microgrooves With Micro-PIV Method

Evaporation of liquid meniscus formed in microgrooves is associated with very high heat transfer rates, but the cross-section shape of air-liquid interface has a great influence to the heat transfer in microgrooves. But the real cross-section shape of interface in microgrooves is still unknown for us. In this work, the micro-PIV (Particle Image Velocimetry) method is used to test the cross-section shape of air-liquid interface in microgrooves. In the experiment, the camera is focus on different planes from top of the microgrooves to the bottom of the microgrooves. In each plane, we can see the boundary between the air and liquid through small particles added into the liquid. The positions of boundary in each plane for a given cross section are drawn in two-dimension coordinate. Then the cross-section shape of interface in microgrooves can be seen from the fitting curve. The results show that the cross-section shapes of the interface in microgrooves are not round, but polynomial curves. The curvature of interface in microgrooves changes along a single curve. Besides, the polynomial curves also vary along axial direction of the microgrooves. The variations are more obvious in vertical microgrooves than in horizontal microgrooves.