关键词: 液-液混合, 平面激光诱导荧光, 温度场, 离析度, 传热

Abstract: Two-dimensional temperature distributions were instantaneously visualized in a liquid-liquid cross-flow mixing process with flow channels at millimeter scale using planar laser induced fluorescence (PLIF) technique, where the excited fluorescence strength of Rhodamine B dye had linear relationship with the temperature. The mixing process of two liquids with different temperatures could then be characterized by the measured temperature fields. The intensity of segregation (IOS) was applied to quantify the non-uniformity of the mixing process along the flow development. The effect of momentum ratio of two liquid flows on the mixing process was studied. Larger momentum ratio between the jet and bulk flow benefited the mixing efficiency of the two liquids. Meanwhile, the heat transfer coefficient of water in the liquid sheets impingement process was compared with the turbulent heat transfer coefficient calculated by an empirical formula. The results show that the impingement process can promote the heat transfer between the two liquids with different temperatures. Higher momentum ratio of two liquid flows leads to better mixing performance in terms of the transport phenomenon of temperature.

Key words: liquid-liquid mixing, planar laser induced fluorescence, temperature field, intensity of segregation, heat transfer