New metrics for measuring multiphase mixing effects in a direct-contact heat exchanger

摘要

We propose a new method to measure uniformity of gas-liquid mixing in a direct-contact heat exchanger by moment balance and image analysis. A mapping technique is developed to project the pixels distribution from binary image to 3D domain. We present a rigorous theoretical base of the applied method based on moments and equilibrium theory. An inclination angle with direction is derived to characterize the imbalanced structure caused by heterogeneity of mass distribution, which is used to quantify the global uniformity of spatial distribution of mixtures in any irregular area. A characteristic curve obtained by local inclination angles can be used to test the homogeneous, heterogeneous and pseudo-homogeneous mixtures, leading to a useful parameter to quantify the mixing effects. The uniformity obtained by similar patterns are compared with existing methods. The experimental results show a good fitting curve between mixing effects and heat transfer performance. This test could also be applied for studying a variety of multiphase mixing problems in which assessment of uniformity is required.