Li, H. and Hrnjak, P., "An Infrared Thermography Based Method for Quantification of Liquid Refrigerant Distribution in Parallel Flow Microchannel Heat Exchanger," SAE Int. J. Mater. Manf. 8(3):603-608, 2015, doi:10.4271/2015-01-0357.
This paper presents a method of utilizing infrared images to quantify the distribution of liquid refrigerant mass flow rate in microchannel heat exchangers, which are widely used in automobile air conditioning systems. In order to achieve quantification, a relationship is built between the liquid mass flow rate through each microchannel tube and the corresponding air side capacity calculated from the infrared measurement of the wall temperature. After being implemented in a heat exchanger model, the quantification method is validated against experimental data. This method can be used for several types of heat exchangers and it can be applied to various heat exchanger designs.