Modeling Research Of Liquid Entrainment In Flooded Evaporator

National Development and Reform Commission Environment and Resources Comprehensive Utilization Department promulgated " The minium allowable values of the energy efficiency and energy efficiency grades for water chillers ", and on March 1st, 2005 into effect. It puts forward new demands to domestic energy efficiency chillers. Flooded evaporator has a high heat transfer performance, compact structure, etc., which help improve the chiller energy efficiency rating, and has a wide future on commercial development and application as well. As a highly efficient energy-saving heat exchanger, flooded evaporator has increasingly attracted more attention at home and abroad. In the refrigeration and air conditioning industry flooded evaporator has a decades history, and the issues on heat transfer surface, the tube bundle arrangement and operating conditions have been continuously optimized due to the researches of many literatures, while liquid entrainment problems were mostly resolved rely on experience, difficult to optimize. Therefore, through the optimization and analysis on the liquid entrainment, it's significant to provide theoretical guidance on its design and operation.In this paper an overview of the progress in experimental research on pool entrainment was presented in recent years. Pool entrainment is classified into two categories on the basis of whether the liquid phase disturbed by bubbles, and the mechanism of each occurrence was analyzed, also a series of empirical correlation was presented, compared and analyzed, and each shortcoming and weakness was illustrated. the necessity of the enhanced research of pool entrainment has been emphasized, and the direction for study of entrainment has been pointed out.In this paper, a dimensionlessformula on the calculation of liquid entrainment volume of flooded evaporatoris put forward rely onπtheorem, and based on the experimentaldata of a series of flooded evaporator with liquid entrainment the model was fitted. Meanwhile, liquid entrainment distribution parameter model is established. Under different evaporator structures, and the limits of liquid entrainment volume aresimulated based on the model, the compared results between simulated results and test results have a good agreement, prove that the model is correct.The modelis applicable to all liquid entrainment flooded evaporator.The study for the flooded evaporatorsupports the calculation of liquid entrainment volume, also provide reference forthe design and analysis over the performance of evaporator.