Investigation on the effect of ejector liquid recirculation system on the performance of falling-film water chiller with R134a

To analyze the influence of liquid spraying flow rate on the performance of a falling-film evaporator with R134a, the finite difference model of the horizontal-tube falling-film evaporator is established, and a falling-film air-cooled water chiller with ejector liquid recirculation system (LRS) is presented; then the comparison between numerical simulation and experimental tests are performed. The analysis results show that the experimental and numerical evaporating capacities increase 9.5% and 6.7%, respectively, when the liquid recirculating ratio Rl increases from 1.0 to 1.21; and the deviation between the experimental and numerical capacities of the evaporator is about 3.3%. And that the evaporated liquid flow rate rises quickly at first and then increases slightly as Rl increases. Moreover, the results show that the optimum value of Rl is about 1.2, the corresponding value of integrated falling-film factor φ with about 0.85. This suggests that attempting to eliminate completely the dryout patch outside of tubes is unadvisable.