Numerical And Experimental Investigation Of Heat Transfer Enhancement In Condensers Fitted With Rotor Assembled Strands

With the rapid development of human civilization, the energy consumption worldwide keeps growing rapidly. As the biggest developing country in the world, China is heavily dependent on energy resources, due to the large population and prosperous economic development. However, the extensive mode of economic growth and predatory use of resources in the past20to30years has led to waste in energy and pollution in environment, many cities are under the threaten of PM2.5, China is now under the pressure of energy shortage and environmental pollution, energy saving and emission reduction policy is the only way to solve this problem. Heat exchanger is a kind of heat transfer apparatus widely used in industry, a large amount of energy can be saved by increasing the heat transfer efficiency of heat exchanger.The development, classification and industrial application of heat transfer enhancement technology were described in this paper, and a series of experimental and numerical investigations were conducted on the insert structure—’JNX’rotor assembled strands. First, heat transfer and friction factor characteristics of tubes fitted with different rotor assembled strands were investigated numerically and experimentally, by comparing the velocity field contours, temperature field contours and turbulence intensity contours of different kinds of rotor structures qualitatively, and by comparing the Nusselt number, friction factor and PEC value quantitatively, the rotor structure was improved and optimized. Second, the heat transfer and friction factor characteristics of tubes fitted with different kinds of rotor structures were studied experimentally on the heat transfer performance test bench, the rotor structure suitable for being assembled in regularly free space lengths was selected among the three kinds of rotor structures. Finally, by introducing the user defined function (UDF), the influence of rotor structure on vapor-water two-phase flow was studied numerically, both the qualitative and quantitative results indicated that the rotor structure was suitable for the two-phase flow working conditions, and the influence of rotor structure on heat transfer enhancement of different regions of tube bundles was also investigated tentatively.