Review Heat Exchanger: Research Development of Self-rotating Inserts in HeatExchanger Tubes

Heat exchangers are widely used in power engineering and industrial applications. Many techniquessuch as coiled tube, surface tension devices, rough surfaces and extended surfaces have beeninvestigated to enhancethermal performance and minimize the cost and size of the heat exchangerequipment. One of the most important techniques is tube insert. In general,tube inserts can be classifiedinto two broad categories: stationary inserts and self-rotating inserts.Compared with stationary inserts,the self-rotating inserts can rotate in the tube by fluid and the comprehensive performance of selfrotatinginserts is improved significantly.This paper mainly focuses on reviewing the large number ofexperimental and numerical works taken by researchers on self-rotating inserts such as twistedtapes,miniature hydraulic turbine,turbine-type swirl generators, etc. To improve the thermal efficiencyof heat exchanger and serviceable to designers implemention of passive enhancement techniques inheat exchanger are required. The authors found that self-rotating inserts can streng then the heattransfer efficiency, meanwhile achieve on-line automatic anti-scaling and descaling effect. When thefluid velocity is more than 0.2m/s, most of self-rotating inserts can be applied.The heat transferperformance and frictional loss have been discussed to get the optimal configuration of self-rotatinginserts. The convective heat transfer correlations have also been discussed. Determining how to findthe optimal self-rotating insert is the main objective of this paper

کلیدواژه ها:

TubeInsertsSelf-rotating ، Heat Transfer EnhancementAnti-scaling and Descaling