Performance Study About Heat Transfer Enhancement By Pulsating Flow On Round Bubble Tube

With the development of modern society,in the world,energy needs is growing rapidly.In the process of production,most of the energy is transferred through various heat transfer equipment.Therefore,improving the heat transfer efficiency of heat exchanger has become a hot research topic.In this paper,a combined type of heat transfer enhancement is studied.Using the combination of round bubble tube and fluid pulsating flow,enhances the heat transfer efficiency,realizes the enhancement of heat transfer.The research project is of great significance for energy conservation and utilization.The round bubble tube is a special-shaped reinforced heat exchange tube,it is based on the ordinary round tube on the wall treatment,getting the staggered bubble.Through the optimization study of round bubble tube's bubble height,the distance between bubbles drum and pulsating amplitude,frequency of pulsating flow in a fluid flow,get the heat transfer parameters of optimized under the condition of laminar and turbulent flow.Single-factor optimization and orthogonal experiment is used in this paper,simulation and analysis the heat transfer fluid in circular bubble tube when the fluid pulsating flows.The main research is as follows:1)According to several changes in heat transfer effect and some widely used heat transfer enhanced tube,design a new type of enhanced heat transfer tube-round bubble tube,the bubble is symmetrical and according to the laws of distribution on the tube wall.2)The physical model of the structure of round bubble tube was established,combine the knowledge of heat transfer and fluid dynamics,used FLUENT software to analyze the pulsating flow in the round bubble tube.In the case of laminar and turbulent flow,analyze the effect of round bubble tube's height h,bubbling distance d and fluid pulsation's amplitude A,frequency f to heat enhanced,using single factor method to solve the optimization of various factors.3)On the basis of single factor optimization solution,design the orthogonal test,study on the optimal combination of parameters affecting heat transfer performance,the results of orthogonal test shows that: to the fluid in pulsating flow on round bubble tube,in the case of laminar flow,the order of the parameters affecting the heat transfer performance is f > A > h > d,under turbulent case is A> d> h > f;the optimal combination of parameters for heat transfer performance,under laminar h=2.6mm,d=30mm,A=1,f =1Hz,the evaluation criteria of enhanced heat transfer technology E=23.2512;under turbulent h=1.5mm,d=30mm,A=0.85,f=2Hz,the evaluation criteria of enhanced heat transfer technology E=0.2100.Knows that when under laminar,the heat transfer enhancement is better for fluid pulsating flow on the round bubble tube.