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Numerical Simulation And Experimental Research On Heat Transfer Performance Of Twisted Tube Double Shell Side Heat Exchanger

Posted on:2011-07-05Degree:MasterType:Thesis
Country:ChinaCandidate:L YangFull Text:PDF
GTID:2121360308464536Subject:Chemical Engineering
Abstract/Summary:PDF Full Text Request
In recent years, the situation of energy utilization is becoming more and more intense,people begin to pay more attention on the work of saving energy and reducing emissions,especially developing high efficient enhanced heat transfer technology to increase theefficiency of heat exchanger. Twisted tube is a new kind of high efficient heat transfer tube,which is made by contorting round tube. Compared to the round tube, twisted tube canenhance the heat transfer of liquid both in tube side and shell side, which means great toincreasing the efficiency of heat exchanger and saving energy. So it is quite essential toinvestigate the heat transfer performance and flow resistance of twisted tube.Based on the foundation of research in the enhanced heat transfer technologies andenhanced heat transfer tubes, the heat transfer performance and flow resistance of twisted tubein both shell side and tube side are investigated by the means of theoretical analysis,numerical simulation and experimental testing in this paper, and the computer design programof twisted tube heat exchanger is also researched.The main research work and conclusions include the following:1. The heat transfer performance and flow resistance of round tube and twisted tube aremeasured in the single tube experiment system, the heat transfer performance of heatexchanger is also investigated. The result show that twisted tube can enhance the heat transferperformance of liquid in the tube side, meanwhile, its flow resistance increase compared tothe round tube, but its overall performance is still better than the round tube. The twisted tubecan enhance the heat transfer by 5%~50% compared to the round tube in the experiment Re.By investigating the heat transfer performance of double shell side twisted tube heatexchanger, its heat transfer performance and flow resistance with the change of Re areobtained. By calculating the experiment data, the heat transfer correlations of twisted tubeheat exchanger are also built.2. The Fluent software is applied to study the heat transfer and flow resistanceperformance of different heat transfer tubes, meanwhile the distribution of temperature andvelocity in the outlet section are obtained. The result show that compared to the round tubeand elliptical tube, the liquid is combined more plenitudinous in twisted tube due to its special structure, so the heat transfer is enhanced. The result also show that when the twist length isshort, the squash of cross-section is obvious and the Pr of liquid is big, the heat transferperformance of twisted tube is better, but the flow resistance will also increase. Then, thetwisted tube heat exchanger and the round tube heat exchanger are also investigated bynumerical simulation and the result show that compared to the round tube heat exchanger, thetwisted tube heat exchanger has a better heat transfer performance in the shell side.3. Based on the heat transfer correlations of twisted tube heat exchanger obtained in theexperiment, a twisted tube heat exchanger design program and its main interface are built bythe language of Visual Basic 6.0. This design program can help the designer to design thetwisted tube heat exchanger, which can meet the request of specific heat duty.By the experiment research and computer simulation on the heat transfer performanceand flow resistance of twisted tube in both shell side and tube side, the research means andtheoretical analysis system of twisted tube is abounded, and supply reference for furtherresearch on the heat transfer performance of twisted tube and optimal design for twisted tubeheat exchanger design program.
Keywords/Search Tags:twisted tube, round tube, heat transfer enhancement, design program for twisted tube heat exchanger
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