Experimental and Numerical Investigation of Double Pipe Heat Exchanger with different Configuration

Abstract

ABSTRACT newline Heat energy is transfer of heat from one surface to another surface and it newlineis very important to all aspects in day to day life. The heat transfer is takes newlineplace by means of heat exchangers. The heat exchangers are used to transfer newlineheat from hot body to cold body and it has been utilized in various industries newlineand engineering applications to improve the performance of the heat exchanger newlinedevices. newlineMany researchers attempted to study on the heat transfer and fluid flow newlinein a tube induced with twisted tape inserts with influence on cuts different newlinegeometrical shapes and different twist ratio has been reported. Hence the newlinepresent research work reported the use of different types of twisted tapes fitted newlinein a double pipe heat exchanger to improve the heat transfer and friction factor newlinecharacteristics of water in tubes induced with twisted tape inserts with different newlineshapes, equal area and same twist ratio was investigated experimentally and newlinenumerically. The present studies pay attention to the heat transfer newlinecharacteristics of laminar flow of water through the circular tube fitted with newlinetwisted tape inserts with different configuration of twisted tape. The newlinegeometrical configuration of twisted tape used has three models of twisted tape newlinevi newlineinserts, like plain twisted tape, triangular cut twisted tape and circular hole cut newlinetwisted tape. newlineThe test was performed to find the heat transfer, friction factor, heat newlinetransfer coefficient, Nusselt number and Reynolds number with different newlineconfiguration of twisted tape inserts. In first phase conducted the experiment newlineon plain tube as working fluid is water and experiment data was collected to newlinecalculate the performance of heat transfer. In second phase experiment was newlineconducted with plain twisted tape inserts and third phase experiment conducted newlinewith circular cut twisted tape with 5mm diameter cut inserts as working fluid is newlinewater. In fourth phase experiment was conducted with triangular cut twisted newlinetape with 5mm depth of cut inserts in a double pipe heat exchanger. newlineThe numerical simulation also carried in this work by using Ansys fluent newlinesoftware. The RNG K- model employed for the laminar flow. The newlineexperimental results indicate that the plain tube, plain twisted tape, triangular newlinecut twisted tape and circular hole cut twisted tape are compared with CFD newlinesimulation results. The superior fluid mixing provided by the alternative axis newlinetriangular cut twisted tape gives more heat transfer enhancement and it is one newlineof the reasons why its offer higher heat transfer enhancement than the other newlinetwisted tapes. Interestingly the heat transfer enhancements were increases as newlinethe size of the cuts on the twisted tape. newlinevii newline Based on these studies, the following major conclusion has been arrived newlinethe Nusselt number and heat transfer coefficient of thermal performance of newlineenhancement of triangular cut twisted tape is higher than the plain twisted tape newlineand circular hole cut twisted tape for the twist ratio is 5.4 respectively. Among newlinethe three variant twisted tapes used in the present work, the triangular cut newlinetwisted tape gives better performance of heat transfer in laminar flow due to newlinethe effect of increases the surface contact area of the flow motion and improves newlinethe better fluid mixing near the wall of the test tube. Sequentially the newlinecorrelation of empirical relation were developed for the Nusselt number and newlinefriction factor for PT, PTT, CCTT and TCTT under the laminar flow. The newlineexpected data of the PT, PTT, CCTT and TCTT used in the present study are newlinematching with the experimental data within the maximum deviation of Nusselt newlinenumber + 12% and + 10% for the friction factor respectively. Similarly the newlinesimulation results are compared with the experimental results of PT, PTT, newlineCCTT and TCTT with the maximum deviation of errors +8 % for both friction newlinefactor and Nusselt number. newline newline