Heat Transfer Performance Of Nanofluids In The Built-in Twisted Belt External Thread Tubes Experimental Research

This article is through experiment research and analysis in the range of Reynolds number in2000-12000,nanofluids mass fraction in the range of 0.1% to 0.6%,in order to study the convective heat transfer and flow resistance characteristics of six different nanofluids in the light copper tube and the built-in twisted belt external thread tube,according to the different structural parameters of external thread tube,selected three kinds of different built-in twisted belt external thread tube and analysis effect of different pitch on the heat transfer performance.Analyses the influence of different nanofluids strengthening the heat transfer effect,the heat transfer coefficient of the Cu?Graphite and other nanofluids is greater than deionized water of2.5?2.1 and 1.5 times,these strengthen heat transfer effects are better than deionized water,the effect of strengthening heat transfer of Cu and graphite nanofluids is more outstanding.Analysis the mass fraction of nanofluids are Impact on strengthening the effects of heat transfer,with the increase of mass fraction of nanofluids convection heat transfer coefficient will increase and the convection heat transfer coefficient of nanofluids is will reach high in the mass fraction of 0.5%,there is the best nanofluids mass fraction.The convective heat transfer coefficient of the built-in twisted belt external thread tube is better than the light copper tube by 50.34%,strengthening of heat exchange effect of the built-in twisted belt external thread tube is better than the light copper tube,but the flow resistance coefficient is larger than the light copper tube.Analyzed the influence of different pitch on the heat transfer performance,with the pitch decreases make the heat transfer coefficient increases and with the pitch decreases make the flow resistance coefficient increases.Thermal performance coefficient is used to analysis and evaluation strengthening heat transfer performance and flow resistance performance of the overall effect of the built-in twisted belt external thread tube and nanofluids.The thermal performance coefficient of nanofluids are greater than 1,strengthening of heat exchange effect of nanofluids in the built-in twisted belt external thread tube is very significant,thermal performance coefficient of each type of nanofluids has a peak.So it is concluded that the heat transfer correlations and flow resistance correlations in the built-in twisted belt external thread tube when the pitch is 2mm and it is concluded that experimental values and calculated value has good consistency.