Heat Transfer Enhancement and Entropy Generation Characteristics in Twisted Elliptical Tubes
To investigate the heat transfer enhancement and entropy generation characteristics of twisted elliptical tubes,based on the experimental verification,the effects of the structural parameters,including twist ratio(P/D),ratio of major to minor axis(A/B),and the flow parameter Reynolds number(Re)on the heat transfer and flow resistance performance in twisted elliptical tubes were analyzed by numerical simulation method in the range of Re from 710 to 4 790.According to entropy generation theory,the entropy generation characteristics of the twisted elliptical tubes were discussed to reveal the mechanism of fluid convection heat transfer enhancement inside twisted elliptical tubes.The results showed that the convective heat transfer performance,flow resistance,and total entropy generation inside the twisted elliptical tubes were increased,decreased,and increased with the rise of Re,respectively;all increased with a decrease of P/D or an increase of A/B,and irreversible losses in the heat transfer process mainly caused the total entropy generation.When A/B=2.16 and P/D=11.90,the heat transfer coefficient(h)and pressure drop(Δp)reached their maximum value.Furthermore,the total entropy generation reached the minimum at P/D=26.33 and A/B=1.34.
twisted elliptical tubesheat transfer enhancementnumerical simulationentropy generation theory
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