Experimental investigation on thermo-physical properties and overall performance of MWCNT–water nanofluid flow inside horizontal coiled wire inserted tubes

Abstract

The present study is aimed to measure and analyze the thermo-physical properties and overall performance of MWCNT–water nanofluid in turbulent flow regimes under constant heat flux conditions inside horizontal coiled wire inserted tubes. For this purpose, stable MWCNT–water nanofluids with different particle weight fractions of 0.05, 0.1 and 0.2 % as well as deionized water were utilized as the working fluids. It was found that the existing theoretical models could not predict the thermo-physical property values accurately, especially in case of specific heat capacity. Therefore, new empirical correlations are presented based on the obtained experimental results to predict such properties for the nanofluids. In addition, the overall performance of heat transfer techniques considered in this paper was evaluated based on thermal performance factor. The results revealed that thermal performance factor for all cases are greater than unity which indicate that simultaneous usage of nanofluids and wire coil inserts enhances the heat transfer without huge penalty in pumping power. Hence, using nanofluids as the working fluid in combination with coiled wire inserted tubes can be considered for some practical applications.