Significance of quadratic radiation and variable thermal conductivity on heat transfer of hybrid nanofluid using Xue model: A Legendre wavelet approach

Abstract

Carbon nanotubes have a broad spectrum of applications in thermal management, enhanced cooling, lubricants, sensors and detections, environmental remediation, biomedical, and drug delivery. Motivated by its industrial applications, this work analyses the effects of nonuniform heat source/sink and quadratic thermal radiation on the thermal characteristics of hybrid nanofluid flow over a curved stretching sheet using the Legendre wavelet collocation technique (LWCT). The base fluid is found to be composed of ethylene glycol and water in the ratio of 30:70, and the nanoparticles are taken as single-wall carbon nanotube (SWCNT) and multi-wall carbon nanotube (MWCNT) in the ratio of 2% each. The thermal conductivity models, namely Xue, modified Maxwell and Hamilton-Crosser, are compared for heat transfer enhancement. From the results up to 5% volume fraction, the Xue model shows the maximum rate of heat transfer enhancement, while the above 5% Hamilton-Crosser model shows the maximum rate of heat transfer enhancement. The temperature profiles of existing hybrid nanofluid are increased with a heat source, radiation and variable thermal conductivity. Moreover, the graphs describing the local Nusselt number display the heat transfer rate depreciation with an increase in variable thermal conductivity and radiation parameters.