Numerical investigation to study the effect of loop inclination angle on thermal performance of nanofluid-based single-phase natural circulation loop

Abstract

The main objective of this paper is to numerically investigate the effect of inclination angle on thermal-hydraulic characteristics of a rectangular natural circulation loop (NCL). The density gradients generated due to simultaneous heating and cooling at heater and cooler sections, respectively, create buoyancy. Operating parameters that are varied in the present study are particle concentration, power input and inclination angle. The 3-D NCL model is developed and simulated using commercial software ANSYS-Fluent 14.5. The heat transfer behaviour of NCL is analysed after validation with the experimental results available in open literature. The results show that steady-state mass flow rate increases with particle concentration and decreases with loop inclination angle at a given power input. Rayleigh number and the average heat transfer coefficient are enhanced with particle concentration at a given power input, and these will have a marginal effect at lower inclinations for any particle concentration. The effectiveness variation is also analysed.