Comparative appraisal of nanofluid flows in a vertical channel with constant wall temperatures: an application to the rocket engine nozzle

Abstract

ABSTRACT This study aims to investigate the entropy generation of fully developed nanofluid flow in a spongy medium between two fixed absorbent vertical plates with a transpiration cooling mechanism. For heat transfer analysis exponential space-dependent heat source and thermal dependent heat source along with linear radiation are employed. Three distinct scenarios for thermal wall boundary conditions are investigated: i) Constant walls temperature ii) Convective boundary condition on the left wall of the channel and iii) convective boundary conditions on both walls of the channel. Two nanofluids combinations i.e. copper (cylindrical shape) nanoparticles immersed in water and silver (platelet shape) nanoparticles in water are used. It is also noted that studies on the transpiration of nanofluid in rocket engines for cooling purposes are scrutinized when walls are stretchy. But the walls of the rocket engine are fixed. Keeping this in mind, we analyzed the cooling process of the rocket nozzle with a fixed wall channel. The numerical solution of the model equations is attained using the bvp4c method in MATLAB. Findings indicate that the copper/water nanofluid combination performs better than silver/water as for as cooling the nozzle of a rocket engine is concerned. Moreover, convective boundary conditions lower the fluid temperature.