Inthis paper we study heat transfer augmentation of Kerosene-Alumina nanofluidpast an impulsive motion of vertical porous plate in the presence of viscousdissipation. A robust Galerkin finite element procedure is used to solve thegoverning nonlinear dimensionless partial differential equations. We usekerosene as a base fluid containing nanoparticles of copper (Cu) , Titanium oxide (TiO2) , Alumina (Al2O3) , Cobalt (Co) .
The model parameters like viscosityparameter( ) , Eckert Number (Ec),nanofluid volume fraction ( ) , are analyzed for velocity components, temperature distributions,skin-friction coefficient and Nusselt number. the governing equations are takenaccording to Tiwari-Das nanofluid model with Bossiness approximation. This studycontributes to enhance the cooling process of chamber and nozzle walls ofrocket engine.
Keywords: Freeconvection, Kerosene-nanofluids, vertical porous plate, Galerkin finite elementmethod, viscous dissipation, Liquid rocket engine (LRE). IntroductionAnotable provocative interdisciplinary area of research in launching rocketvehicle technology development is cooling of liquid rocket engine (LRE). Duringthe process of rocket launching vehicle both fuel and oxidizer are burnt in LREcombustion chamber as a consequence, hot gases are released from a nozzle togain the required thrust.
As a consequence, both the nozzle and chamber undergoes high temperature. In order to safeguard the nozzle and chamber of rocketengine they need to be cooled. Numerous ways of cooling strategies are implementedto safeguard the nozzle and chamber walls. Thermo physical properties of thefluid and flow velocity are the key factors which controls the coolingperformance of the nozzle and the chamber walls. Enhance in pressure dropresults in the growth of fluid velocity along with requisite pumping power.Kerosene the fuel, is being used as regenerative coolant in the case ofsemi-cryogenic engine.
During the regenerative passage the temperature of thekerosene should not reach coking limits as thermal conductivity of kerosene islow. In this regard the thermo physical properties of the kerosene can beimproved which can enhance the heat transfer capacity of kerosene whichinfluences the exploration of cooling system for semi-cryogenic engine.The idea of improving heat transferperformance of fluids with the inclusion of solid particles was firstintroduced by Maxwell 2.
Suspensions involving milli or microsized particlescreate problems, such as sedimentation, clogging of channels, high pressuredrop and severe erosion of system boundaries, to overcome these problems Choi3 used ultra fine nanometered sized particles (diameter less than 50nm) likeAluminium, Copper, Silicon, Silver and Titanium or their Oxides dispersed in abase fluid such as water, ethylene, glycol, toluene and oil. Nanofluids is the term first coined by Choi 2. Nanofluidshave several cooling applications which includes nuclear reactors, vehicle, transformer,silicon mirror and electronics cooling.
In addition these nanofluids can also employedin several areas such as auto-mobile engines, lubricants, heat exchangers,micro channel heat sinks, welding equipment, micro-electro-mechanical system andWang et al 1. The natural convective flow of ananofluid over a convectively heated vertical plate was investigated by Azizand khan 4. The natural convection flow past an isothermal horizontal platein a porous medium saturated by a nanofluid was studied by Gorla and Chamka 8.
Free convection boundary layer flow past a vertical plate was examined by Kuznetsovand Nield 9. Turkyilmazoglu 11 examined the heat transfer in transient flowof some nanofluids over a vertical flat plate. The natural convection flow of awater-Al2O3 nanofluid was developed by Congedo et al. 16. Inengineering and industrial systems buoyancy-driven flow and heat transfer in verticalgeometries have several important applications for instance solar-collectors, electricaland microelectronic equipments containers, petroleum reservoirs, geothermalengineering, thermal buildings insulation, etc. To discuss the importance ofbuoyancy force on fluid flow and heat transfer under various physicalconditions, many studies have been published. The combined effect of buoyancyforce and Navier slip on magneto-hydrodynamic flow of a nanofluid over aconvectively heated vertical porous plate was numerically investigated byMutuku-Njane and Makinde 18.The forced convective heat transfer due to flowof Al2O3–water nanofluidthrough a pipe filled with a metal foam was studied experimentally by Nazari etal.
19. Duringthe motion of fluid particles, viscosity of the fluid converts some kineticenergy into thermal energy. Since this process is irreversible and caused dueto viscosity, so this is called viscous dissipation. Viscous dissipation is quiteoften a negligible effect inmacro scale systems, in laminar flow in particular, except for very viscousliquids at comparatively high velocities, but it’s contribution mightbecome important when the fluid viscosity is very high. It changes thetemperature distributions by playing a role like an energy source, which leadsto affected heat transfer rates.
The effect of viscous and joules dissipationon MHD flow past a streaching poroussurface embedded in a porous medium for ordinary fluid was studiedby Anjali devi and Ganga 21 .The effect of thermal radiation and viscousdissipation on boundary layer flow of nanofluids over a moving flat plate wereinvestigated by Motsumi and Makinde 22.The flow of MHD viscous fluid in porous medium through a moving verticalplate was inspected by singh23. The stagnation point flow of micropolar fluidthrough porous medium and heat transfer with viscous dissipation was discussedby Kishan et al 24