Natural convection in fully open parallelogrammic cavity filled with Cu–water nanofluid and heated locally from its bottom wall

Abstract

The natural convection in fully open parallelogrammic cavity filled with Cu–water nanofluid and heated locally from its bottom wall is investigated numerically for the first time in the present paper. The finite volume method together with the body fitted coordinates system are used to deal with the governing non-linear partial differential equations. The top wall of the cavity is considered fully open to the surrounding, while a specific location in the bottom wall is subjected to a local hot heat source. The other regions of the bottom wall are kept adiabatic. Both right and left sidewalls of the cavity are considered inclined and maintained to an isothermal cold temperature. The nanofluid entering form the top wall is considered cold, while it leaves in adiabatic condition from the same wall. The flow and thermal fields together with the Nusselt number are investigated for various values of Rayleigh number (103≤Ra≤105), heat source location (0.2≤δ≤0.8), cavity inclination angle (0°≤θ≤60°), volume fraction of nanoparticles (0≤φ≤0.2). The results show that for both pure and nanofluids the highest counter-clockwise circulation occurs at (δ=0.8) and (θ=0°) for all Rayleigh numbers, while the highest clockwise circulation occurs at (δ=0.5) and (θ=30°) for Ra=103 and at (δ=0.8) and (θ=30°) for Ra=105. In order to increase the heat transfer for both pure and nanofluids in the cavity, it is recommended to select (θ=60°) and make the heat source adjacent to the left sidewall (δ=0.2).