Numerical simulation of free convection of nanofluid in a square cavity with an inside heater

In the present paper, free convection fluid flow and heat transfer of various water based nanofluids in a square cavity with an inside thin heater has been investigated numerically. The left and right walls of the cavity are maintained at constant temperature Tc, while its top and bottom walls are insulated. A thin heater with the temperature of Th (Th > Tc) is located inside the cavity which its location and length is varying. The governing equations were discretized using the finite volume method and SIMPLER algorithm. Using the developed code, a parametric study was undertaken, and the effects of pertinent parameters, such as, Rayleigh number, the position and location of the heater, the volume fraction of the nanoparticles, and various types of the nanofluids on the fluid flow and heat transfer inside the cavity were investigated. It was observed from the results that at low Rayleigh numbers the horizontal positioned heater have higher Nusselt number compared to the vertical positioned heater while at high Rayleigh numbers the position of the heater does not affect the heat transfer rate. For a horizontal heater when it is located in lower half of the cavity, more heat transfer occurs compared to the case of heater located in upper half of the cavity. Moreover, it was found that at high Rayleigh numbers, the Ag-water nanofluid is more effective to enhance the heat transfer rate while at low Rayleigh numbers the type of nanofluids does not affect the heat transfer rate.