Numerical investigation of electro-thermo-convection in a square enclosure with incorporated hot solid body

Abstract

The electro-thermo-convection in a square cavity with incorporated hot solid body is numerically investigated. The finite volume method associated with Patankar’s “blocked-off-regions” technique is applied. A potential difference is applied between the hot obstacle and the horizontal walls in order to eliminate the so-called dead zone created at the bottom of the cavity. The flow movement is induced not only by thermal buoyancy forces but also by the electric Coulomb force. Calculations are made for several injection levels (1 ≤ C ≤ 10), various obstacle shape factors (1 ≤ l/w ≤ 9), different number of electric Rayleigh (0 ≤ T ≤ 800), multiple thermal Rayleigh numbers (2000 ≤ Ra≤ 30,000) and 03 obstacle positions. The results show that according to the intensity of the applied electrical forces, two types of regimes are identified: a thermally dominated regime characterized by a low heat exchange at the bottom of the obstacle and conversely an electrically dominated regime with an excellent heat exchange over the entire cavity. It has been demonstrated that it is possible to improve the heat transfer up to: 43% by changing the shape factor of the obstacle; 82% by varying the injection level and 532% by applying electrical forces.