Role of multiple discrete heaters to minimize entropy generation during natural convection in fluid filled square and triangular enclosures

The discrete heating strategy has been identified as an energy efficient method. The current work is aimed at achieving a thermally efficient triangular-design 1 (regular isosceles triangle), triangular-design 2 (inverted isosceles triangle) and square enclosures based on the entropy generation studies involving strategic positioning of the double heaters along each side wall (case 1: larger heater in lower half and smaller heater in central half, case 2: larger heater in central half and smaller heater in lower half, case 3: two heaters of identical lengths located at central and lower halves) for Pr = 0.015 and 7.2 involving Ra = 10(3)-10(5). The numerical results of the cases 1-3 have been further compared with the case involving single heater along each side wall (case 0). Galerkin finite element method is implemented for the accurate evaluation of the entropy generation terms based on elemental basis set. Cases 1-3 exhibit lower entropy generation and higher heat transfer rates in the convection dominant regime (Ra = 10(5)) compared to the case O. Overall, case 3 is concluded to be optimal based on higher rate of heat transfer and lower entropy generation. (C) 2018 Elsevier Ltd. All rights reserved.