Role of multiple discrete heaters to minimize entropy generation during natural convection in fluid filled square and triangular enclosures. (December 2018)

• Record Type: Journal Article
• Authors: Das, Debayan; Lukose, Leo; Basak, Tanmay
• Is Part Of: International journal of heat and mass transfer. Volume 127(2018)Part A
• Page Start: 1290
• Page End: 1312
• Publication Date: 2018-12
• Subjects: Multiple discrete heaters -- Natural convection -- Triangular enclosure -- Entropy generation minimization; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2018.05.163
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Discrete solar heating is beneficial for achieving optimal thermal efficiency. Natural convection in discretely heated square and triangular enclosures is examined. Effect of various positioning of double solar heaters on entropy generation is analyzed. Strategic assemblies of double solar heaters on side walls minimize entropy generation. The case 3 heating strategy in square or triangular cavity is energy efficient. Abstract: 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 0. Overall, case 3 is concluded to be optimal based on higher rate of heat transfer and lower entropy generation.