The effect of four elliptical cylinders with different aspect ratios on the natural convection inside a square enclosure. (July 2018)

• Record Type: Journal Article
• Authors: Seo, Young Min; Ha, Man Yeong; Park, Yong Gap
• Is Part Of: International journal of heat and mass transfer. Volume 122(2018)
• Page Start: 491
• Page End: 503
• Publication Date: 2018-07
• Subjects: Natural convection -- Immersed boundary method -- Four elliptical cylinders -- Rectangular array -- Heat transfer performance; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2018.02.016
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Two-dimensional numerical simulations were conducted for the natural convection. The Immersed Boundary Method was used, based on the Finite Volume Method. The main parameters are the Rayleigh number and aspect ratio of the cylinders. The transition of the flow regime was investigated at Ra = 10 6 according to AR . The effects of AR of the cylinders on the heat transfer characteristics are highlighted. Abstract: This study conducted two-dimensional numerical simulations of the natural convection phenomena in a cold square enclosure containing four hot elliptical cylinders with a rectangular array. Rayleigh numbers in the range of 10 4 ≤ Ra ≤ 10 6 and a Prandtl number of Pr = 0.7 were considered. The immersed boundary method (IBM) was used to capture the virtual wall boundary of the cylinders based on the finite volume method (FVM). The main parameters investigated include the Rayleigh number and aspect ratio of the cylinders. The aspect ratio of the cylinders was varied in the range of 0.25 ⩽ AR ⩽ 4.00 . The flow and thermal structures and corresponding heat transfer characteristics were investigated with respect to the transition of the flow regime from steady state to unsteady state. As a result, 〈 Nu CYL ‾ 〉 increased by about 4.38% and 〈 Nu EN ‾ 〉 increased by about 5.24% at AR = 4.00 with increasing AR compared to AR = 1.00 (Circular cylinder). Thus, the variation in AR has a remarkable influence on the heat transfer characteristics at the cylinder surfaces and the walls of the enclosure.