Numerical assessment of thermal characteristics of metal foams of orderly varied pore density and porosity under different convection regimes

• Published in: International journal of thermal sciences 2022-02, Vol.172, p.107288, Article 107288
• Main Authors: G, Trilok, Kumar, K. Kiran, Gnanasekaran, N., Mobedi, Moghtada
• Format: Article
• Language: English
• Subjects: Asymptotic solution; LTNE; Metal foams; Mixed convection; Pore density; Porosity
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2021.107288

The present study is done to analyze heat transfer and fluid flow in a channel with orderly varied pore density and porosity combination of foam samples. Darcy Forchheimer flow and LTNE thermal models are considered to estimate heat transfer characteristics. Considering the effect of orderly varied combinations of the dual structural properties, forced convection over a range of flow velocities and natural convection phenomenon are studied numerically in the channel housing porous samples. Two limiting solutions for Nusselt number (Nu) i.e., Nun (for natural convection) and Nuf (for forced convection) for Ri→∞ and Ri→0 respectively, as a function of independent variable Richardson number (Ri) with structural properties pore density and porosity are obtained with the help of local thermal non-equilibrium (LTNE) thermal model and Darcy-Forchheimer flow model. Further these asymptotic solutions are blended using technique illustrated in the literature in order to obtain solution for Nusselt number for mixed convection (Num). Correlations for Nusselt number as a function of combination of porosity and pore density are obtained emphasizing on the varied significance of these parameters in different convection regime. The present study not only emphasizes on effect of combination of structural properties of metal foams on heat transfer characteristics, but also illustrates a technique that enables to arrive at suitable correlation for an intermediate phenomenon existing between two other extremes, with zero computational cost. Effect of pore density on heat transfer characteristics at a given porosity, is found to be not much influencing in natural convection dominant regime. However, in mixed and forced convection dominant scenario it is illustrated that, effect of variation in pore density and porosity plays a significant role in expressing distinguishable heat transfer characteristics, along with other well-known independent parameters such as porosity and Reynolds number. •Heat transfer of metal foams of orderly varied pore density and porosity is analyzed under various convection regimes.•Numerical modeling is accomplished using LTNE and Darcy-Forchheimer thermal and flow models respectively.•Nusselt number correlations are obtained for forced, natural and mixed convection dominant regimes.•A solution blending technique is illustrated that can provide solution for an intermediate phenomenon.•Degree of influence of both pore density and porosity on heat tran