科研之友
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摘要
Analysis of 'entropy generation' is an important strategy to build, optimize and operate the heat exchange systems within their maximum operating efficiency. Porous rhombic cavities with various inclination angles, phi and various thermal aspect ratios, A, have been considered for the numerical investigation of thermal processing of various fluids (Prandtl number, Pr = 0.015 and 1000) in the range of Darcy number (Da = 10(-3)-10) due to its extensive energy related applications. The effect of A and phi for various governing parameters during convection are discussed in detail via heat transfer irreversibility (S-theta) and fluid friction irreversibility, S-psi. At lower A, the entropy generation in the cavity is dominated by both S-theta and S-psi for all phi s irrespective of Da and Pr. As A increases, S-theta as well as S-psi decreases for all phi s which in turn decreases S-total with A irrespective of Da and Pr. The total entropy generation (S-total) is found to be lower for phi = 30 degrees and higher for phi = 75 degrees for all Pr and Da. Analysis of variations of Be-a nu with A for higher Da (Da = 10) indicates that, entropy generation is highly fluid friction dominant irrespective of phi and A. Lesser entropy generation (S-total) with larger heat transfer rate ((Nu(b)) over bar) and reasonable heat transfer rate ((Nu(b)) over bar) occurs for Pr = 0.015 and Pr = 1000, respectively at phi = 30 degrees cavities with all A irrespective of Da. Current work attempts to analyze energy efficient thermal convection strategies and role of thermal aspect ratio within porous rhombic enclosures based on entropy generation minimization vs heat transfer rates for various fluids.
- 出版日期2013-9
