| Exergy maximization in cryogenic regenerators (1994) | |||||||||||||
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| Exergy maximization cryogenic regenerators Sahoo and Das Department Mechanical Engineering Regional Engineering College Rourkela Orissa India Received June revised September This paper presents improved irreversibility analysis regenerators with single blow operation Unlike earlier analyses this investigation deals with the gas and matrix temperature variation along spatial and temporal ordinates The results this study show that the earlier analyses involving lumped model and averaged model applied high Ntu regenerators may run the risk operating the zone high irreversibility while the models are well suited for Ntu and Ntu respectively The present analysis more relevant for exergetic analysis applied cryogenic regenerators with high Ntu Keywords regenerators exergy maximization theoretical analysis Nomenclature E G J Nf Nst Re Heat transfer area matrix Specific heat fluid Specific heat solid matrix Exergy content fluid Friction factor Special functions given Appendix Mass velocity fluid Heat transfer coefficient Irreversibility Irreversibility rate Length solid matrix bed Mass flow rate fluid Total mass solid Dimensionless friction coefficient V f Nst Stanton number Number transfer units Cp Fluid pressure drop Fluid pressure outlet Ideal gas constant Reynolds number Specific entropy K To Entropy generation Entropy generation rate Time ordinate Temperature Ambient temperature Distance ordinate Greek letters hAt MmCm NtuO Ratio optimum maximum storage capacity Fluid density hA. This paper presents an improved irreversibility analysis of regenerators with singleblow operation. Unlike earlier analyses, this investigation deals with the gas and matrix temperature variation along spatial and temporal co-ordinates. The results of this study show that the earlier analyses involving a lumped model and an averaged model applied to high Ntu regenerators may run the risk of operating in the zone of high irreversibility, while the models are well suited for Ntu < 1.0 and Ntu < 2.0, respectively. The present analysis is more relevant for exergetic analysis applied to cryogenic regenerators with high Ntu. | |||||||||||||
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