Entropy generation behaves normally for low gradient systems. The entropy generation equation stops with first order Taylor series. In case of systems like rocket re-entry, the temperature gradient will be high between nozzle and the body of the rocket. In those case, first order entropy equation will not behave properly and gives accurate result. Anyone working on entropy generation to show some light with your idea?
Dear N.R.,
perhaps it may help reading
J. Non-Newtonian Fluid Mech 96 (2001) 255-290
B.R. W.M.
@Cao Bingyang and @W. Muschik : Thank you Sir! I will give it a read and get back to you if I need any further clarification. I appreciate your help Sir!
Some researchers and I recently completed a project for the US Department of Energy to study entropy generation in transitional fluid flows. Here are some papers:
Walsh, E.J., McEligot, D. M., Brandt, L. Schlatter, P., 2011, “Entropy Generation in a Boundary Layer Transitioning Under the Influence of Freestream Turbulence,” J. of Fluids Engineering, 133, 061203(10 pages).
McEligot, D. M., and E. J. Walsh, 2014. Entropy generation in steady laminar boundary layers with pressure gradients. Entropy, 16, pp. 3808-3813.
Ghasemi, E., D. M. McEligot,, K. P. Nolan, J. C. Crepeau, A. Tokuhiro and R. S. Budwig, 2013. Entropy generation in a transitional boundary layer region under the influence of freestream turbulence using transitional RANS models and DNS. Int. Comm. Heat Mass Transfer. 41, pp. 10-16.
You can search the references to get additional papers.
Best of luck, John Crepeau
Some relevant results concerning entropy production in systems with large gradients (including shock waves) are discussed in A. Di Vita, Phys. Rev. E 81, 041137 (2010)
Exergy analysis is based on iI law of TD, which stipulates that all macroscopic processes are irreversible. Every such irreversible process entails a non-recoverable loss of exergy. This is expressed as a product of ambient temperature, and entropy generated (the sumof the values of entropy increases for all the bodies taking part in the process). Some of the components of entropy generation can be hegative, but some is always possitive.
Ref: Advanced Renewable Energy Sources
By G. N. Tiwari, Rajeev Kumar Mishra
Entropy: A concept that is not a physical quantity
https://www.researchgate.net/publication/230554936_Entropy_A_concept_that_is_not_a_physical_quantity
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