On the principle of minimal entropy production for Navier-Stokes-Fourier fluids

1999 ◽  
Vol 11 (5) ◽  
pp. 327-330 ◽  
Author(s):  
Elvira Barbera
Keyword(s):  
Entropy Production ◽  
Navier Stokes ◽  
Minimal Entropy Production

scholarly journals Die physikalischen Grundlagen der Uran235-Anreicherung nach dem Trenndüsenverfahren / The Physics of Uranium235-Enrichment in the Separation Nozzle Process

1973 ◽  
Vol 28 (8) ◽  
pp. 1273-1280 ◽  
Author(s):  
P. Bley ◽  
R. Dürr ◽  
W. Ehrfeld ◽  
G. Eisenbeiß
Keyword(s):  
Energy Consumption ◽  
Kinetic Energy ◽  
Entropy Production ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Navier Stokes ◽  
Nozzle Flow ◽  
Production Mechanism ◽  
Separation System ◽  
Type Pressure

The energy consumption of the separation nozzle process for enrichment of U235 is discussed in terms of the entropy production in the separation system. Experimental results obtained from measurements with Pitot type pressure probes and a numerical Navier-Stokes analysis of the nozzle flow show that ordinary viscous dissipation is the most important entropy production mechanism. The relatively large amount of kinetic energy observed at the end of the nozzle indicates some possibilities of lowering the specific energy consumption of the process.

On Master Operators with Extremal Entropy Production

1978 ◽  
Vol 33 (10) ◽  
pp. 1122-1132
Author(s):  
O. Seeberg
Keyword(s):  
Entropy Production ◽  
Maximal Entropy ◽  
Extremal Points ◽  
Minimal Entropy Production

Abstract The master operators B which cause the entropy production dH/dt = - k-1 dS/dt to become extremal for fixed statistical operators W are constructed and discussed. There are boundaries of the set B of master operators, B = {B | Σ B2vu = b} for which the problem is solvable yielding minimal entropy production, while no solution exists in the set B without any constraints. Operators with maximal entropy production must be extremal points of B.

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