General Thermodynamics

Author(s):  
Donald Olander
Author(s):  
J. B. Young ◽  
R. C. Wilcock

This paper is Part I of a study concerned with developing a formal framework for modelling air-cooled gas turbine cycles and deals with basic thermodynamic issues. Such cycles involve gas mixtures with varying composition which must be modelled realistically. A possible approach is to define just two components, air and gas, the latter being the products of stoichiometric combustion of the fuel with air. If these components can be represented as ideal gases, the entropy increase due to compositional mixing, although a true exergy loss, can be ignored for the purpose of performance prediction. This provides considerable simplification. Consideration of three idealised simple cycles shows that the introduction of cooling with an associated thermal mixing loss does not necessarily result in a loss of cycle efficiency. This is no longer true when real gas properties and turbomachinery losses are included. The analysis clarifies the role of the cooling losses and shows the importance of assessing performance in the context of the complete cycle. There is a strong case for representing the cooling losses in terms of irreversible entropy production as this provides a formalised framework, clarifies the modelling difficulties and aids physical interpretation. Results are presented which show the effects on performance of varying cooling flowrates and cooling losses. A comparison between simple and reheat cycles highlights the rôle of the thermal mixing loss. Detailed modelling of the heat transfer and cooling losses is discussed in Part II of this paper.


1977 ◽  
Vol 10 (9) ◽  
pp. 589-595 ◽  
Author(s):  
Edward F. Blick ◽  
Paul D. Stein

1963 ◽  
Vol 41 (11) ◽  
pp. 2839-2843
Author(s):  
G. A. Elliott

The Barieau–Li controversy shows the need for a general method of discussing conditions of validity of thermodynamic equations. Such a method is here developed and illustrations of its usefulness are given. It is shown how Barieau's principle can be applied in all cases.


2010 ◽  
Vol 25 (27) ◽  
pp. 2333-2348 ◽  
Author(s):  
NAIRWITA MAZUMDER ◽  
RITABRATA BISWAS ◽  
SUBENOY CHAKRABORTY

This paper deals with general thermodynamics for the universe filled with a perfect fluid, obeying an equation of state p = ω(z)ρ where the varying equation of the state parameter is chosen as two-index parametrization models namely: (a) linear redshift parametrization: ω(z) = ω0 + ω1z or (b) Jassal–Bagla–Padmanabhan (JBP) parametrization: [Formula: see text] where ω0, ω1 are constants. The behavior of temperature and the thermodynamic stability have been discussed. The thermal equation of state depends on both temperature and volume. As the universe evolves the fluid cools down obeying third law of thermodynamics and there will be thermodynamic stability during the expansion process without any phase transition or passing through any critical point.


Physics Today ◽  
1966 ◽  
Vol 19 (9) ◽  
pp. 93-93
Author(s):  
Howard Reiss ◽  
George N. Hatsopoulos ◽  
Joseph H. Keenan ◽  
Stuart A. Rice

The question of fluctuations in electromagnetic radiation played an important part during the first period of the development of quantum theory. After having introduced (Einstein 1905) the conception of light quanta or photons in order to explain the observed phenomena of the photoelectric effect, Einstein (1909) considered the consequences of this idea for other properties of the radiation. Planck’s formula for the energy density of radiation implies, by arguments of general thermodynamics and statistics, the following expression for the mean square fluctuation of the energy contained in a volume v in terms of the mean energy Ē v .


Nature ◽  
1956 ◽  
Vol 177 (4518) ◽  
pp. 1006-1006
Author(s):  
R. W. HAYWOOD

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