Journal ArticleDOI
On the efficiency of thermal engines with power output: Consideration of inertial effects
Victor Fairén,John Ross +1 more
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In this article, an idealized heat engine with nonzero power output was considered and the equations of motion including inertial effects including Newton's equation for conservation of momentum were considered.Abstract:
We consider an idealized heat engine with nonzero power output, which receives heat from and rejects heat to reservoirs by linear heat conduction and produces work in the surroundings by providing kinetic and potential energy to a mass in the gravitational field. The working fluid of the engine is in internal equilibrium. For this engine we write the equations of motion including inertial effects, i.e., we include Newton’s equation for conservation of momentum. We define variables, controls, parameters, and boundary conditions in these equations in connection with the optimization of some performance (cost) functional. The conceptual neglect of inertial effects, as has been done previously, is shown to change the set of variables and controls, thus changing the optimization problem. Furthermore, the neglect of these terms leads to requirements of energy balance which must be incorporated as boundary conditions. We do not solve any optimization problem explicitely but show that appropriate inclusion of inertial effects in such engines precludes in the optimal cycle the existence of isothermal branches which are not preceded and followed by acceleration and deceleration branches.read more
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Entropy generation minimization: The new thermodynamics of finite-size devices and finite-time processes
TL;DR: Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer, fluid mechanics, and thermodynamics as mentioned in this paper.
Journal ArticleDOI
Finite Time Thermodynamic Optimization or Entropy Generation Minimization of Energy Systems
Lingen Chen,Chih Wu,Fengrui Sun +2 more
TL;DR: In this article, the authors reviewed the state-of-the-art of finite time thermodynamic theory and applications from the point of view of both physics and engineering, focusing on the performance optimization of thermodynamic processes and devices with finite-time and/or finite-size constraints.
Journal ArticleDOI
Thermodynamics for Processes in Finite Time
TL;DR: The provision of limits of performance is the main concern of the work and research during the past 9 years has led to new ways of finding natural bounds on performance under the constraint that the system operate at a nonzero rate, thereby giving more realistic bounds than those derived from reversible processes.
Journal ArticleDOI
Optimal process paths for endoreversible systems
TL;DR: This review is dedicated to the dynamical investigation of endoreversible systems and the necessary mathematical tools to determine optimal process paths for such systems, including internal combustion engines and by a number of further selected applications.
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The generalized Carnot cycle: A working fluid operating in finite time between finite heat sources and sinks
TL;DR: In this paper, the authors derived the maximum work obtainable in finite time from such a system, and found that strongly dependent upon the reservoir heat capacity, the efficiency (work produced/heat put in) is a strictly decreasing function of the reservoir's heat capacity.
References
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Book
Mathematical Theory of Optimal Processes
TL;DR: The fourth and final volume in this comprehensive set presents the maximum principle as a wide ranging solution to nonclassical, variational problems as discussed by the authors, which can be applied in a variety of situations, including linear equations with variable coefficients.
Journal ArticleDOI
The Mathematical Theory of Optimal Processes
Richard Bellman,L. S. Pontryagin,V. G. Boltyanskii,Revaz Valerianovich Gamkrelidze,E. F. Mishchenko,K. N. Trirogoff,Lucien W. Neustadt +6 more
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Optimal control: An introduction to the theory and ITs applications
Stephen Kahne,E. Lee +1 more