نتایج جستجو برای: heat engine

تعداد نتایج: 270828  

2016
Michele Campisi Rosario Fazio

Since its inception about two centuries ago thermodynamics has sparkled continuous interest and fundamental questions. According to the second law no heat engine can have an efficiency larger than Carnot's efficiency. The latter can be achieved by the Carnot engine, which however ideally operates in infinite time, hence delivers null power. A currently open question is whether the Carnot effici...

Journal: :Science 2013
Jean-Philippe Brantut Charles Grenier Jakob Meineke David Stadler Sebastian Krinner Corinna Kollath Tilman Esslinger Antoine Georges

Thermoelectric effects, such as the generation of a particle current by a temperature gradient, have their origin in a reversible coupling between heat and particle flows. These effects are fundamental probes for materials and have applications to cooling and power generation. Here, we demonstrate thermoelectricity in a fermionic cold atoms channel in the ballistic and diffusive regimes, connec...

A. Shidfar, M. Garshasbi ,

 Abstract: This study deals with modeling of heat flux at the external surface of combustion chamber wall in an internal combustion (IC) engine as a function of crank angle. This investigation results in an inverse heat conduction problem in the cylinder wall. Alifanov regularization method is used for solving this inverse problem. This problem study as an optimization problem in which a square...

Journal: :Entropy 2009
Marco A. Barranco-Jiménez Norma Sanchez-Salas Marco A. Rosales

In the present paper, the thermoeconomic optimization of an endoreversible solardriven heat engine has been carried out by using finite-time/finite-size thermodynamic theory. In the considered heat engine model, the heat transfer from the hot reservoir to the working fluid is assumed to be the radiation type and the heat transfer to the cold reservoir is assumed the conduction type. In this wor...

In internal combustion engines, only about a third of the total fuel input energy is converted into useful work. If the energy rejected into the cooling system and the exhaust gases could be recovered instead and put into useful work, fuel economy would have been substantially improved. The main aim of this research paper was to evaluate the effects of the hybrid nano-catalyst containing ce...

Journal: :Physical review letters 2012
O Abah J Rossnagel G Jacob S Deffner F Schmidt-Kaler K Singer E Lutz

We propose an experimental scheme to realize a nanoheat engine with a single ion. An Otto cycle may be implemented by confining the ion in a linear Paul trap with tapered geometry and coupling it to engineered laser reservoirs. The quantum efficiency at maximum power is analytically determined in various regimes. Moreover, Monte Carlo simulations of the engine are performed that demonstrate its...

Journal: :Physical review letters 2014
J Roßnagel O Abah F Schmidt-Kaler K Singer E Lutz

We consider a quantum Otto cycle for a time-dependent harmonic oscillator coupled to a squeezed thermal reservoir. We show that the efficiency at maximum power increases with the degree of squeezing, surpassing the standard Carnot limit and approaching unity exponentially for large squeezing parameters. We further propose an experimental scheme to implement such a model system by using a single...

2014
Alias Mohd Noor Rosnizam Che Puteh Srithar Rajoo

Significant waste heat recovery technologies have been developed to recover exhaust heat and turn it into useful energy such as in downsizing the engine or to regain the auto-electricity. Extensive work and research in energy recovery have been identified in the automotive sector; therefore the main objective of this paper is to assess each waste heat recovery technology based on current develo...

2017
Jan Klaers Stefan Faelt Atac Imamoglu Emre Togan

The efficient conversion of thermal energy to mechanical work by a heat engine is an ongoing technological challenge. Since the pioneering work of Carnot, it has been known that the efficiency of heat engines is bounded by a fundamental upper limit—the Carnot limit. Theoretical studies suggest that heat engines may be operated beyond the Carnot limit by exploiting stationary, nonequilibrium res...

R. Khoshbakhti Saray, S.V. Pirouzpanah,

The dual fuel engines at part loads inevitably suffer from lower thermal efficiency and higher carbon monoxide and unburned fuel emission. This work is carried out to investigate combustion characteristics of a dual fuel (dieselgas) engine at part loads, using a single zone combustion model with detailed chemical kinetics for combustion of natural gas fuel. The authors developed software in ...

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