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以活塞式外燃机为研究对象,考虑工质与外热槽间传热服从辐射传热定律[q∝△(T4)],以循环输出功最大为优化目标进行了优化。给出了辐射传热定律下的数值算例,并与牛顿传热定律下的结果进行了比较。结果表明,热导率增加,最优完全循环和半循环的输出功和效率均减小,与完全循环相比,最优半循环的压缩比、输出功和效率较大;结果还说明虽然两种传热定律下最优完全循环和最优半循环的欧拉-拉格朗日(E-L)弧部分的工质体积随时间的变化曲线均类似于正弦曲线,并且均由3部分组成,但不同传热定律下工质体积随时间的变化曲线是不相同的。 相似文献
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SHIRO HOZUMI 《国际可持续能源杂志》2013,32(5):257-280
Finite time exergoeconomic performance optimization of a universal irreversible heat-engine cycle model, which consists of two constant thermal-capacity heating branches, two constant thermal-capacity cooling branches and two adiabatic branches, is investigated by taking the profit rate criterion as the optimization objective. The analytical formulae for power, efficiency and profit rate function of the universal irreversible heat-engine cycle model with the losses of heat transfer, heat leakage and internal irreversibility are derived. The focus of this article is to search the compromised optimization between economics (profit rate) and the energy utilization factor (efficiency) for irreversible cycles. Moreover, analysis and optimization of the model are carried out in order to investigate the effects of these losses and cycle process on the performance of the universal irreversible heat-engine cycle model using numerical examples. The results obtained herein include the performance characteristics of seven typical irreversible heat engines, including Carnot, Diesel, Otto, Atkinson, Brayton, Dual and Miller cycles. 相似文献
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The finite-time exergoeconomic performance of an endoreversible Carnot heat pump with a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law q∝ (Δ T n ) m , is investigated in this paper. The focus of this paper is to obtain the compromised optimization between economics (profit) and the energy utilization factor (coefficient of performance, COP) for the endoreversible Carnot heat pump, by searching the optimum COP at maximum profit, which is termed as the finite-time exergoeconomic performance bound. The obtained results include those obtained in much of the literature and can provide some theoretical guidance for the design of practical heat pumps. 相似文献
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The efficiency bounds at maximum profit are obtained from finite-time exergoeconomic analysis for three common heat transfer laws: Newton's law (n = 1), a linear pheomenological law in irreversible thermodynamics (n = 1), and the radiative heat law (n = 4). The relation between optimal profit and efficiency of an endoreversible Carnot engine is derived on the basis of the general heat-transfer law q∝Δ(Tn). 相似文献
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