恒温热源条件下不可逆闭式中冷回热布雷顿循环的功率优化

考虑高低温侧换热器、回热器和中冷器的热阻损失，以及压气机和涡轮中的不可逆损失，以功率为优化目标，借助数值计算，研究了恒温热源条件下不可逆闭式中冷回热布雷顿循环输出功率最大时高低温侧换热器、回热器和中冷器的热导率分配以及中间压力与总压比的关系。     

闭式内可逆中冷回热布雷顿循环的功率优化

考虑高低温侧换热器、回热器和中冷器的热阻损失，以功率为优化目标，对恒温热源条件下内可逆闭式布雷顿循环的高低温侧换热器、回热器和中冷器的热导率以及中间压比的分配进行了优化。借助数值计算，分析了一些主要循环特征参数对最大功率及相应热导率和中间压比分配、双重最大功率的影响。     

中冷回热燃气轮机循环换热器热导率最优分配——生态学性能优化

用有限时间热力学方法优化恒温热源条件下闭式中冷回热燃气轮机循环的生态学性能,计入工质与高低温侧换热器、回热器以及中冷器之间的热阻损失、压气机内不可逆压缩和涡轮内部不可逆膨胀损失,导出了循环生态学函数解析式,通过数值计算优化各换热器热导率分配以及中间压比和总压比,得到了循环最优生态学性能.     

变温热源条件下内可逆闭式中冷回热布雷顿循环的功率优化

计入工质与高低浊侧换热器、回热器和中冷器的热阻损失以功率为优化目标，借助数值计算，研究了变温热源条件下内可逆闭式中冷回热布雷顿循环输出功率最大时，高低温侧换热器、回热器和中冷器的热导率分配以及中间压比与总压比的关系；分析了工质与热源间的热容率匹配对双重最大功率的影响。     

变温热源内可逆中冷回热布雷顿循环功率密度优化

以功率密度为目标，用有限时间热力学的方法，通过数值计算，对变温热源条件下的内可逆中冷回热布雷顿循环的高、低温侧换热器的热导率分配和中间压比、循环总压比和工质与热源间的热容率匹配进行优化。分别得到了最大功率密度、双重最大功率密度和三重最大功率密度，并分析了热力学参数对高低温侧换热器的热导率最优分配、最佳中间压比、最大功率密度和双重最大功率密度的影响。     

恒温热源条件下内不可逆布雷顿循环的功率密度特性

用有限时间热力学方法分析恒温热源条件下不可逆布雷顿循环的功率密度特性,计入工质与高、低温侧换热器的热阻损失及压气机、透平的不可逆压缩和膨胀损失,导出了功率密度与压比间的解析式,并通过数值计算将对应于最大功率密度时的一些参数与对应于最大功率时的同样参数进行了比较,说明了功率密度设计的优点与不足.     

恒温热源条件下内不可逆布置顿循环的功率密度特性

用有限时间热力学方法分析恒温热源条件下不可逆布雷顿循环的功率密度特性，计入人工质与高、低温侧换热器的热阻损失及压气机、透平的不可逆压缩和膨胀损失，导出了功率密度与压比间的解析式，并通过数值计算将对应于最大功率密度时的一此参数对应于最大功率时的同样参数进行了比较，说明了功率密度设计的优点与不足。     

不可逆中冷回热太阳能布雷顿循环系统的优化分析

建立了由太阳能集热器模型和不可逆中冷回热布雷顿循环模型组成的恒温热源条件下太阳能布雷顿循环系统,以系统总效率为目标函数,考虑了高低温侧换热器、回热器和中冷器的热阻损失以及压缩机和涡轮机的不可逆损失,借助数值计算对太阳能集热器的工作温度进行了优化,并分析了主要特征参数对总效率的影响．结果表明：太阳能布雷顿循环系统中存在一个最佳的太阳能集热器工作温度和相应的最大总效率及最大总输出功率;在此基础上,通过优化中间压比可使循环系统的总效率和相应的总输出功率达到双重最大值;系统总效率随着回热器传热有效度和光学效率的增加而提高;系统运行时存在一个最佳的总压比．     

不可逆中冷焦耳_布雷顿功热并供系统火用分析

运用热力学火用分析的方法,分别考虑了高低温侧换热器、热回收装置侧换热器和中冷器的热阻损失,以及压缩机和涡轮机中的内不可逆损失,以无因次总输出火用和火用效率为目标函数,借助数值分析的方法,研究了恒温热源条件下不可逆中冷焦耳—布雷顿功热并供系统的火用性能,分析了主要特征参数对无因次总输出火用及火用效率的影响。分析结果表明,当中间压比不变而总压比变化时,存在一组最佳运行参数,使无因次总输出火用达到最大,还存在最大的总输出火用和火用效率以及相对应的一组最佳运行参数。提高中冷器换热有效度可以增加无因次总输出火用和火用效率。     

闭式中冷回热燃气轮机循环经济性能优化

建立了考虑变温热源的闭式中冷回热(ICR)燃气轮机循环有限时间热力学(FTT)模型,导出了循环利润率和效率解析式,优化各换热器热导率分配和中冷压比,得到了最大利润率;进一步优化总压比,得到双重最大利润率;并分析了总热导率等重要设计参数对循环最优性能的影响。结果表明,随着高低温侧热源进口温比、低压压气机效率、高压压气机效率、涡轮效率、各换热器有效度以及压力恢复系数的增大,循环最大利润率和对应的功率和效率增大。随着价格比的增大,循环利润率增大,但对应的效率却有所减小。存在一个最佳的工质与热源热容率匹配值使变温热源闭式不可逆中冷回热燃气轮机循环的利润率取得三重最大值。     

A Parametric Study of an Irreversible Closed Intercooled Regenerative Brayton Cycle

Entropy generation minimization technique is used in the analysis of an irreversible closed intercooled regenerative Brayton cycle coupled to variable-temperature heat reservoirs. Mathematical models are developed for dimensionless power and efficiency for a multi-stage Brayton cycle. The dimensionless power and efficiency equations are used to analyze the effects of total pressure ratio, intercooling pressure ratio, thermal capacity rates of the working fluid and heat reservoirs, and the component (regenerator, intercooler, hot- and cold-side heat exchangers) effectiveness. Using detailed numerical examples, the optimal power and efficiency corresponding to variable component effectiveness, compressor and turbine efficiencies, intercooling pressure ratio, total pressure ratio, pressure recovery coefficients, heat reservoir inlet temperature ratio, and the cooling fluid in the intercooler and the cold-side heat reservoir inlet temperature ratio are analyzed.     

回热式变温热源空气制冷循环容积制冷率优化

考虑热阻损失、压缩机与膨胀机的内损失及管路系统的压力损失，研究一个比较接近实际装置的回热式交温热源空气制冷循环，得出了循环容积制冷率制冷系数的解析关系式。由数值计算分析了压比、热导率分配以及工质与热源间的热容率匹配等参数对容积制冷率的影响。     

Performance comparison of an irreversible closed Brayton cycle under maximum power density and maximum power conditions

In this paper, the power density, defined as the ratio of power output to the maximum specific volume in the cycle, is taken as objective for performance analysis of an irreversible closed Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of finite time thermodynamics (FTT) or entropy generation minimization (EGM). The analytical formulas about the relations between power density and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers and the irreversible compression and expansion losses in the compressor and turbine. The obtained results are compared with those results obtained by using the maximum power criterion. The influences of some design parameters on the maximum power density are provided by numerical examples, and the advantages and disadvantages of maximum power density design are analyzed. The power plant design with maximum power density leads to a higher efficiency and smaller size. However, the maximum power density design requires a higher pressure ratio than maximum power design. When the heat transfer is carried out ideally, the results of this paper become those obtained in recent literature.     

Closed intercooled regenerator Brayton-cycle with constant-temperature heat-reservoirs

The performance of an irreversible closed intercooled regenerator Brayton-cycle coupled to constant-temperature heat reservoirs is analyzed by using the theory of finite-time thermodynamics (FTT). Analytical formulae for dimensionless power and efficiency are derived. Especially, the intercooling pressure-ratio is optimized for the optimal power and the optimal efficiency, respectively. The effects of component (the intercooler, the regenerator, and the hot- and cold-side heat-exchangers) effectivenesses, the compressor and turbine efficiencies, the heat-reservoir temperature-ratio, and the temperature ratio of the cooling fluid in the intercooler and the cold-side heat reservoir on the optimal power and the corresponding efficiency and corresponding intercooling pressure ratio, as well as the optimal efficiency and the corresponding power and corresponding intercooling pressure-ratio are analyzed by detailed numerical examples.     

Power,power density and efficiency optimization of an endoreversible Braysson cycle

The performance optimization of an endoreversible Braysson cycle with heat resistance losses in the hot- and cold-side heat exchangers is performed by using finite-time thermodynamics. The relations between the power output and the working fluid temperature ratio, between the power density and the working fluid temperature ratio, as well as between the efficiency and the working fluid temperature ratio of the cycle coupled to constant-temperature heat reservoirs are derived. Moreover, the optimum heat conductance distributions corresponding to the optimum dimensionless power output, the optimum dimensionless power density and the optimum thermal efficiency of the cycle, and the optimum working fluid temperature ratios corresponding to the optimum dimensionless power output and the optimum dimensionless power density are provided. The effects of various design parameters on those optimum values are studied by detailed numerical examples.     

Power optimization of an endoreversible closed intercooled regenerated Brayton cycle

In this paper, power is optimized for an endoreversible closed intercooled regenerated Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of finite-time thermodynamics (FTT) or entropy generation minimization (EGM). The effects of some design parameters, including the cycle heat reservoir temperature ratio and total heat exchanger inventory, on the maximum power and the corresponding efficiency are analyzed by numerical examples. The analysis shows that the cycle dimensionless power can be optimized by searching the optimum heat conductance distributions among the hot- and cold-side heat exchangers, the regenerator and the intercooler for fixed total heat exchanger inventory, and by searching the optimum intercooling pressure ratio. When the optimization is performed with respect to the total pressure ratio of the cycle, the maximum dimensionless power can be maximized again.     

Power optimization of an endoreversible closed intercooled regenerated Brayton-cycle coupled to variable-temperature heat-reservoirs

In this paper, in the viewpoint of finite-time thermodynamics and entropy-generation minimization are employed. The analytical formulae relating the power and pressure-ratio are derived assuming heat-resistance losses in the four heat-exchangers (hot- and cold-side heat exchangers, the intercooler and the regenerator), and the effect of the finite thermal-capacity rate of the heat reservoirs. The power optimization is performed by searching the optimum heat-conductance distributions among the four heat-exchangers for a fixed total heat-exchanger inventory, and by searching for the optimum intercooling pressure-ratio. When the optimization is performed with respect to the total pressure-ratio of the cycle, the maximum power is maximized twice and a ‘double-maximum’ power is obtained. When the optimization is performed with respect to the thermal capacitance rate ratio between the working fluid and the heat reservoir, the double-maximum power is maximized again and a thrice-maximum power is obtained. The effects of the heat reservoir’s inlet-temperature ratio and the total heat-exchanger inventory on the optimal performance of the cycle are analyzed by numerical examples.