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针对微型燃气轮机板翅式换热器结构参数与燃气轮机性能之间的耦合关系,建立了板翅式换热器多目标分析和优化模型。在此基础上,分析了2种设计条件(定燃烧室吸热量和定涡轮出功)下板翅式换热器关键参数对板翅式换热器和燃气轮机性能的影响。结果表明:影响燃烧室吸热量和涡轮出功的主要因素为换热器压损而并非换热器效能,2种设计条件下各参数的变化趋势一致(除燃烧室吸热量和涡轮出功外);在对翅片结构进行优化后,涡轮出功增大了6.8%,燃烧室吸热量减少了5.1%;相对于基本参数,优化后翅片厚度、翅片间距和波纹角减小,翅片高度增加,保证了板翅式换热器具有较小的压损;采用■耗散最小和采用熵产最小为优化目标时无明显区别。 相似文献
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在设计和选择换热器时,冷、热流体之间的温度差是首先要确定的参数。本研究表明:在高温换热器中,提高流体间的换热温差,可以减少换热器的面积;而在低温换热器中,较低的流体换热温差有助于热交换品质的改善。通过技术经济对比分析可以得到最佳的换热温差。分析研究了换热器设计中,如其对数平均温差不变,则换热器的热交换性能也不变这个普遍认可的观点。发现:即使当时数平均温差相同时,热交换过程的ying的损失也和流体进、出换热器两端的温度差之比有关。在相向流动的换热器中,热流体进口处的最佳温差值应该比其在冷流体进口处的值要大,热流体的比热容应该比冷流体的比热容要小。对于一个给定的热交换过程,可以应用本文所得的热论确定换热器两端的流体温差的最佳关系式或冷、热流体比热的最佳比率。 相似文献
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带中间冷却和回热的燃气轮机动态性能的研究 总被引:2,自引:0,他引:2
对某舰用燃气轮机进行了中间冷却和回热(ICR)的改造设计,采用按比例缩小压气机的方法,使改造设计后的燃气轮机各部件性能达到了良好的匹配.依照模块化建模的原理,建立了换热器等部件模块,在此基础上,在EASY 5仿真平台上搭建了ICR燃气轮机的系统模型,并对其进行了稳态和动态的仿真试验计算.结论认为,舰用燃气轮机改造为ICR燃气轮机,需要重新设计压气机以平衡由于中间冷却器造成的高压压气机入口折合流量降低的影响;ICR燃气轮机具有较高的效率和良好的变工况性能.图5表1参5 相似文献
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板翅式换热器是舰载燃气轮机首选换热器形式。针对平直型翅片的矩形通道的结构特点,建立了流动换热分析的耦合计算模型,采用计算流体动力学(CFD)方法对间冷器的通道流场进行了数值模拟。给出并分析了计算区域内多个截面的温度、压力、速度、局部传热系数等参数的分布图形和变化趋势,并考察了不同工况下间冷器的工作能力。 相似文献
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Theory and experimental validation of cross-flow micro-channel heat exchanger module with reference to high Mach aircraft gas turbine engines 总被引:1,自引:0,他引:1
Robert Nacke Brittany Northcutt Issam Mudawar 《International Journal of Heat and Mass Transfer》2011,54(5-6):1224-1235
This study explores the design, analysis, and performance assessment of a new class of heat exchangers intended for high Mach aircraft gas turbine engines. Because the compressor air that is used to cool turbine blades and other components in a high Mach engine is itself too hot, aircraft fuel is needed to precool the compressor air, cooling is achieved with a new heat exchanger. The heat exchanger consists of a large number of miniature, closely-spaced modules. Within each module, the fuel flows through a series of parallel micro-channels, while the air flows externally over rows of short, straight fins perpendicular to the direction of fuel flow. A theoretical model was developed to predict the thermal performance of the module for various operating conditions. To confirm the accuracy of the model, a single module was constructed and tested using water to simulate the aircraft fuel. The theoretical model was used to predict the air temperature drop, water temperature rise, and heat transfer rate for each fluid stream. Comparisons between theory and experiment show good overall agreement in exit temperatures and heat transfer rates. This study shows the theoretical model is a reliable tool for predicting the performance of heat exchanger modules under actual fuel and air turbine engine conditions and for the design of aircraft heat exchangers of different sizes and design envelopes. 相似文献
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基于SIMULNK的单轴重型燃气轮机建模与仿真研究 总被引:1,自引:0,他引:1
通过面向对象的模块化建模方法,在MATLAB/SIMULINK软件中建立了燃气轮机部件模块库,并进行了燃气轮机系统变工况仿真研究。为了提高仿真精度,本文采用变比热容的计算方法,并考虑气体组分的变化对整个系统模型的影响,建立了一种考虑容积惯性和转动惯性的、非线性的单轴重型燃气轮机实时动态仿真模型。仿真结果表明,该模型设计合理、结构清晰,可应用于重型燃气轮机控制系统的研制和测试,并具有很好的通用性和扩展性。 相似文献
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Based on the dynamic model of the gas engine heat pump (GEHP) system, an intelligent control simulation is presented to research the dynamic characteristics of the system in the heating operation. The GEHP system simulation model consists of eight models for its components including a natural gas engine, a compressor, a condenser, an expansion valve, an evaporator, a cylinder jacket heat exchanger, an exhaust gas heat exchanger and an auxiliary heater. The intelligent control model is composed of the prediction controller model and the combined controller model. The Runge–Kutta Fehlberg fourth–fifth order algorithms are used to solve the differential equations. The results show that the model is very effective in analyzing the effects of the control system, and the steady state accuracy of the intelligent control scheme is higher than that of the fuzzy controller. 相似文献
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This paper has proposed an improved liquefied natural gas (LNG) fuelled combined cycle power plant with a waste heat recovery and utilization system. The proposed combined cycle, which provides power outputs and thermal energy, consists of the gas/steam combined cycle, the subsystem utilizing the latent heat of spent steam from the steam turbine to vaporize LNG, the subsystem that recovers both the sensible heat and the latent heat of water vapour in the exhaust gas from the heat recovery steam generator (HRSG) by installing a condensing heat exchanger, and the HRSG waste heat utilization subsystem. The conventional combined cycle and the proposed combined cycle are modelled, considering mass, energy and exergy balances for every component and both energy and exergy analyses are conducted. Parametric analyses are performed for the proposed combined cycle to evaluate the effects of several factors, such as the gas turbine inlet temperature (TIT), the condenser pressure, the pinch point temperature difference of the condensing heat exchanger and the fuel gas heating temperature on the performance of the proposed combined cycle through simulation calculations. The results show that the net electrical efficiency and the exergy efficiency of the proposed combined cycle can be increased by 1.6 and 2.84% than those of the conventional combined cycle, respectively. The heat recovery per kg of flue gas is equal to 86.27 kJ s?1. One MW of electric power for operating sea water pumps can be saved. The net electrical efficiency and the heat recovery ratio increase as the condenser pressure decreases. The higher heat recovery from the HRSG exit flue gas is achieved at higher gas TIT and at lower pinch point temperature of the condensing heat exchanger. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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在建立压气机、燃烧室、透平、回热器、湿化器、气水换热器、转轴转动惯性模型、气道热惯性模型和燃料供给系统模型等单元部件动态模型的基础上,建立了恒转速微型HAT循环的系统动态模型及其控制系统模型。对其阶跃降负荷过渡过程进行了动态模拟,并与微燃机简单、回热循环进行了对比。结果表明,该动态模型能够有效地对系统的过渡过程进行模拟与分析,计算稳定可靠,可为微型HAT循环控制系统设计与分析提供模型基础;控制系统设计合理,能够满足调节负荷和转速的要求,保证循环系统安全运行;水路的热惯性对系统响应影响较小,而回热器的热惯性是影响微型HAT循环和回热循环过渡过程响应的主要因素。 相似文献
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Recently, there has been wide-ranging research on the idea of biomass fuel powered externally firing micro gas turbines; but only a small subset of these studies has used experimental work to evaluate the systems. These systems have not yet been employed in Malaysia for applications in thermal energy or power generation. The objective of this study is to determine the performance of a stainless steel high-temperature heat exchanger, which was built to transfer thermal power from a biomass gasifier-combustor to the pure air turbine working fluid. The study is based on experimental work using different air blower capacities as an air supply. The heat exchanger achieved 694 °C turbine inlet temperature with an average effectiveness of 62.5%. 相似文献