A combined-cycle power plant (CCPP) is broadly utilized in many countries to cover energy demand due to its higher efficiency than other conventional power plants. The performance of a CCPP is highly sensitive to ambi...A combined-cycle power plant (CCPP) is broadly utilized in many countries to cover energy demand due to its higher efficiency than other conventional power plants. The performance of a CCPP is highly sensitive to ambient air temperature (AAT) and the generated power varies widely during the year with temperature fluctuations. To have an accurate estimation of power generation, it is necessary to develop a model to predict the average monthly power of a CCPP considering ambient temperature changes. In the present work, the Monte Carlo (MC) method was used to obtain the average generated power of a CCPP. The case study was a combined-cycle power plant in Tehran, Iran. The region’s existing meteorological data shows significant fluctuations in the annual ambient temperature, which severely impact the performance of the mentioned plant, causing a stochastic behavior of the output power. To cope with this stochastic nature, the probability distribution of monthly outdoor temperature for 2020 was determined using the maximum likelihood estimation (MLE) method to specify the range of feasible inputs. Furthermore, the plant was accurately simulated in THERMOFLEX to capture the generated power at different temperatures. The MC method was used to couple the ambient temperature fluctuations to the output power of the plant, modeled by THERMOFLEX. Finally, the mean value of net power for each month and the average output power of the system were obtained. The results indicated that each unit of the system generates 436.3 MW in full load operation. The average deviation of the modeling results from the actual data provided by the power plant was an estimated 3.02%. Thus, it can be concluded that this method helps achieve an estimation of the monthly and annual power of a combined-cycle power plant, which are effective indexes in the economic analysis of the system.展开更多
针对一个并联式涡轮基组合循环(Turbine Based Combined Cycle,TBCC)发动机排气系统的气动方案,对其在整个飞行包线范围内典型工作点上的流场进行了数值模拟研究,获得了飞行包线范围内排气系统相应的推力系数、升力、俯仰力矩随飞行马...针对一个并联式涡轮基组合循环(Turbine Based Combined Cycle,TBCC)发动机排气系统的气动方案,对其在整个飞行包线范围内典型工作点上的流场进行了数值模拟研究,获得了飞行包线范围内排气系统相应的推力系数、升力、俯仰力矩随飞行马赫数的变化关系。计算结果显示,在整个飞行包线范围内,排气系统的轴向推力系数随着飞行马赫数先减小后增大,在跨声速飞行时降到最低Ma=0.9,涡喷不加力时为0.562,加力时0.662),在设计点附近达到最大;升力和俯仰力矩性能在亚声速及跨声速飞行时较差,在超声速飞行时随着飞行马赫数增加逐渐好转。表明排气系统在跨声速飞行范围内工作时应采取措施以改善其性能。展开更多
随着对远程、宽马赫数范围内高速飞行器的需求日益迫切,超燃冲压发动机(Scramjet)、甚至未来涡轮基组合循环发动机(Turbine Based Combined Cycle,TBCC)等已成为国内外研究的焦点。推进系统是高超声速飞行器能否实现宽马赫数范围内高效...随着对远程、宽马赫数范围内高速飞行器的需求日益迫切,超燃冲压发动机(Scramjet)、甚至未来涡轮基组合循环发动机(Turbine Based Combined Cycle,TBCC)等已成为国内外研究的焦点。推进系统是高超声速飞行器能否实现宽马赫数范围内高效工作的关键,而非对称喷管(Single Expansion Ramp Nozzle,SERN)是其重要组成部分和关键技术之一。本文主要分析了远程、宽马赫数范围内高速飞行器对其发动机尾喷管的特殊要求,简要回顾了国内外相关的研究进展,重点介绍了本课题组针对超燃冲压及组合循环发动机尾喷管设计方法的主要工作和研究进展。结果表明:在大落压比下,不同的设计方法对非对称喷管的气动性能,特别是升力和俯仰力矩影响较大。最后对未来的研究进行了展望,旨在总结目前的相关研究进展,梳理关键科学与技术问题,为后续的研究工作提供参考。展开更多
基于CFD数值模拟方法,分析了并联式涡轮基组合循环发动机(Turbine Based Combined Cycle,TBCC)排气系统的内外流场特性,提出了在涡轮喷管下壁面处喷入高压二次流以提升排气系统性能的方式,研究了不同飞行状态下二次流喷射对排气系统性能...基于CFD数值模拟方法,分析了并联式涡轮基组合循环发动机(Turbine Based Combined Cycle,TBCC)排气系统的内外流场特性,提出了在涡轮喷管下壁面处喷入高压二次流以提升排气系统性能的方式,研究了不同飞行状态下二次流喷射对排气系统性能(推力系数、推力矢量角)的影响规律。计算结果表明:二次流喷射会产生弓形激波,与喷管上膨胀壁面附面层作用产生新的分离区,提升涡轮喷管和冲压喷管内的整体压力,从而改善并联式TBCC排气系统的推力及推力矢量性能,且对亚声速和跨声速飞行状态下的并联式TBCC排气系统性能改善比较明显,可使轴向推力系数最大提升7.34%,推力矢量角提升12.76°。展开更多
文摘A combined-cycle power plant (CCPP) is broadly utilized in many countries to cover energy demand due to its higher efficiency than other conventional power plants. The performance of a CCPP is highly sensitive to ambient air temperature (AAT) and the generated power varies widely during the year with temperature fluctuations. To have an accurate estimation of power generation, it is necessary to develop a model to predict the average monthly power of a CCPP considering ambient temperature changes. In the present work, the Monte Carlo (MC) method was used to obtain the average generated power of a CCPP. The case study was a combined-cycle power plant in Tehran, Iran. The region’s existing meteorological data shows significant fluctuations in the annual ambient temperature, which severely impact the performance of the mentioned plant, causing a stochastic behavior of the output power. To cope with this stochastic nature, the probability distribution of monthly outdoor temperature for 2020 was determined using the maximum likelihood estimation (MLE) method to specify the range of feasible inputs. Furthermore, the plant was accurately simulated in THERMOFLEX to capture the generated power at different temperatures. The MC method was used to couple the ambient temperature fluctuations to the output power of the plant, modeled by THERMOFLEX. Finally, the mean value of net power for each month and the average output power of the system were obtained. The results indicated that each unit of the system generates 436.3 MW in full load operation. The average deviation of the modeling results from the actual data provided by the power plant was an estimated 3.02%. Thus, it can be concluded that this method helps achieve an estimation of the monthly and annual power of a combined-cycle power plant, which are effective indexes in the economic analysis of the system.
文摘针对一个并联式涡轮基组合循环(Turbine Based Combined Cycle,TBCC)发动机排气系统的气动方案,对其在整个飞行包线范围内典型工作点上的流场进行了数值模拟研究,获得了飞行包线范围内排气系统相应的推力系数、升力、俯仰力矩随飞行马赫数的变化关系。计算结果显示,在整个飞行包线范围内,排气系统的轴向推力系数随着飞行马赫数先减小后增大,在跨声速飞行时降到最低Ma=0.9,涡喷不加力时为0.562,加力时0.662),在设计点附近达到最大;升力和俯仰力矩性能在亚声速及跨声速飞行时较差,在超声速飞行时随着飞行马赫数增加逐渐好转。表明排气系统在跨声速飞行范围内工作时应采取措施以改善其性能。
文摘基于CFD数值模拟方法,分析了并联式涡轮基组合循环发动机(Turbine Based Combined Cycle,TBCC)排气系统的内外流场特性,提出了在涡轮喷管下壁面处喷入高压二次流以提升排气系统性能的方式,研究了不同飞行状态下二次流喷射对排气系统性能(推力系数、推力矢量角)的影响规律。计算结果表明:二次流喷射会产生弓形激波,与喷管上膨胀壁面附面层作用产生新的分离区,提升涡轮喷管和冲压喷管内的整体压力,从而改善并联式TBCC排气系统的推力及推力矢量性能,且对亚声速和跨声速飞行状态下的并联式TBCC排气系统性能改善比较明显,可使轴向推力系数最大提升7.34%,推力矢量角提升12.76°。
