共查询到19条相似文献,搜索用时 500 毫秒
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针对发动机安全性、减少油耗、降低热应力问题,研究某型涡扇发动机非线性数学模型,在满足发动机各部件物理约束条件和推力相等的条件下,采用遗传算法就巡航状态下耗油率最低,对性能指标进行寻优,寻优过程用GAlib类库的遗传算法和涡扇发动机非线性数学模型结合编程实现.在地面及空中巡航状态下分别进行仿真,在推力相等的条件下,地面巡航状态的耗油率在优化后比优化前降低了13.8%,空中巡航状态的耗油率在优化后比优化前降低了9.45%.研究表明:遗传算法适用于像涡扇发动机巡航状态性能寻优这样大规模、高度非线性及无解析表达式的性能优化. 相似文献
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航空发动机的控制规律作用巨大,它决定了发动机能否获得设定的稳态工作下性能指标,同时保证工作过程中的压气机和涡轮的气动稳定性;双转子涡喷发动机气动性能优化控制的目的就是有效地挖掘发动机的使用潜力;研究方法采用部件特性法对发动机进行稳态建模,并针对某双转子涡喷发动机的稳态模型进行三种不同稳态控制规律下的仿真,得到发动机性能参数的不同变化趋势,并对其进行了详细的分析;结果表明:保持低压转子转速不变的情况下,随着压气机进口总温的增加,高压转子转速上升,涡轮前温度升高,发动机推力增加;保持涡轮前温度不变的情况下,随着压气机进口总温的升高,低压压气机气动负荷变重,低压转子转速降低;高压转子转速也下降,但是下降幅度很小;燃油流量增加;保持高压转子转速不变的情况下,随着压气机进口总温的升高,燃油流量有一定的增加,低压转子转速有所降低;推力受多重因素的影响,推力值变化趋势较为复杂。 相似文献
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通过结构分析某型发动机高压压气机,利用三维建模软件NX对其主要零部件开展3D建模,并进行装配,使得高压压气机的结构更加直观。使用ANSYS软件模态分析带有损伤的叶片,主要目的是得到在不同频率下带有损伤的转子叶片的振动形态,提高航空发动机的维修效率,加强飞机的飞行安全。 相似文献
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航空发动机转子叶尖间隙测量 总被引:6,自引:0,他引:6
简述了航空发动机转子叶尖间隙控制的意义及作用,转子叶尖间隙设计选择的依据.以某型风扇和某型高压压气机转子叶尖间隙测量为例,具体分析了间隙对性能的影响作用和变化规律,论证了间隙测试技术作为一种指导和验证手段在工程应用中的重要作用. 相似文献
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为了深入研究水滴对发动机性能的影响和提高发动机性能仿真的精确,采用逐级计算的加法进行多级轴流压气机吸雨性能计算。通过将压气机各级计算模型拆分为“干压气机模型”和“湿压气机模型”,利用交叉计算得到压气机各级的性能参数,然后逐级计算得到整体压气机的性能。针对某10级轴流式压气机,采用上述方法对压气机在吸雨条件下的性能进行仿真,计算得到该压气机在不同吸雨状态下的特性,温度和压力分布等性能参数,对于1%和2%吸雨量压气机出口的温度降低了6.9%和11.2%,水气比分别为2%、1%和0.5%,压气机出口压力分别增加了7.4%、5.3%和4.4%。为发动机在吸雨状态下的性能仿真和参数预测提供支撑。 相似文献
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一体化变几何冲压发动机控制规律研究 总被引:1,自引:0,他引:1
为达到减轻导弹发射总重和提高导弹机动性的目的,建立了基于能量法的一体化超声速导弹/冲压发动机控制规律优化设计模型,通过合理调节尾喷管喉部面积,减小进气道的亚声速溢流阻力和提高总压恢复系数,降低冲压发动机的耗油率,实现一体化控制规律,在优化设计模型中,包含导弹升阻特性预测模型、冲压发动机特性与安装特性计算模型.将相应的计算程序在iSIGHT软件平台中进行集成并利用其优化功能,实现了尾喷管最优控制规律设计.对某型冲压发动机的计算结果表明,通过优化调整尾喷管喉部面积,可以显著降低导弹的发射总重,并明显提高导弹机动性. 相似文献
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为了解压差式空压机二级缸内压力相互作用情况,提高工作效率,基于CZ60/30船用空压机气缸和活塞的结构以及该型空压机工作特点,建立高、低压级气缸内压力和压差关系的数学模型,通过MATLAB进行模拟.通过模拟结果分析气缸余隙高度对缸内压力和压差的影响情况,并得到高、低压级气缸压力随时间的变化曲线,为高效的空压机设计和故障分析提供参考. 相似文献
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N. Lawrence Ricker 《Control Engineering Practice》2010,18(6):608-617
Predictive control is applied to a supermarket refrigeration process in which all actuators are on/off devices. This process has been proposed as a benchmark for the evaluation of hybrid control methods. It is shown that decentralized predictive control of display case temperatures, when combined with predictive control of suction manifold pressure, can greatly reduce or eliminate on/off compressor cycling. The strategy is scalable to large systems. Results are presented for an application involving 10 display cases and six compressors. Traditional hysteresis control causes synchronization of display case temperature oscillations. The proposed predictive approach includes desynchronization, which is shown to be necessary for minimization of compressor cycling. Finally, it is shown that the minimum possible number of compressor cycles can be estimated. This limit on control system performance is imposed by process design and operating conditions. It is also shown that the recommended predictive control strategy operates close to the minimum possible number of compressor cycles for the benchmark process. 相似文献
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The dynamic method of the determination of the piezoelectric hydrostatic coefficients, dh, was improved. We have constructed new equipment for more exact measurement by means of the direct dynamic method. The piston for the high-pressure mechanical excitation of pressure changes was used. The advantage of the proposed method is a low frequency (about 1 Hz) pressure excitation. The lever hydraulic press is able to create the hydrostatic pressure inside the pressure chamber up to 70 MPa. The temperature control is realised by the PID temperature controller with a resistivity heater and by the compressor cooler. 相似文献
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Zhou Shengbing Chen Lingen Sun Fengrui Wu Chih 《Open Systems & Information Dynamics》2002,9(4):325-337
The performance optimization of an irreversible simple Brayton refrigerator coupled to constant-temperature heat reservoirs
is carried out by taking the cooling load density, i.e., the ratio of cooling load to the maximum specific volume in the cycle,
as the optimization objective using finite-time thermodynamics (FTT) or entropy generation minimization (EGM) in this paper.
The analytical formulae about the relations between cooling load density and pressure ratio, as well as between coefficient
of performance (COP) 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 expander. The influences of the effectiveness
of the heat exchangers, the temperature ratio of the reservoirs, and the efficiencies of the compressor and expander on the
cooling load density versus COP are provided by numerical examples. The cooling load density optimization is performed by
searching the optimum pressure ratio of the compressor, and searching the optimum distribution of heat conductance of the
hot- and cold-side heat exchangers for the fixed total heat exchanger inventory. The influences of some design parameters,
including the effectiveness of the heat exchangers between the working fluid and heat reservoirs, the efficiencies of compressor
and expander, the temperature ratio of heat reservoirs, on the maximum cooling load density, the optimum heat conductance
distribution and the optimum pressure ratio are provided by numerical examples. The refrigeration plant design with optimization
leads to a smaller size including the compressor, expander, and the hot- and cold-side heat exchangers. 相似文献
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彭文 《自动化与仪器仪表》2011,(5):86-89
川化股份有限公司化肥厂二化尿素装置为日产2460T尿素的大型化肥装置,其CO2压缩机采用日本三菱3V-7B型两缸四段压缩机,由抽汽注汽冷凝式透平驱动。该透平的转速控制由505E控制器实现,并与ProTech 203相结合实现压缩机的两级超速保护。Woodward 505E数字控制器适用于具有一次可调整的纯抽汽、抽补结合或纯补汽型式透平的控制,可现场编程组态,使标准的设计能适用于各种不同的控制场合。文中介绍了505E控制器在U-GB151 CO2压缩机上的调速应用,并例举调速系统出现的故障,进行分析排除。 相似文献
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示功图和指示参数是压缩机综合性能的体现;针对传统示功图绘制存在的缺陷,开发了基于计算机自动测试技术的压缩机示功图测试、分析系统;该系统通过对气缸内的动态压力信号、压力标定信号及活塞止点信号进行数据采样.并对实测采样数据分析处理,得到示功图;该系统界面友好,操作方便,有较高的控制精度和较快的采样分析速度。 相似文献