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121.
Fuel tank inerting technologies are able to reduce the fire risk by injection of inert gas into the ullage or fuel, the former called ullage washing and the latter fuel scrubbing. The Green On-Board Inert Gas Generation System (GOBIGGS) is a novel technology based on flameless catalytic combustion, and owning to its simple structure and high inerting efficiency, it has received a lot of attentions. The inert gas in the GOBIGGS is mainly comprised of CO2, N2, and O2 (hereinafter, Mixed Inert Gas (MIG)), while that in the On-Board Inert Gas Generation System (OBIGGS), which is one of the most widely used fuel tank inerting technologies, is Nitrogen-Enriched Air (NEA). The solubility of CO2 is nearly 20 times higher than that of N2 in jet fuels, so the inerting capability and performance are definitely disparate if the inert gas is selected as NEA or MIG. An inerting test bench was constructed to compare the inerting capabilities between NEA and MIG. Experimental results reveal that, if ullage washing is adopted, the variations of oxygen concentrations on the ullage and in the fuel are nearly identical no matter the inert gas is NEA or MIG. However, the ullage and dissolved oxygen concentrations of MIG scrubbing are always higher than those of NEA scrubbing. 相似文献
122.
限流活门是把液体从固定流量转到限流和减少压力脉动的一种液压元件。本文对强5飞机X2A-5570-850限流活门进行了计算,对限流活门的设计和限流参数起到一定的作用。 相似文献
123.
High-efficiency aircraft antiskid brake control algorithm via runway condition identification based on an on-off valve array 总被引:1,自引:1,他引:1
The aircraft antiskid braking system is an important hydraulic system for preventing tire bursts and ensuring safe take-off and landing. The brake system adjusts the force applied on the brake discs by controlling the brake pressure. Traditional aircraft antiskid braking systems achieve antiskid performance by controlling the braking pressure with an electrohydraulic servo valve. Because the pilot stage of an electrohydraulic servo valve is easily blocked by carbonized hydraulic oil, the servo valve would become a dangerous weak point for aircraft safety. This paper proposes a new approach that uses an on-off valve array to replace the servo valve for pressure control. Based on this new pressure control component, an efficient antiskid control algorithm that can utilize this discontinuous feature is proposed. Furthermore, the algorithm has the ability to identify the runway circumstances. To overcome the discontinuity in the process of using an on-off valve array, the Filippov framework is introduced. The conditions of convergence of the system are also discussed. The results of the digital simulations and the hardware-in-the-loop (HIL) braking experiments are used to verify the efficiency and stability of the proposed control algorithm. The method also proves that the on-off valve array can replace the servo valve perfectly as a new type of antiskid braking pressure control component. 相似文献
124.
125.
介绍了旅客/货主运输决策模型,并根据有关方法做出旅客/货主运输决策模型。然后通过将运输决策模型应用于中枢航线网络的USAPHMP模型,得到旅客/货主运输决策对中枢航线网络效益的影响因素。列举了中国民航某航空公司的实例。 相似文献
126.
127.
利用校正环节提高三级电液伺服阀动态响应的探讨 总被引:2,自引:0,他引:2
许明理 《航空精密制造技术》1997,(5)
论述了通过三级电液伺服阀控制器的改进,利用校正环节提高三级电液伺服阀的阻尼,降低谐振峰值,进而提高三级电液阀的动态响应. 相似文献
128.
129.
高速开关阀PWM控制电路的开发 总被引:10,自引:0,他引:10
田静 《中国民航学院学报》2003,21(6):26-30
高速开关阀是电液伺服机构的惯性环节,伺服机构的品质依赖于阀的动态特性,因此阀的响应快速性很重要。提高高速开关阀的快速性,驱动电路是一个重要方面。采用2051单片机,设计了一种新型的PWM信号发生器,并开发了上下限保护电路,使其快速性得到了进一步的提高。 相似文献
130.
电容式传感器在飞机燃油测量系统中的应用 总被引:2,自引:0,他引:2
叙述了电容式传感器在飞机燃油测量系统中应用。首先,分析了电容式传感器在飞机燃油测量系统中工作的基本原理:因燃油液面位置变化而使电容量产生变化,将其转化为实时电信号,可以实现对飞机油箱油量变化的实时测量。其次,分析了测量误差产生的原因,并提出了改进措施。 相似文献