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进口温度畸变对发动机稳定性影响的数值研究 总被引:3,自引:1,他引:3
发动机进口温度畸变是影响发动机稳定性的关键因素之一。进口温度畸变对某新型涡轮风扇发动机稳定性和性能的影响进行了数值研究,得到了该发动机的温升率阈值和温升阈值。分析了畸变在发动机流道中的发展情况,同时给出了温度畸变对发动机主要性能参数推力和耗油率的影响。 相似文献
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首先概述了故障的主要现象与特征。然后着重描述了直升机空中振荡故障的试验研究:包括研究途径;直升机模型的建立;两个回路振荡试验及其主要研究结果。据此提出了在设计,使用中的一些预防原则和措施。 相似文献
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旨在为战斗机发动机技术研究和产品研制提供参考与借鉴,全面综述了美国战斗机发动机技术研究与产品研制的发展历程和典型成果,并归纳和总结了其发展特点与趋势:技术研究是产品研制的坚实基础,而核心机和发动机验证机只是用于开发与验证技术,特别是正在验证的自适应循环技术还需要深入验证;型号研制受国防武器需求牵引,是众多先进技术的有机集成;提高技术指标始终是战斗机发动机的发展趋势;高可靠性和耐久性是型号使用的必然要求,并逐步成为发展趋势;提高经济可承受性是航空发动机最终追求目标。 相似文献
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Experimental and Numerical Studies of Vitiated Air Effects on Hydrogen-fueled Supersonic Combustor Performance 总被引:2,自引:0,他引:2
This paper deals with the vitiation effects of test air on the scramjet performance in the ground combustion heated facilities. The primary goal is to evaluate the effects of H2O and CO2, the two major vitiated species generated by combustion heater, on hydrogen-fueled supersonic combustor performance with experimental and numerical approaches. The comparative experiments in the clean air and vitiated air are conducted by using the resistance heated direct-connected facility, with the typical Mach 4 flight conditions simulated. The H2O and CO2 species with accurately controlled contents are added to the high enthalpy clean air from resistance heater, to synthesize the vitiated air of a combustion-type heater. Typically, the contents of H2O species can be varied within the range of 3.5%-30% by mole, and 3.0%-10% for CO2 species. The total temperature, total pressure, Mach number and O2 mole fraction at the combustor entrance are well-matched between the clean air and vitiated air. The combustion experiments are completed at the fuel equivalence ratios of 0.53 and 0.42 respectively. Furthermore, three-dimensional (3D) reacting flow simulations of combustor flowpath are performed to provide insight into flow field structures and combustion chemistry details that cannot resolved by experimental instruments available. Finally, the experimental data, combined with computational results, are employed to analyze the effects of H2O and CO2 vitiated air on supersonic combustion characteristics and performance. It is concluded that H2O and CO2 contaminants can significantly inhibit the combustion induced pressure rise measured from combustor wall, and the pressure profile decreases with the increasing H2O and CO2 contents in nonlinear trend; simulation results agree well with experimental data and the overall vitiation effects are captured; direct extrapolation of the results from vitiated air to predict the performance of actual flight conditions could result in over-fueling the combustor, possible inlet un-start and inappropriate combustion mode transition. The detailed analysis and discussion are presented and the research conclusions are summarized. 相似文献