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This paper studies on a division method of the whole aeroengine loading spectrum flight mission segment and rotor speed mission segment, which is based on the actual flight actions and related to the flight operations of aeroengine and is suitable for the variable-speed aeroengines such as turbojet and turbofan. Through the research, the aeroengine loading spectrum operation-related mission segments can be divided, which can provide important data basis for the life research on the structures wh... 相似文献
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为研究双转子轴间滑油颗粒运动对环下润滑收油效率及轴承腔油气分离效率的影响,建立了对转轴间在边界层流场结构下基于质点运动学的滑油颗粒运动轨迹参数化模型,并采用经实验验证的计算流体力学(CFD)数值计算结果进行验证。双转子轴间的边界层流场结构的确定运用了对湍流边界层卡门三层结构速度分布进行修正的方法。结果表明:给出的参数化模型可以很好地描述双转子轴间的滑油颗粒运动规律。直径较大的颗粒径直或沿弧线迅速到达外轴,而直径较小的颗粒中存在一个在给定停留时间内使颗粒无法到达外轴的最大直径,小于这一临界直径的颗粒在有轴向气流时将被吹离轴间环腔。 相似文献
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离心泵中流动不稳定现象与流场中旋涡的形成及演化过程密切相关。为解决传统涡识别法在高速离心泵流场涡结构捕捉方面的缺陷,引入新Omega涡识别法,对液体火箭发动机涡轮氧泵流场中的涡结构进行了分析。确定了新Omega涡识别法在高速离心泵流场涡结构捕捉方面的优势,利用该方法对涡轮氧泵中离心轮与扩压器之间的动静干涉机理进行了阐释。结果表明:对于高速离心泵,传统Q准则以及λ2准则涡识别法错误地将壁面强剪切层识别为旋涡,而新Omega涡识别方法能够有效滤除流场中非旋转涡量部分,较好地捕捉流场中涡结构,可作为高速离心泵流场涡结构识别的首选方法。通过离心轮与扩压器动静干涉区域旋涡演化过程分析可知,涡轮氧泵离心轮与扩压器之间的动静干涉效应主要源自于扩压器叶片压力面上的周期性涡脱落现象。 相似文献
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Based on the acoustic mapping, a prediction model for the ground noise radiated from an in-flight helicopter is established. For the enhancement of calculation efficiency, a high-efficiency second-level acoustic radiation model capable of taking the influence of atmosphere absorption on noise into account is first developed by the combination of the point-source idea and the rotor noise radiation characteristics. The comparison between the present model and the direct computation method of noise is done and the high efficiency of the model is validated. Rotor free-wake analysis method and Ffowcs Williams-Hawkings (FW-H) equation are applied to the aerodynamics and noise prediction in the present model. Secondly, a database of noise spheres with the characteristic parameters of advance ratio and tip-path-plane angle is established by the helicopter trim model together with a parametric modeling approach. Furthermore, based on acoustic mapping, a method of rapid simulation for the ground noise radiated from an in-flight helicopter is developed. The noise footprint for AH-1 rotor is then calculated and the influence of some parameters including advance ratio and flight path angle on ground noise is deeply analyzed using the developed model. The results suggest that with the increase of advance ratio and flight path angle, the peak noise levels on the ground first increase and then decrease, in the meantime, the maximum Sound Exposure Level (SEL) noise on the ground shifts toward the advancing side of rotor. Besides, through the analysis of the effects of longitudinal forces on miss-distance and rotor Blade-Vortex Interaction (BVI) noise in descent flight, some meaningful results for reducing the BVI noise on the ground are obtained. 相似文献
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The heat transfer in a novel smooth wedge-shaped cooling channel with lateral ejection of turbine blade trailing edge is experimentally investigated in both non-rotating and rotating cases. Beside the conventional inlet at the bottom of the channel, an extra coolant injection from 8 lateral non-equant holes is introduced to improve the overall heat transfer. The total mass flow rate ratio (lateral mass flow rate/total mass flow rate) varies from 0 to 1.0. The major inlet Reynolds number and rotation number respectively vary from 10000 to 20000 and from 0 to 1.16. Experimental results show that the lateral inlet decreases local bulk temperature and increases local heat transfer at the middle and the top of the static channel. In rotating cases, the lateral inlet notably improves the heat transfer at the high-radius half channel and compensates the negative effects induced by the rotation. Both intensity and uniformity of heat transfer inside the channel are enhanced while flow resistance decreases with proper mass flow rate ratio of coolant from two inlets. The most satisfactory total mass flow rate ratio is around 2/3. This new structural style of cooling channel has huge potential and provides new direction of heat transfer of turbine blade trailing edge. 相似文献
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