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| 1 | 叶顶间隙尺度的不确定性对压气机性能影响的CFD模拟显示文摘本文研究了转子叶顶间隙尺度的不确定性对某轴流压气机的气动性能的影响。采用非嵌入式概率配置点法模拟间隙尺度不确定性在流场中的传播。先以二维随机方腔流动为模型,通过与蒙特卡洛模拟进行对比对非嵌入式概率配置点法进行验证。验证后采用该不确定性方法模拟了当叶顶间隙大小服从Beta分布时气动性能及流场参数的变化。 | 刘智益 王晓东 康顺 | 2013 | 工程热物理学报2013，34，4： | 12 |
| 2 | Numerical Investigation of Rotating Stall in Centrifugal Compressor with Vaned and Vaneless Diffuser显示文摘This study presents a numerical simulation of the stall and surge in a centrifugal compressor and presents a description of the stall development in two different cases.The first case is for a compressor with vaneless diffuser and the second is for a compressor with vaned diffuser of the vane island shape.The main aim of this study is to compare the flow characteristics and behavior for the two compressors near the surge operating condition and provide further understanding of the diffuser role when back flow occurs at surge.Results showed that for a location near the diffuser entrance,the amplitude of the static pressure fluctuations for the vaneless diffuser case is higher than that for the vaned diffuser case near surge condition.These pressure fluctuations in the case of the vaneless diffuser appear with a gradual decrease of the mean pressure value as a part of the surge cycle.While for the case of the vaned diffuser,the pressure drop during surge occurs faster than the case of the vaneless diffuser.Also,results indicated that during surge in the case of vaneless diffuser,there is a region with low velocity and back flow that appears as a layer connecting all impeller passages near shroud surface and this layer develops in size with time.On the other hand,for the case of vaned diffuser during surge,the low velocity regions appear in random locations in some passages and these regions expand with time towards the shroud surface.Results showed that during stall,the impeller passages are exposed to identical impact from stall cells in the case of vaneless diffuser while the stall effect varies from passage to another in the case of the vaned diffuser. | Taher Halawa Mohamed Alqaradawi Mohamed S.Gadala Ibrahim Shahin Osama Badr | 2015 | Journal of Thermal Science2015，24，4： | 6 |
| 3 | Dual stability enhancement mechanisms of axial-slot casing treatment in a high-speed mixed-flow compressor with various tip clearances显示文摘The influence of Axial-Slot Casing Treatment(ASCT)on the performance and stability enhancement mechanisms of ASCT were experimentally and numerically investigated in a highspeed mixed-flow compressor under three different tip clearances.Unsteady simulations showed the compressor stalled through end-wall stall route,i.e.the spike stall inception originating from rotor tip region,which was validated by dynamical measurements.When the ASCT was applied,greater than 20%of Stall Margin Improvement(SMI)could be achieved for the compressor under each tip clearance size.The streamwise velocity contours and flow structures in the tip region and axial slots were deeply analyzed to explore how the so called‘‘suction and injection effects'generated by the ASCT manipulate tip clearance flow and enhance the stability of compressor under different tip clearances.It was found that the dominant stability enhancement mechanisms of ASCT varies with tip clearance size for the mixed-flow compressor.(A)For the small tip clearance,the dominant mechanism of stability enhancement is the blockage reduction generated in the blade passage by the suction effect of ASCT.(B)For the large tip clearance,the injection effect of the ASCT is the dominant mechanism of stability enhancement with ASCT,which plays the leading role in delaying the spillage of incoming/tip leakage flow interface at the rotor Leading Edge(LE)plane. | Qianfeng ZHANG Juan DU Jichao LI Ming ZHAO Hongwu ZHANG | 2021 | Chinese Journal of Aeronautics2021，34，4： | 2 |
| 4 | Theoretical and numerical investigations on the headspace of cartridge cases considering axial deformation and movement显示文摘The cartridge case headspace is the axial clearance between the cartridge and bolt of an automatic weapon,and influences the reliability and security of the weapon.Accordingly,theoretical and numerical studies were conducted to analyze the dynamic response of cartridge cases during internal impact considering the initial radial clearances between the cartridge case and chamber.A theoretical model was proposed to predict the cartridge case headspace considering both the deformation and movement of the cartridge case and confirmed by the results of nonlinear finite element simulations.The differences between the results of the conventional static model and the dynamic model were then comprehensively evaluated.The effects of the angle between the cartridge and chamber,the cartridge case material,and the intermal impact pressure on the predicted headspace value were also analyzed.The dynamic response of the cartridge case predicted by the dynamic model was more accurate than that predicted by the conventional static model.The internal impact pressure,pressure change rate,and cartridge material were all found to affect the predicted headspace. | Song Cai Chen-lei Huang Kun Liu Zhong-xin Li Zhi-lin Wu | 2020 | Defence Technology(防务技术)2020，16，1： | 0 |
| 5 | 不同叶顶几何形状对压气机叶栅间隙泄漏流动的影响显示文摘为揭示不同叶顶几何形状对压气机叶栅间隙泄漏流动的影响,以压气机平面叶栅作为研究对象,应用数值模拟方法,采用6种不同的叶顶几何形状对比研究泄漏涡的变化.结果表明,合理的叶顶几何形状可以在一定程度上降低叶尖损失,不同叶尖几何方案对于改善气流偏转、提高叶栅流通能力有较好效果.吸力面全部片削叶顶对调控叶尖损失、改善叶栅性能效果最为显著. | 钟兢军 桑则林 韩少冰 | 2016 | 大连海事大学学报2016，42，1： | 0 |
| 6 | 转子叶尖间隙形状对跨声速轴流压气机性能影响机理分析显示文摘为研究转子不同叶尖间隙形状对跨声速轴流压气机性能的影响机理,分别对平行式叶尖间隙进行渐变式和阶梯式改型优化,并利用商业软件NUMECA进行数值模拟。结果表明:对平行式叶尖间隙进行渐变式和阶梯式改型优化后,压气机性能有较大提高,改型后0.204-0.408的各类间隙压气机性能优于0.408-0.204间隙的。相比较平行间隙PTC 0.204-0.204,渐变式TTC0.204-0.408和阶梯式STC 0.204-0.408的失速裕度分别提高1.12%和1.61%,峰值效率基本不变,同时近失速工况下的总压比和效率也略有提高。叶尖泄漏涡得到抑制,间隙处的流体低速区明显减小,流动损失减小,流场得到较大改善。转子通道的总压比在85%叶高处明显提高,分别提高了1.01%和3.13%。阶梯式叶尖间隙压气机的静子通道40%叶高处总压损失系数减小达75.4%。对平行式叶尖间隙进行改型处理能够有效提高压气机性能,且阶梯式叶尖间隙比渐变式的对压气机性能提高的效果更加显著。 | 张成烽 张国臣 徐志晖 孙丹 刘鹏程 | 2023 | 航空发动机2023，49，3： | 0 |
| 7 | 叶顶间隙对高压比离心压气机性能的影响机理显示文摘为了研究高压比离心压气机叶顶间隙流动损失的产生机理,建立了18个不同叶顶间隙的压气机叶轮模型,采用数值方法对其进行流场求解计算,对比分析有叶顶间隙与无叶顶间隙下压气机叶轮流道内的流场特性,进行不同叶顶间隙下叶轮流动的对比研究.结果表明:在设计转速与流量下,等熵效率与压比随叶顶间隙比率的增加而近似线性减小;叶轮流道内产生的泄漏涡与主叶片前缘激波相互作用造成有叶顶间隙下的流动损失,高速流体与机匣壁面作用产生的壁面涡与主、辅叶片前缘的激波共同造成了无叶顶间隙下的流动损失;随着叶顶间隙的不断增加,泄漏涡与激波相互作用产生的影响力不断向下游移动,导致压气机性能的不断降低. | 温华兵 宋震 洪良星 刘悦 申华 | 2018 | 江苏科技大学学报(自然科学版)2018，32，6： | 0 |
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