静叶栅上游端壁双射流气膜冷却特性实验

为了进一步挖掘上游端壁气膜冷却的潜力,在低速叶栅风洞的静叶片上游端壁上,实验研究了双射流构型的气膜冷却特性,并与双排圆孔进行了对比。探究了吹风比(M=0.5,1.0,1.5,2.0)、密度比(Rd=1.0,1.5)的效应。端壁表面的气膜冷却效率通过压力敏感漆(PSP)测得。结果表明,吹风比的增大虽然会加剧吹离现象,但同时也会促进叶栅通道中、后段的气膜覆盖。密度比的增大会抑制气膜吹离,促进气膜横向覆盖和提高平均冷却效率。双射流孔相比于圆形孔,冷却气流在孔下游形成了反肾形涡,较好抑制了气膜吹离;但从双射流孔喷出的冷却气流对于叶栅通道内的涡系也更加敏感。在高吹风比下,双射流孔的冷却效率相对于圆形孔有一定的优势,特别是双射流I构型。     

基于AMESim的火工作动装置仿真方法研究

针对一种小型化、低冲击活塞式火工作动装置,基于AMESim仿真软件建立了火工装置的数学模型,得出了活塞杆推力曲线的影响规律。同时进行试验验证,试验数据与仿真结果高度接近,验证了理论分析与仿真模型的正确性,大幅缩短了火工装置研制周期,并节约了研制成本,为火工装置的研究开拓了一种新型研制模式。     

A scaling procedure for measuring thermal structural vibration generated by wall pressure fluctuation

This paper attempts to develop a scaling procedure to measure structural vibration caused simultaneously by wall pressure fluctuations and the thermal load of hypersonic flow by a wind tunnel test. However, simulating the effect of thermal load is difficult with a scaled model in a wind tunnel due to the nonlinear effect of thermal load on a structure. In this work, the temperature variation of a structure is proposed to indicate the nonlinear effect of the thermal load,which provides a means to simulate both the thermal load and wall pressure fluctuations of a hypersonic Turbulent Boundary Layer(TBL) in a wind tunnel test. To validate the scaling procedure,both numerical computations and measurements are performed in this work. Theoretical results show that the scaling procedure can also be adapted to the buckling temperature of a structure even though the scaling procedure is derived from a reference temperature below the critical temperature of the structure. For the measurement, wall pressure fluctuations and thermal environment are simulated by creating hypersonic flow in a wind tunnel. Some encouraging results demonstrate the effectiveness of the scaling procedure for assessing structural vibration generated by hypersonic flow. The scaling procedure developed in this study will provide theoretical support to develop a new measurement technology to evaluate vibration of aircraft due to hypersonic flow.     

Experimental study of rotating gliding arc discharge plasma-assisted combustion in an aero-engine combustion chamber

The combustion chamber is the core component of an aero-engine, and affects its reliability and security operation, even the performance of the aircraft. In this work, a Plasma-Assisted Combustion(PAC) test platform was developed to validate the feasibility of using PAC actuators to enhance annular combustor performance. Two plans of PAC(rotating gliding arc discharge plasma) were designed, Assisted Combustion from Primary Holes(ACPH) and Assisted Combustion from Dilution Holes(ACDH). Comparative experiments and analysis between conventional combustion and PAC were conducted to study the effects of ACPH and ACDH on the performances including average outlet temperature, combustion efficiency, pattern factor under four different excessive air coefficients(0.8, 1, 2, and 4), and lean blowout performance at different inlet airflow velocities. Experimental results show that the combustion efficiency is improved after PAC compared with that in normal conditions, and the combustion efficiency of ACPH increases2.45%, 1.49%, 1.04%, and 0.47%, while it increases 2.75%, 1.67%, 1.36%, and 0.36% under ACDH conditions. The uniformity of the outlet temperature field and the lean blowout performance are improved after PAC. Especially for ACPH, the widening of the lean blowout limit is8.3%, 12.4%, 12.8%, and 25% respectively when the inlet velocity ranges from 60 m/s to120 m/s. These results offer new perspectives for using PAC devices to enhance aero-engine combustors' performances.     

爆震波在开缝式弯管内的传播特性研究

为了解旋转爆震波在单侧部分受限情况下产生的波系结构及环缝内压力波动特点,以恰化学当量比的氢气/氧气混合物作为反应物,采用9组分19步的基元反应模型,忽略粘性、热传导和扩散等输运效应,对爆震波在开缝式弯管内的传播情况进行了数值模拟。研究结果表明,爆震波在开缝式弯管内传播时,爆震波及爆震区内的反射激波后的高压区都会在环缝内产生透射激波,但环缝内激波不单纯依赖弯管内高压区的侧向膨胀产生,且环缝内的一些反射激波产生的波后高压区还会反过来在爆震区内产生透射激波;环缝内第二道斜激波会被接触面分为两部分,在接触面前方的惰性气体一侧具有更大的倾斜角;环缝位于外侧时爆震波的倾斜程度比位于内侧时更大;当环缝处于外侧和内侧时,会由于激波相交、反射产生比第一道斜激波更大的压力峰值,内侧开缝时环缝内最大压力峰值约为第一道斜激波后的两倍,且内侧开缝时环缝内压力大于4倍填充压力的高压区域范围比外侧开缝时大36.4%。     

低成本U-blox模块的单频GPS/BDS增强PPP定位性能分析

以U-blox单频接收机采集数据,在GPS与GPS/BDS两种解算模式下进行局域增强精密单点定位(PPP)解算,并进行模糊度固定,对其在不同环境下的定位性能进行实验研究和分析。实验结果表明:在静态环境下,GPS/BDS浮点解收敛至cm级需3min左右,较GPS缩短64%,GPS/BDS定位精度RMS在平面与高程方向分别为(3.2cm,2.7cm),较GPS提升(47%,59%);GPS/BDS在30s左右可固定模糊度,固定后定位精度为(0.4cm,1.0cm),较GPS/BDS浮点解提升(88%,63%)。在动态环境下,GPS/BDS浮点解收敛至cm级需4min左右,较GPS提升59%,定位精度为(3.1cm,5.9cm),较GPS提升(34%,43%);GPS/BDS获得固定解需2min左右,固定后定位精度为(0.7cm,1.0cm),较GPS/BDS浮点解提升(77%,83%)。     

后处理温度对邻苯二甲腈基复合材料高温性能的影响

制备了MT300/邻苯二甲腈复合材料,分析了不同后处理温度对其在室温和400℃下力学性能的影响。结果表明,复合材料的后处理温度由315℃提高到330℃,会使其室温下的弯曲强度和模量明显提高;但继续提高后处理温度至375℃,室温下的弯曲强度则不断下降而弯曲模量未出现显著变化;在400℃的测试温度下,复合材料的弯曲强度、模量和压缩强度则均随后处理温度提升逐步提高。复合材料的室温压缩性能随后处理温度升高呈下降趋势,但在350℃处理后其室温压缩强度又出现明显上升。室温、400℃下层间剪切强度则均随后处理温度由315℃升高至375℃而呈先下降后上升趋势。     

C/C复合材料螺栓紧固特性

为了获得C/C螺栓紧固特性,采用紧固力矩试验方法开展了不同结构C/C螺栓紧固特性研究,研究内容包括不同垫片材料、单螺母和双螺母、涂胶和不涂胶等组合情况下C/C螺栓K值的变化趋势,并研究了C/C螺栓的极限抗扭能力。结果表明:碳基螺栓的扭矩系数值K与金属螺栓差异很大,不同材料结构也有差异,涂胶对增加夹紧力有明显的提高作用。     

机器人自动钻铆技术在卫星整流罩上的应用

为保证运载火箭舱段钻铆过程质量稳定性,减少人为因素造成的缺陷,开展了机器人自动钻铆技术在卫星整流罩应用技术研究。针对机器人自动钻铆设备,通过阐述结构组成及相应的关键技术、开展钻孔和铆接等工艺研究为手段,实现了某运载火箭Φ3 800 mm卫星整流罩的试制。结果表明,采用主轴转速12 000 r/min,进给速度500 mm/min时,能有效控制钻孔出口毛刺高度;通过控制插钉深度、扭矩、悬停时间等工艺参数,可提高铆钉送钉成功率;试制产品加工精度均满足设计要求,验证了机器人自动钻铆技术在运载火箭舱体研制中的可行性与可靠性。     

基于AVSIMM算法的高超声速再入滑翔目标跟踪

针对跟踪高超声速目标的交互式多模型（IMM）算法中存在模型数量过多,模型之间竞争导致滤波精度降低的问题,在自适应网格交互式多模型（AGIMM）算法的基础上,提出了一种自适应变结构交互式多模型（AVSIMM）算法跟踪高超声速再入滑翔目标。根据高超声速无动力再入滑翔目标当前机动状态的角速度参数,在自适应调整当前时刻模型集中参数的同时,针对AGIMM算法运动学模型的单一性,设计了具有多种跟踪滤波运动学模型的AVSIMM算法,通过模型集参数与算法结构的双重自适应调整实现了对目标高精度的跟踪。仿真结果表明,与AGIMM算法相比,所设计的AVSIMM算法不仅对结构和参数都具有更强的自适应性,同时提高了高超目标的跟踪精度和跟踪效率。