基于非接触式测量的旋转叶片动应变重构方法

基于叶端定时非接触式测量和振动响应传递比的概念,开展高速旋转叶片动应变重构方法的研究。在频域内推导了叶片任意测点位移与任意测点动应变的传递比,给出了单模态共振下响应传递比关于位移和应变模态振型的解析表达式;建立旋转叶片的三维(3D)有限元模型,开展考虑旋转预应力效应的叶片模态分析,提取位移和应变模态振型,获得任意转速下叶端位移与叶根关键点动应变的传递比。开展高速旋转叶片叶端定时非接触式测量实验,采用周向傅里叶算法对叶端定时信号进行处理,获得叶片在不同转速单模态共振下的叶端位移,结合响应传递比,重构5个旋转叶片的关键点动应变。结果表明:旋转叶片在9000r/min和13000r/min转速下发生1阶共振时,与应变片实测结果相比,叶根处应力最大点、次大点和边缘点3个关键点的动应变平均重构误差均小于15%,验证了旋转叶片动应变重构方法的有效性。     

面向一体化计算的整体式液体冲压发动机建模及性能评估

为发展冲压发动机性能工程预估方法,建立了面向一体化计算的整体式液体冲压发动机性能计算模型,并使其兼容基团贡献算法,提高了拓展性。利用模型分析了冲压发动机在攻角0°～6°、高度0～18km、马赫数2.0～3.5、余气系数1.0～2.9范围工况多维度连续变化下,比冲、推力系数和燃油质量流量的速度-高度特性、高度-节流特性、节流-速度特性以及攻角特性。研究结果表明:性能计算模型可在一体化计算条件下、基团贡献算法允许范围内,不依赖试验数据对冲压发动机性能预估,计算结果与技术参考值相比相对误差均小于14%。推力系数和比冲具有基本一致的速度-高度特性和相似的高度-节流特性,受燃气组分影响,推力系数和比冲的节流-速度特性差异明显。燃油质量流量的变化规律不同于比冲和推力系数,在进入平流层后呈现折缓趋势,而呈现连续性,速度越大、高度越低、余气系数越小,燃油质量流量越高,反之则越小。引入攻角以后,攻角越大,比冲和推力系数越低,进气道起动马赫数越高;攻角-起动马赫数曲线小范围内近似线性,攻角超过5.6°非线性加剧。     

传输激光能量的光纤滑环结构设计与试验研究

本文设计了一种光纤滑环结构,可实现将激光能量从固定平台传输到旋转平台。该光纤滑环结构可精确控制对接光纤的端面间隙,有效保护传能光纤。实验表明,光纤耦合效率可达90%左右,可满足科研及工业应用需求。     

基于任意多项式中弧线的单级高效率风扇设计

为了在压气机通流设计阶段考虑叶片弯掠效应,开发了基于流线曲率法的通流设计程序,提出一种基于四次多项式的任意中弧线叶片造型方法,并推导了任意回转面上的中弧线表达式。以此方法为基础,采用通流设计与叶片造型相互迭代的方式开展大流量跨声速风扇设计研究。此风扇级的设计点为巡航状态,设计流量为155kg/s、压比为1.54。研究结果表明:在设计状态,此风扇级的总压比为1.545,转子和级效率分别为0.939、0.916;在设计转速下,失速裕度为17%,转子和级最高效率分别为0.945、0.923;在起飞状态,流量接近440kg/s,效率与巡航状态相当,压比高于巡航状态。     

CONTROL OF TWO DIMENSIONAL JETS USING MINIATURE ZERO MASS FLUX JETS

Zero mass flux jets, synthesized by acoustic actuators, have been used for the purpose of jet mixing enhancement and jet vectoring. Zero mass flux jets composed of entirely entrained fluid allow momentum transfer into the embedding flow. In the present experiments, miniature-scale high aspect ratio actuator jets are placed along the long sides and near the exit plane of a primary two-dimensional jet. In different modes, the primary jet can be vectored either towards or away from the actuator jets and the jet mixing is enhanced. The disturbance of the excitation frequency is developed while the unstable frequency of the primary jet is completely suppressed.     

A Parallel Adaptive 3D MHD Scheme for Modeling Coronal and Solar Wind Plasma Flows

A parallel adaptive mesh refinement (AMR) scheme is described for solving the governing equations of ideal magnetohydrodynamics (MHD) in three space dimensions. This solution algorithm makes use of modern finite-volume numerical methodology to provide a combination of high solution accuracy and computational robustness. Efficient and scalable implementations of the method have been developed for massively parallel computer architectures and high performance achieved. Numerical results are discussed for a simplified model of the initiation and evolution of coronal mass ejections (CMEs) in the inner heliosphere. The results demonstrate the potential of this numerical tool for enhancing our understanding of coronal and solar wind plasma processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

来流马赫数对引射火箭引射量的影响研究

研究引射火箭引射量随来流马赫数的变化关系,对引射量由火箭引射主导向冲压主导之间转换点的选取以及一次火箭的质量管理具有重要意义.采用数值分析和实验研究,探索了引射火箭引射量随来流马赫教的变化关系.结果表明,针对所采用的引射火箭发动机构型,引射量随来流马赫数变化的拐点约为Ma=1.3～1.5,当来流马赫数Ma<1.3时,引射量由火箭引射主导,随来流马赫数的增加,引射量变化较缓慢;当来流马赫数Ma>1.5时,引射量由冲压主导,随来流马赫教的增加,引射量迅速增加.     

Progress of continuously rotating detonation engines

Continuously rotating detonation engine (CRDE) is a focus for concern in the field of aerospace propulsion. It has several advantages, including one-initiation, high thermal efficiency and simple structure. Due to these characteristics, it is expected to bring revolutionary advance-ments to aviation and aerospace propulsion systems and now has drawn much attention throughout the world. In this paper, an overview of the development of CRDE is given from several aspects:basic concepts, applications, experimental studies, numerical simulations, and so on. Representative results and outstanding contributions are summarized and the unresolved issues for further engi-neering applications of CRDE are provided.     

关于大众传媒在高校音乐传播中作用的调查及思考

为了解大众传媒所传播的音乐信息及其在大学生中所产生的效应，笔者在南京三所不同类型的高校进行了一次问卷调查，对问卷中反映的问题进行初步探讨。     

POD和DMD方法分析不同间隙压气机旋转不稳定性特性

对一台单级低速轴流压气机旋转不稳定性(RI)进行分析。在前期的旋转不稳定性特性、流场成因和不同间隙影响的研究基础上,进一步基于全通道数值模拟,采用两种流场降阶方法分析不同叶顶间隙条件下旋转不稳定性各阶模态对应的流场成分、模态能量占比和稳定性等特性。计算结果表明,前几阶模态能量占比大,对流场起主要贡献,并且稳定性相对较强。随着间隙的减小,旋转不稳定性的能量占比和稳定性下降,各阶的叶片转动成为流场的主要成分。