高精确性和高效率天平校准系统

为解决已有天平校准设备存在加载架初始定位精度、加载载荷准度和天平校准效率偏低的问题,研发了一套高精确性天平校准设备,采取激光跟踪仪的加载架初始定位、力传感器配合电动缸的加载和六连杆并联复位机构等关键技术,实现了天平的“全自动”校准。天平校准结果表明:天平的综合加载误差和综合加载重复性达到了国军标的先进指标要求,天平校准用时从10 h以上降低到3 h以内,提高了天平校准效率。     

一台大载荷比Φ32 mm六分量天平的研制

研究隐身巡航导弹的气动特性,需要采用风洞试验测力天平进行气动载荷的测量。隐身布局导弹的气动特性反映到气动载荷上是较大的升阻比和较大的升侧比,而常规测力天平升阻比为15:1左右,升侧比为2:1左右,不能满足隐身巡航导弹气动载荷测量的需求。针对此问题,采用片梁组合方式测量侧力,采用大偏心“π”形梁阻力元件结构测量阻力,实现了升侧比为21:1且升阻比为42:1的大载荷比测力天平的研制,解决了载荷不匹配这一严重的测力天平研制难题,为进一步研究隐身巡航导弹的气动特性奠定了基础。     

航空发动机风扇管道径向声模态模拟与识别技术

针对航空发动机风扇管道径向声模态模拟与测试问题,研究了径向声模态模拟技术以及径向声模态识别技术。采用基于径向排布的声源阵列形式,调节阵列预设的各扬声器幅值及相位实现径向模态声源模拟。建立声源管道下游多圈环形阵列,根据阵列位置信息构造求解模态的传递函数矩阵,运用Tikhonov正则化方法减小传递函数矩阵的条件数,从而实现径向声模态识别能力。通过理论推导和数值计算,设计风扇管道径向声模态试验装置,并在消声室进行试验验证。通过试验验证了该系统具备周向4阶以内,径向2阶以内的径向声模态模拟与识别能力。     

Investigation on Temperature Field Calibration and Analysis of Wind Tunnel

风洞温度场校测研究与分析

任兆琨,马占元,张悦,许红达,王云祥,徐辉

（中国航空工业空气动力研究院,哈尔滨 150001）

摘要：对于风洞来说,对其试验段进行温度和流场校准至关重要,这是评估风洞流场品质的重要指标。本文利用一个由温度传感器组成的桁架对一个完整风洞截面的温度场进行了标定。通过调整测温桁架与喷嘴之间的距离以及风速,可以获得不同位置的温度场分布数据。通过分析这些数据,以确定影响温度场分布的重要因素,同时对风洞的温度场进行了相应的数值模拟,目的是进一步分析空气和风洞壁之间的流体传热情况。通过以上分析方法,进一步验证了风洞内温度场的品质,为未来相关模型的风洞试验提供了参考。

关键字：风洞;温度场;数值模拟;流体传热

     

Investigation of shedding patterns and its influences on lift performances of a cylinder bundle in cross flow

Journal of Mechanical Science and Technology - Shedding vortices in cross flow are of much practical importance in the analysis of flow induced vibrations of a steam generator. However, studies of...     

Heat transfer in the flow through a bundle of tubes and transitions of the flow

Heat transfer in the flow through a bundle of heated tubes are investigated numerically at Reynolds numbers around which the flow makes a transition from a steady state to an oscillatory one, as a model of micro heat exchanger. It is found that physical quantities such as the Nusselt number and the pressure loss exhibit discontinuous jumps with continuous change in the Reynolds number. The origin of the sudden changes in these physical quantities is identified to come from the existence of multiple stable solutions which leads to hystereses in these quantities.     

高负荷跨音速压气机转子气动设计及附面层抽吸研究

本文设计了一跨音速压气机转子,其叶尖切线速度420 m/s,在确保动叶出口参数的同时,压比达到3.2,绝热等熵效率88.7%。数值模拟表明,60%叶高到叶顶区域,气体分离严重。为了有效控制分离,本文初步探讨了抽吸附面层对转子性能的影响。结果表明抽气能明显影响附面层的发展与激波的空间结构,转子局部性能得到改善。     

A harmony search algorithm for high-dimensional multimodal optimization problems

Harmony search (HS) and its variants have been found successful applications, however with poor solution accuracy and convergence performance for high-dimensional (≥200) multimodal optimization problems. The reason is mainly huge search space and multiple local minima. To tackle the problem, we present a new HS algorithm called DIHS, which is based on Dynamic-Dimensionality-Reduction-Adjustment (DDRA) and dynamic fret width (fw) strategy. The former is for avoiding generating invalid solutions and the latter is to balance global exploration and local exploitation. Theoretical analysis on the DDRA strategy for success rate of update operation is given and influence of related parameters on solution accuracy is investigated. Our experiments include comparison on solution accuracy and CPU time with seven typical HS algorithms and four widely used evolutionary algorithms (SaDE, CoDE, CMAES and CLPSO) and statistical comparison by the Wilcoxon Signed-Rank Test with the seven HS algorithms and four evolutionary algorithms. The problems in experiments include twelve multimodal and four complex uni-modal functions with high-dimensionality.Experimental results indicate that the proposed approach can provide significant improvement on solution accuracy with less CPU time in solving high-dimensional multimodal optimization problems, and the more dimensionality that the optimization problem is, the more benefits it provides.