矿用对旋轴流主通风机叶轮改造设计与验证

针对矿用主通风机存在的效率低和可靠性差两个根本问题,采用国内先进的航空发动机压气机叶片造型技术,完成了通风机叶片改造气动设计;结合成熟的旋转机械结构设计经验,将传统鼓筒受力方式改为腹板受力方式,有效减轻了鼓筒质量,同时采取带不同锥角定位块的方式实现叶片角度精确调节和减小同级叶片角度偏差。经空载调试、带网运行、性能测试及运行考核表明,改造后通风机的风量、效率等性能参数明显提高,运行安全可靠,满足用户使用要求。     

燃油喷嘴对燃烧性能的控制研究

在WP-7发动机单管燃烧室上采用三种不同形式的燃油喷嘴(离心式、空气雾化式及气旋离心式)进行燃烧试验以研究燃油喷嘴对燃烧性能的控制作用.实验显示了不同形式的喷嘴产生出燃烧性能的差别.通过考察该三种喷嘴对出口温度场燃烧效率、温度不均匀系数、点火、火焰稳定等的控制程度得出:根据需要,可以选择适当的喷嘴来控制性能.特别是本文研究的气旋离心式喷嘴易于控制出口温度场的热点位置,具有离心式和空气雾化式两种喷嘴的优点.     

分段吹气高层建筑的减阻性能数值研究

为减小高层建筑的风致阻力,改善结构的抗风性能,本文采用CFD方法研究了分段吹气高层建筑模型的风荷载减阻性能,分析了侧风面和竖向开孔位置、吹气孔高度hi和吹气速度Vci等参数对减阻性能的影响。结果表明:孔洞位于离侧风面前缘3%宽度时模型的减阻性能优于其它侧风面开孔方案;分段吹气模型的最佳竖向开孔位置发生在0.425m高度处;保持Vci不变时,增加hi使得模型顺风向的阻力折减系数和基底弯矩折减系数增大,且风压减阻效率随hi的增加而减小并逐渐趋近于1.0;当吹气流量或顺风向吹气动量不变时,分段吹气模型的风压减阻效率均不如全高吹气模型。基于最大减阻效率和最小吹气功率比较了分段和全高吹气模型的减阻性能,发现后者的减阻性能优于前者,然而对于某些考虑局部风压的折减,我们可在高层建筑中上部设置吹气装置来改善其局部风压特性。最后,拟合了减阻效率(ηDR和ηMR)关于吹气孔中心高度、hi和Vci的经验公式,为分段吹气控制的应用提供参考。     

小功率单轴燃气轮机及其功热并供装置变工况典型解析特性

采用动力机械变工况特性解析分析方法［１,２］,分析总结了使用离心式压气机的小功率单轴恒速燃气轮机稳态变工况的典型特性及一些定量规律。所得燃气轮机装置典型效率曲线及统计公式得到了实际数据的验证。计算了该种燃气轮机功热并供装置用饱和蒸汽供热时的典型情况及其他一些变工况性能,如大气温度的影响等     

通风机结构参数的优化

本文对离心式及轴流式通风机采用不同的目标函数、设计变量、约束条件和优化方法进行优化设计。其结果表明两者具有共同的特点。优化设计比传统设计效率提高 5～ 1 0 %,以静压总效率为目标效果更加令人满意。      

基于航空煤油重整的SOFC-GT混合动力系统性能

建立了基于航空煤油重整固体氧化物燃料电池-涡轮发动机（SOFC-GT）混合动力系统仿真模型,比较了两种回热方式的重整装置以及不同涡轮布置位置时的系统性能变化,优选出最佳的混合动力系统架构。进一步分析了压气机压比、燃料利用率、燃油流量以及空气流量等运行参数对SOFC-GT混合动力系统性能的影响。研究结果表明：设计点工况下,最佳混合动力系统的发电效率能达到45%,体现出良好的系统性能;当燃料利用率为082时混合动力系统的效率和功率最高;随着燃油流量(0051 1~0058 4 mol/s)的增加,混合动力系统的效率和功率均增加;而随着压气机压比(25~33)或者空气流量(37~44 mol/s)的增加,混合动力系统的效率和功率都减小。     

放电室长径比对射频离子推力器影响的数值模拟研究

为获得推力器的性能与推力器工况之间的变化规律,利用等离子体密度平衡方程、中性气体密度平衡方程、中性气体功率平衡方程、电子功率平衡方程构成的全域模型对氙工质射频离子推力器开展了数值模拟研究.结果表明,放电室长径比(L/R)的改变引起放电室壁上消耗功率的变化,从而影响推力器的性能.在放电室体积和工质流率不变的情况下,放电室...     

TD-SCDMA 中外环功率控制的研究

CDMA系统是干扰受限的系统,降低干扰可以提高系统的容量.TD-SCDMA系统的功率控制就是在保证用户的QoS前提下,降低发射功率,减少系统干扰从而增大系统的容量.本文介绍了TD-SCDMA中外环空率控制的算法,并且分析了功率控制参数对系统性能的影响.     

离心式压气机耦合松弛多学科设计优化方法

为提高多学科设计优化的寻优效率,以离心式压气机为对象,开展了耦合松弛多学科设计优化方法的研究.针对松散耦合方法建立的离心式压气机的流-热-固耦合分析模型,为了避免反复迭代导致的分析、优化时间过长,构建了分层次的离心式压气机耦合松弛优化设计系统.在气动优化中采用全局寻优算法探索系统最优气动设计方案;在耦合优化阶段,综合考虑学科间耦合及相互作用,在气动优化的基础上局部寻优校验气动优化结果并得到最终设计方案.这种不同复杂层次模型的优化设计有效缩减了系统优化设计周期.     

40cm离子推力器功率宽范围工作实验研究

深空探测任务要求太阳能电推进系统具有大推力、高比冲特性,同时随着航天器离开太阳距离的增加,太阳能效率快速降低,要求电推进系统具备功率宽范围高效工作能力。为了研究兰州空间技术物理研究所研制的40cm离子推力器功率宽范围工作能力,从实验角度研究了1~10k W 40cm离子推力器的工作性能及其变化规律。通过对离子推力器工作参数和性能的分析与计算,依据功率调节方法确定了40cm离子推力器1~10k W多模式工作点电参数;通过阴极流率优化和放电损耗优化实验确定了多模式工作点最佳供气参数。在设计确定的电参数和实验确定的供气参数下,开展了1~10k W调节实验,获取了40cm离子推力器的工作性能及其变化规律。实验结果表明:40cm离子推力器可在1~10k W内稳定工作,推力42~336m N,比冲2174~4389s,效率41%~72%;随功率增加效率增高,当功率大于2.5k W时效率大于63%。     

基于F2812的多处理器串行加载系统设计

阐述了一种基于F2812的多处理器串行加载系统,对加栽系统的工作原理和软件设计进行了详细介绍。系统可实现系统集成环境下多处理器软件代码的在线编程。经过大量测试和环境试验考核,串行加载系统工作稳定可靠。     

The Genesis Discovery Mission: Return of Solar Matter to Earth

The Genesis Discovery mission will return samples of solar matter for analysis of isotopic and elemental compositions in terrestrial laboratories. This is accomplished by exposing ultra-pure materials to the solar wind at the L1 Lagrangian point and returning the materials to Earth. Solar wind collection will continue until April 2004 with Earth return in Sept. 2004. The general science objectives of Genesis are to (1) to obtain solar isotopic abundances to the level of precision required for the interpretation of planetary science data, (2) to significantly improve knowledge of solar elemental abundances, (3) to measure the composition of the different solar wind regimes, and (4) to provide a reservoir of solar matter to serve the needs of planetary science in the 21st century. The Genesis flight system is a sun-pointed spinner, consisting of a spacecraft deck and a sample return capsule (SRC). The SRC houses a canister which contains the collector materials. The lid of the SRC and a cover to the canister were opened to begin solar wind collection on November 30, 2001. To obtain samples of O and N ions of higher fluence relative to background levels in the target materials, an electrostatic mirror (‘concentrator’) is used which focuses the incoming ions over a diameter of about 20 cm onto a 6 cm diameter set of target materials. Solar wind electron and ion monitors (electrostatic analyzers) determine the solar wind regime present at the spacecraft and control the deployment of separate arrays of collector materials to provide the independent regime samples. This revised version was published online in August 2006 with corrections to the Cover Date.     

Optimum blade loading for a powered rotor in descent

The optimum loading for rotors has previously been found for hover, climb and wind turbine conditions;but, up to now, no one has determined the optimum rotor loading in descent. This could be an important design consideration for rotary-wing parachutes and low-speed des-cents. In this paper, the optimal loading for a powered rotor in descent is found from momentum theory based on a variational principle. This loading is compared with the optimal loading for a rotor in hover or climb and with the Betz rotor loading (which is optimum for a lightly-loaded rotor). Wake contraction for each of the various loadings is also presented.     

光盘形结构风荷载的风洞实验研究

应用风洞模拟实验研究了光盘形状结构的风荷载特性.风洞实验结果表明,在没有周围建筑物影响时,由于光盘形结构的截面具有对称翼型,上、下表面受到风荷载基本上都是负压分布,叠加后作用在光盘结构上的总体风荷载很小.周围建筑的存在对光盘形的风荷载影响很大,有周围建筑时光盘形结构所受的升力要比没有周围建筑时的值大1～3倍以上.特别有趣的是单独光盘形结构的整体风荷载除了受到一个升力的作用外,还受到了一个迎风低头的翻转力矩,为类似结构的风荷载设计提供了有益的启示.     

Influence of the Interplanetary Magnetic Field on the Solar Wind Flow about Planetary Obstacles

The main effects caused by the interplanetary magnetic field (IMF) are analyzed in cases of supersonic solar wind flow around magnetized planets (like Earth) and nonmagnetized (like Venus) planets. The IMF has a relatively weak strength in the solar wind but it is enhanced considerably in the so-called plasma depletion layer or magnetic barrier in the vicinity of the streamlined obstacle (magnetopause of a magnetized planet, or ionopause of a nonmagnetized planet). For magnetized planets, the magnetic barrier is a source of free magnetic energy for magnetic reconnection in cases of large magnetic shear at the magnetopause. For nonmagnetized planets, mass loading of the ionospheric particles is very important. The new created ions are accelerated by the electric field related to the IMF, and thus they gain energy from the solar wind plasma. These ions form the boundary layer within the magnetic barrier. This mass loading process affects considerably the profiles of the magnetic field and plasma parameters in the flow region.     

Solar Wind Conditions and Composition During the Genesis Mission as Measured by in situ Spacecraft

We describe the Genesis mission solar-wind sample collection period and the solar wind conditions at the L1 point during this 2.3-year period. In order to relate the solar wind samples to solar composition, the conditions under which the samples were collected must be understood in the context of the long-term solar wind. We find that the state of the solar wind was typical of conditions over the past four solar cycles. However, Genesis spent a relatively large fraction of the time in coronal-hole flow as compared to what might have been expected for the declining phase of the solar cycle. Data from the Solar Wind Ion Composition Spectrometer (SWICS) on the Advanced Composition Explorer (ACE) are used to determine the effectiveness of the Genesis solar-wind regime selection algorithm. The data collected by SWICS confirm that the Genesis algorithm successfully separated and collected solar wind regimes having distinct solar origins, particularly in the case of the coronal hole sample. The SWICS data also demonstrate that the different regimes are elementally fractionated. When compared with Ulysses composition data from the previous solar cycle, we find a similar degree of fractionation between regimes as well as fractionation relative to the average photospheric composition. The Genesis solar wind samples are under long-term curation at NASA Johnson Space Center so that as sample analysis techniques evolve, pristine solar wind samples will be available to the scientific community in the decades to come. This article and a companion paper (Wiens et al. 2013, this issue) provide post-flight information necessary for the analysis of the Genesis array and foil solar wind samples and the Genesis solar wind ion concentrator samples, and thus serve to complement the Space Science Review volume, The Genesis Mission (v. 105, 2003).     

飞机超差结构疲劳寿命量化评定

依据美机实用手册介绍的疲劳寿命S-N方程,对超差结构疲劳寿命推导出了一个量化评定方程。并应用该方程对一些典型结构超差形式具体地进行了疲劳寿命量化评定。实践证明,用本文介绍的方法对超差结构疲劳寿命进行定量评定,不仅简捷明快,而且结果可靠。     

大型飞机穿越微下击暴流风场的实时仿真(英文)

为在飞行模拟器中高逼真度地模拟在扰动风场中的飞行,研究了大型飞机在起飞着陆阶段遭遇微下击暴流风切变的实时仿真。基于涡环和Rankine复合涡原理建立了参数化三维微下击暴流模型。通过涡环倾斜和多涡环叠加方法实现了各种复杂微下击暴流风场的模拟。基于Boeing747-100飞机建模数据,系统推导了含风切变影响的六自由度动力学模型,给出了扰动风下气动模型修正的一般方法。对该机遭遇微下击暴流时实施纵向和横侧改出分别进行了控制器设计与仿真。研究结果表明,建立的三维微下击暴流模型可扩展性强,可用于模拟实际复杂风场。含风切变影响的大型飞机动力学模型合理有效。针对飞机从不同位置穿越风场,可采用不同的改出策略。整个模型可应用于飞行模拟器的实时飞行仿真。     

Working Group 1 Report: Solar Wind Models from the Sun to 1 AU: Constraints by "in situ" and Remote Sensing Measurements

The goal of Working Group 1 was to discuss constraints on solar wind models. The topics for discussion, outlined by Eckart Marsch in his introduction, were: (1) what heats the corona, (2) what is the role of waves, (3) what determines the solar wind mass flux, (4) can stationary, multi-fluid models describe the fast and slow solar wind, or (5) do we need time dependent fluid models, kinetic models, and/or MHD models to describe solar wind acceleration. The discussion in the working group focused on observations of "temperatures" in the corona, mainly in coronal holes, and whether the observations of line broadening should be interpreted as thermal broadening or wave broadening. Observations of the coronal electron density and the flow speed in coronal holes were also discussed. There was only one contribution on observations of the distant solar wind, but we can place firm constraints on the solar wind particle fluxes and asymptotic flow speeds from observations with Ulysses and other spacecraft. Theoretical work on multi-fluid models, higher-order moment fluid models, and MHD models of the solar wind were also presented. This revised version was published online in June 2006 with corrections to the Cover Date.     

FERA in parameter identification with application in low speed wind tunnel test

This paper presents a new approach which consists of a fuzzified eigensystem realization algorithm (FERA) to identify the parameters of the designed mini-UAV model performance in the low speed wind tunnel (LSWT) power on testing system. On the basis of the identification scheme, it is able to reduce system operational cost of wind tunnel tests and provide a tool for predicting results without resorting to on-site experiments. A variety of variables in model types and testing environment such as model profile, angle of attack, elevator, tunnel wind speed and power system (motor and propeller) are considered. The method based on logic devices is simple yet effective. The results obtained are compared to those obtained by the conventional wind-tunnel testing method. To verify effectiveness of the proposed methodology, both of simulations and real-world experiments are conducted. The results show that the working performance of the proposed method correlates well with expectation.