组合压气机中尾迹与势流同频/异频干涉的叠加特性

为揭示多级压气机中上下游叶轮对中间叶片叠加气动影响特性,阐述不同叠加干涉情况下下游叶轮进气角度变化,采用数值方法模拟了一级轴流和一级离心组成的组合压气机非定常流场。详细讨论了上游动叶尾迹和下游动叶势流对中间导流叶栅段气流非定常流动的异频和同频叠加干涉特性,依据计算结果,直观地展示了静叶通道中两种干涉间相互激励和抑制作用的位置和时间,与数学公式的推导结果相互印证。研究结果表明:当上下游动叶对中间静叶段异频干涉时,干涉的激励、抑制区域的轴向位置随时间发生变化；当上下游动叶对中间静叶干涉频率相同时,干涉的相互激励、抑制区域的轴向位置不随时间发生变化,但干涉的激励、抑制区域的轴向位置受时序位置影响。另外,上游动叶尾迹与下游离心叶轮势流的不同叠加情况,决定着下游离心叶轮进口相对气流角的大小及波动幅值。      

基于最小二乘支持向量机和遗传算法的除尘效率优化

采用最小二乘支持向量机进行除尘效率建模，并利用遗传算法对运行工况寻优，获得优化除尘效率的调整方式。仿真计算表明遗传算法能很好地对以除尘效率为目标的除尘模型优化。以优化调整方式的相应参数作为当前负荷下的基准值，可指导运行人员进行参数优化调整。现场试验表明，按此基准值运行，可以提高除尘效率，从而使除尘系统性能达到优化。     

舵机关节轴承失效分析与结构优化研究

以某型导弹舵机钴动机构向心关节轴承径向承载工况为背景，对关节轴承进行失效研究。通过硬度金相分析、断裂分析和有限元仿真计算，得到关节轴承在静态载荷作用下的受力特点、应力分布和失效形式，并以此为依据进行关节轴承结构优化设计。通过计算，结果表明，改进后的关节轴承完全满足舵机传动机构的承载和性能要求，且可靠性显著提高。     

基于CFD的KCS船尾伴流场快速预报方法研究

在船舶设计过程中,船尾伴流均匀度是改善螺旋桨的推进效率及螺旋桨脉动压力引起的振动、噪声等问题的关键。因此在船舶设计初期,船尾伴流场的精确预报对船型的优化,桨机船的匹配设计等有着重要意义。本文立足于实际工程应用,以KRISO的3600TEU集装箱船模型KCS(KRISOContainerShip)为研究对象,对船尾伴流场的快速预报方法进行研究。     

五征计算机三维设计获奖

1月13日,山东省机械工业办公室和省国防机械电子工会联合举办了山东省装备制造业计算机三维设计大赛,五征两垄四行花生联合收获机、载货汽车的三维设计分别获得整机类二等奖和三等奖。据了解该大赛旨在提高全省企业的工业设计水平和自主创新能力,提高工程技术人员的设计开发能力。五征技术人员在奥驰系列载货汽车和两垄四行花生联合收获机研发过程中,创新性地将CAD三维建模及CAE分析技术应用于产品性能分析及优化研究中,有效地提高整车的可靠性、操纵稳定性、驾乘舒适性等性能指标,同时缩短了设计周期,有效地提高了设计效率。     

基于ERSM涡轮盘径向变形的非线性动态概率分析

为了准确设计高压涡轮盘和叶尖间隙,从概率的角度进行了涡轮盘径向变形的分析。介绍了高精度高效率的非线性动态概率分析的极值响应面方法(Extremum Response Surface Method, ERSM),并建立了其数学模型。考虑材料属性和边界条件的非线性,以及热载荷和离心载荷的动态性,基于ERSM对涡轮盘径向变形进行了非线性动态概率分析,得到了输入输出参数的分布特征和影响涡轮盘径向动态变形的主要因素。最后,通过方法比较,验证了ERSM在保证计算精度的前提下能大大提高计算速度,节约计算时间,改善计算效率。为进行更有效的涡轮盘设计和优化,改善叶尖间隙设计和控制的合理性提供了有效依据。      

300MW机组锅炉引风机节能技术改造研究

本文针对河北某电厂300MW汽轮发电机组在增减负荷过程中存在的重大问题,如锅炉引风机采用调整入口挡板开度改变出力,系统存在较大的节流损失,引风机严重偏离高效区运行等,经比较研究决定采用效率高、高效区宽的静叶可调轴流风机代替离心式引风机进行节能改造,使机组锅炉引风机在安全稳定运行的前提下,在中低负荷运行时节能效果显著.通过采用静叶可调轴流技术对锅炉引风机进行改造,改善了锅炉引风机机的启动性能,达到了机组中低负荷时节能降耗、减少噪声污染和提高企业效益的目的.     

串级控制系统的特性

该文对串级控制系统的特性等方面进行了比较定性、粗浅的分析,通过研究总结我们知道：串级控制在改善过程的动态特性,提高系统控制质量,迅速克服进入副回路的二次扰动,提高系统的工作频率,对负荷变化的较强适应等方面较简单单回路控制有明显的优势,从而在实际控制中得到了广泛的应用。     

紫铜电阻点焊电极温度场模拟及结构改进

使用钨作为电极,可以实现纯铜零件的点焊,但对电极的散热能力提出了更高的要求。使用Ansys软件,按照长时间工作工况对钨-铜复合点焊电极进行温度场模拟,分析稳态下标准形状电极的散热能力及散热瓶颈位置,针对分析结果,对电极的散热结构进行优化,通过稳态温度场来分析改进结构后的温度场分布,以冷却水沸点为标准,计算了钨极端面的热输入平均值。发现采用钨-铜复合结构的电极时,热量在钨极内大量积聚,钨极端面温度较高,增加铜层厚度后,散热情况得到改善,改变工作负荷,冷却水温度降低到沸点以下。     

国内外机械增压技术研究现状分析

增压技术是一种提高发动机进气能力的方法,即采用专门的压气机将气体在进入气缸前预先进行压缩,提高进入气缸的气体密度.减小气体的体积。一般来说,充入气缸内的空气的充量越大,气缸内燃油的燃烧效率越高,可参与燃烧的燃油也越多,则内燃机输出功率和转化的燃料热能也越高。在气缸容积不变、内燃机转速恒定的情况下,空气充量与空气密度成成比。因此,通过对进入气缸的空气进行预压缩,可以提高内燃机的输出功率,以达到改善动力性能的目的。针对国内外机械增压技术的研究现状进行了分析与阐释,旨在为相关领域的其他研究提供一些可以参考的借鉴。     

论螺杆空压机卸载故障处理方法

螺杆空压机以其稳定的工作性能是现在各行各业应用非常普遍的一种设备,使用中通过正确的操作方法和保养检修,可使机器达到理想的工作状态,但使用过程中难免会出现一些故障问题。这里主要针对螺杆空压机启动后,机器正常加载运行,但达到卸载压力时,机器不卸载问题进行研究。以便在以后的工作中可以快速修复该故障。     

Brown＇s Blossom in Britain-China

The overall strategic relationship between U.K. and China is ＂better than ever＂, China- Britain relations have maintained good momentum, with increased high-level exchanges and the reinforcement of strategic mutual trust, with more room for growth in the future.     

Challenge and Opportunity Go Hand in Hand——What Global Economic Agitation Brings to the China's Economy?

Domino effects of the global finance agitation As the origin of the subprime crisis,US financial institutions lost USS45 billion last year,accounted for over half of the total US,EU & Japan loss.Since January 15th,Chtigroup released its financial statement of the 4th quarter,showing a net deficit of USS9.83 billion,which marked the hisoric high of its quarterly deficit.     

Universal Coverage, Pinpoint Illustration and Profound Impact HTC 2008 Intermedia Recommendation and Introduction Meeting

Holding 88 percent of train media resources across China, based on "Time Cube", on the 2008 Intermedia Recommendation and Introduction Meeting on December 19, 2007, HTC announced its high-profile strategy of tour marketing and tapping the immeasurable potentials on the train. Meanwhile, HTC officially launched its brand new product Olympic Train on the meeting, providing a fabulous platform for all the brands that are prepared to do a smart marketing on the occasion of 2008 Olympic Games.     

Market presence in China strengthened Network growth and Dual-Chinese-Hub Strategy More frequet Flyer Benefit——Air China and shanhai Airlines Join Star Alliance

In the end of 2007, Air China Limited (hereinafter "Air China") and Shanghai Airlines, formally joined Star Alliance at a ceremony held in the new Terminal Three at Beijing Capital International Airport. With the addition of the two Chinese airlines, Star Alliance now has 19 member carriers operating 17,000 daily flights to 897 destinations in 160 countries.     

China''''s Stock Market Wave

The annual meeting of the World Economy Forum was held in Davos,a little town in Switzerland,on January 23rd to the 27th this year,with the theme"the Power fo Collaborative Innovation",over 2500 celebrates from ture political and cconomic circles of more than 80 countries and challengred logether to talk about the future of the global economy in 2008,A Forum for the problems and challenges that face whole world,some of the keywords which drew attention during the event were:the U.S.subprime mortgage crisis,soaring energy prices,the economic slowdown in the U.S.ermerging economic bodies,authority funds and the general unpredictable nature of the global economy.     

Trade Promotion from Neighborhood

If you are considering to trade with companies in Japan or expanding your .business to Japan, we are ready to help from the very beginning.＂ You will find this greeting at the first sight on the Chinese website of Japan External Trade Organization （JETRO）. JETRO has committed itself in delivering highly efficient and quality services to meet the demand of internal and external customs including Japanese companies, hence winning a good reputation in the international trade arena. In recent years, with its priority in advancing business cooperation in South and East Asia, JETRO has made great achievement in promoting trade between China and Japan. Therefore, China＇s Foreign Trade interviewed Mr. Yoichi Maine, Deputy Director General of JETRO BEIJING.     

Auto Parts Market Potential Coming into Surface

Looking at the increasingly fierce competition in the world auto market. global automobile manufacturing industry, taking Europe, the U.S. and Japan as representatives, is gradually forming a new type of relationship, mutual cooperation between whole vehicle and parts manufacturers. We can clearly see that auto parts manufacturers have become independent from the whole vehicle manufacturing companies, which means that the former structure of auto industry has greatly changed, and a new relationship,     

Jean-Pierre Duprieu： Willing to Be A Legate of Sino-French Business

Estaing, former French president, Valery Giscard d＇Estaing attended Sino-French Economic Seminar held in Shanghai in early April and said that the world center has shifted from the west to the east with many European and US companies entering into Asia, and China has the ability to play an important role in the world stage. Estaing, naming himself＂French Confucian＂, then said in Chinese that a cook-group includes 10 people in ancient Chinese soldier system and the cook is in charge of cooking for them. And people who belong to the same cook are actually ＂Partners＂.     

Domino Effect on Electricity and Coal Prices

In the middle of last December, the key purchase contracts for coal used in power generation in 2008 were signed, reflecting a demand for more than 1.085 billion tons. It is important to note that the country＇s five biggest power producers, China Huaneng Group, China Guodian Corporation, China Power Investment Corporation, China Huadian Corporation and China Datang Corporation, had settled on the prices on their purchase contracts, and they are expected to consume 290 million tons of coal for generating electricity,