H2O/CO2污染对煤油燃料超声速燃烧影响数值研究

在纯净空气与H₂O/ CO₂污染空气来流对比试验结果基础上,采用数值计算方法和化学动力学方法,研究了H₂O和CO₂污染组分对煤油燃料超声速燃烧的影响,获得了试验手段难以得到的燃烧室流场参数和性能数据。完成了相应的煤油燃料超声速燃烧室二维数值计算,其中匹配了进口总温、总压、马赫数、氧气摩尔分数和工作当量油气比。将数值计算结果与相应试验测量值进行了对比分析,并结合燃烧室流场数据、性能参数分析了H₂O和CO₂污染的动力学影响、以及对燃烧室性能的影响。研究表明:(1)数值计算结果与实验测量值总体上吻合,两种手段均体现了纯净空气来流时不同煤油当量油气比的燃烧室性能,并反映了一致的“污染效应”影响趋势；(2) H₂O污染、H₂O+ CO₂污染的存在降低了煤油燃料超声速燃烧室性能,体现在燃烧诱导压升、燃烧效率、流向冲量增量的下降,而且随着污染组分含量的增加,燃烧室性能下降越加显著。      

矫形工艺对6N01-T5铝合金焊接接头性能的影响

以轨道车辆车顶、侧墙用6N01铝合金为研究对象,采用Gleeble热模拟试验机模拟6N01铝合金焊接接头火焰矫形过程,测量火焰矫形温度及火焰矫形次数对车顶侧墙铝合金材料力学性能的影响,建立铝合金力学性能与矫形温度、矫形次数的关系,在确保铝合金车体关键大部件不发生失稳的前提下,确定多次矫形下的合适矫形温度区间和矫形次数。     

节能型燃煤大棚温室热风机

<正>该产品是大棚温室升温的热力专用设备,它由燃烧室、集热管和吹送机三大部分组成,其三部分为封闭整体连接,煤炭在设备底部燃烧,产生的热量直接传导给炉腔内的吸热管,由吸热管储热,经管内热介质散热,在专用风机吹送下,将热能转化为热风吹送出去,使空间温度快速上升,从而达到制热升温的效果。采用该方式升温,具有提温速度快、易于控温和安全方便的特点,     

充氮气调储粮3种充气工艺经济效益比较

本试验对充氮气调储粮3种充气工艺在对粮堆充入同量的氮气条件下使用何种工艺可以取得最低氧浓度(最高含氮量),取得最理想的杀虫效果即最佳经济效益进行了探索。试验证明,密闭条件下从粮面向粮堆充气,当气囊鼓起使粮膜离开粮面时,在向粮堆继续充气的条件下打开地槽口排气阀排气,当打开地槽口排气阀后继续充入的气量相当于粮堆内空气量时停止充气,停止排气,将仓房密封好,环流均匀后氧浓度最低(氮浓度最高),吨粮成本最低。     

碳中和对我国经济的影响及其发展路径研究

当前,我国提出了碳中和、碳达峰的发展目标,各地方政府出台碳中和相关政策,在供给侧调整产业结构、优化能源结构,在需求侧推动绿色出行,减少一次能源消费。本文通过分析中国碳排放的区域分布来判断2030年碳达峰压力下可能受影响最大的区域。结果发现,碳排放总量大、强度高、增长率高的区域以及高耗能行业较为发达的区域受影响较大,同时中国实现碳达峰的可能路径为零碳电力。     

挡土墙的土压力分布特征的研究

档土墙上的土压力是一个古老的课题,经典的库仑土压力理论和朗肯土压力理论,因其计算简单和力学概念明确,在土木工程中得到广泛应用.但长期以来挡土墙的研究对象-般是针对墙背为直线的挡土墙,而对于阶梯式的挡土墙,特剐是对于平面内非直线的阶梯状拱形挡土墙的土压力分布特征少有研究.     

发动机燃烧室内壁材料热环境的气动热试验模拟技术研究

利用超声速矩形湍流导管和等离子电弧加热器模拟了发动机燃烧室内流和高超声速飞行器外壁面外流热环境,进行了平板表面冷壁热流测量和燃烧室内壁材料考核试验。结果表明:由于辐射换热的影响,在选取的两个典型来流条件下,发动机燃烧室内流热环境下的冷壁热流比外流热环境下的高出21%和40%,但是冷壁热流的增量基本相当,约为0.70~0.80MW/m²。随着冷壁热流的增加,辐射换热产生的热流增量的影响力会逐渐减小。材料考核时,相同配方的C/SiC复合材料在内流热环境下的表面温度高出约400℃,背面温度高出约90℃,这种差异对于发动机燃烧室内壁面材料考核至关重要,必须在材料考核试验中加以考虑。      

高强箍筋混凝土简支梁斜裂缝分形理论研究和有限元分析

通过对8根集中荷栽作用下高强箍筋t形截面简支梁的试验研究,运用分形理论和有限元法对试件中斜裂缝分布特征进行分析.分别计算分形维数表征的混凝土损伤断裂能和有限元分析的应力强度因子进行比较,结果表明:分形理论对斜裂缝自相似性有很好的量化关系,两种理论有很好的拟合.     

燃烧加热污染空气对超燃冲压发动机性能影响研究

针对燃烧加热地面试验设备存在的工质污染问题,采用数值模拟方法研究了燃烧加热污染空气对氢燃料超燃冲压发动机性能的影响。以飞行马赫数Ma=6.5,当量油气比ER=0.6为计算基准状态,分别对纯净空气和污染空气来流下氢燃料超燃冲压发动机的整机流场和性能进行了对比计算分析。燃烧化学反应模拟采用了改进的H₂/O₂七组分八方程模型,湍流模型为标准的 k-ε模型,并采用直连式燃烧室试验数据进行了数值方法的验证。研究结果表明:(1)相对于纯净空气来流,污染空气来流下的超燃冲压发动机推力和比冲均有所下降。(2)采用酒精燃烧加热器的前提下,来流参数匹配静温、静压、马赫数时,发动机性能与纯净空气来流下的结果最为接近,而匹配总温、总压、马赫数时相差最大。(3)来流参数匹配总焓、静压、马赫数的前提下,采用氢燃烧加热器时发动机性能与纯净空气来流下的结果最为接近,而采用甲烷燃烧加热器时相差最大。      

基于试验经济学的金融危机模型研究综述

金融危机发生机制和传播途径的研究种类繁多,常以一些具体危机为背景,难从总体上把握。李雪等从模型演化和全局博弈的角度综述了这类工作。本文则从试验经济学的角度做进一步的概括,介绍一些相关的新进展,说明试验经济学方法在金融危机模型研究中的必要性。     

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.     

Sinosteel：Extraordinary Moves in Industry Chess

Among the Fortune 500 firms,more and more images from China emerge out.On the 2008 list,Sinosteel Corporation,a landmark group of China industries quietly squeezes into the candidate line.As the largest steel service ＆ trade enterprise,its sales reached at RMB 111.24 billion,with a year-on-year increase of 83.03 percent,and the profit grew by 180.03 percent.On the Sinosteel 2008 Work Meeting,the president Huang Tianwen uttered,＂In the coming year,we will work for US$20 billion sales,and look forward to getting a position in Fortune 500 firms for ourselves.＂     

Walk Through Unusual Five Years—— An Exhibitor＇s Canton Fair Course

When the 103rd Canton Fair is approaching, an old friend of Canton Fair, Li Ying from Jiangsu prov-ince recollected his past five years＇ experiences to the grand trade meeting. Each year is special, with some unforgettable memories colored by the year.     

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＂.     

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,     

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,     

China's Auto Industry Steps Forward

Last year,the volume of China's auto trade reached US$66.878 bil- lion,of which imports accounted for US$25.982 billion,a year-on- year increase of 24.45 percent;while ex- ports totaled US$40.896 billion,growing by 45.31 percent.The China Association of Automobile Manufacturers(CAAM) predicts that the number of autos sold in 2008 will break the 1 million barrier for the first time in history,representing an increase of about 20 percent.