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1.
<正>近年来一些主要国家正在大力发展高超声速飞行器技术,也就是飞行速度大于马赫数(即飞行速度与声音速度之比值。标准大气压、零海拔高度、15℃时声速约340米/秒)5的航空航天飞行器。在航天领域实现高超声速飞行不难,如弹道导弹、运载火箭和航天飞机、宇宙飞船等航天飞行器,最大速度超过马赫数20。但在航空领域航空飞行器的速度和高度纪录还停留在"双3"门槛上,即飞行速度马赫数3和飞行高度3万米。人类正在探索在传统航天飞行器和航空飞行器  相似文献   

2.
邓超 《创业家》2012,(9):47-49
造旋翼机不难,考飞行驾照也不难,但飞机拿到上天的资质很难,中联航空的刘军正在想法破解审批流程长、缺少资金等瓶颈。 刘军制造的飞行器叫旋翼机,或者说自转旋翼机,其外形与直升机类似,但顶端的旋翼并不与发动机相连,而是利用飞行时的气流吹动其自转以产生升力,前进的推力则靠机舱后部带动力的螺旋桨提供。有人将直升机比作会飞的电风扇,将旋翼机比作会飞的风车。  相似文献   

3.
进气道是飞行器动力装置的重要组成部分,准确测量进气道流量系数是进气道风洞试验的重要内容。对来流马赫数Ma=4.5,5.0和6.0状态下皮托管进气道开展流量系数测量研究,通过对比理论值和实测值,获取各状态流量系数修正系数。试验结果表明,随着来流马赫数增加,进气道流量系数与理论值偏差较明显,并逐渐增大。超声速风洞试验通常认为测量截面总温与来流总温相等,通过对测量截面总温与来流总温偏差以及测量截面流场畸变情况的分析,判断测量偏差主要是由测量截面总温等于来流总温的假设导致的。在高超声速风洞试验中,由于模型壁面热交换的存在,测量截面总温低于来流总温,进气道流量系数测量时需要进行总温修正,以提高流量测量精度。   相似文献   

4.
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。   相似文献   

5.
目前计算导管桨的方法大体上可以分为两种,一种是基于升力面和面元法混合计算方法,一种是基于CFD数值计算。两种各有各自的优势,前者基本上可以达到工程应用程度,并可以进行导管桨的优化,节省大量的计算时间,应用较广。但是基于工程实际要求,对于某些船舶,需要计算系住状态下的推力,如其出现较大误差,会出现推力达不到要求,甚者出现船只沉没。因此用更准确的方法计算导管螺旋桨的水动力性能显得极为重要。本文基于CFD技术,研究其网格划分方法,并与试验结果对比,可以将推力系数和十倍扭矩系数误差降低到0.02以下。  相似文献   

6.
本文主要分析了某一飞行事故中起飞重量、推力以及阻力等各因素对事故飞机起飞性能的影响,并就某些主要因素对事故原因作了综合的分析.本文旨在通过对这些结果的分析,使读者对导致整个飞行事故的主要因素能够有一个更为直观的认识和理解.  相似文献   

7.
在针对下一代低噪音、低污染民用航空器的设计中,翼身融合布局(BWB)结合分布式推进系统被认为是最有可能替代传统客机的设计方案。结合NASA提出的N3-X下一代BWB飞行器,首先建立了BWB飞行器模型,随后针对该模型在有无分布式动力推进系统的工作状态下的气动性能进行了CFD计算。通过对计算结果的分析,发现采用分布式动力的BWB飞行器相比传统不考虑动力与翼面气动耦合的飞行器其升力更高,升阻比更高。此种构型的飞行器对降低能源消耗、提高飞行都产生了积极影响。  相似文献   

8.
根据有旋特征线理论,设计出了沿程马赫数下降规律可控的轴对称基准流场,分析了基准流场的几何参数(前缘压缩角及中心体半径)的影响规律,发现选取较小的前缘压缩角和中心体半径有利于得到性能优良的基准流场;然后在设计状态Ma=6时研究了三种典型的马赫数下降规律对这种轴对称流场性能的影响。最后考虑了粘性的影响,并进行了粘性修正探索,结果表明,采用附面层位移厚度修正方法后,基准流场的壁面压力分布和无粘情况吻合良好。   相似文献   

9.
采用计算流体力学软件Fluent开展了某飞机机身外挂吊舱的三维气动性能研究, 得到了外挂吊舱的表面流速/压力分布、吊舱的尾流、飞行阻力,以及吊舱的偏航力矩等信 息。根据气动计算结果,就吊舱的强度、尾流、偏航力矩等影响飞行安全性的问题展开了讨 论。研究结果和试飞一致显示该电子设备外挂吊舱的气动外形是良好的,吊舱的设计是成功 的,可供同类产品设计提供参考。  相似文献   

10.
JF12复现高超声速飞行条件激波风洞研制成功 “据我所知,这个设备是世界唯一的,不仅在于它产生的流场区域大,气流速度高,试验时间长,更重要的是应用了最独特的爆轰驱动技术,克服了自由活塞驱动技术的弱点,是在俞先生的指导下由你们研究所发展起来的。你们将为获得的可靠的高超声速试验数据感到骄傲。”这是国际著名激波管技术专家、国际激波研究院刨始人高山和喜教授对JF12复现高超声速飞行条件激波风洞的赞誉。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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."  相似文献   

14.
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.  相似文献   

15.
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".  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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,  相似文献   

19.
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,  相似文献   

20.
Last November the State Council of China decided to renew its holiday system by reducing the seven-day May Day holiday to three days and introducing three new one-day public holidays, namely the Qingming Festival, Dragon Boat Festival and Moon Festival. By doing so, the three golden-week holidays that were introduced in 1999, namely the Spring Festival, May Day and National Day, could be better distributed.  相似文献   

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