问题 问答题 简答题

喘振的机理原因是什么?

答案

参考答案:

机理性研究结果表明,喘振产生的内部原因与叶道内的脱离密切相关。当气体流量减少到一定程度时,压缩机内部气流的流动方向与叶片的安装方向发生严重偏离。使进口气流角与叶片进口安装角产生较大的正冲角,从而造成叶道叶片凸面气流的严重脱离。此外,对于离心式压缩机的叶轮而言,由于轴向涡流的存在和影响,更极易造成叶道里的速度不均匀,上述气流脱离现象进一步加剧。气流脱离现象严重时,叶道中气体滞流、压力突然下降,引起叶道后面的高压气流倒灌,以弥补流量的不足的,缓解气流脱离现象,并可使之暂时恢复正常。但是,当将倒灌进来的气体压出时,由于级中流量缺少补给,随后再次重复上述现象。这样,气流脱离和气流倒灌现象周而复始地进行,使压缩产生一种低频高振幅的压力脉动,机器也强烈振动,并发出强烈的噪声,这就是喘振的内部原因。

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Stuck on a desert island?
Started on 23rd April by Steve          Posts 1 -7 of  42
Post 1 Steve USA Hi,everyone. What would you miss most and least if you were stuck on a desert island? For me, it would be the changing seasons in New England. I guess this will sound stupid but I'd probahly miss the rain. too. I wouldn't miss getting up at six every day to go to work,though !  What about you?

Post 2  Tomas Germany Good question, Steve. I think I'd miss different types of bread, and shopping at the supermarket. I'd miss the food most. What would I miss least? My mobile phone-l'd like to be completely quiet-at least for a little while.

Post 3 Paola  Italy I would miss the company of people because I know I'd  like to have someone to share experiences with. I'd go mad on my own. And I sure wouldn't  miss junk  mail (垃圾邮件 ) -I hate coming home every evening and finding a pile of junk mail in my post box.

Post 4 Miko Japan Hi, I would miss Manga cartoon. the Internet and Japanese food, like sushi. I'd also miss Tv shows and shopping for clothes…
Post 5 Roger UK I would miss my daily newspaper and listening to the news on Tv and radio. I'd feel very cut off if I didn't know what was happening in the world.What l'd miss least would be traffic jams in the city, particularly my journey to work.

Post 6 Jayne Canada Why hasn't anyone mentioned their family? l'd be lost without my husband and two kids.They're the most important for me. And I can't get started in the morning without a cup of black coffee.  I wouldn't miss doing the housework !

Post 7 Jaime Mexico It would have to be music.  I couldn't live without my  nlusic. I wouldn't miss going to school at all or doing homework!

1. Who would miss his or her family most?
A. Jaime.      
B. Jayne.      
C. Miko.      
D. Paola.
2. Which of the following people would feel most uncomfortable without the news media?    
A. Steve.      
B. Jaime.      
C. Roger.    
D. Tomas.
3. How many of them mentioned that they would miss food or drink?  
A. One.        
B. Two.        
C. Three.      
D. Four.
单项选择题