汽轮机启动前为什么要暖管？_爱下问搜题

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问题问答题简答题

汽轮机启动前为什么要暖管？

答案

参考答案：

由于启动前主蒸汽管道和阀门、法兰等处于冷状态，故先以0.05～0.5MPa压力进行暖管，使管路缓慢受热膨胀均匀，不致于产生过大的热应力。暖管工作的要求是控制主蒸汽管道及其附件的温升速度，在一定压力下，把蒸汽管道连接法兰，阀门和汽门均匀地逐渐升温，然后升压，升压的目的是为了暖管，升压时以每分钟0.15—0.35MPa速度逐渐升至额定压力。（本汽轮机升压速度规定为0.35MPa／min）。

单项选择题

以下关于简单程序设计的步骤和顺序的说法中正确的是( )。

A．确定算法后，整理并写出文档，最后进行编码和上机调试

B．首先确定数据结构，然后确定算法，再编码，并上机调试，最后整理文档

C．先编码和上机调试，在编码过程中确定算法和数据结构，最后整理文档

D．先写好文档，再根据文档进行编码和上机调试，最后确定算法和数据结构

完形填空

Tuesday the twelfth was my birthday. I 16 a day of cake and presents 17__     it turned into a day of mystery(神秘). Someone sent a bottle with a letter and a treasure map   18 . It said there was a treasure of over 20 million dollars. I didn’t know if it was a trick(恶作剧) or if I should   19  it. If it was   20 , it would be the best present I had ever got. I decided to 21 . Two of my friends came and we rented a truck.   22 , I thought about turning back twice during this trip, but I didn’t think it was a 23 decision for me to make. I   24 to give this trip twice the effort(努力) I had been putting in. This would take all my trust in order for me to find the 25  .
“The map says you have to turn when you see a large stone with a red circle,” said one of them.
“What do we do after the turn?” I asked   26 .
“It says we should see a tree. We are   27  to turn 20 meters north of it and dig.　
We got there and dug. We had   28  at first digging but we got better and worked very   29 . My trousers were dirty but I kept digging   30  I hit something. It was a large metal box. We   31  the lock and looked inside. There was a letter. It read:
　　“The lesson you have learned will be very   32  . If you put as much   33 in anything you do as you did in finding the   34  , you will have found the key to making over 20 million dollars.”
　　This was a trick from my parents. I thought I would never forget this   35    birthday present.

C．interesting