问题
问答题 简答题
为什么要采用多级压缩，级数是如何确定的？
答案
参考答案：
1）降低排气温度；
2）节省功率消耗；
3）提高气缸容积利用率；
4）降低活塞上的最大气体作用力。
压缩机采用多级压缩，级数的确定一般应综合考虑这样几条原则：每一级的压缩温度在允许范围之内；压缩机的总功耗最少；机器结构尽量简单，易于制造；运转可靠。
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为什么要采用多级压缩，级数是如何确定的？
参考答案：
1）降低排气温度；
2）节省功率消耗；
3）提高气缸容积利用率；
4）降低活塞上的最大气体作用力。
压缩机采用多级压缩，级数的确定一般应综合考虑这样几条原则：每一级的压缩温度在允许范围之内；压缩机的总功耗最少；机器结构尽量简单，易于制造；运转可靠。
One day, my English teacher asked me to help her save back-up（备份） copies of her work in the computer. I then realized I was able to know the grades of all of her students. I her how to copy files（文件）from one disk to another and she thanked me. A few days later, she asked me to help her again, because she how to do it. When I showed it to her, some students in my class noticed and began to talk among themselves .Later that day, at lunch time, several of them came up to me. "Hey, could you help us change our grades? We'll for it." I could not believe what I heard. I could get paid for something very . "All right. I'll do it." The next day, my English teacher asked me to help him out again. When he was not paying attention, I changed their grades from Fs to As. I soon became very popular among my friends. They began to treat me like God who could do . Word spread quickly and I became very rich. Everything was going fine I was called into the headmaster's office. When I got there, both of my teacher and the headmaster were very angry. "I don't want to what your teacher said, but I have to. She has too much evidence(证据)," the headmaster said. "Do you have anything to say for yourself?" "No," I said finally. I didn't realize how my behavior had been. I had disappointed my teacher and the headmaster. And there was no way . I had to leave my school. That was a good lesson for me.
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