问题 问答题 简答题

离心压缩机的主要构件有哪些?

答案

参考答案:

叶轮:它是离心压缩机中唯一的作功部件。气体进入叶轮后,在叶轮片的推动下随叶轮旋转,由于叶轮对气体作功,增加了气体的能量,因此气体流出叶轮时,压力和速度均有增加。

扩压器:气体由叶轮流出的速度很高,为了充分利用这部分能量,常常在叶轮后部设置流通截面逐渐扩大的扩压器,以便降速度能转化为静压能。一般常用的扩压器是一个环状通道,其中装有叶片扩压器,不装叶片的是无叶片扩压器。

弯道:为了把扩压器的气流引导到下一级叶轮去进行压缩,在扩压器后设置了使气流由离心方向改变为向心方向的弯道。

回流器:为了使气流以一定方向均匀地进入下一级叶轮

进口,所以设置了回流器,在回流器中一般装有导叶。

蜗壳:其主要作用是将需要压缩的气流汇集起来引出机器。此外,由于蜗壳的外径及流通截面积逐渐扩大,也起到了降速扩压的作用。

吸气室:其作用是将需要压缩的气流,由进气管(或中间冷却器出口)均匀的导入叶轮去进行增压。因此,在每一段的第一级前都置有吸气室。

在离心式压缩机中,一般把叶轮与轴的组件称为转子,而将扩压器、弯道、蜗壳、吸气室等称为固定元件。

阅读理解

第三部分:阅读理解(每小题2分,满分40分) 

A

Hello, Listeners. Welcome to Henton Hospital Radio. Before our music programme at four, I’m going to repeat some of our hospital rules.

The hospital can sleep 800 patients. There’re 8 beds in each ward (病房). The visiting hours are in the afternoon from 2:30 to 3:30 and in the evening from 7:00 to 8:00. But remember only two people can see you at the same time. Sorry about that, but you can see what would happen if we didn’t have these rules.

The other rules are about our hours. We start quite early---you might not be used to that. We wake you at 6 o’clock, and breakfast is at 8 o’clock, lunch is at noon.

There’s tea at 3:30 and supper is at 6 o’clock.

You can see the non-smoking sign –-- we don’t allow smoking in the wards. I’m sure you understand why. However, if you do need to smoke, there are some smoking rooms where It is allowed.

You will find the radio switch (开关) on the wall near your bed, with your own headphones, if you want to listen. It’s our own hospital radio wishing you a quick recovery (康复).

56. Who do you think the listeners might be?  

A. Patients.     B. Visitors.    C. Doctors     D. Nurses

57. How many wards are there in this hospital? 

A. 8       B. 80      C. 100      D. 800

58. Which is Not allowed in the hospital?

A. Listening to the hospital radio.               B. Visiting patients in the morning.

C. Smoking in smoking-rooms.               D. Getting up early in the morning.

59. What programme will follow this radio talk?

A. Hospital rules.  B. A weather report.   C. A free talk.     D. A music programme.

问答题 简答题