问题 问答题 简答题

单元机组燃烧自动调节有什么特点?

答案

参考答案:

单元机组燃烧自动调节主要特点有:

(1)单元机组不存在锅炉之间负荷分配的任务,调节系统比母管制简单。

(2)在大型单元机组中由于在低压缸之前增加了中间过热器,当主汽门突然开大时汽轮机高压缸的出力相应迅速增加,而低压缸出力的变化比较迟缓有惰性,功率变化对调峰不利。为消除惰性和提高对负荷变化的适应性,要求处理能很快跟随汽门开度变化而变化。因此在开始时就将汽门多开大一些,这给调节带来一些困难。

(3)外部负荷变动时调速系统动作,主汽压力发生变化,使锅炉调节系统相应动作,实现锅炉、汽轮机两个调节系统的协调控制。

阅读理解

Scientists (科学家) think that many animals cannot see colours. The world is black and white to them. Scientists want to find out if (是否) dogs can see colours. When the scientists give the dogs food, they show them a certain colour every time. The dogs get ready to eat when they see this colour. The scientists then show the dogs another colour. Again the dogs get ready to eat. The colours are all the same to them.

Colours are not all the same to monkeys. For example, if we put food in a red box, and do this every day, a monkey will always go to the red box to get food. If we put food in a blue box, the monkey won’t go to it.

小题1:Scientists show the dogs colours ____________.

A.to tell them to eat

B.to find out if they can see black and white things

C.for fun

D.to find out if they can see colours小题2:The dogs get ready to eat when they ____________.

A.hear different pieces of music

B.see the monkeys

C.see black things

D.see all the colours小题3:Colours are _____________.

A.all the same to monkeys

B.not all the same to dogs

C.different to dogs

D.not all the same to monkeys小题4:If we put food in a blue box and do this every day, a monkey will always go to ____________.

A.the red box to get food

B.the blue box and put food in it

C.the blue box to get food

D.the red box and put food in it小题5:Which of the following is TRUE?

A.Scientists find that dogs don’t like colours.

B.Dogs like to hear different pieces of music.

C.Monkeys like the food in the box.

D.Monkeys will not go to the blue box if we don’t show them before.

单项选择题 A4型题