问题 问答题 简答题

计算题:

某双管热水采暖系统,供回水温度为85℃/60℃,散热器采用M132型,每片散热器散热面积为0.24m2,室内计算温度为tn=18℃,散热器的传热系数为:K=2.237(tpj—tn)0.302W/m2.℃,某房间设计热负荷2500,且散热器明装于室内,同侧连接,试求散热器片数。(n=6片时,β1=0.95;n=6—10片时,β1=1;n=11—21片时,β1=1.0)(15分)

答案

参考答案:

n=β1β2β3×Q/A(tpj-tn)1-B

=β1×2500/2.237×(72.5-18)

1-0.302

=68.59β1

=69片

写作题

书面表达

Daniel最近迷上了手机游戏,经常玩到深夜。现在他因为睡眠不足,上课不能认真听课,成绩也在下降。他妈妈很生气,不再让他使用手机。假如你是他的朋友Tina,请你写一封信给他,建议他要合理使用手机,如查阅资料、记单词等。同时,考试在即,要理解父母、老师的心情,要主动去沟通,得到他们的原谅和帮助。

要求:

1.包含所给的要点,语言流畅,意思连贯,适当扩展。

2.词数:90词左右,开头和结尾已给出,不计入总次数。

Dear Daniel,

I am sorry to hear that you quarrelled with your parents about playing mobile phone games.

                                                                                           

                                                                                           

                                                                                           

                                                                                           

                                                                                           

                                                                                           

                                                                                           

                                                                                           

                                   

I hope my suggestions are of great value to you.

Yours,

Tina

判断题