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绵阳师范学院 本科生毕业论文（设计）

题 目 气体的绝热膨胀和节流过程探讨 专 业 物理学 院 部 物理与电子工程学院 学 号 0709420424 姓 名 李 飞 指 导 教 师 廖碧涛 讲师 答 辩 时 间 2011年5月

论文工作时间： 2010 年 11 月 至 2011 年 05 月

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气体的绝热膨胀过程和节流过程探讨

学 生: 李 飞

指导教师: 廖碧涛

摘 要：目前低温技术越来越受到人们的关注，低温制冷技术已经广泛应用于气象，军事，航空航天，低温电子技术，低温医学领域等。气体的绝热膨胀和节流过程是获得低温的两种途径。在绝热的条件下高压气体经过多孔塞或节流阀流到低压一边的稳定流动过程称为节流过程。测量气体在多孔塞或节流阀两边的温度表明，在节流过程前后，气体的温度发生了变化，这效应称为焦耳-汤姆逊效应，简称焦-汤效应。这是焦耳和汤姆逊在1852年用多孔塞实验研究气体内能时发现的。绝热膨胀是指与外界没有热量交换，但气体对外界做功，气体膨胀。根据热力学第一定律，可证明这是等熵过程，在这个过程中气体体积增大，压强降低，因而温度降低。所以绝热膨胀经常用于降低气体的温度，起到冷冻的效应。本篇文章主要是对理想气体和范德瓦耳斯气体在节流过程和绝热膨胀两种过程中热力学特征以及各状态函数变化的研究，得出各状态参量的变化情况。加深对节流过程和绝热膨胀过程的理解和认识。节流过程和绝热膨胀过程制冷都有着各自的优点和缺点，将节流过程和绝热膨胀过程结合使用可以充分弥补各自的缺点，发挥优点，达到极好的制冷效果，获得低至1K的低温。目前节流过程和绝热膨胀过程被广泛运用与化工生产中。

关键词 低温； 绝热膨胀； 节流过程； 焦耳一汤姆孙效应

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The Insulation the Expansion Process and in

The Throttling process to

Undergraduate: Li fei

Supervisor: Liao Bitao

Abstract：At present technology has been getting attention.Temperatures refrigeration technology is widely applied to meteorological, military, the cooler the air space and technology, medicine, etc. low temperatures. Of hot gas expands and throttling process is a low temperature two ways. In the insulation of high pressure gas after the plug or throttling the valve to the stability of the low side of the current process is called the throttling process. the gas or throttling the valve in the plug on the temperature that, in the throttling process, the temperature of the gas has changed, the effect is called joule - thompson, short dark - soup joule and effect. thompson is in the membrane in the plug experimental research on the gas can find. insulation expansion is from outside world and no calories But gas to do work, expansion of gases. according to law of thermodynamics to the first, but that this is the process of entropy, volume of gas, lower pressure and temperature is lower. therefore, the insulation is often used for lowering the temperature of the gas, to freeze effect. this article is in an ideal gas and vande gas in the throttling process and the insulation the expansion process thermodynamics characteristics and the condition function That the state the throttling process and the insulation. the expansion process of refrigeration have their respective advantages and disadvantages, will the throttling process and the insulation the expansion process can be used for their faults and virtues, a chilling effect, the low temperatures. in addition, 1k in temperatures constant concern and to explore technology, The throttling process and the insulation the expansion process was widely used and chemical production.

Key words: Temperatures；Insulation expansion；The throttling process Joule and

tom effect.

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目 录

引言................................................................ 1

1节流过程和绝热膨胀过程 ............................................ 1

1.1节流过程 ...................................................... 1

1.1.1节流过程的定义及特征 ...................................... 1

1.1.2焦耳-汤姆逊效应 ........................................... 2

1.2 绝热膨胀过程 .................................................. 4

1.2.1绝热膨胀的定义 ............................................ 4

1.2.2绝热膨胀的特征 ............................................ 5

2理想气体的绝热膨胀和节流过程 ...................................... 6

2.1理想气体的绝热膨胀过程 ........................................ 6

2.2理想气体的节流过程 ............................................ 8

3范德瓦尔斯气体的绝热膨胀和节流过程 ................................ 8

3.1范德瓦耳斯气体的绝热膨胀 .............................................. 8

3.2范德瓦耳斯气体的节流过程 .............................................. 9

4绝热膨胀与节流过程的比较和应用 ................................... 11

4.1绝热膨胀与节流过程的比较 ............................................. 11

4.2两种过程获得低温的优缺点 ............................................. 11

4.3绝热膨胀和节流过程的应用 ............................................. 12 结束语．．．．．．．．． …… 此处隐藏：8654字，全部文档内容请下载后查看。喜欢就下载吧 ……