So now we have a relationship between the ratios of these volumes that are reached during these adiabatic paths.
现在我们有了一个联系,这些绝热过程中,体积比的关系式。
And they even put different facades on some of the buildings
他们甚至还在一些建筑上放上不同的绝热板,
Adiabatic can be either reversible or not, and we're going to do that probably next time or two times.
绝热过程可以是可逆的,也可以不是,我们可能会在下一次或下下次课上,研究这个问题。
So there's going to be a line that's going to connect the initial point to the final point, and that line mathematically is not going to be the same as this one here.
连接绝热过程,初末态的曲线的方程,和等温线的方程,也不会相同。
dq=0 But if it's adiabatic, then dq is equal zero, du=dw and for an adiabatic process, then du is equal to dw.
但如果它是绝热的,那么,因此对于绝热过程。
T2 So this is an isotherm at some different temperature T2, a cooler temperature, because this was an expansion.
这个绝热过程的温度是,比T1低,因为这是个膨胀过程。
In the opposite case, if you have a compression, then it's the opposite of expansion.
绝热压缩,的情况,与此相反。
You've just done an adiabatic compression of the ideal gas, you can pretend there is an ideal gas.
这就是对理想气体的,绝热压缩,---我们把空气近似作为理想气体处理。
That'll be inside our calorimeter. It's insulated, and there's still a thermometer, so we can measure the temperature.
被放置在量热计里面,它是绝热的,同样有一个温度计,让我们可以测量温度。
Yes, exactly, it's adiabatic, right constant pressure.
对,没错,它是绝热的。
The boundary is impervious to transfer of heat like a thermos Anything that happens inside of the thermos is an adiabatic change because the thermos has no connection in terms of energy to the outside world.
边界不能传递热量,像热水瓶一样,热水瓶里发生的任何事,都是绝热变化,因为热水瓶与外部世界,没有能量方面的联系。
So this is still adiabatic. It's insulated, but now it's constant volume, OK.
这仍然是绝热的,是隔热的,但现在它的体积是恒定的。
It's set up to be well-insulated so it's adiabatic.
所以它是绝热的。
And it's still adiabatic, but now it's constant volume. And it's also reversal right.
它仍然是绝热的,但现在是,在等体条件下,它也是可逆的。
Now to make that happen, it's not adiabatic, right. If I wanted to do that, I'd need a heating element or something to cool, so I could make that temperature change happen, right.
要实现这点,它就不会是绝热的,对吧,如果我想做到这点,我需要一个加热元件或什么制冷的东西,这样我才能让温度变化。
So your time scale it just fast enough that this is basically an adiabatic compassion.
你的时间足够快以至于,基本上是一个绝热过程。
T2 Is the temperature T2 in this process smaller or larger than if I were to do the process reversibly with the same endpoint pressure.
这里的末态温度,与经过可逆绝热过程,到达相同压强的末态温度相比哪个比较高呢?
We're going to take a piston here which is going to be insulated.
容器与气缸,都是绝热的。
And the whole thing is insulated right.
整个装置是绝热的,对吧?
So we're going to start at one, T1 and this is going to be in isotherm at temperature T1, and all the paths here are going to be reversible.
我们从一开始,这是个绝热恒温过程,温度是,所有路径都是可逆的。
These are all constant. It's isothermal.
它们都是常数,这个过程是绝热的。
This is going to end up at a different temperature by the way. You saw this last time in a slightly different way. Last time what you saw is we compared isothermal and adiabatic paths that ended up at the same final pressure, and what you saw is that therefore they ended up in different final volumes.
末态温度是不一样的,上次你们看到的,和这个有一点不一样,上次我们比较的是末态压强,相等的等温过程和绝热过程,因此它们的末态,体积是不一样的。
It's well insulated. Heat is not going in or out adiabatic. q is equal to zero.
绝热性很好,热量不会变化,是绝热的,Q等于零。
Adiabatic meaning there's no heat involved, and we're going to see how that differs from the isothermal expansion and compression.
绝热意味着没有热量的传递,我们将看到它,与等温过程的区别。
And you already saw last time there was this relationship between the temperature and volume changes along an adiabatic path.
是条绝热路径,而上次你已经看到,沿着绝热路径温度和体积,的变化有这个关系。
As long as it's reversible, you know what the efficiency has to be, and in principle, you could break it down into a bunch of steps that you could formulate as isothermal and adiabatic.
只要这个循环过程是可逆的,你们知道效率是多少,从理论上说,可以将总过程,分解成一系列绝热,和等温的小过程。
OK, so let's go through this and see what we would do which is to calculate the heat and the work. This is well insulated.
好的,让我们开始然后看看,我们该怎样计算热量和功的大小,这是完全绝热的,所以。
It is taking place inside this thing, and it's a constant pressure, and we'll do it reversibly, right. So that's what we've got.
它是绝热的,在这个内反应,是在恒压下,它是可逆的,对吧?
OK, so we have constant temperature, because it's isothermal.
好,现在系统有恒定的温度,因为它是绝热的。
You take a throttle valve, which consists of some sort of porous plug between two cylinders that is insulated. There is insulation here.
有一个节流阀,它由一些多孔的塞子组成,这些多孔塞在两个绝热的汽缸之中,这里是绝热的,底下也是绝热的。
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