Thermodynamics by Coursera
[BLANK_AUDIO].
Welcome back.
So last time we talked about work transfer as a form of energy transfer across the system boundary.
Now there are a few key points we need to remember. Work transfer is not a system property.
Where transfer depends on the process path and there are many different types and forms of work transfer so last time we introduced expansion and compression work and that's the work to raise or lower a piston.
Now that type of work is very important because that's pretty much the power generation that's used in all of the transportation sector, is the expansion and compression work.
And so we looked at that as a specific example and then we left with a question of what would a constant pressure compression process look like on a pressure volume diagram?
So we're starting to put some of our tools together.
The PV, pressure volume diagram are state diagrams, we're going to discuss those quite a bit in the coming lectures.
But we also talked about work as being, in it's most general form, an integral expression. And then, we said, okay, there's a specific form of that expression for expansion and compression work.
So, let's answer that question now.
Okay, so we talked about the PV diagram.
And again we said that work in its most general form could be expressed as an intergral moving from one state condition to a second state condition so that's S1 to S2 and the most general form of that expression is one where we use just some force. Times the distance, that it, that force has executed in that process.
So from state one to state two forced integrated over that distance, over that process distance.
And we said for expansion and compression work in particular, we would move from state one to state two and that the form of the expression was pressure times the differential D volume so remember the V with the cross hash is a volume
expression
Welcome back.
So last time we talked about work transfer as a form of energy transfer across the system boundary.
Now there are a few key points we need to remember. Work transfer is not a system property.
Where transfer depends on the process path and there are many different types and forms of work transfer so last time we introduced expansion and compression work and that's the work to raise or lower a piston.
Now that type of work is very important because that's pretty much the power generation that's used in all of the transportation sector, is the expansion and compression work.
And so we looked at that as a specific example and then we left with a question of what would a constant pressure compression process look like on a pressure volume diagram?
So we're starting to put some of our tools together.
The PV, pressure volume diagram are state diagrams, we're going to discuss those quite a bit in the coming lectures.
But we also talked about work as being, in it's most general form, an integral expression. And then, we said, okay, there's a specific form of that expression for expansion and compression work.
So, let's answer that question now.
Okay, so we talked about the PV diagram.
And again we said that work in its most general form could be expressed as an intergral moving from one state condition to a second state condition so that's S1 to S2 and the most general form of that expression is one where we use just some force. Times the distance, that it, that force has executed in that process.
So from state one to state two forced integrated over that distance, over that process distance.
And we said for expansion and compression work in particular, we would move from state one to state two and that the form of the expression was pressure times the differential D volume so remember the V with the cross hash is a volume
expression