00:01
Hi everyone, so what we have is an exhaust gas regenerator that is heating up air.
00:05
So we have air moving from 1 to 2 and gas going from 3 to 4.
00:09
We know the air is entering this regenerator at 1mpa and at a temperature of 550 kelvin at a mass flow rate of 800 kilograms a minute.
00:19
We know that there's 32 kilowatts of heat transfer that is being added to the gas, added to the air.
00:26
And we also know that our exhaust gas enters at 140 kpa.
00:30
And 800 kelvin and leaves at 130 kpa and 600 kelvin.
00:35
What we're asked to find is the exit temperature of the air that's being heated and the mass flow rate of the recirculating gas.
00:42
So what we're going to write down first is our assumptions.
00:46
So we're going to assume that this is a steady state process, so conditions will not be changing the time.
00:51
We're going to assume that any changes in kinetic energy, potential energy, and work are equal to zero.
01:00
And we're also going to assume that our exhaust gases are going to be treated as air.
01:10
So next what we're going to do is write down the properties that we're concerned with.
01:14
So since we are dealing with air, we know that our gas constant is going to be equal to 0 .287 kilojoules per kilogram kelvin.
01:26
And given that we have all these temperatures, we can also go ahead and determine our enthopies using the fact that enthalpy, is just going to be listed on table a17.
01:37
So the fact that t1 is 550 kelvin gives us an enthalpy equal to 556 .0 kilojoules per kilogram.
01:50
The fact that temperature 3 is equal to 800 kelvin leads us to an enthalpy h3 equal to 822 kilojoules per kilogram and since we know that t4 is 600 kelvin, we know that our enthalpy of 4 is equal to 607 kilojoules per kilogram.
02:13
So next what we're going to do is define our system.
02:16
We're going to define the air side, so the air that's going through the heat exchanger as our system...