Okay thanks, so basically the method of main resistance cannot be used since the difference is not that low. Although, say if the water side heat transfer coefficient was 700 (1/10 of pentane), I can use that as the overall heat transfer coefficient (and this would mean using the method of main...
Yes, you are correct. My equation is basically the same, i just haven't simplified it as you. I also realized I forgot to enter a value into my equations, now I am getting the exact same result as you.
Once again, Thank you
Can you just have a quick look at the other thread regarding the heat...
Okay, so using your equations I get temperature at center: 528.85K and at surface: 510.35. So yes, there is not a major difference.
'You also need to make sure that the two answers you get in part ii are exactly the same (as they should be).' <------------- This is bothering me now.
So in my...
Okay, so your comment were obviously helpful it helped me finish the question. I have attached screenshots of my working, solely for the benefit of other user if they want to know how to work it out. I will explain the main steps, if anyone needs any clarifications I will type out the detailed...
Chet, my man. Thanks a billion for all your input, it is very much appreciated. I did not reply for the past few days because I was still working on it. I finished my working, realized my mistakes and even got it verified by a phD student. I will show the correct working, so if anyone come...
'see if you can use your solution to determine the time constant for exponential decay of the temperature difference. Are you able to come up with a number for this'
The thing is i don't think I have to make it as complicated as your are suggesting, I am probably wrong. But I have no clue how...
Homework Statement
In Attachment
Homework Equations
The Attempt at a Solution
Second Attachment.
- I have only attempted part (i) so far, because I am not sure if I am doing it correctly. I was thinking since the value of the latent heat of pentane is given, surely it has to be...
These plots of dimensionless temperature as a function of dimensionless time, they are not in my lecture handouts but I did look online and got some graphs. I just want to add this question is from a Past Exam Paper and all the information on the question given was only that, meaning no extra...
Okay, thanks for your reply. Yes, indeed in my book it says that the characteristic length is the radius, so what I have done is correct. Cylinder 1 with a Biot number of 0.15 would be appropriate. But then in my calculations, I calculated the temperature for that. But my question is how to...
Homework Statement
Problem is in attachment pic.
Homework Equations
The Attempt at a Solution
My attempt is on the pics 1 and 2.
Firstly, is it valid to assume length as 0.075m?
- For part (i), from the question it infers that one of the cylinders is applicable to the lumped...
Homework Statement
A counterflow, concentric tube heat exchanger is used to cool the lubricating oil for large industrial gas turbine engine. The flow rate of cooling water through the inner tube (Di = 25 mm) is 0.2 kg/s, while the flow rate of oil through the outer annulus (Do = 45 mm) is...