Thanks for the help. I'll have to hold off on the heat exchanger for now until I free up some time. I'll definitely get back to it at some point and I'll post about it. Thanks for the help with the problem in general.
Yeah. Using your way you get -15.9 kW. So, they're fairly close. If you were to say the pump is about 80% efficient then, 19.875 kJ/s needs to be supplied to the pump for the water to be pumped from ##P_{atm}## to 1.69 MPa.
I was thinking it was a little low alright. Why isn't it ##C_v## as opposed to ##C_p## in the above equation though? h = u + Pv, so ##\Delta h = \Delta u + \Delta Pv## and ##\Delta u = C_v \Delta T## no?
It's just one stream so ##m_{in}## will equal ##m_{out}##, yes? If so, then: $$W = m(h_{in} - h_{out})$$
We're given the mass flow rate so we'll end up with the equation: $$\dot{W} = \dot{m} (h_{in} - h_{out})$$ Is this correct? The water is initially at 20 C and atmospheric presure, thus it's...
I'm currently taking thermo. I think our terminology may be different to yours, or else I'm not following. A flow system, as in a control volume at steady state? One form of the first law which comes to mind that may be applicable to the pump is is: $$Q - W + \Sigma m_{in}h_{in} - \Sigma...
I see. I'll have a look into that now and then try play around with the possible values of N, D and L that may be a little more suitable.
Could we leave the HE for now and focus on the final part, the pump, briefly? I feel like I may be going into a little too much detail with the HE as we...
I see. Well, rearranging the above equation you get:$$NDL = 27 m^2$$
To avoid having the heat exchanger being impractically long, L has to be capped and to avoid having the tubes too wide so does D. That leaves N.
I'm not really sure what the value of N is usually. I mean, I know it must...
Sorry about those blunders. I ended up trying to fly through the calculation and obviously wasn't taking much care.
So, the heat transfer area is 85 m^2. Would this be considered large or about the norm for the sort of process in question? Can't really tell myself as I don't have too much...
That equation is completely alien to me, but I assume I'll cover it some time over the next year.
##A = \frac{Q}{h\Delta T}##
Just edited this post as I made a mistake with the LMTD. I had thought you made a mistake using 160C and 30C as your temps but it was actually just me not fully...
The only reason I bring it up, is because in the problem statement it states 'Consider briefly the issues of pressure relief, recycle and isolation'. I though that this was a good opportunity to think about recycle. It was just a thought really. Though, I was more so thinking that the water...
Actually, I just got my hands on Transport Phenomena an had a quick look at chapter 14. While most of it is quite out of context, as I haven't studied Transport Phenomena before, I found the table of heat transfer coefficients. Is what we have in this case, Forced Convection? (Seeing as there's...
I think determining the heat transfer coefficient is a little too involved for the purpose of the current module that I'm taking. I'm not so sure that our lecturer would expect us to be able to design a HE in great detail seeing as haven't covered that yet. I'll ask him though just to be sure...