Thank you for that! I understand it much better now!!! In my thermo course, I think we just used steam tables for pure substances and the ideal gas equation for air. So I'd never dealt with a situation where the temperature was a function of time. I'm doing a second course later this year which...
Ah! Sorry
Here goes,
$$\dot{Q} + \dot{m}(h_1 - h_2) = \dot{m}(u_2 - u_1)$$
Heat is from convection so,
$$hA_c(T_h-T_o) = \dot{m}(c_p + c_v)(T_o-T_i)$$
Is that correct?
Why would ##T_i## be a constant but not ##T_o##?
$$\dot{Q} - \dot{W} = \sum_{out} \dot{m} (h+ke+pe) -\sum_{in} \dot{m} (h+ke+pe) $$
Hence,
$$\dot{Q} = \sum_{out} \dot{m} h -\sum_{in} \dot{m} h $$
So for convection,
$$hA_c(T_h - T_o) = \dot{m}(h_2-h_1) = \dot{m}c_p(T_o-T_i)$$????
Why would ##T_i## be a constant but not ##T_o##??
Thanks Chestermiller.
The way I derived your expression is,
$$\dot{Q_{in}} - \dot{Q_{out}} = \frac{d(mc(T_o - T_i))}{dt}$$
but there is no ##\dot{Q_{out}}## if you consider the inner chamber as the system and there is no heat loss to the surroundings. So,
$$\dot{Q_{in}} = \frac{d(mc(T_o -...
Hey Chestermiller, could you provide more insight into how you derived that equation? Reading online I've only seen the expression $$Ah(T-T_{\infty}) = -\rho Vc \frac{dT}{dt}$$ after googling transient heat convection transfers.
I'm still not quite convinced. Why would ##T_h - T_0## be the overall temperature difference?? Would the "overall" temperature difference be the average temperature difference? Which is $$T_h - \frac{T_0 - T_i}{2}$$ ???
Hello Chestermiller; really apologise I didn't fill out the homework template. What does the over heat transfer coefficient ##h_c## have anything to do with the temperature difference being ##T_h - T_o##? I would argue that the temperature difference used in ##q = h_c A \Delta T## should be...
Hello guys, in the question attached, my understanding is that there is a heat transfer that heats the fluid from an initial at the input, to at the output. This heat transfer is via convection from walls of temperature .
Firstly, .
Because the walls are and the fluid is of a lower...