|
[Sponsors] |
March 23, 2017, 07:20 |
Issue with heat transfer coefficient
|
#1 |
New Member
Thomas
Join Date: Jan 2017
Posts: 14
Rep Power: 9 |
Hello!
My simulation involves a turbulent water flow in an inclined rectangular cavity: inlet velocity = 0.003 m/s Pressure outlet = Patm Top plate heat flux imposed (different for every simulation, q= 100-1000 W/m2) Bottom plate and side walls adiabatic, q=0 W/m2 Water is flowing between the plates in a cavity. When I take an Area Weighted Average value for convective heat transfer coefficient (htc) between the Top surface and the water, I get the same value despite the heat flux applied. I think htc should change when I change heat flux value, because the temperature varies along the Top surface. However, in my case, for the constant velocity (and hence the mass flow rate) the heat transfer coefficient remains the same. Could anyone see what is wrong here? Any help is appreciated. |
|
March 23, 2017, 10:07 |
|
#2 |
New Member
Thomas
Join Date: Jan 2017
Posts: 14
Rep Power: 9 |
Please, could someone help me with this.
|
|
March 23, 2017, 10:55 |
|
#3 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,676
Rep Power: 66 |
The heat transfer coefficient is a property of the flow. If you change only the heat flux and nothing else, then the heat transfer coefficient should not change.
|
|
March 23, 2017, 11:11 |
|
#4 | |
New Member
Thomas
Join Date: Jan 2017
Posts: 14
Rep Power: 9 |
Quote:
I don't understand why heat transfer coefficient was changing when I tested the natural convection flow. Instead of velocity-inlet I then had a pressure-inlet boundary condition. Considering that q=h*A*(Ts-Tf), h should not change in natural convection flow either, should it? |
||
March 23, 2017, 11:17 |
|
#5 | |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,676
Rep Power: 66 |
Quote:
In natural convection, the density changes due to temperature change and hence buoyancy force changes. In this situation, the flow changes. |
||
March 23, 2017, 11:55 |
|
#6 | |
New Member
Thomas
Join Date: Jan 2017
Posts: 14
Rep Power: 9 |
Quote:
|
||
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Heat transfer coefficient - what is waht | Stan | FLUENT | 28 | December 29, 2021 16:29 |
Ansys CFX problem: unexpected very high temperatures in premix laminar combustion | faizan_habib7 | CFX | 4 | February 1, 2016 17:00 |
Heat flux and Heat transfer coefficient | sakil2k3 | FLUENT | 4 | July 5, 2015 15:07 |
Constant velocity of the material | Sas | CFX | 15 | July 13, 2010 08:56 |
Convective Heat Transfer - Heat Exchanger | Mark | CFX | 6 | November 15, 2004 15:55 |