No variation in the temperature contour in the results

madan · February 1, 2015, 00:02

Hello,
I am doing a project on cooling of turbine stator. As the preliminary stage of the project, I am doing the analysis of the blade without cooling in CFX. But I am not getting the variation in the temperature contour around the blade in results. I have mentioned the mass flow rate and total temperature at the inlet b.c's and static pressure at the outlet b.c's. I have used the k-epsilon turbulence model for the simulation. For the meshing purpose I have used ICEM CFD software. I have attached the snapshot of the results I have got in CFX-post. Pls see it and point any mistakes I have done in my simulation.

Thanks,

Madan

ghorrocks · February 1, 2015, 18:47

Are you sure you defined a sensible thermal circuit? In steady state flows, You need to have a heat source, a heat path and a heat sink. Otherwise the results will be bizarre. When you remove something (like the cooling circuit in this case) if you have not replaced it with something else to take the heat away then you will get very strange results.

madan · February 2, 2015, 10:51

Hello sir,
Thanks for your response first. I have given the flow conditions with the inlet mass flow rate of 0.529 kg/s and total temperature of 1200 K, outlet boundary condition is static pressure of 341.08 kPa. I think that the boundary conditions are right but the cfx-post results are very strange. The temperature contour is 1200 K all around the blade. What does that mean sir? Is there any flaw in the input of the flow parameters. The blade height is 40 mm(for reference). Please help me to get rid of this problem sir

Thank you

madan · February 2, 2015, 11:07

Sir,
I have attached the result of my simulation

https://imageshack.com/i/hj0o8LUqj

Dyls · February 2, 2015, 15:05

What are the other thermal boundary conditions? If you only have temperature incoming at 1200K, then that is the temperature that every node will be... Because there are no other sources or sinks anywhere. If you had some other surface that was 300 K in addition to the 1200K inlet, then you would see a non-constant temperature distribution.

Dylan

ghorrocks · February 2, 2015, 17:46

Dylan is exactly right, and this is what I said in my previous post. With nothing else in the thermal circuit then everything will just be your inlet temperature of 1200K.

madan · February 2, 2015, 22:05

sir,

I have given the exit static pressure of 341 kPa which is the another flow b.c's and at the inlet I have given the total temperature, so the static temperature will change while moving in the domain know?

singer1812 · February 3, 2015, 11:32

I assume he is running a compressible flow problem and wants to see the variation of the gas static temperature due compressible effects, and no in the blade?

Use a plane cut across the gas flow instead of surface temperature.

February 1, 2015, 00:02	No variation in the temperature contour in the results	#1
madan New Member Madan Mohan Join Date: Jan 2015 Posts: 8 Rep Power: 11	Hello, I am doing a project on cooling of turbine stator. As the preliminary stage of the project, I am doing the analysis of the blade without cooling in CFX. But I am not getting the variation in the temperature contour around the blade in results. I have mentioned the mass flow rate and total temperature at the inlet b.c's and static pressure at the outlet b.c's. I have used the k-epsilon turbulence model for the simulation. For the meshing purpose I have used ICEM CFD software. I have attached the snapshot of the results I have got in CFX-post. Pls see it and point any mistakes I have done in my simulation. Thanks, Madan

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February 1, 2015, 18:47		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Are you sure you defined a sensible thermal circuit? In steady state flows, You need to have a heat source, a heat path and a heat sink. Otherwise the results will be bizarre. When you remove something (like the cooling circuit in this case) if you have not replaced it with something else to take the heat away then you will get very strange results.

February 2, 2015, 10:51		#3
madan New Member Madan Mohan Join Date: Jan 2015 Posts: 8 Rep Power: 11	Hello sir, Thanks for your response first. I have given the flow conditions with the inlet mass flow rate of 0.529 kg/s and total temperature of 1200 K, outlet boundary condition is static pressure of 341.08 kPa. I think that the boundary conditions are right but the cfx-post results are very strange. The temperature contour is 1200 K all around the blade. What does that mean sir? Is there any flaw in the input of the flow parameters. The blade height is 40 mm(for reference). Please help me to get rid of this problem sir Thank you

February 2, 2015, 11:07		#4
madan New Member Madan Mohan Join Date: Jan 2015 Posts: 8 Rep Power: 11	Sir, I have attached the result of my simulation https://imageshack.com/i/hj0o8LUqj

February 2, 2015, 15:05		#5
Dyls New Member Dylan Join Date: Mar 2012 Posts: 25 Rep Power: 14	What are the other thermal boundary conditions? If you only have temperature incoming at 1200K, then that is the temperature that every node will be... Because there are no other sources or sinks anywhere. If you had some other surface that was 300 K in addition to the 1200K inlet, then you would see a non-constant temperature distribution. Dylan

February 2, 2015, 17:46		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Dylan is exactly right, and this is what I said in my previous post. With nothing else in the thermal circuit then everything will just be your inlet temperature of 1200K.

February 2, 2015, 22:05		#7
madan New Member Madan Mohan Join Date: Jan 2015 Posts: 8 Rep Power: 11	sir, I have given the exit static pressure of 341 kPa which is the another flow b.c's and at the inlet I have given the total temperature, so the static temperature will change while moving in the domain know?

February 3, 2015, 11:32		#8
singer1812 Senior Member Edmund Singer P.E. Join Date: Aug 2010 Location: Minneapolis, MN Posts: 511 Rep Power: 21	I assume he is running a compressible flow problem and wants to see the variation of the gas static temperature due compressible effects, and no in the blade? Use a plane cut across the gas flow instead of surface temperature.