pressure drop calculation

ayad · October 15, 2014, 14:56

I was simulating finned tube heat exchanger shown in figure, how can i calculate pressure drop(pressure losses by H.E)? Does it calculated by drawing a line or vertex before and after the pipes? Where is the best position to draw the line or vertex?

ayad · October 20, 2014, 08:39

Any way please?

swiftaircraft · October 20, 2014, 16:08

If the left side is the inlet and the right side the outlet you can simply take the mass weighted pressure averages over both and then take one from the other. Or are your inlets and outlets not in these places?

ayad · October 20, 2014, 16:27

thank u for your reply
As u say, the left side is inlet and the right side is outlet.
this duct is one part,did the result will be average of all duct if i do that ?
i thought that the pressure drop can be calculated by drawing a plain after and before the pipe and take the first from the other, is this way right?

swiftaircraft · October 21, 2014, 03:22

Assuming that you have applied translational periodics then taking the mass weighted average pressure on the inlet and the outlet will be the average of the complete duct. If you need to define the pressure loss at different locations to where you have the inlet and the outlet then you will need to set up different surfaces. However to do this precisely these lines should have been set up before the model was meshed. By the looks of the model you have used periodics with a symmetry plane. Is that correct?

ayad · October 21, 2014, 06:27

Thank you for your interesting
I've got a result by drawing two plane(surface) after and before the tubes, and take one from the other after computing the face average pressure for each plane.
is this the first way you told me about?

swiftaircraft · October 21, 2014, 08:34

That is a valid way to do it.

ayad · October 21, 2014, 09:32

Thank you so much

October 15, 2014, 14:56	pressure drop calculation	#1
ayad New Member ayad Join Date: Apr 2014 Location: Iraq Posts: 25 Rep Power: 12	I was simulating finned tube heat exchanger shown in figure, how can i calculate pressure drop(pressure losses by H.E)? Does it calculated by drawing a line or vertex before and after the pipes? Where is the best position to draw the line or vertex?

October 20, 2014, 16:08		#3
swiftaircraft Member David Stanbridge Join Date: Apr 2010 Location: Norwich, UK Posts: 59 Rep Power: 16	If the left side is the inlet and the right side the outlet you can simply take the mass weighted pressure averages over both and then take one from the other. Or are your inlets and outlets not in these places? Maddin likes this. __________________ David Stanbridge Swift TG Solutions Limited www.swifttgsolutions.com

October 21, 2014, 03:22		#5
swiftaircraft Member David Stanbridge Join Date: Apr 2010 Location: Norwich, UK Posts: 59 Rep Power: 16	Assuming that you have applied translational periodics then taking the mass weighted average pressure on the inlet and the outlet will be the average of the complete duct. If you need to define the pressure loss at different locations to where you have the inlet and the outlet then you will need to set up different surfaces. However to do this precisely these lines should have been set up before the model was meshed. By the looks of the model you have used periodics with a symmetry plane. Is that correct? __________________ David Stanbridge Swift TG Solutions Limited www.swifttgsolutions.com

October 21, 2014, 08:34		#7
swiftaircraft Member David Stanbridge Join Date: Apr 2010 Location: Norwich, UK Posts: 59 Rep Power: 16	That is a valid way to do it. ayad likes this. __________________ David Stanbridge Swift TG Solutions Limited www.swifttgsolutions.com

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October 20, 2014, 08:39		#2
ayad New Member ayad Join Date: Apr 2014 Location: Iraq Posts: 25 Rep Power: 12	Any way please?

October 20, 2014, 16:27		#4
ayad New Member ayad Join Date: Apr 2014 Location: Iraq Posts: 25 Rep Power: 12	thank u for your reply As u say, the left side is inlet and the right side is outlet. this duct is one part,did the result will be average of all duct if i do that ? i thought that the pressure drop can be calculated by drawing a plain after and before the pipe and take the first from the other, is this way right?

October 21, 2014, 06:27		#6
ayad New Member ayad Join Date: Apr 2014 Location: Iraq Posts: 25 Rep Power: 12	Thank you for your interesting I've got a result by drawing two plane(surface) after and before the tubes, and take one from the other after computing the face average pressure for each plane. is this the first way you told me about?

October 21, 2014, 09:32		#8
ayad New Member ayad Join Date: Apr 2014 Location: Iraq Posts: 25 Rep Power: 12	Thank you so much