How to calculate swirl without using swirl generators

drsrinivasan · November 21, 2012, 23:28

Sir,
I am working on simulation of combustion process in axial flow gas tubine combustor. The main reference journal paper has s 2-D model and no information about the swirler. They have solved for swirl number 0.37,0.76 and 1.2. The air inlet ratios are as follows
primary(axial):secondary(axial):dilution(axial) as 5:7:8. Now, I am looking forward for a method to calculate swirl. Is there any formula/method to calculate swirl in terms of velocities. I request you to help me.

Rami · November 22, 2012, 03:06

I believe the swirl is defined (in tensor notation) as 2Wik=Ui,k - Uk,i (where Ui is the velocity vector and "," denotes covariant derivative), i.e., the antisymmetric part of the strain rate tensor. In 2D x-y plane flow the only non-zero Wik's are Wxy = -Wyx = (Ux,y-Uy,x)/2.

November 21, 2012, 23:28	How to calculate swirl without using swirl generators	#1
drsrinivasan New Member srinivasan Join Date: Nov 2012 Location: pulivendula Posts: 5 Rep Power: 13	Sir, I am working on simulation of combustion process in axial flow gas tubine combustor. The main reference journal paper has s 2-D model and no information about the swirler. They have solved for swirl number 0.37,0.76 and 1.2. The air inlet ratios are as follows primary(axial):secondary(axial):dilution(axial) as 5:7:8. Now, I am looking forward for a method to calculate swirl. Is there any formula/method to calculate swirl in terms of velocities. I request you to help me.

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November 22, 2012, 03:06		#2
Rami Senior Member Rami Ben-Zvi Join Date: Mar 2009 Posts: 155 Rep Power: 17	I believe the swirl is defined (in tensor notation) as 2Wik=Ui,k - Uk,i (where Ui is the velocity vector and "," denotes covariant derivative), i.e., the antisymmetric part of the strain rate tensor. In 2D x-y plane flow the only non-zero Wik's are Wxy = -Wyx = (Ux,y-Uy,x)/2.