# torque calculation of impulse turbine

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May 30, 2012, 01:34
torque calculation of impulse turbine
#1
Member

liping_he
Join Date: Feb 2011
Posts: 35
Rep Power: 6
Dear foamers

I created a case by combining the interDyMFoam (tutorials/multiphase/interDyMFoam/ras/damBreakWithObstacle) and pimpleDyMFoam (tutorials/incompressible/pimpleDyMFoam/propeller) to achieve the simulation of impulse turbine (multiphases flow and AMI). The screenshot of velocity field is shown in attachment containing three nozzles and a runner.
And now, I want to calculate the efficiency. A great issue comes out HOW can i obtain the torque (pressure and viscocity torque ) of runner. I have no idea about this issue. Any advice will be appreciated.
Attached Images
 turbine.jpg (78.2 KB, 46 views)

 May 30, 2012, 03:54 #2 Senior Member   lore Join Date: Mar 2010 Location: Italy Posts: 463 Rep Power: 9 Haven't got much of experience on this but… couldn't you just use a force calculation to computer the moment aruond the axis of rotation?

May 30, 2012, 20:44
#3
Member

liping_he
Join Date: Feb 2011
Posts: 35
Rep Power: 6
Hi,

Now, I dont know how to report force in multiphase case. So i cant obtain torque without force. In singlephase case, the force/torque can be obtained by adding the following code in controlDict
Quote:
 functions { forces { type forces; functionObjectLibs ("libforces.so"); //Lib to load patches (sphere_region0); // change to your patch name rhoName rhoInf; rhoInf 1000; //Reference density for fluid CofR (2 0 0); //Origin for moment calculations outputControl timeStep; outputInterval 1; } forceCoeffs { // rhoInf - reference density // CofR - Centre of rotation // dragDir - Direction of drag coefficient // liftDir - Direction of lift coefficient // pitchAxis - Pitching moment axis // magUinf - free stream velocity magnitude // lRef - reference length // Aref - reference area type forceCoeffs; functionObjectLibs ("libforces.so"); patches (sphere_region0); rhoName rhoInf; rhoInf 1000; CofR (2 0 0); liftDir (0 1 0); dragDir (1 0 0); pitchAxis (0 0 1); magUInf 1e-7; lRef 0.06; // sphere diameter Aref 0.0014137; //1/2 * projected area = pi*r2/2 outputControl timeStep; outputInterval 1; } }
more detail visit:
Forces in OF15

regards,
liping

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