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-   -   Torque Converter Pump Torque = Engine Torque? (http://www.cfd-online.com/Forums/main/109077-torque-converter-pump-torque-engine-torque.html)

Torque_Converter November 8, 2012 14:26

Torque Converter Pump Torque = Engine Torque?
 
This seems like the silliest thing to be caught up in, but I keep seeing correct Turbine output torques, but the Pump torque from analysis puts out higher values than Engine input torque. It would seem this is impossible by conservation of energy, but the torque production in the Turbine is always so right at every SR, even in other Torque Converters.

Is it possible the pump reaction torque from spinning at a given RPM is different from the engine input torque?

husker November 9, 2012 01:16

Can you please give more details?

Torque_Converter November 9, 2012 08:12

The pump is connected directly to the engine. But when I simulate it moving at the same speed in CFX it produces a different torque than the engine. Should it produce the same torque due to conservation of energy, or a different torque because CFX is calculating "reaction" torque which is different?

husker November 12, 2012 02:30

Please let me explain what I understand.

You are simulating the flow inside a pump and the resultant torque value is higher than the test value. Is this true?

If so, there may be many reasons involving the over-estimation of the torque. Such as working conditions of the pump, the physical assumptions and the flow differences between the test and the simulation.

Can you please share a diagram or a screenshot of your problem? Also the details of the physical setup, boundary conditions and the mesh.

Regards

Torque_Converter November 12, 2012 06:44

I'm sorry, I'm still not explaining it right.

The engine is turning a pump at a certain RPM with a certain engine torque.

However, there is a torque calculated inside the pump in CFX based on the reaction of the fluid. The absolute value of this torque is higher, and the direction is the opposite of the engine.

I believe the two should be different due to blade differences, wall shear, and the fluid not always moving circumferentially the same speed as the solid of the walls blades. I.e. speed ratio effect.


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