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Why does the fan flow field simulation have negative Power values?

The physical experimental fan rotates counterclockwise. This setting is also set to rotate counterclockwise, but there is a negative Power value. Is it because I choose to rotate counterclockwise that the negative value appears?

Thanks!

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Hi there,

from your screenshot it seems like you are using old v0.96 of QBlade. I suggest updating to the newest release since quite a few things have changed. Also, the old release it not supported anymore.

Regarding your question: In your simulation the inflow is coming from the “back” of the turbine, depending on the aerodynamic rotor design this can indeed result in a negative power coefficient. In such a scenario the turbine rather accelerated the flow, which you can also check with a velocity cut-plane.

BR,

David

I would like to ask if the experiment shows a counter-clockwise rotation direction, how can I set my simulation to rotate counter-clockwise, and the wind flows in from the “front” of the turbine?

thanks!

David

Hi,

the option to set the direction of rotation is found in the turbine design dialog. See the attached image.

BR,

David

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