- #1
eng_hussain
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is there a way to calculate torque without knowing the power? consider this:
P = T * rpm
I can calculate rpm easily as I have a tachometer but without power, I can never find the torque.
In case of translation, you can find the force propelling an object without knowing the power. For example, if you want to find the force propelling a car at a constant speed, you find it by calculating drag, which is exactly the force the car is experiencing the opposite way
Force propelling the car = drag = 0.5 * rho * V2 * A * CD
All quantities in the equation are readily available (or almost)
- rho is tabulated
- v is easily calculated through speedometer or speed gun
- A can be provided
- CD can be providedAs seen from the equation, no need to know the power. So no need for the equation P = F*V to calculate the force.
Now, is there such a way to calculate torque by only knowing rpm and some other variables other than power?
I'm asking this because I'm working on a small gas turbine (single shaft - single centrifugal compressor - single turbine) project and I want to calculate the torque acting on the shaft at a constant rpm. I can obtain the rpm through my cheap tachometer but I'm having troubles with calculating the power.
P = T * rpm
I can calculate rpm easily as I have a tachometer but without power, I can never find the torque.
In case of translation, you can find the force propelling an object without knowing the power. For example, if you want to find the force propelling a car at a constant speed, you find it by calculating drag, which is exactly the force the car is experiencing the opposite way
Force propelling the car = drag = 0.5 * rho * V2 * A * CD
All quantities in the equation are readily available (or almost)
- rho is tabulated
- v is easily calculated through speedometer or speed gun
- A can be provided
- CD can be providedAs seen from the equation, no need to know the power. So no need for the equation P = F*V to calculate the force.
Now, is there such a way to calculate torque by only knowing rpm and some other variables other than power?
I'm asking this because I'm working on a small gas turbine (single shaft - single centrifugal compressor - single turbine) project and I want to calculate the torque acting on the shaft at a constant rpm. I can obtain the rpm through my cheap tachometer but I'm having troubles with calculating the power.
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