# General energy equation for transfer of energy between fluid and machine

**Q. What is the general energy equation for transfer of energy between the fluid and machine?**

Where,

V_{w1} = Tangential component of the velocity of fluid at the entry of the rotor

V_{w2} = Tangential component of the velocity of fluid at the exit of the rotor

u_{1} = Peripheral velocity of fluid at the entry of the rotor

u_{2} = Peripheral velocity of fluid at the exit of the rotor

ṁ = Flow rate of fluid*- Published on 16 Sep 15***a.** E = ṁ (V_{w1} – V_{w2}) x (u_{1} – u_{2})

**b.** E = ṁ (V_{w1} – V_{w2}) / (u_{1} – u_{2})

**c.** E = ṁ (V_{w1} u_{1} – V_{w2} u_{2})

**d.** E = ṁ (V_{w1} u_{1} – V_{w2} u_{2})^{2}

**ANSWER: E = ṁ (V**_{w1} u_{1} – V_{w2} u_{2})