Nozzles and diffusers regulate flow [[Velocity|velocity]] by either increasing or decreasing flow speed. Flow speed can be altered very easily by changing the cross-sectional [[Area|area]] of a channel. Decreasing the outlet area will increase flow speed, creating a nozzle. Likewise, increasing the outlet area will decrease flow speed, acting as a diffuser.
Nozzle:
![[diffuser.png|center|500]]
Diffuser:
![[nozzle.png|center|500]]
Equation Summary:
| Conservation Item | Condition | Result |
| -------------------- | -------------------- | ------------------------------------------------- |
| Heat | Adiabatic | $\dot{Q}=0$ |
| Work | Zero Work | $\dot{W}=0$ |
| Enthalpy | Non-negligible | |
| Kinetic | Non-negligible | |
| Potential | Typically negligible | $\Delta P=0$ |
| Mass Conservation | | $\rho_1v_1A_1=\rho_2v_2A_2\to\dot{m}_1=\dot{m}_2$ |
| Total Energy Balance | | $0=h_2−h_1+0.5(v_2^2−v_1^2)$ |