The formula to calculate the Cavitation Number (σc) is:
\[ \sigma_c = \frac{p - P_v}{\rho_m \left( \frac{u_f^2}{2} \right)} \]
Cavitation number is used to evaluate whether a fluid system will cause cavitation or not.
Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
Vapour Pressure is a measure of the tendency of a material to change into the gaseous or vapour state, and it increases with temperature.
The Mass Density of a substance is its mass per unit volume.
Fluid velocity is the volume of fluid flowing in the given vessel per unit cross-sectional area.
Let's assume the following values:
Using the formula:
\[ \sigma_c = \frac{800 - 6}{997 \left( \frac{12^2}{2} \right)} \approx 0.011060960659757 \]
The Cavitation Number is approximately 0.011060960659757.
| Pressure (Pa) | Vapour Pressure (Pa) | Mass Density (kg/m³) | Fluid Velocity (m/s) | Cavitation Number |
|---|---|---|---|---|
| 750 | 6 | 997 | 12 | 0.01036442661317 |
| 760 | 6 | 997 | 12 | 0.01050373342249 |
| 770 | 6 | 997 | 12 | 0.01064304023181 |
| 780 | 6 | 997 | 12 | 0.01078234704112 |
| 790 | 6 | 997 | 12 | 0.01092165385044 |
| 800 | 6 | 997 | 12 | 0.01106096065976 |
| 810 | 6 | 997 | 12 | 0.01120026746907 |
| 820 | 6 | 997 | 12 | 0.01133957427839 |
| 830 | 6 | 997 | 12 | 0.01147888108771 |
| 840 | 6 | 997 | 12 | 0.01161818789702 |
| 850 | 6 | 997 | 12 | 0.01175749470634 |