Issues with the coefficients in the formula for cavitation specific speed
Thread Content
One of the formulas for calculating the NPSH ratio of centrifugal pumps is: S=5.62*N*Q1/2 /NPSHr3/4. Where does the coefficient 5.62 come from?
Generally, the coefficients in the formula for calculating the cavitation specific speed are empirical values rather than standard values. The sources of these empirical values include experimental data, theoretical derivations, and industry experience, among others. Therefore, the specific origin of the 5.62 coefficient may require reference to relevant literature or consultation with industry experts. It should be noted, however, that differences may exist among different industries, different pump models, and various operating conditions; therefore, it is recommended to verify whether the parameters in the formula are suitable for the specific pump and its operating environment before using the formula for calculations. .
Thank you; this is also something I’ve never been able to figure out. Some pump manufacturers use 5.62, while others use 51.64. I simply don’t understand the principle behind these coefficients. I asked several technicians in the pump industry, and they too couldn’t explain why 5.62 is used; they only knew it was based on past experience
\"Modern Pump Theory and Design\" 5.3.2 contains the derivation for the cavitation specific speed C, which is 5.62