Simulators and spreadsheets are the mainstay of pressure drop calculations in the modern world. However, to avoid excessive reliance on these tools, the engineer requires conceptual understanding of the phenomena and associated correlations. This assists with reasonableness checking, avoiding “Garbage In, Garbage Out” issues, and sometimes just defining the problem to be solved.
Pressure drop correlations can take quadratic, power law, or many other forms. Converting from one to another is desirable because certain forms provide greater insights into the underlying phenomena. Furthermore, the available equation does not always match the form that the simulation requires for input, and the engineer must be able to provide the inputs that will help their model yield the best results.
This article posits a relationship between the power law correlation and the zero-intercept quadratic correlation, and establishes rules of thumb to convert between the two.