Screw Compressors- Mathematical Modelling And Performance Calculation Access
Three primary modelling approaches exist:
Due to stiffness (rapid pressure changes), explicit solvers require very small ( \Delta\theta ). Implicit methods or adaptive step size are recommended. Typical run time for one operating point: 0.5–2 seconds on a modern CPU for a chamber model; full 3D CFD models may take hours.
Assume: inlet pressure p1, inlet temperature T1, rotational speed n, rotor geometry known, discharge pressure p2 target. Use polytropic segmented model with N axial slices. Three primary modelling approaches exist: Due to stiffness
Initialize slice states:
For each slice i from 1..N:
Optionally enforce polytropic step: p_i = p_i−1 (V_i−1/V_i)^n_local with n_local set by local heat transfer estimate.
Sum element work:
Compute mass flow and actual volumetric flow: Assume: inlet pressure p1, inlet temperature T1, rotational
Account for mechanical losses:
Output performance metrics:
