Regression models for the leakage flow in screw extruders

Excel spreadsheet containing analytical regression models for the leakage flow across screw flights
(model equations given as text and coefficients as numeric values).

The following functional relationships are available:

- Dimensionless leakage flow rate vs. dimensionless cross-channel pressure gradient
- Dimensionless dissipation rate vs. dimensionless leakage flow rate

Modifications compared to the previous version:
- rearranged expression for the dissipation model to avoid nested fractions
- additional stabilisation of the dissipation model by truncating the denominators below working precision (2-16)