A Modified Orifice Flow Formula for Numerical Simulation
Ellman, A. U.
and Piché, R. A.
Tampere University of Technology
Journal of Dynamic Systems, Measurement, and Control,121
(4), 721-724. also in Fluid Power Systems and Technology Collected Papers
1996, S. S. Nair and R. S. Chandran (eds.), ASME Press, 1996, pp. 59-62.
The conventional turbulent orifice flow formula has an infinite derivative
when the pressure drop is zero. This can cause ODE solvers to crash during
numerical simulation of fluid power circuits. A two-regime orifice flow
formula is proposed in which an empirical polynomial laminar flow formula
is used for small pressure differences. The proposed formula has a smooth
transition between laminar and turbulent regimes and does not have a singular
derivative, and so is well-suited for accurate and trouble-free simulation.
Compressed postscript document