An analytical and experimental study of hydraulic vortex resistors

Steady-state empirical and analytical models were developed for symmetric and nonsymmetric vortex resistors. The empirical model for the nonsymmetric (NSVR) configuration (with flow in the high resistance direction) has been developed from experimental data taken on 24 different geometries and at temperatures of 35.0 C to 57.2 C (with MIL-5606A hydraulic oil). The model predictions exhibit a maximum error of 30 percent over the range of the experimental data. Empirical models were also developed for the NSVR configuration with flow in the low resistance direction, and for the SVR configuration. Approximate analytical models have been developed for the symmetric and non-symmetric vortex resistors. Two steady-state analytical models have been developed for the non-symmetric vortex resistor. A one-dimensional model has been developed for the symmetric vortex resistor configuration. Noise measurements made on three typical NSVR geometries (6.35 mm vortex chamber diameter) indicate that the signal-to-noise ratio (for signal levels up to 1,722 kN/sq m pressure drop) of a vortex resistor operating in the laminar flow regime is better than 900.