Modeling and experimental study of flow forces for unstable valve design

Qinghui Yuan, Perry Y. Li

Research output: Contribution to conferencePaperpeer-review

7 Scopus citations


Single stage electrohydraulic flow control valves are currently not suitable in high flow rate and high frequency applications. This is due to the very significant flow induced forces and the power/force limitation of electromagnetic actuators that directly stokes the spool. An unstable valve has been proposed that can utilize the flow forces to achieve fast responses at high flow rate. In this paper, we model the flow forces, including both steady and transient, of a directional flow control valve for incompressible and viscous fluid. In particular, the viscosity effect and non-orifice flux are investigated. The new models have been verified by CFD analysis to be more accurate than the old models. The paper also presents a systematic experimental study on the flow forces, in particular on the steady flow forces. The estimates according to our new models, revised slightly due to the limitation of the experiment, are consistent with the experimental results. Both the experimental results and the modeling estimation show that, for an unstable valve with negative damping length, both transient and steady flow forces can help to achieve the higher spool agility. The satisfactory modeling and experimental study on the flow forces give us a grounding for the future research of unstable valve design.

Original languageEnglish (US)
Number of pages10
StatePublished - 2003
Event2003 ASME International Mechanical Engineering Congress - Washington, DC., United States
Duration: Nov 15 2003Nov 21 2003


Other2003 ASME International Mechanical Engineering Congress
Country/TerritoryUnited States
CityWashington, DC.


  • Computational fluid dynamics (cfd)
  • Damping length
  • Steady flow force
  • Transient flow force
  • Unstable valve
  • Viscosity


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