International Journal of Fluid Machinery and Systems

Korean Society for Fluid machinery (한국유체기계학회)
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Numerical Simulation and Experimental Research of the Flow Coefficient of the Nozzle-Flapper Valve Considering Cavitation

  • Li, Lei (School of Mechanical and Electrical Engineering, Beijing Jiaotong University) ;
  • Li, Changchun (School of Mechanical and Electrical Engineering, Beijing Jiaotong University) ;
  • Zhang, Hengxuan (Beijing research institute of precision electromechanical control equipment)
  • Received : 2016.10.05
  • Accepted : 2017.02.12
  • Published : 2017.06.30
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Abstract

The nozzle-flapper valves are widely applied as a pilot stage in aerospace and military system. A subject of the analysis presented in this work is to find out a reasonable range of null clearance between the nozzle and flapper. This paper has presented a numerical flow coefficient simulation. In every design point, a parameterized model is created for flow coefficient simulation and cavitation under different conditions with varying gap width and inlet pressure. Moreover, a new test device has been designed to measure the flow coefficient and for visualized cavitation. The numerical simulation and test results both indicate that cavitation intensity gets fierce initially and shrinks finally as the gap width varies from small to large. From the curve, the flow coefficient mostly has experienced three stages: linear throttle section, transition section and saturation section. The appropriate deflection of flapper is recommended to make the gap width drop into the linear throttle section. The flapper-nozzle null clearance is optionally recommended near the range of $D_N/16$. Finally through simulation it is also concluded that the inlet pressure plays a little role in the influence on the flow coefficient.

Keywords

References

  1. Zhu Y, Fei S. 2016, "Design criterion involving comprehensive performance characteristics of nozzle-flapper valves," Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems & Control Engineering, Vol. 230, No. 5, pp. 452-466.
  2. Khodaii z., Zareinejad m., Shiry g s., et al, 2016, "Modeling the effects of the external acceleration on the two stage flapper-nozzle servo electrohydraulic valves," MODARES MECHANICAL ENGINEERING, Vol. 15, No. 11, pp. 1-8.
  3. Chen Q., Stoffel B., 2004, "CFD Simulation of a Hydraulic Servo Valve With Turbulent Flow and Cavitation," ASME/JSME 2004 Pressure Vessels and Piping Conference. pp. 27-30.
  4. Aung N Z, Li S., 2014, "A numerical study of cavitation phenomenon in a flapper-nozzle pilot stage of an electrohydraulic servo-valve with an innovative flapper shape," Energy Conversion & Management, Vol. 77, No. 110, pp. 31-39. https://doi.org/10.1016/j.enconman.2013.09.009
  5. Aung N Z., Yang Q., Chen M., et al., 2014, "CFD analysis of flow forces and energy loss characteristics in a flapper-nozzle pilot valve with different null clearances," Energy Conversion & Management, Vol. 83, No. 7, pp. 284-295. https://doi.org/10.1016/j.enconman.2014.03.076
  6. Peng G., Okada K., Yang C., et al. 2016, "Numerical Simulation of Unsteady Cavitation in a High-speed Water Jet," International Journal of Fluid Machinery & Systems, Vol. 9, No.1, pp. 66-74. https://doi.org/10.5293/IJFMS.2016.9.1.066
  7. Mchenya J M. 2011, "A Study of Flow-field Distribution between the Flapper and Nozzle in a Hydraulic Servo-valve," International Conference on Fluid Power and Mechatronics. pp. 658-662.
  8. Chern M J, Hsu P H, Cheng Y J, et al. 2013, "Numerical Study on Cavitation Occurrence in Globe Valve[J]. Journal of Energy Engineering," Vol. 139, No. 1, pp. 25-34. https://doi.org/10.1061/(ASCE)EY.1943-7897.0000084
  9. Kagawa T., 1985, "Heat transfer effects on the frequency response of a pneumatic nozzle flapper," Journal of dynamic systems, measurement, and control, Vol. 107, No. 4, pp. 332-336. https://doi.org/10.1115/1.3140744
  10. Sijun Wei, 1989, "Nozzle structure and flow coefficient of nozzle flapper," Applied Science and Technology, Vol. 8, No. 3, pp. 21-25.(in Chinese)
  11. Babic M., SUSTERSIC G., 2002, "Determination of Values for Flow Coefficients of First Stage Orifices in Two-Stage Electrohydraulic Servovalves," Heavy Machinery (HM), Vol. 5, No. 10, pp. 27-30.
  12. Zhang L, Luo J, Yuan R B, et al., 2012, "The CFD analysis of twin flapper-nozzle valve in pure water hydraulic," Procedia Engineering, Vol. 31, No. 4, pp. 220-227. https://doi.org/10.1016/j.proeng.2012.01.1015
  13. Desantes J M., Lopez J J., Carreres M., et al. 2016, "Characterization and prediction of the discharge coefficient of non-cavitating diesel injection nozzles," Fuel, Vol. 184, pp. 371-381. https://doi.org/10.1016/j.fuel.2016.07.026
  14. YANG G., YE Q., Lin N., 2007, "The Research of the Flow Field Cavitation inside Water Hydraulic Poppet Valve by CFD," Machine Tool & Hydraulics, Vol. 1, pp. 049.
  15. Wang T., Cai M., Kawashima K., et al., 2005, "Modelling of a nozzle-flapper type pneumatic servo valve including the influence of flow force," International Journal of Fluid Power, Vol. 6,No. 3, pp. 33-43. https://doi.org/10.1080/14399776.2005.10781228
  16. Urata E., 2007 , "On the torque generated in a servo valve torque motor using permanent magnets," Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, Vol. 221, No. 5, pp. 519-525. https://doi.org/10.1243/0954406JMES584
  17. Sijun Wei, 1989, "Nozzle structure and flow coefficient of nozzle flapper," Applied Science and Technology, Vol.8, No.3, pp.21-25.(in Chinese)
  18. Merritt H E., 1967, Hydraulic control systems, John Wiley & Sons, New York.
  19. Johnston D N., Edge K A., Vaughan N D., 1991, "Experimental investigation of flow and force characteristics of hydraulic poppet and disc valves," Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, pp.161-171.