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Open AccessArticle

A Numerical Research on Vortex Street Flow Oscillation in the Double Flapper Nozzle Servo Valve

1
School of Mechanical Engineering, Tongji University, Shanghai 200092, China
2
Shanghai Institute of Aerospace Control Technology, Shanghai 201109, China
3
Shanghai Servo System Engineering Technology Research Center, Shanghai 201109, China
*
Author to whom correspondence should be addressed.
Processes 2019, 7(10), 721; https://doi.org/10.3390/pr7100721
Received: 27 August 2019 / Revised: 7 October 2019 / Accepted: 8 October 2019 / Published: 11 October 2019
(This article belongs to the Special Issue Smart Flow Control Processes in Micro Scale)
The oscillating flow field of the double nozzle flapper servo valve pre-stage is numerically analyzed through Large Eddy Simulation (LES) turbulent modeling with the previous grid independence verification. The vortex street flow phenomenon can be observed when the flow passes through the nozzle flapper channel, the vortex alternating in each side produces the periodical flow oscillation. The structural and flow parameter effects on the oscillating flow are emphasized, and it could be determined that the pressure on the flapper is nearly proportional to the flow velocity and inversely proportional to the actual distance between the flapper and the nozzle. On the other hand, the main frequency of oscillation decreases with the velocity and increases with the distance between the nozzle flapper. The main stage movement is further considered with a User Defined Function (UDF), and it could be determined that the influences of the structural and flow parameters on the flow oscillation are rarely changed, but the main frequencies drop, generally. View Full-Text
Keywords: double flapper nozzle servo valve; Karman vortex; self-sustained flow oscillation; computational fluid dynamics double flapper nozzle servo valve; Karman vortex; self-sustained flow oscillation; computational fluid dynamics
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MDPI and ACS Style

Lu, L.; Long, S.; Zhu, K. A Numerical Research on Vortex Street Flow Oscillation in the Double Flapper Nozzle Servo Valve. Processes 2019, 7, 721.

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