Modeling of two stage nozzle-flapper type electrohyraulic servovalves

Download

index.pdf

Date

2019

Author

Afatsun, Ahmet Can

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

90
views

45
downloads

In this thesis, a detailed mathematical model for a double stage nozzle-flapper type servovalve is developed focusing on its hydraulics. Such valves must comply with very strict performance requirements of aerospace and military industries. To meet these requirements, parts of such a servovalve must be manufactured within the tolerances as low as a few microns. Considering the servovalve consists of many parts that influence overall performance, it becomes obvious that the servovalve must be designed carefully as a system by understanding the effect of deviations of all parameters related to it. Unfortunately, the relations used to define the behavior of servovalve hydraulics in the literature have shortcomings around the operating point. This study is conducted with the intention of fulfilling the need of a simulation model that offers high accuracy on the entire working range. To create such a model, several CFD analyses are carried out using the commercial software ANSYS Fluent®. Available turbulence models’ and wall treatment functions’ performances are compared with the experimental data to find out which models are most suitable to conduct such analyses. Results of these numerical analyses are used to develop more accurate analytical models for both first and second stages. These models are combined in a system simulation model created by using SimScape® blocks. This final model is tested with a commercial valve’s parameters, provided by the manufacturer. The results are accurate comparing to the datasheet values

Subject Keywords

Nozzles., Servovalve, Nozzle-Flapper Valve, Spool Valve, Flow Through Orifice, Parameter Optimization.

URI

http://etd.lib.metu.edu.tr/upload/12623234/index.pdf
https://hdl.handle.net/11511/43410

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Numerical Simulation of Rarefied Laminar Flow past a Circular Cylinder Çelenligil, Mehmet Cevdet (2014-07-18) Numerical simulations have been obtained for two-dimensional laminar flows past a circular cylinder in the transitional regime. Computations are performed using the direct simulation Monte Carlo method for Knudsen numbers of 0.02 and 0.2 and Mach numbers of 0.102 and 0.4. For these conditions, Reynolds number ranges from 0.626 to 24.63 and the flows are steady. Results show that separation occurs in the wake region for the flow with Mach number of 0.4 and Knudsen number of 0.02, but for the other eases flow...
Mathematical modeling of a small-scale helicopter and mrac design with time based uncertainty parametrizations Gürler, Mustafa; Kutay, Ali Türker; Department of Aerospace Engineering (2018) In this thesis, nonlinear mathematical modeling of a small scale model helicopter is presented. In addition, problems in uncertainty parametrization component of Model Reference Adaptive Control (MRAC) is investigated and external uncertainty on the system is parametrized using universal approximators such as Fourier Series and Chebyshev Polynomials in time dependent form. Advantages of using times based universal approximators in MRAC design of MIMO systems are presented. Proposed controller is tested on t...
Calculation of parameters of single-phase PM motor for design optimization Ertan, Hulusi Bülent; Capolino, GA (2005-09-01) This paper presents methods of calculation of parameters of single-phase permanent-magnet (SPPM) motor, in terms of motor dimensions and material properties, which are utilized in the dynamic model of the motor. The intention of the study is to develop means of SPPM performance calculations, which lend themselves to be employed within a mathematical design optimization approach. The calculated parameters are compared with measured values and are shown to be accurate for the purpose of the study.
Nonlinear modelling and control of the flow over aerofoils using CFD simulations Karaca, H. D.; Alıcı, Gökçen Deniz; KASNAKOĞLU, Coşku (2016-09-01) A simulation based approach for nonlinear dynamical modelling and feedback control of the drag to lift ratio for aerofoils is investigated through case studies involving NACA 23012, ag13 and b737a aerofoils. The flow around the aerofoils is studied via numerical solutions of the 2D Navier-Stokes (NS) equations. A standard computational fluid dynamics (CFD) solver is extended to be able to measure desired feedback values and to apply a control input to the flow field. The proposed modelling and control appro...
Vibration analysis of washing machines in the drum plane Baykal, Cem; Ciğeroğlu, Ender; Yazıcıoğlu, Yiğit (Springer, Cham; 2019-02-20) In this study, a nonlinear mathematical model for drum-type washing machines is developed considering rotating unbalance type excitation. Nonlinear differential equations of motion are converted into a set of nonlinear algebraic equations by using harmonic balance method (HBM). The resulting nonlinear algebraic equations are solved by using Newton’s method with arc-length continuation. Several case studies are performed in order to observe the effects of orientation angles of springs and dampers supporting ...

Citation Formats

A. C. Afatsun, “Modeling of two stage nozzle-flapper type electrohyraulic servovalves,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Mechanical Engineering., Middle East Technical University, 2019.