An Empirical Discharge Coefficient Model for Orifice Flow

Wu, Duqiang; Burton, Richard; Schoenau, Greg

doi:10.1080/14399776.2002.10781143

Cited by 51 publications

(38 citation statements)

References 2 publications

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“…For incompressible fluid, the flow through the orifice (Q) is related to the piston movement as, where A r is the area of the rebound face. Using the equation for flow through a thin wall orifice (Wu, Burton, & Schoenau, 2002), the velocity can be related to the pressure difference in the compression (P c ) and rebound (P r ) chambers as, where C d is the discharge coefficient, A o is the orifice area and ρ is the liquid density. Equation 2 shows the linear dependence of the velocity on the orifice area A o .…”

Section: Public Interest Statementmentioning

confidence: 99%

Design and analysis of a rotary motion controller

2015

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This paper presents the design of a rotary motion controller based on the peritrochoid geometry of the rotary (Wankle) engine. It uses an orifice limited flow of incompressible fluid between the chambers of the Wankle-type geometry to control the rotation of the rotor. The paper develops the theory of operation and then implements the design as a Matlab model to simulate the motion control under various conditions. It is found that the time to reach stabilised motion is determined by the orifice size and fluid density. When stabilised motion is achieved, the motion dependence on material and geometry factors is determined by the orifice flow equation. The angular velocity is also found to have a square root dependence on the applied torque when in the stabilised regime. Subjects: Mechanical Engineering; Mechanical Engineering Design; Technology

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Section: Public Interest Statementmentioning

confidence: 99%

Design and analysis of a rotary motion controller

2015

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“…In [31,32] the flow rate in short clearances is described by the following formula: (14) where: − A -cross-sectional area of the clearance, − a, b, δ 1 , δ 2 , -specific flow dependent coefficients, − C d∞ -turbulent discharge coefficient.…”

Section: Known Methods Describing the Flow In Short Clearancesmentioning

confidence: 99%

Influence of Water and Mineral Oil on the Leaks in Satellite Motor Commutation Unit Clearances

Śliwiński

2017

Polish Maritime Research

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“…This has been done when analysing the closed-centre system for stability, which is described in chapter 6. For most study cases, however, the bicycle model has been used as load, which can be found in the book by Wong (2001). Small steering wheel and slip angles are assumed.…”

Section: Load Modelmentioning

confidence: 99%

On Electrohydraulic Pressure Control for Power Steering Applications : Active Steering for Road Vehicles

Dell’Amico¹

2016

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This thesis deals with the Electrohydraulic Power Steering system for road vehicles, using electronic pressure control valves. With an ever increasing demand for safer vehicles and fewer traffic accidents, steering-related active safety functions are becoming more common in modern vehicles. These are functions that aim at assisting the driver in more or less critical situations and could be anything from applying a guiding steering torque to taking over the steering completely. Future road vehicles will also evolve towards autonomous vehicles, with several safety, environmental and financial benefits. A key component in realising such solutions is active steering. This refers to the possibility to control the steering angle or steering torque with an electronic signal.The power steering system was initially developed to ease the driver's workload by assisting in turning the wheels. This is traditionally done through an open-centre hydraulic system and heavy trucks must still rely on fluid power, due to the heavy work forces. The system provides a robust solution but suffers from poor energy efficiency and lacks the possibility of active control. Since the purpose of the original system is to control the assistive pressure, one way would be to use proportional pressure control valves. Since these are electronically controlled, active steering is possible and with closed-centre, energy efficiency can be significantly improved on.In this work, such a system is analysed in detail with the purpose of investigating the possible use of the system for Boost curve control, the most common control strategy in power steering systems, and position control for autonomous driving. Commercially available valves are investigated since they provide an attractive solution. A model-based approach is adopted, where simulation of the system is an important tool. Detailed models at both a component level and a system level are developed and form the basis of the analysis and control design. Another important tool is hardware-in-the-loop simulation. A test rig of the system, that also includes the original system, is developed. The rig supports the modelling and validation process, as it also makes it possible to verify control concepts on a real system. This work has shown how proportional pressure control valves can be used for Boost curve control and position control and what implications this has i on a system level. As it turns out, the valves add a great deal of phase shift and with the high gain from the Boost curve, this creates a control challenge. The problem can be handled by tuning the Boost gain, pressure response and damping and has been effectively shown through simulation and experiments. For position control, there is greater freedom to design the controller to fit the system. The pressure response can be made fast enough for this case and the phase shift is much less critical.Keywords: Electrohydraulic power steering, pressure control, closed-centre steering, Boost curve control, autonomous driving, hardware-...

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An Empirical Discharge Coefficient Model for Orifice Flow

Cited by 51 publications

References 2 publications

Design and analysis of a rotary motion controller

Design and analysis of a rotary motion controller

Influence of Water and Mineral Oil on the Leaks in Satellite Motor Commutation Unit Clearances

On Electrohydraulic Pressure Control for Power Steering Applications : Active Steering for Road Vehicles

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