Search results for "Flow control"
showing 10 items of 22 documents
Flow Control of Fluid in Pipelines Using PID Controller
2019
In this paper, a PID controller is utilized in order to control the flow rate of the heavy oil in pipelines by controlling the vibration in a motor pump. A torsional actuator is placed on the motor pump in order to control the vibration on a motor and consequently controlling the flow rates in pipelines. The necessary conditions for the asymptotic stability of the proposed controller are validated by implementing the Lyapunov stability theorem. The theoretical concepts are validated utilizing numerical simulations and analysis, which proves the effectiveness of the PID controller in the control of flow rates in pipelines.
Shock control bump design optimization on natural laminar aerofoil
2011
The chapter investigates Shock Control Bumps (SCB) on a Natural Laminar Flow (NLF) aerofoil; RAE 5243 for Active Flow Control (AFC). A SCB approach is used to decelerate supersonic flow on the suction/pressure sides of transonic aerofoil that leads delaying shock occurrence or weakening of shock strength. Such an AFC technique reduces significantly the total drag at transonic speeds. This chapter considers the SCB shape design optimisation at two boundary layer transition positions (0 and 45%) using an Euler software coupled with viscous boundary layer effects and robust Evolutionary Algorithms (EAs). The optimisation method is based on a canonical Evolution Strategy (ES) algorithm and inco…
Control subsystem design for wireless power transfer
2014
Recently, the wireless power transfer has been increasingly employed. Particularly for the electric vehicles, the wireless solution is attractive for contactless battery charging, based on the Inductive Power Transfer (IPT). In this paper, a 150W prototype for IPT-based battery charging is presented and design criteria are reported. In addition to the power stage analysis, a proper control strategy is proposed. Simulation and experimental results are shown. The proposed control method aims at regulating the load current against variations in the magnetic coupling, so that the required amount of power can be supplied despite of unexpected decreases in the coupling efficiency.
Three-Dimensional Modeling and Geometrical Influence on the Hydraulic Performance of a Control Valve
2007
The ability to understand and manage the performance of hydraulic control valves is important in many automatic and manual industrial processes. The use of computational fluid dynamics (CFD) aids in the design of such valves by inexpensively providing insight into flow patterns, potential noise sources, and cavitation. Applications of CFD to study the performance of complex three-dimensional (3D) valves, such as poppet, spool, and butterfly valves, are becoming more common. Still, validation and accuracy remain an issue. The Reynolds-averaged Navier–Stokes equations were solved numerically using the commercial CFD package FLUENT V6.2 to assess the effect of geometry on the performance of a …
Boom Motion Control Using Pressure Control Valve
2014
This paper focuses on the reduction in oscillations created by counterbalance valves by using a proportional pressure control valve. The motion control of a cylinder boom is presented using this valve, which is a 4/3-way directional control valve with the main spool in series with an upstream compensator. The input to the valve control is a main spool position reference and, indirectly, the compensator downstream pressure. This gives a different flow gain and, therefore, a different feedforward scheme as compared to applications with the more common pressure compensated flow control valve. The theory behind the pressure control valve is presented and applied to both a theoretical and experi…
Three-mode pneumatic management of marine U-tank systems
2012
Abstract This paper deals with a new pneumatic control strategy for the roll damping enhancement of marine U-tank stabilizers. The proposed technique consists in a three-mode operation, where the control is active only within a limited resonant range around the ship natural frequency, whereas the control valves are kept closed in the remaining frequency range. Moreover the connection valve between the two air chambers is either closed or partially opened for the low or high frequencies, respectively. The pressurized air for the active control is fed by a turbo-blower set aboard and operates accelerating the motion of the water mass in the U-duct. The theoretical analysis is conducted in the…
Improving the Efficiency and Dynamic Properties of a Flow Control Unit in a Self-Locking Compact Electro-Hydraulic Cylinder Drive
2019
Abstract The introduction of low cost electric motor and drive solutions provides the possibility to design cost competitive compact speed-variable drives as potentially feasible alternatives to conventional valve-controlled solutions. A main drawback in existing self-contained drive technology is the power consumption in stationary load carrying situations. However, the recent introduction of compact self-locking drive topologies with separate forward and return flow lines allow to significantly minimize the power consumption, but introduces another problem. Dependent on the control of the flow device, a continuous, but lower power consumption compared to non-self-locking drive topologies …
Power tracking with maximum efficiency for wireless charging of E-bikes
2014
Wireless charging techniques, based on Inductive Power Transfer (IPT), are attractive for Electric Vehicles (EV), due to benefits such as convenience and safety. An accurate valuation of the maximum achievable efficiency in an IPT system is extremely unlikely due to the high sensitivity to parasitic elements variations. Therefore, an “on site” procedure of power efficiency characterization is useful to get a precise description of the efficiency curve and obtain the actual maximum efficiency. In this paper, a power tracking algorithm aiming at efficiency maximization is proposed for a Wireless Charging system. The algorithm aims at finding the maximum power transfer efficiency with respect …
An evaluation of switched ethernet and linux traffic control for real-time transmission
2008
Switched Ethernet networks are spreading to industrial environments more are more. The current trend is using them at all levels of a factory, replacing this way field-buses and other industrial networks. Switched Ethernet lacks the drawback of the non-deterministic collision resolution of coax cabling. However there are still some sources of indeterminism, mostly due to contention problems in message queues at switches and network interfaces. These problems can be dealt with using traffic control mechanisms for packet prioritisation and scheduling. These features have been largely inaccessible in Ethernet for a long time but, nowadays, they are widely available in industrial switches and a…
Gigabit Ethernet backbones with active loops
2001
The current standard Ethernet switches are based on the Spanning Tree (ST) protocol. Their most important restriction is that they can not work when the topology has active loops. In fact, the ST protocol selects a tree from the real topology by blocking the links that are not involved in the tree. This restriction produces a network traffic unbalancing behavior saturating those link near the root switch while rest of links will be idle or with a very low utilization. This paper proposes a new transparent switch protocol for Gigabit Ethernet backbones that considerably improves the performance of current ones. The proposed protocol is named ALOR for Active Loops and Optimal Routing. ALOR pr…