scholarly journals Mathematical Modelling and Dynamic Analysis of a Direct-Acting Relief Valve Based on Fluid-Structure Coupling Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wen Song ◽  
Chenshi Yang ◽  
Xiaoyi Zhang ◽  
Yongdong Li
Keyword(s):  
Water Depth ◽  
Vertical Direction ◽  
Relief Valve ◽  
Fluid Structure ◽  
Wake Oscillator ◽  
Contact Nonlinearity ◽  
Simulation Based ◽  
Coupling Dynamic ◽  
Pump Inlet ◽  
Direct Acting

To explain the sudden jump of pressure as the variation of water depth for a direct-acting relief valve used by torpedo pump as the variation of water depth, a 2-DOF fluid-structure coupling dynamic model is developed. A nonlinear differential pressure model at valve port is applied to model the axial vibration of fluid, and a nonlinear wake oscillator model is used to excite the valve element in the vertical direction; meanwhile, the contact nonlinearity between the valve element and valve seat is also taken into consideration. Based on the developed dynamical model, the water depths for the sudden jumps of pressure can be located precisely when compared with the experimental signals, and the corresponding vibration conditions of the valve element in both the axial and vertical directions are explored. Subsequently, in order to eliminate the sudden jumps of pressure, different pump inlet pressure was tested experimentally; when it was decreased to 0.4 MPa, the pressure jumps ever appeared during the dropping and lifting processes were removed, and the numerical simulation based on the developed mathematical model also verified the experimental measurements.

A Nonhydrostatic Two-Layer Staggered Scheme for Transient Waves due to Anti-Symmetric Seabed Thrust

2017 ◽  
Vol 11 (01) ◽  
pp. 1740002 ◽  
Author(s):  
S. R. Pudjaprasetya ◽  
I. Magdalena ◽  
S. S. Tjandra
Keyword(s):  
Dispersion Relation ◽  
Water Depth ◽  
Numerical Scheme ◽  
Vertical Direction ◽  
Wave Number ◽  
Transient Waves ◽  
Wide Range ◽  
Staggered Scheme ◽  
Wave Trains ◽  
2004 Tsunami

The development of transient waves generated by bottom motion is studied numerically in this work. A nonhydrostatic numerical scheme, based on solving the two-dimensional Euler equations using two-layer approximation for the vertical direction, is implemented. The dispersion relation of this scheme is shown to agree with the analytical dispersion relation over a wide range of [Formula: see text], where [Formula: see text] denotes the wave number and [Formula: see text] the characteristic water depth. To ensure that a good balance between nonlinearity and dispersion is accommodated by the scheme, the propagation of a solitary wave (undisturbed in shape) was simulated. Our next focus was on the simulation of transient waves generated by bottom motion. After conducting a benchmark test against Hammack’s experimental results for downward bottom motion, an anti-symmetric bottom thrust was considered. The resulting transient waves developed different behavior depending on the water depth. Finally, to mimic the December 2004 tsunami, a seabed motion was generated over Aceh bathymetry. This simulation showed that a package of wave trains developed and propagated towards the Aceh coast, and exhibited inter alia the feature of shoreline withdrawal often observed.

Numerical Analysis for Dynamic Characteristics of New Launcher with Coupled Rigid and Flexible Motion

2010 ◽  
Vol 34-35 ◽  
pp. 44-49 ◽  
Author(s):  
Ying Ze Wang
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
High Performance ◽  
Coupling Effect ◽  
The Other ◽  
Flexible Coupling ◽  
Simulation Based ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

This paper is concerned with an analysis of the dynamic characteristics of the high performance launcher—rarefaction wave gun(RAVEN) by numerical simulation. Based on its launch mechanism and launch structure, a rigid-flexible coupling dynamic model which considered the coupling effect between the flexible virbation of the launch barrel and the motion behaviors of the other parts of the RAVEN is established via a subsystems method. The actual motion of the projectile and inertial breech during the lauching are described by the interior ballistic equations of the RAVEN. The dynamic characterisitcs of RAVEN is illustrated by the numerical simulation about a small caliber launcher, and the interaction between launch barrel and the other parts is also studied.

Analysis of Pump Induced Radiated Noise From Undersea Vehicles

2001 ◽  
Author(s):  
Scott E. Hassan ◽  
Raymond W. Roberts
Keyword(s):  
Element Model ◽  
Vane Pump ◽  
Radiated Noise ◽  
Positive Displacement ◽  
Radiated Power ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Undersea Vehicle ◽  
The Many ◽  
Pump Inlet

Abstract Positive displacement pumps are one of the many potential noise and vibration sources associated with undersea vehicles. This paper presents an approach to predict the tonals radiated from vane-type pumps mounted in undersea vehicles. The approach is based on using a numerical model of a vane pump coupled to an analytical model of the pump inlet hose and a finite element model of the hull and internal structure associated with the fluid-loaded undersea vehicle. An illustrative example is presented that demonstrates the influence of the various propagation paths and pump parameters on the overall radiated power. The basic approach can be readily extended and implemented as part of a simulation based design process for managing vehicle acoustics and vibration.

Dynamic Modeling and Computed Torque Control of Flexure Jointed TVC Systems

2018 ◽  
Author(s):  
Ahmet Aydogan ◽  
Eric Rogers ◽  
Ozgur Hasturk
Keyword(s):  
Dynamic Modeling ◽  
Vertical Direction ◽  
Vertical Motion ◽  
Torque Control ◽  
Tracking Accuracy ◽  
Computed Torque Control ◽  
Early Results ◽  
Simulation Based ◽  
Thrust Vector ◽  
Computed Torque

Thrust Vector Control (TVC) is one means of controlling air vehicles to follow a desired flight path where, in particular, those that are flexure jointed are currently the most commonly used. Often, dynamic modeling of such systems is for the case where a universal gimbal joint is present, which neglects uncertainties in the dynamics, such as vertical motion of the pivot point of nozzle and misalignment. This paper gives early results on a new approach to dynamic modeling of TVC systems that includes one more degree of freedom compared to previously reported models and also enables the flexure jointed structure to move along vertical direction on the flight axis. A Computed Torque Control Law (CTCL) is then designed for the new resulting model with the potential for higher tracking accuracy and lower feedback gains. A simulation based case study is given to demonstrate the new design.

A Hybrid Model to Analyze the Fluid-Structure Interaction Phenomenon of a Relief System and Experimental Validation

2019 ◽  
Author(s):  
Feng Jie Zheng ◽  
Fu Zheng Qu ◽  
Xue Guan Song
Keyword(s):  
Hybrid Model ◽  
Pressure Fluctuation ◽  
Fluid Structure Interaction ◽  
Relief Valve ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Model Combining ◽  
Valve Motion ◽  
Practical Engineering ◽  
Cfd Method

Abstract As one essential component of a pressurized system, a relief valve is used to guarantee the pressure within a prescribed range. But in practical engineering, pressure fluctuation caused by the operation of a relief valve will travel along the pipeline and couple with the motion of the valve, which might result in malfunction of the valve and the system. In order to investigate the fluid-structure interaction (FSI) phenomenon, a hybrid model combining the method of characteristics (MOC) and computational fluid dynamics (CFD) method is proposed. In the hybrid FSI model, the characteristics of pressure resource is modeled using the performance curves, the compressible gas transmitting in the pipe is calculated by one-dimensional MOC, and the air flow in the valve as well as the valve motion is simulated by a two-dimensional CFD model. To validate the hybrid model, 1:1 scaled test rig is conducted. The compared results show that the hybrid model not only can accurately capture the pressure fluctuation in straight pipeline induced by the closure of the valve but also can accurately predict the forms of the valve motion.

Functional Diagram for Modeling the Electromagnetic Ball Valve with Cylindrical Seat

2014 ◽  
Vol 657 ◽  
pp. 624-628 ◽  
Author(s):  
Dănuţ Zahariea
Keyword(s):  
Volumetric Flow Rate ◽  
Ball Valve ◽  
Functional Diagram ◽  
Pressure Relief Valve ◽  
Hydraulic Pump ◽  
Relief Valve ◽  
Pressure Relief ◽  
Measuring Devices ◽  
Direct Acting ◽  
Valve Pressure

The main objective of this work is to perform numerical analysis of an electromagnetic normally-closed direct-acting ball valve with cylindrical seat. A functional diagram is developed using the MATLAB/Simscape/SimHydraulics programming language. The principal elements of the functional diagram are: the fixed-displacement hydraulic pump, the ball valve which is driven by an electromagnetic actuator, the pressure-relief valve, pressure and volumetric flow rate measuring devices and the hydraulic pipes. Two sets of analyses are performed, the first one for an ideal case, without the effects that are associated with the hydraulic pipes and the second one for the real case, with these effects. The valve flow factor is presented, comparatively, for both cases, as well as the volumetric flow rates through the ball valve and the pressure relief valve, and finally the pressure drop in the valve.

scholarly journals SIMULASI TRANSPORTASI TOMAT DAN PERUBAHAN MUTU TOMAT SELAMA PENYIMPANAN

2021 ◽  
Vol 3 (1) ◽  
pp. 13-20
Author(s):  
Rozana Rozana ◽  
Daud Perdana ◽  
Oktavia Nurmawaty Sigiro
Keyword(s):  
Fruits And Vegetables ◽  
Mechanical Damage ◽  
Vertical Direction ◽  
Face Centered Cubic ◽  
Simulation Based ◽  
Transportation Process ◽  
The Face ◽  
Transportation Simulation ◽  
Vibrating Table ◽  
Face Centered

Chemical, physical, and microbiological damage of fruits and vegetables can occur during the transportation process. The percentage of damage can reach 30-50% if the treatment during transportation is not carried out properly. The research objective was to determine the quality changes in tomatoes after transportation simulation based on the arrangement of the fruit in cardboard packaging. The treatment in this research is tomato arrangement patterns: the face centered cubic (FCC) arrangement, the traditional arrangement and the jumble (farmer) arrangement. The research begins with a transportation simulation using a vibrating table in a vertical direction, using a frequency range of 3.9 Hz and an amplitude of 5.2 cm. The simulation is carried out in 1 hour. After the simulation at the 1st hour, amount of mechanical damage (bruising) on ​​every package was carried out. The results showed that the pattern of arranging tomatoes in cardboard packaging that gave the least damage was the FCC arrangement pattern. The FCC pattern only causes shrinkage of 0.11% and the smallest amount of mechanical damage (bruising) is 0.64%.

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