Conical Valve Research Articles

Research on vibration characteristics of cone valve based on steady state hydrodynamics

The steady-state fluid dynamic force of the cone valve core reduces the stability of the cone valve, thereby affecting its vibration characteristics. This study first derived the formula for calculating the steady-state fluid dynamic force of the valve core using the momentum theorem. Then, the study used the Computational Fluid Dynamics (CFD) method to explore the variation of steady-state fluid dynamic force with the opening degree of the cone valve and the pressure difference at the inlet and outlet. The study also analyzed the steady-state fluid dynamic force of the improved structure cone valve. Combining the CFD calculation results with the established axial vibration and dynamic models of the valve core spring system, a system dynamics simulation model was developed. Innovatively, the study combined experimental and simulation methods to investigate the vibration characteristics of the cone valve and the impact of steady-state fluid dynamic force on these characteristics. The experimental results aligned well with the simulation results, showing that the influence of steady-state fluid dynamic force on vibration characteristics is similar to that of spring force. At a small opening degree, the compensation structure of steady-state fluid dynamic force can reduce axial vibration amplitude. Increasing the inlet pressure from 2.0 MPa to 2.5 MPa results in a decrease in axial amplitude and an increase in the numerical value of the vibration balance position. Increasing the outlet pressure from 0.5 MPa to 0.9 MPa initially decreases axial amplitude and axial waveform factor, followed by an increase. Increasing the spring preload from 9.4 mm to 13.4 mm leads to a decrease in the numerical value of the balance position, a reduction in amplitude, and a decrease in the waveform factor of the axial vibration of the valve core. The study reveals systematic effects of inlet pressure, outlet pressure, and spring preload on the vibration characteristics of the cone valve. The research results in this paper can provide theoretical support for the structural design of hydraulic valves, reduce the impact of fluid dynamics on vibration, and thereby improve the stability of hydraulic system operation.

Precise control of discharge of spherical particles by cone valve configuration: Insert – Converging orifice

The effect of the size and shape of the insert (inverted cone, sphere) when placed axially above an orifice on the mass discharge rate (MDR) of monodisperse spherical particles from a cylindrical silo has been investigated through experiments and DEM simulations. MDR characteristics have been measured for various distances between the insert and the orifice.An important practical finding is that, within a specific range of placement distances, the MDR increases by approximately 10% when a conical insert is used, whereas no such effect was observed when a spherical insert was employed.It was observed that, in some cases, a slight increase in friction coefficient leads to an increase in MDR as result of alterations in the initial grain structure, facilitating faster discharge.In a quasi-2D configuration, significant changes in flow rate occur when the thickness exceeds the natural multiple of dp, allowing the next layer of particles to flow.

Effect of Aeration on the Cavitation Characteristics of the Control Valve in Hydro-Driven Ship Lifts

In hydro-driven ship lifts, plunger valves and fixed cone valves are the most suitable structures for achieving accurate flow control under a wide range of flow conditions. In order to inhibit cavitation in these valve structures, experiments were conducted in which forced aeration was applied before the valve. The cavitation phenomena and aerated flow regime were observed through a transparent glass pipe, and the cavitation noise characteristics were recorded using a hydrophone. The test results show that aeration can reduce the valve working cavitation number, albeit to a limited degree (<5%). Based on the sound velocity theory of aerated flow and the experimental results, the relationship between the aeration concentration and the cavitation inhibition efficiency was obtained. When the aeration concentration is approximately 0.1%, cavitation can be significantly inhibited via forced aeration before the valve. Once the aeration concentration reaches 0.9%, the cavitation inhibition efficiency becomes saturated. The research results presented in this paper provide a reference for the cavitation inhibition of industrial valves.

Effect of valve plug shapes on vortex-induced vibration characteristics through a multistage pressure-reducing valve

Vortex-induced vibration of a regulating valve not only wastes the energy of the control system, but also causes serious damage to the valve trims. It is very important to suppress vortex-induced vibration of the flow field in a valve by optimizing the valve trim structure. In this paper, a multistage pressure-reducing valve is proposed, and the flow fields in the valve with the lightweight, flat bottom, circular truncated cone and cylinder valve plug are simulated using the ANSYS Workbench. To verify the reliability of the simulation, a flow test device for the valve is established and the flow rates at different openings are measured. The test result shows that the valve designed by simulation conforms to the specified flow characteristics. By monitoring the lift coefficient of the vortex cross flow, the amplitude and main frequency of vortex-induced vibration are evaluated. The effect of the valve plug shapes on the vortex-induced vibration characteristics is studied. The results show that the shape of the valve plug has an obvious effect on the amplitude of vortex-induced vibration. The conical valve plugs can play the role of flow guiding, the amplitude of vortex-induced vibration of the valve is smallest, it is about 1/4 of that of other valve plugs at medium and high openings. This work is of significance for suppressing the vortex-induced vibration of the multistage pressure-reducing valve.

Гидравлическое сопротивление системы управления движением инспекционного снаряда с клапаном обтекаемой формы в газопроводе низкого давления

The main problem while developing inspection shells for low-pressure gas pipelines is mainte-nance of their uniform motion under the action of the pumped gas. In the present work, we propose a solution to this problem based on changing the cross-section of the central flow channel of the smart pig by moving an axially symmetric valve along the axis of the channel. Two types of valves with a drop-shaped and a cone-shaped front part were considered. The choice of the valve shape and size can be made by calculating the forces acting on the smart pig during gas flow. The prob-lem was solved by the methods of computational fluid dynamics under the assumption of axial flow symmetry. The gas was considered to be compressible. The calculations showed that the total force acting on the valve and walls of the flow channel does not depend on its shape and, depending on the valve position, can change by more than two times. The optimum length of a drop-shaped valve is nearly half that of a conical valve. Although the drop-shaped valve produces a more inhomoge-neous velocity field than the conical valve, the former is more acceptable for regulating gas flow through the central channel of the inspection smart pig.

Numerical Investigation on the Internal Flow Field of Electronic Expansion Valve as the Throttle Element

<div class="section abstract"><div class="htmlview paragraph">As one of the key components of the heat pump system, the electronic expansion valve mainly plays the role of throttling and reducing pressure in the heat pump system. The refrigerant flowing through the orifice will produce complex phase change. It is of great significance to study the internal flow field by means of CFD calculations. Firstly, a three-dimensional fluid model is established and the mesh is divided. Secondly, the phase change model is selected, the material is defined and the boundary conditions are determined. According to the principle of the fluid passing through thin-walled small holes, the flow characteristics of electronic expansion valve are theoretically analyzed. Then the flow characteristics of expansion valve are numerically calculated, and a bench for testing mass flow rate of the expansion valve is built. Then the theoretical value, CFD value and experimental value are compared to verify the correctness of the established three-dimensional fluid model. The flow rate changes of expansion valve are studied under the condition of changing geometric parameters such as the cone angle of the valve spool and the radius of circular arc at the end of the valve seat. According to the momentum theorem, the steady hydraulic force is theoretically deduced. Then the changes of steady hydraulic force are studied under the conditions of different inlet pressure and outlet pressure. At the same time, there also analyzes the effects of the conditions of different valve spool cone angle and valve seat arc radius on steady hydraulic force on the valve spool. Finally, transient analysis is carried out by using dynamic mesh technology. The speed of spool movement is defined by User Defined Function (UDF). Under constant pressure difference conditions, the influence of the spool movement on the hydraulic force and outlet flow of the valve is studied. And the change of the internal pressure field are shown.</div></div>

Characteristic of Steady-State Flow Force on the Cone Valve Based on Orthogonal Test Method

The steady-state flow force is the fundamental reason that affects the pressure stability, which will reduce the control performance of a hydraulic valve. A mathematical model of the axial steady-state flow force on the valve core is proposed to master the principle and characteristics of steady-state flow force. For understanding the dynamic changes of the steady-state flow force, a two-dimensional axisymmetric model is built to discuss the value of flow force. Different geometric parameters and operating conditions have different effects on the performance of the valve, and analyzing a variety of parameters is difficult because of the complexity of the test. Therefore, the geometric parameters and operating conditions in the steady-state flow force were optimized by the orthogonal test-optimization method. The main significant factors affecting the performance of steady-state flow force on the cone valve core are determined by extreme difference analysis, which are the opening and pressure differential, respectively. Furthermore, a test ring is built to measure the steady-state flow force. The results show that the greater the pressure differential is, the greater the steady-state flow force is. The steady-state flow force does not increase linearly, but increases first and then decreases with the increase of the opening. The study will lay the foundation to precise axial flow force prediction and reference for design optimization of the valve.

Research and Analysis on Cavitation of Different Structures of Cone Valve Ports in Pure Water

In order to study the cavitation problem of the pure water medium hydraulic poppet valve, a three-dimensional model of the poppet control valve under a rated pressure of 31.5MPa was established with the help of Soildworks software, and the poppet valve port model was simplified into a two-dimensional symmetrical model with AutoCAD software. Based on the FLUENT software, the liquid-gas two-phase flow simulation of the cavitation phenomenon in the flow field of the poppet valve is carried out, and the cavitation distribution and intensity change rules of the three valve port structures at three opening degrees are obtained. The results show that for the pure water medium hydraulic cone valve, the cavitation distribution in the new stepped structure is significantly reduced and the strength is significantly reduced under the same opening degree.

Solid particle flow characteristics in the cone valve and its flow rate prediction model

The solid particle flow characteristics inside the cone valve were experimentally and numerically studied. The experiments were conducted at different valve sizes, valve opening positions, pressure drops, and fluidization velocities. Numerical simulation using the computational particle fluid dynamic method was also carried out over broader conditions. It is found that the solid particle flow inside the cone valve demonstrated the three-stage phenomena as the solid particle flew passing through two in-series connected orifice systems. The explanation of the three-stage phenomena of the solid particle flow rate to the valve opening was given according to the double-orifice flow model. Based on the physical nature of the solid particle flow characteristics, a semi-empirical model of the solid particle flow rate inside the cone valve was proposed. The model parameters, such as the saturated solid flow rate, the saturated valve opening, were determined using the experimental data and the existing knowledge of orifice systems. The model was then verified using the experimental data and presented acceptable prediction accuracy.

Моделирование защитных устройств для обеспечения безопасности технологических процессов с использованием взрывоопасных газов

The article presents a calculation algorithm for the theoretical substantiation of the design of protective devices used for the safe operation of explosive equipment and supply lines. Mathematical modeling is applied. The development of protective devices providing explosion and fire safety of gas-flame equipment used in construction is considered. The design of protective devices providing explosive and fire hazardous gases from deflagration to detonation combustion modes and devices developed on the principle of cutting off the flame by means of mechanical actuation of locking elements: a membrane and a conical valve are presented.

Novel designs of pressure controllers to enhance the upper pressure limit for gas-hydrate-bearing sediment sampling

The pressure controller is the most important component of the pressure coring device to obtain natural gas hydrate with the in-situ pressure. However, due to the strength and sealing problems, the coring pressure is generally lower than 70 MPa. This paper contributes to the principle of pressure coring and the optimal design of pressure controllers to enhance the upper pressure limit. To address the shortcomings of the bearing capacity of the existing coring devices, based on Steinmetz solid principle, 5 types of pressure controllers are innovatively designed. The pressure controller failure criterion is proposed through numerical simulations. Based on the self-designed experimental system, the relationship between structural design and ultimate bearing capacity is revealed. The results indicate that according to the numerical simulation, with increasing load, the edge of the minor axis of the valve cover produces a large displacement along the contact surface, which decreases the contact pressure. The pressure controller strength can be improved by increasing the angle of the conical valve cover. The novel saddle-type pressure controller has the best design among those tested, which substantially improves the pressure controller bearing capacity (over 100.9 MPa). The study provides technical methods to explore and evaluate deep resources.

Investigation of the droplet-carrying characteristics of the gas flow in multiphase pump valves

In high gas-bearing conditions, the oil phase—in the form of droplets— often enters the reciprocating multiphase pump via the valves. Understanding the droplet-carrying characteristics of the gas flow is important for determining the transport capacity and stability of multiphase pump valves. In this paper, the turbulent gas flow and droplet movement behaviors in three typical valves of the reciprocating multiphase pumps were studied mainly by the theoretical analysis, the numerical simulation of computational fluid dynamics (CFD) and the verification test of particle image velocimetry (PIV). The steady and transient droplet trajectories, concentration distributions, and passing capacities were comprehensively studied with different valve openings, Reynolds numbers, and two-phase slip conditions. The results show that the ball valve performs steadily during the transport of the small to large droplets, while the cone valve and the disk valve perform well when transporting the small droplets with d≤250μm and the medium-sized droplets with 300μm≤d≤600μm under the initial conditions, respectively. Finally, the correlations of the volume mean diameter (dvm) of the droplets successfully passing through the cavities were proposed for the three valves. The results of this study are beneficial to help optimize and design new high-efficiency multiphase transport systems.

Numerical and experimental studies of gas-liquid flow and pressure drop in multiphase pump valves.

A numerical and experimental study was carried out to investigate the two-phase flow fields of the typical three valves used in the multiphase pumps. Under the gas volume fraction conditions in the range of 0%-100%, the three-dimensional steady and dynamic two-phase flow characteristics, pressure drops, and their multipliers of the ball valve, cone valve, and disk valve were studied, respectively, using Eulerian-Eulerian approach and dynamic grid technique in ANSYS FLUENT. In addition, a valve test system was built to verify the simulated results by the particle image velocimetry and pressure test. The flow coefficient CQ (about 0.989) of the disk valve is greater than those of the other valves (about 0.864) under the steady flow with a high Reynolds number. The two-phase pressure drops of the three valves fluctuate in different forms with the vibration of the cores during the dynamic opening. The two-phase multipliers of the fully opened ball valve are consistent with the predicted values of the Morris model, while those of the cone valve and disk valve had the smallest differences with the predicted values of the Chisholm model. Through the comprehensive analysis of the flow performance, pressure drop, and dynamic stability of the three pump valves, the disk valve is found to be more suitable for the multiphase pumps due to its smaller axial space, resistance loss, and better flow capacity.

Image recognition and diagnosis for vibration characteristics of cone valve core

Research on vibration characteristics of hydraulic valves is helpful to improve the performance of the hydraulic valve. In this article, a visualization experimental method is designed to capture the cone valve core vibration, and the image sequence of the vibration is obtained. And the least-squares contour fitting of the valve core is proposed to analyze the vibration characteristics of the valve core, which could eliminate noise in the vibration signal and improve accuracy. The difference of the least-squares variance between adjacent data points obtained by least-squares contour fitting is one order of magnitude smaller than corner detection method, while the signal-to-noise ratio is more than twice the corner detection. Furthermore, the frequency spectrum and amplitude of the valve core vibration are also discussed. The deviation of the valve core from the coordinate origin will increase with increasing of the pressure difference and decreasing of the pre-compression of the spring and the amplitude of vibration increases too. The vibration signal of the valve core under different conditions has similar frequency spectrum, which is mainly composed of the vibration signal spectrum caused by the fluctuation of oil pressure and turbulence of the liquid system.

Effect of number of the nozzle and cold mass fraction on the performance of counter flow vortex tube using the computational fluid dynamic analysis

ABSTRACT The vortex tube or Ranque–Hilsch vortex tube is a device that separates cold and hot air from compressed air while entering into the vortex chamber through the tangential inlet nozzles. A three-dimensional CFD model has been developed to study the flow behaviour of a vortex tube. The standard k–ϵ model has been used to model the turbulent flow inside the tube. The vortex tube of L/D ratio of 10 with different number of nozzles was analysed. The inlet pressure is varied from 2 bar to 6 bar with a constant inlet temperature of 303 K at different positions of the conical valve. The results of the present CFD study are in good agreement with the experimental results.

On the Capture of a Blue Shark, Prionace glauca (Carcharhinidae), in Peter the Great Bay, Sea of Japan

The capture of a blue shark, Prionace glauca, with a body length of 108.5 cm in Peter the Great Bay, Sea of Japan, is reported. Its measurable traits, dental formula, and number of arterial cone valves are provided.

Analysis of fluid flow through a bidirectional cone throttle valve using computational fluid dynamics

ABSTRACT Hydraulic throttle valve is generally used to change the flow rate of oil in a hydraulic system. There are also other applications. In this paper, a geometry model of a bidirectional cone throttle valve is established. The flow pattern and flow characteristics of a bidirectional throttle valve using computational fluid dynamics are investigated with the increasing of the differential pressure under different valve openings. Fluid passing through the cone throttle valve from two different directions is analysed and the discrepancy is observed for the forward flow and reverse flow. The pressure distribution and velocity contour are derived using Fluent software. Then the cause of the discrepancy is explained based on the flow information obtained. In the end, the bidirectional throttle valve with different cone angle is analysed, validating that the results obtained are appropriate just for bidirectional cone throttle valve with small cone angles. This study is beneficial for engineers who want to exert precise control under special applications and learn the characteristics of a bidirectional throttle cone valve in detail.

Vortex tube shape optimization for hot control valves through computational fluid dynamics

A vortex tube (VT) is a thermofluidic device that generates cold and hot streams from a single injection of compressed gas. This interesting phenomenon of energy separation is due to fluid dynamic effects. In this study, the optimization of the VT geometry was performed to investigate the potential applications of the VT as an expansion device in natural gas processing and air separation industries. A steady-state computational fluid dynamics (CFD) model with the standard k–ɛ turbulence was used to solve the hydrodynamics of the highly compressible, turbulent, and swirling flow within the VT. Velocity streamlines and temperature distributions of the separated air stream were obtained for different control valve shapes located at a hot end. The CFD results showed the effects of the control valve shape, cone valve geometry, and nozzle inlet pressures on the VT performance. A truncated cone control valve with an optimized geometry was found to be the best choice for thermal performance enhancement of the VT. The CFD results were validated with experimental data, and the difference in the cold temperatures between the numerical and experimental values were less than 4.12% for the 2D and 2.3% for the 3D vortex tube models.

Valve nozzle shape effect on gas lift system performance

Experiments were carried out using conical, bevelled entrance, bullet and orifice gas lift valve nozzle shapes with port diameter of 5 to 12 mm to study the effect of gas lift valve nozzle shape on the continuous flow gas lift system efficiency. A nitrogen-glycerin with nitrogen injection rate of 0.033 to 0.167 L/s flow through 50 mm diameter transparent vertical pipe and 3 m height to simulate a continuous flow gas lift system. Taylor bubble length and liquid produced mass were measured. The flow pattern was observed and the image was recorded using digital single-lens reflex camera. It was found that only slug flow occurred and gradual conical nozzle shape enlargement reduced the energy loss within the valve. The overall results show that conical nozzle produced the highest efficiency due to the less energy losses within the valve nozzle and most stable gas flow achieved in the fluid column pipe. [Received: December 24, 2015; Accepted: June 6, 2017]

On some features of the use of high-speed conical valve for the incident shock wave formation in shock tubes

On some features of the use of high-speed conical valve for the incident shock wave formation in shock tubes