Reliability Of Valves Research Articles

تقييم إمكانية االعتماد على نظام السالمة اآللي و صمامات اآلمان لخزانات فصل الزيت الخام في حقل نفط

A crude oil separator is a pressure vessel used to separate oil and gas in an oil well stream. The separators are provided with a Basic Process Control System (BPCS) and a protection system which consists of a Safety Instrumented System (SIS) and a Pressure Relief System (PRS). Failure of the crude oil separator might result in fire, explosion, and toxic dispersions. The world has witnessed several fire and explosion incidents due to the operation of crude oil separators. Reliability of the control and protective systems of crude oil separators is very important to verify their abilities to perform their functions. This technical article presents an overview of the layers of protection of crude oil separator and the reliability of protective systems. The article also presents an evaluation of the reliability of SIS and safety valves of crude oil separators in an oil field. The crude oil separators are arranged in the form of three parallel trains of separators each train divided into three stages. The first stage consists of two separators and each stage of the second and third stages consists of one separator. The reliability of the different configurations of the SIS and safety valves of a train of production separators has been estimated and found to be acceptable.

Research on the Throttling Performance and Anti-Erosion Structure of Trapezoidal Throttle Orifices

The throttling performance of conventional throttle orifice structures of fluid control valves is very low. Therefore, this paper proposes a novel trapezoidal throttle orifice with excellent throttling performance. The effect of the taper of the throttle orifice on the erosion was researched. Firstly, two schemes of trapezoidal throttle orifice were proposed according to the fluid control valve. Secondly, the excellent throttling performance of the trapezoidal throttle orifice was compared and optimized. Finally, a numerical simulation method of the erosion-resistant ability of the trapezoidal throttle orifice was established. It was found that for the same throttling area, the differential pressure of the trapezoidal orifice was higher than that of the conventional rectangular orifice by about 18.6%. The taper had little effect on the gas production, which increased by only 3.3% during the 10° to 30° change. The maximum erosion was firstly reduced and then increased with increases in the angle from 0 to 25°of the taper. Moreover, the minimum was achieved at about a 20° taper angle. The above research methods provide a theoretical basis for optimizing the size and structure of orifices and the sealing reliability of fluid control valves.

Numerical Investigation of Butterfly Valve Performance in Variable Valve Sizes, Positions and Flow Regimes

Reliability and efficiency of valves are necessary for precise control and sufficient heat-flow to heat application plants for the integrated energy systems of nuclear power plants (NPPs). Strategic Management Analysis Requirement and Technology (SMART) valves’ ability to control flow and assess environmental parameters stands out for these requirements. Their ability to sustain the downstream flow rate, prevent reverse flow, and maintain pressure in the heat transport loop is much more efficient with the integration of sensors and intelligent algorithms. For assessing valve performance and monitoring, mechanical design and operating conditions are two important parameters. In this study, the butterfly valves of three different sizes are simulated with water and steam using STAR-CCM+ in various flow regimes and positions to analyze performance parameters to strategize an automated control system for efficiently balancing the heat–transport network. Also, flow behavior is studied using velocity and pressure fields for valve–body geometry optimization. It can be observed, through performance parameters, that the valves are suitable for operation between 30° and 90° positions with significantly low loss coefficients and high flow coefficients, and the performance parameters follow a certain pattern in both water and steam flow in each scenario.

Study on Quantitative Evaluation Method for Failure Risk Factors of the High-Temperature and High-Pressure Downhole Safety Valve

Downhole safety valves are essential equipment for oil and gas extraction, and it is crucial to carry out a downhole safety valve failure risk evaluation and reliability analysis to ensure the safety of oil and gas production. In order to improve the operation and maintenance management level of downhole safety valves and explore the key failure risk factors of downhole safety valves, this study firstly carries out a Failure Mode and Criticality Analysis of downhole safety valves; identifies the causes of failure of downhole safety valves and the consequences of accidents through the Bow-tie method; and quantitatively evaluates the failure risk factors based on the improved Decision-making Trial and Evaluation Laboratory method and obtains the influence and importance ranking of 14 types of failure risk factors. Specific preventive measures for key failure risk factors are proposed in several aspects: optimising the structural design of downhole safety valves, improving the processing and manufacturing process, setting up an efficient field management team, carrying out equipment operation and maintenance management training, establishing a field failure response mechanism, and setting up an intelligent O&M management platform for downhole safety valves. The research results of this study are conducive to improving the reliability of downhole safety valves, ensuring the safety and integrity of on-site operation and maintenance management, and providing theoretical guidance for the analysis of the risk of failure and operation and maintenance management of downhole safety valves.

Modelling and characteristics analysis of an electro-hydraulic proportional valve with a discrete pilot stage for underwater hydraulic manipulators

As the harshness of the underwater operating environment and complexity of underwater tasks gradually increase, underwater hydraulic manipulators with high reliability and precision attract more research attention. To improve the reliability and dynamic performance of the traditional electro-hydraulic proportional valve (EHPV) used in the underwater hydraulic manipulator, an improved electro-hydraulic proportional valve with a discrete pilot stage (DEHPV) is proposed. In the pilot stage, two 2-position 3-way normally open high speed switching valves (HSVs) are used, and the initial oil spring stiffness in the control chamber is large enough to maintain the dynamic performance of the DEHPV. First, the working principle and configuration of the DEHPV are both given, and the coupled electric-magnetic-mechanical-fluid model of the DEHPV is presented. Moreover, a dual-valve hybrid pulse width modulation (DVHPWM) control strategy is proposed to improve the position tracking accuracy of the DEHPV. Furthermore, a co-simulation model of the DEHPV considering the multi-field coupling law is established to study the dynamic characteristics. Extensive experiments are carried out to verify the effectiveness of the proposed structure as well as its good dynamic performance and control accuracy.

Multi-objective cooperation optimization research on dynamic response and energy loss of high-speed solenoid valve for diesel engine injector

The dynamic response and operational reliability of high-speed solenoid valve (HSV) for diesel engine injector are the main indicators to measure their performance. At high-frequency, the eddy current energy and Joule energy generated by the HSV will be converted into heat, which has a significant impact on the service life of HSV. The optimization of HSV involves the interaction between energy loss and the dynamic response of HSV. To optimize the HSV dynamic response time considering energy loss, the HSV work process simulation model was established in this paper, and the model was verified based on armature lift experimental data. Without changing the structural parameters of the HSV, the four parameters of electroconductibility, spring stiffness, damping coefficient, and coil resistance were selected as the key parameters affecting the dynamic response and energy loss. The response surface models (RSMs) of opening response time, closing response time, eddy current energy and Joule energy of the HSV were constructed by using the smoothing spline-analysis of variance method. The multi-objective cooperation optimization of HSV under the interaction of dynamic response characteristics and energy loss was completed by using non-dominated sorting genetic algorithms. After optimization, the opening and closing response times of HSV were reduced by 15.1% and 16.6% respectively, while the eddy current energy and Joule energy were reduced by 5.2% and 48.4% respectively. In this paper, the dynamic response and energy loss were jointly optimized. The presented results provide theory instruction for multi-objective cooperative optimization of HSV.

Modeling and Reliability Constraint Analysis of MMC Valve

The VSC-converter valve is the core equipment of the VSC-HVDC transmission system, and its reliability directly affects the availability of the VSC-HVDC system. The reliability model of the existing VSC-converter valve mainly considers the relationship between different redundancy and the reliability of the VSC-converter valve. This paper first analyzes the impact of the failure of key components of the VSC-converter valve. According to the different effects, the arm reliability model of the VSC-converter valve is established, and finally, the comprehensive reliability model of the VSC-converter valve is established. Then, based on the model of the VSC-converter valve, the reliability constraints of the VSC-converter valve that meet the engineering requirements are finally derived. An example is given to verify the correctness of the classification reliability evaluation. Finally, according to the reliability model proposed in this paper, the design recommendations for a highly reliable VSC converter valve are given.

Three-dimensional fluid-structure interaction simulation of the Wheatley aortic valve.

Valvular heart diseases (such as stenosis and regurgitation) are recognized as a rapidly growing cause of global deaths and major contributors to disability. The most effective treatment for these pathologies is the replacement of the natural valve with a prosthetic one. Our work considers an innovative design for prosthetic aortic valves that combines the reliability and durability of artificial valves with the flexibility of tissue valves. It consists of a rigid support and three polymer leaflets which can be cut from an extruded flat sheet, and is referred to hereafter as the Wheatley aortic valve (WAV). As a first step towards the understanding of the mechanical behavior of the WAV, we report here on the implementation of a numerical model built with the ICFD multi-physics solver of the LS-DYNA software. The model is calibrated and validated using data from a basic pulsatile-flow experiment in a water-filled straight tube. Sensitivity to model parameters (contact parameters, mesh size, etc.) and to design parameters (height, material constants) is studied. The numerical data allow us to describe the leaflet motion and the liquid flow in great detail, and to investigate the possible failure modes in cases of unfavorable operational conditions (in particular, if the leaflet height is inadequate). In future work the numerical model developed here will be used to assess the thrombogenic properties of the valve under physiological conditions.

Design and Analysis of the Inlet Valve for the CFETR Torus Cryopump

The China Fusion Engineering Test Reactor (CFETR), a superconducting magnetic confinement tokamak fusion reactor, will develop a high-performance torus cryopump to pump torus plasma exhaust gas. The inlet valve is one of the key components of the cryopump, and it is used to isolate the cryopump from the plasma for regeneration, to control the pumping speed of the cryopump, and to operate as a pressure relief valve in case of a failure, such as the cryopipe breaking inside the cryopump chamber. This paper presents a novel inlet valve. Ensuring that the design of the inlet valve meets the above requirements will be a challenge. In order to verify the reliability of the inlet valve, its critical components are analyzed and optimized by the Finite Element Method. The effect of the stroke of the inlet valve on pumping performance is then estimated by the Monte Carlo Method, and the pressure profile in the whole flow field is studied to predict the cryopump’s behavior. Finally, the seismic capacity of the optimized inlet valve is analyzed, and the mechanical performance of the inlet valve is shown to meet CFETR design criteria. These design and analysis results will provide technical support and references for the development of the CFETR torus cryopump.

Theoretical and experimental study on performance of compound-driven MR valve-controlled damper

A compound-driven magnetorheological (MR) valve is designed to cope with the low reliability and high energy consumption of traditional MR valves. The operating magnetic field of the valve is applied by both the excitation coil and ring magnet, maintaining excellent pressure drop performance even at zero current. To analyze the performance and obtain the variation law of the magnetic flux density and pressure drop, a pressure drop mathematical model and a magnetic field simulation model are established. The key parameters of the MR valve are also optimized using non-dominated sorting genetic algorithms-II. A dynamic performance test system is built, and the influence of the load on the pressure drop and hysteresis characteristics of the MR valve is studied. The results show that the optimized pressure drop and adjustable coefficient are improved by 4.7% and 8.6% respectively. The pressure drop grows nonlinearly with the electric current and reaches saturation at a current of 1.5 A, and a pressure drop of 1485 kPa is still generated at zero current. The output damping force of the compound-driven MR valve-controlled damper can be continuously adjustable, indicating that the dynamic performance of the damper can be controlled by adjusting the input current.

Study on the sealing test method of hydraulic solenoid valve in nuclear power station

In order to improve the reliability of tripping solenoid valve and switching solenoid valve of steam turbine valve in nuclear power plant and reduce abnormal valve closing. According to the working principle of valves in nuclear power plant, this paper designs a kind of electromagnetic valve sealing test system, including test base, measurement and control system and hydraulic system. The detection system is an offline system. By simulating the real load condition of the steam turbine system, the tightness of the tripping solenoid valve and the switching solenoid valve is tested to improve the reliability of the solenoid valve. The actual application results show that the system operates stably and reliably, is simple to operate, has high detection efficiency and accuracy, and has good use effect.

Research of Property and Calibrate Method for Pressure Release Device of Power Transformer in the Grid

This paper introduces the types, internal structures and working principles of common non-electricity protection devices, and theoretically analyzes the cooperation between non-electricity protection devices. For pressure relief devices, the requirements of relevant standards for pressure relief valves are introduced, matters needing attention in field use of pressure relief valves are summarized, and factors affecting the performance of pressure relief valves are analyzed. Finally, using the calibration platform, through a large number of experiments, the influence of external environment temperature, caliber and pressure release times on pressure release performance parameters was studied. The results show that the average opening pressure at high temperature (95°C) is significantly lower than the average opening pressure of 10 times at normal temperature. At the same time, with the increase of ambient temperature, the aging opening pressure and the average opening pressure will obviously decrease, while the average closing pressure will increase. In addition, under normal temperature environment, the test values of aging opening pressure, average opening pressure and average closing pressure have little change. For pressure relief valves with different calibers, under the same rated opening pressure, the calibers of the pressure relief valves are different, which has little influence on the actual opening pressure. Through the research on the operation reliability of qualified pressure relief valves, it is found that the opening pressure after 50 operations and the first measured opening pressure and closing pressure data after 500 operations are relatively stable.

Dynamic simulation and analysis of steam dump valve failure using secondary side model of PWR

The safety system reliability is a key issue for the nuclear power plant (NPP), and the steam dump system (SDS) is an important pressure stabilizing system used in Hualong Pressurized Reactor (HPR1000) to enable nuclear steam supply system to accept loss of load without incurring a reactor trip and to remove stored energy and decay heat following a reactor trip without actuation of the steam generator safety valves. The SDS is consisted of many steam dump valves, and its reliability is dominated by the reliability of steam dump valves. During the steam dump interlock inspection test of a NPP, the pressure of the main steam pipe in the second loop appeared shock, which triggered the protection signal because of the high main steam pressure difference between the second and other main steam pipes. The purpose of this study is to simulate the failures and explore the mechanism of SDS failure process. A dynamic simulation model is developed with APROS version 6.10, which includes components between the steam generator (SG) and the main steam valves of NPP. The compressed air leakage failure for the steam dump valve, which causes valve position reduction (0%, 10% and 20%) and adjust speed change, is included in the dynamic simulation, and it causes fluctuations and steady-state errors in system parameters such as the main steam pressure and valve opening position. In the case of 10% and 20% valve position reduction, the main steam pressure fluctuates between 7.3 MPa and 7.45 MPa, and the steady-state errors are about 0.02 MPa. Then, the safety valve will jump in the fluence of water hammer due to the unsteady mass flow rate of condensate water. The pressure can drop to 6.75 MPa caused by safety valve jump, and the safety injection system will be triggered to form a serious accident reaction if the take-off action sustains over 0.13 s. Results of this study would be helpful for the understanding of the SDS failures process and dynamic characteristics of the SDS for nuclear power units, and provide guidance for failure identification and safety system improvement work.

Solid-body disc valve with a shape memory alloy seat

The relevance of the study is due to the need to increase the technical resource and structural reliability of the disc valve by modernizing its design. Disc valve is the most promising type of shut-off and control valves for oil and gas and chemical industries. Its main problem is a small technical resource and a significant unrealized reliability potential. An increase in the technical resource and the realization of potential reliability will minimize the operating costs due to scheduled repairs, as well as the risks of downtime of production lines due to emergency shutdowns, meet the requirements of industrial safety and environmental legislation, and accelerate the introduction of shut-off and control valves of this class in production. The purpose of this study is to improve the technical life and reliability of a disc valve by modernizing the design with the use of shape memory alloys. To achieve this goal, an analysis of the strength characteristics and resulting deformations of the seat of the developed and existing designs of disc shut-off valves was carried out, the results of studies on the abrasion and cavitation resistance of the Ni – Ti alloy with shape memory effect were described, a seat model made of alloys capable of thermoelastic phase transitions, as well as the deformation behavior of the seat, which ensures installation, was demonstrated. The result of the research was the proposed design of shut-off and control valves, which, in terms of manufacturing complexity, is comparable with existing designs in labor intensity, but at the same time has a large technical resource due to the absence of an additional parting line in it, which is formed in existing designs due to the coupling of the branch pipe and case. Mounting the seat in the case groove is ensured by the peculiarity of materials with a shape memory effect, and increased performance is due to the peculiarity of the properties of alloys with the shape memory effect, in particular, pseudoelasticity, which is manifested during operation in the temperature range Af < T < Md.

Safety and reliability analysis for butterfly valves in the offshore oil and gas industry

Valve systems are essential components in piping systems in a variety of industries, including oil and gas to stop and start the flow of fluid, regulate and control fluids, prevent backflows, and provide safety. The safety and reliability of industrial valves is an increasingly critical issue that has been addressed in previous studies. In case of valve failure due to mechanical failure, material corrosion, poor manufacturing and testing, there can be negative consequences including loss of assets, leakage into the environment, and other issues. The objective of this study is to develop a method for measuring the safety and reliability of safety critical butterfly valves by combining safety integrity level (SIL) and failure mode and effect analysis (FMEA). On the basis of operational data, butterfly valve failure rates are estimated. Safe failure fraction (SFF) are calculated at approximately 89% for the valves and converted into SIL2 that meets the end-user requirements.

Preparation and assessment of reliable organic spin valves

The long spin relaxation time of organic semiconductors up to millisecond level make organic spintronics an emerging and promising field, which has attracted wide range of interests since the birth of the first spin valve. Organic spin valve with sandwich structure is the typical device for spintronic study, and it is generally the vertical structure. During the device fabrication process, the organic semiconductor spacer is easily to be penetrated by top ferromagnetic metal atoms with high energy, and thus causes the formation of ill-defined layer at the interface between the top electrode and organic spacer. The ill-dedfined layer commonly includes filaments or pinholes, which will seriously affect the spin transport performance and spin-related multifunctional exploration. Therefore, reliable organic spin valve charactered by filament- and pinhole-free at the interface is strongly required. So far, a series of reliable spin valve preparation methods have been developed. In this review, following a simply introduction of spin valve, the advances of reliable spin valve preparation methods have been systematically discussed. Subsequently, the assessment approaches of reliable spin valve are presented. Finally, the challenges and perspectives towards the preparation and assessment of reliable spin valve are outlined to clarify the future efforts needed in this area. • This article reviews the preparation and assessment technologies of reliable organic spin valves. • Several methods for preparing reliable vertical spin valve are described and compared in detail. • Commonly used assessment methods of reliable spin transport in the organic spacer are outlined to demonstrate the reliability of spin valves.

Application of two-phase hybrid stepping motor based on three-phase inverter chopping control strategy in aircraft electric drive servo valve

With the development of multi-/all-electric technology, more and more aircraft platforms use electrically driven servo valves as the driving source to realize real-time adjustments of flow, pressure and temperature in the area network. The new generation of aircraft applies a stepper motor to drive the servo valve as the drive source, and utilizes the holding torque and open-loop control characteristics of the stepper motor when the stepper motor could not meet aircraft’s requirements of the reliability of the servo valve, the controllability of the opening and closing angle, and the environmental resistance. This paper develops a set of stepper motor drive servo valve control system. The system is mainly composed of flight tube bus, electromechanical management computer, remote actuation unit, remote interface unit and motor-driven servo valve. The stepper motor driver is integrated in the remote execution unit and is used to control the two-phase hybrid stepper motor to drive the servo valve. The topology of a three-phase inverter bridge drive is used to achieve the two-phase double four-shot drive, which saves about 25% power drive hardware. By controlling the two-phases motor, the direction and amplitude of the current one can realize micro-step control. The test and simulation result show that the system has higher control accuracy and better acceleration. The deceleration characteristics in two-phase full step and micro step working modes can expand the application of electric servo valve and improve aircraft performance.

TEST RESULTS OF A HIGH-SPEED SOLENOID VALVE FOR THE ELECTRIC PROPULSION FEED SYSTEM

Today in the world there are many electric propulsion systems based on the different types of thrusters. Most of them used gaseous propellent. Typical Electric propulsion system (EPS) consists of following main subsystems: the electric propulsion thruster that creates thrust; the power-processing and control unit which provides energy to all subsystems; the storage and feed system that performs functions of storing working substance in the tank and supplying the required amount of working substance to the thruster; Solenoid valve is a part of storage and feed systems. The feed system is an essential part of any electric propulsion system. The life cycle of the feed system is largely determined by lifetime of the valves and the amount of working substance in tank. Whereas the amount of working substance is selected based on the requirements for each specific mission valve parameters must be satisfying for various missions. Accordingly, the valves must have low power consumption, high reliability with a long lifetime (more than 106 cycles), low weight and dimensions. Solenoid valve is an electromechanical device that consists of moving part controlled by an electromagnet. Movement of the movable element and the seal are key parts of valve reliability. Presented solenoid valve design uses two membranes, which perform the function of centering the moving element and with the spring provide the required closing speed and the seal of the valve. The paper presents the problem of selecting critical elements that affect the solenoid valve's performance, procedure and test results required for the qualification of space equipment. Manufactured valve was successfully tested (vibration testing, response time testing with inlet pressure change, response time testing at different operating voltages, dependence of the valve actuation current on the operating voltage, temperature testing, lifetime tests) separately and as part of XFS according to the ECSS standards. As well as the successful implementation of presented valve into the flight xenon feed system for electric propulsion.

An Integrated Co-Design of Flow-Based Biochips Considering Flow-Control Design Issues and Objectives

With increasing effectiveness of flow-based microfluidic biochips in the field of biochemical experiments and point-of-care diagnosis, design automation demands enormous attention to integrate the flow-layer design and control-layer design instead of considering them in isolation. Some severe design issues like valve reliability, control-channel delay, pressure skew, etc. are obvious and they must be tactfully dealt along with minimization of several cost-driving issues like schedule length, pin count, and control-channel length while ensuring planarity of the flow-layer components as well as control-layer channel routes. Hence, this paper aims to propose a unified flow-control co-design methodology considering various flow-control cost-driving issues while reducing the design cycles to obtain a low-cost and efficient platform. The performance is evaluated over several benchmark bioassays that show the efficacy of the proposed co-design method which reduces the number of required valves by 30%, control-channel length by 48.5%, and number of flow-channel crossings by 72.2% than the existing works, on an average.

Dynamic Simulation of a Warship Control Valve Based on a Mechanical-Electric-Fluid Cosimulation Model

Control valves have an important function in the warship power system. In engineering practice, the fluid oscillation inside the control valve causes the additional load to the valve actuator. When the additional load is added to the original load of the valve, it is possible that the required driving force (or driving moment) of the valve is greater than the maximum force (or moment) output by the actuator, which may cause the abnormal stop of the actuator. Conventionally, the interaction effect of the valve mechanical and electric components on the valve chamber’s flow field cannot be considered in computational fluid dynamics (CFD) simulations, so the oscillating fluid loads cannot be accurately obtained. In order to solve this problem, the mechanical-electric-fluid integrated valve model, using the FLUENT and AMESim cosimulation method, was developed to embody the interaction effect between the components of each part of the control valve and exhibit the fluid oscillation during the operating process of the control valve. Compared with the pure software simulations, the unsteady flow characteristics and dynamic response of the actuator were synchronously obtained in this study, which accurately captured the sudden fluid loads required for further compensation. At the same time, the differences in performance of different valve plugs were compared. The stability time of the valve plug and oscillation amplitude of the unstable fluid loads were distinct for control valves with different flow characteristics. The results can aid in understanding the instability mechanism of the fluid load in the control valve better, which provides the calculation basis for compensating the additional load on the valve plug and improve the reliability of the control valve.