Butterfly Valve Research Articles

Numerical simulation on a throttle governing system with hydraulic butterfly valves in a marine environment

Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters in a throttle governing system with a hydraulic butterfly valve. It also determines the type and specification of the hydraulic butterfly valve and the design of motion parameters of the transported fluid.

Performance enhancement of a complex chilled water system using a check valve: Experimental validation

Abstract The large primary–secondary chilled water systems often suffer from the excess flow demand and low chilled water temperature difference, which is known as the low ΔT central plant syndrome, during operation. This paper presents an approach for experimental validation of the possible utility of a check valve (i.e., putting a one-direction check valve in the chilled water by-pass line) to solve this operational problem and enhance the overall system performance, prior to a check valve is really installed. The experimental tests were carried out on the complex central chiller plant in a super high-rise building using a simulated check valve through fully closing one of the butterfly valves in the by-pass line when the system operated with a significant excess flow demand and experienced the low ΔT syndrome. The results from the tests showed that the system operational performance can be improved when the simulated check valve was used. Compared to that without using the check valve, about 9.2% of the total energy of the chillers and secondary water pumps was saved in the test period when the simulated check valve was used.

Experimental study for flow characteristics and performance evaluation of butterfly valves

The industrial butterfly valves have been applied to transport a large of fluid with various fields of industry. Also, these are mainly used a control of fluid flux to the water and waste-water pipeline. Present, butterfly valves are manufacturing for multiplicity shape of bodies and discs with many producers. However, appropriate performance evaluation was not yet accomplished to compare about these valves through experiments. This study is performed the experiment of flow characteristics and performance of manufactured 400A butterfly valves for the water and waste pipeline, and compared experimental results. We performed experiments that were controlled fixed a differential pressure condition (1 psi) and the range of the flow rate conditions (500 m3/hr ~ 2500 m3/hr), and also opened the disc of valves to a range of angle from 9 degree to 90 degree. We investigated and compared the valve flow coefficient and the valve loss coefficient of results through experiments with each butterfly valve.

Flow characteristics and performance evaluation of butterfly valves using numerical analysis

The industrial butterfly valves have been applied to various fields that transport fluid in volume, especially water supply and drainage pipeline for flow control. The butterfly valves in various shapes are manufactured, but a fitting performance comparison is not made up. For this reason, we carried out numerical analysis of some kind of butterfly valves for water supply and drainage pipeline using commercial CFD code FLUENT, and made a comparative study of these results. Also, the flow coefficient, the loss coefficient, and pressure distribution of valves according to valve opening rate were compared each other and the influence of these design variables on valve performance were checked over. Through flow around the valve disk, such as pressure distribution, flow pattern, velocity vectors, and form of vortex, we grasped flow characteristics.

버터플라이 밸브의 유량측정 불확도에 대한 영향

For testing large-capacity pumps, the accurate flow rate measurement is needed in the test loop. As a measuring method of flow rate, venturi tube is recommended due to its low pressure loss. However, upstream disturbance of loop component such as a valve has an effect upon the accuracy of flow rate measurement. For controlling flow rate in case of high flow rate and large-scale piping system, a butterfly-type valve is generally used due to its compactness. However, a butterfly valve disturbs downstream flow by generating turbulence, cavities, or abrupt pressure change. In this study, the effect of downstream disturbance of butterfly valve on the flow rate measurement using a venturi tube is investigated. Test loop consists of circulation pump, reservoir, butterfly valve, venturi tube, and reference flow meter. The test is conducted with regard to a different valve opening angle of butterfly valve. According to the valve opening angle, the uncertainty of flow rate measurement is investigated.

Calculating Study on Flow Characteristics of Butterfly Vacuum Control Valves

Aiming at the actual demand, the gas flow characteristics of butterfly vacuum control valves are investigated in this paper. Classification and characteristic of vacuum control valves are discussed in detail. The geometric and mathematic models for two kinds of butterfly vacuum control valves, with seal and without seal, are respectively built. The gas flows through the valve at different opening angles are simulated under different pressure by means of the Fluent software. The flow percentage function and adjustment sensitivity are introduced and formulated to describe the flow regulating characteristic of control valves. The flow conductance coefficient and flow loss coefficient are defined and formulated to describe the resistance characteristic of control valves. The dates and curves of some simulating examples are given and discussed.

Flows around moving bodies using a dynamic unstructured overset-grid method

In this article, a computational fluid dynamics algorithm is presented for simulations of complex unsteady flows around rigid moving bodies using an unstructured overset-grid method. For this purpose, a highly automated, three-dimensional, tetrahedral, unstructured overset-grid method is developed with one-cell-width overlapping zone in order to model the arbitrary geometries for steady and unsteady flow simulations. A method has been described to obtain the inter-grid boundaries of the one-cell-wide overlapping zone shared by a background grid and a minor grid. In the overset-grid methodology, vector intersection algorithm and bounding box techniques have been utilised. The mesh refinement and overset-scheme conservation studies proved the accuracy and efficiency of the method developed here. The applications of the developed algorithms were also performed through simulations that included complex internal flows around a flow-control butterfly valve as well as flows in an internal combustion engine with a moving piston. Lastly, validations with experimental data were conducted for both steady and unsteady flows around rigid bodies with relative motions.

Transonic Moist Air Flow around a Symmetric Disc Butterfly Valve with Non-Equilibrium Condensation

Transonic flow around a symmetric disc butterfly valve is associated with the appearance of shock waves on valve surfaces. In this case, the interaction between shock waves and boundary layers becomes complex and thus generates the flow-induced aerodynamic instability. In the transonic or supersonic flow where vapour is contained in the main flow, the rapid expansion of the flow may give rise to non-equilibrium condensation. In the present study, the effect of non-equilibrium condensation of moist air on the shock-induced flow field oscillation around a butterfly valve was investigated numerically. The results showed that in cases with non-equilibrium condensation, the flow field aerodynamic instabilities such as root mean square of pressure oscillation and shock-induced oscillation frequency are reduced significantly compared with those without the non-equilibrium condensation. Moreover, the total pressure loss increases and the vortex shedding frequency is reduced with non-equilibrium condensation.

Dynamic analysis of three-dimensional flow in the opening process of a single-disc butterfly valve

A numerical dynamic analysis is carried out to simulate a three-dimensional flow and to study the performance of a single-disc butterfly valve with a diameter of 1.35 m in the opening process. The unsteady fluid flow during the opening process is studied by using the moving grid technique. The turbulent separated flow is also studied to understand the unsteady flow better through velocity distributions and pressure distributions on the mid-symmetric plane. The formation of vortexes is also discussed. Then the characteristics of butterfly valves such as the flow coefficient, the dynamic torque coefficient, and the drag coefficient are studied. The curves of these characteristics corresponding with the variational valve opening angle are obtained to investigate the performance of the single-disc butterfly valve.

1002 バタフライ弁のキャビテーション抑制に関する研究 : 管内速度分布が低騒音化に及ぼす影響(GS-5 キャビテーション)

1002 バタフライ弁のキャビテーション抑制に関する研究 : 管内速度分布が低騒音化に及ぼす影響(GS-5 キャビテーション)

양방향 삼중편심 버터플라이 밸브 개발

In naval architecture and offshore engineering, the development and a broad use has been achieved in the field of flow control valves for pipe system. Butterfly valves are also widely used for flow control, but there are not many studies for triple-eccentric butterfly valves. Moreover, if the fluid of pipeline flows in the bi-direction then it makes more complicate to adapt triple-eccentric butterfly valves to flow control. In this study, we are trying to develop a bi-directional triple-eccentric butterfly valve through sealing mechanism and stem design study. Digital mockup using 3D CAD was constructed for shape interference check and structural analysis was conducted for structural safety. Also we performed leakage test to check out the durability of the bi-directional pressure for the developed valve.

Communications orales du GPCM - lundi 16 novembre 2009

A butterfly valve is a type of flow control device, typically used to regulate fluid flow. This paper proposes a new process to meet desired needs in valve design that is characterized by the complex configuration. First, the need is identified according to the valve user/company, and then the problem is defined with a characteristic function. Second, the initial model of valve is made, and then the initial analysis including fluid and/or structural analysis is carried out to predict the fluid and/or structural performance of the valve. Third, the optimization in the form of mathematical functions, which considers single or multiple objective and/or discipline, is handled. This part includes the design of computer experiment, approximation technique, topology optimization and sizing optimization. Finally, the validation experiment is conducted based on the optimum result to verify the accuracy of the optimization. An example is provided to confirm the availability of the process proposed here.

Intelligent Decoupling Control of Gas Collection Process of Multiple Asymmetric Coke Ovens

This paper presents a hierarchical intelligent decoupling control method for the gas collection process of three asymmetric coke ovens of an iron and steel company. The process features strong asymmetric coupling, large disturbances, and strong nonlinearity. These characteristics are exploited in the following steps to implement intelligent decoupling control. First, three fuzzy expert controllers and two feedforward controllers stabilize the pressure of each gas collector. Then, the three collectors are divided into two groups based on an analysis of the couplings among them to facilitate decoupling control. An intelligent decoupling control method is used to design intragroup and intergroup decoupling controllers. Finally, expert valve control handles the nonlinearity of butterfly valves, and a multirate sampling strategy further improves the control performance. The results of actual runs show that the system satisfactorily performs the intelligent decoupling control of the gas pressures of the coke ovens, sufficiently suppresses disturbances, and accurately stabilizes the pressures.

FLUID AND STRUCTURAL ANALYSIS OF A LARGE DIAMETER BUTTERFLY VALVE

A butterfly valve of large diameter is commonly used as control equipments in applications where the inlet velocity is fast and the pressure is relatively high. Because the size of the valve is too large, it's too difficult to conduct testing experiment in a laboratory. In this paper, the numerical simulation using commercial package-CFX and ANSYS was conducted. In order to perform fluid analysis and structural analysis perfectly, large valve models are generated in three dimensions without much simplification. The result of fluid analysis is imported to structure analysis as a boundary condition. In addition, to describe the flow patterns and to measure the performance when valve are opened for various angles, the verification of the performance whether the valve could work safely at these different conditions or not was conducted. Fortunately, the result shows that the valve is safe in a given inlet velocity of 3 m/s, and it's not necessary to be strengthened anywhere. In the future, the shape of valve disc can be optimized to reduce the weight, and also to make the flow coefficient be closer to the suggested level.

Multidisciplinary optimization of a butterfly valve

A butterfly valve is a type of flow control device, typically used to regulate fluid flow. This paper proposes a new process to meet desired needs in valve design that is characterized by the complex configuration. First, the need is identified according to the valve user/company, and then the problem is defined with a characteristic function. Second, the initial model of valve is made, and then the initial analysis including fluid and/or structural analysis is carried out to predict the fluid and/or structural performance of the valve. Third, the optimization in the form of mathematical functions, which considers single or multiple objective and/or discipline, is handled. This part includes the design of computer experiment, approximation technique, topology optimization and sizing optimization. Finally, the validation experiment is conducted based on the optimum result to verify the accuracy of the optimization. An example is provided to confirm the availability of the process proposed here.

Analysis and optimization of a butterfly valve disc

A butterfly valve is a type of flow control device, which is widely used to regulate a fluid flowing through a section of pipe. Currently, analyses and optimization are of special important in the design and usage of butterfly valves. For the analysis, finite element method (FEM) is often used to predict the safety of valve disc, and computational fluid dynamics (CFD) is commonly used to study the flow characteristics of valve. However, it is difficult to obtain accurate results for the optimization of butterfly valve due to the high non-linearities. For this reason, metamodels or surrogate model methods are extensively employed. This paper integrates metamodel with FEM and CFD analysis to optimize a traditional butterfly valve, where the weight of the valve disc is the design objective, and the strength safety of disc and the pressure loss coefficient of valve are constraints. Kriging model is employed as a surrogate model to formulate the objectives and constrains, and the orthogonal array is used as design of experiment to sample the computer analysis. The optimum results with the corresponding variable combinations for the valve disc are obtained easily by this method. Moreover, the structural and fluid analyses with the obtained optimum variable combinations are conducted again to verify the accuracy of the optimization method. The results demonstrate the capability and potential of this method, which integrates the Kriging model with FEM and CFD analysis, in solving the optimization of a butterfly valve.

Product Platform Design Method Based on Axiomatic Design

The product platform design is the key technology to mass customization. It satisfies different customer needs by adding,modifying or removing personal modules. The framework based on function independence of axiomatic design is applied to zigzagging mapping between functional and physical structures simultaneously according to the customer needs and then the independent function hierarchy is constructed. The modularity of product is built by analyzing the influencing relationship of decomposed functions. The product platform is identified according to the relation of modules realizing customer needs. Then the universal physical architecture of product platform is built on principle of physical integration and separation for design parameter and under the premise of ensuring the independence of functions. The butterfly valve of cooperated company is a case study and its product platform is constructed to rapidly respond the different market requirement.

A 3-fold “Butterfly Valve” in Command of the Encapsulation’s Kinetic Stability. Molecular Baskets at Work

Molecular basket 1, composed of a semirigid tris-norbornadiene framework and three revolving pyridine-based gates at the rim, has been built to "dynamically" enclose space and as such regulate molecular encapsulation. The gates were shown to fold via intramolecular hydrogen bonding and thereby form a C3nu symmetrical receptor: the 1H NMR resonance for the amide N-H protons of the pyridine gates appeared downfield (delta= 10.98 ppm), and the N-H vibrational stretch (IR) was observed at 3176 cm(-1). Accordingly, density functional theory (DFT, B3LYP) investigations revealed for the closed conformers of 1 to be energetically the most stable and dominant. The gearing of the pyridine "gates", about their axis, led to the interconversion of two dynamic enantiomers 1A and 1B comprising the clockwise and counterclockwise seam of intramolecular hydrogen bonds. Dynamic 1H NMR spectroscopic measurements and line-shape simulations suggested that the energy barrier of 10.0 kcal/mol (DeltaG++(A/B), 298 K) is required for the 1A/B interconversion, when CCl4 occupies the cavity of 1. Likewise, the activation free energy for CCl4 departing the basket was found to be 13.1 kcal/mol (DeltaG++, 298 K), whereas the thermodynamic stability of 1:CCl4 complex was -2.7 kcal/mol (DeltaGdegrees, 298 K). In view of that, CCl4 (but also (CH3)3CBr) was proposed to escape from, and a molecule of solvent to enter, the basket when the gates rotate about their axis: the exit of CCl4 requires the activation energy of 12.7 kcal/mol (DeltaG++(A/B) + DeltaGdegrees), similar to the experimentally found 13.1 kcal/mol (DeltaG++).

극저온 버터플라이 밸브의 유속에 따른 캐비테이션 발생 예측

The butterfly valve is widely used in the industrial field as an on-off or a flow control valve. When the butterfly valve is used as a flow control valve, cavitation sometimes occurs in the range of high flow rate because of the small valve opening. Therefore, the pressure loss and the cavitation characteristics are investigated by use of a commercial CFD code. The results show that the possibility of cavitation occurrence in the cryogenic butterfly valve is very high in the case of valve opening angle below 10 degree and incident velocity over 6m/s. By increasing the inlet velocity at 10 degree of valve opening angle, the value of loss coefficient increased. However, by increasing the inlet velocity at 50 degree of valve opening angle, the value of loss coefficient decreased.

Hydroacoustic modeling of the butterfly valves - some industrial applications

The French PWR units include a large number of control valves which are sometimes at cavitation working for certain operating conditions. The very high excitations which are then created may lead to the cracking of some small lines located nearby. These devices have been tested on laboratory test loops. An hydroacoustic behaviour model has been set up on the basis of very precise identifications obtained from numerous experimental tests. The model obtained describes the acoustic transfers through the valve and the sources generated by turbulence and cavitation in the low frequency domain, according to the main operating parameters: aperture, flow rate, cavitation number, upstream pressure and diameter. Hydraulic and vibratory measurements were carried out on several Residual Heat Removal circuits for many control configurations. When this circuit is functioning under certain conditions, the two valves which regulate the hot and cold flow rates operate according to a cavitation system. The hydroacoustic valve model is used to simulate of the valves under the hydraulic conditions of measurements. The results are compared at the vibratory levels recorded on site. The model also makes it possible to determine the optimal operating conditions in order to limit the vibrations of the circuit.