Dissertations / Theses on the topic 'Butterfly valve'

Butterfly valves are commonly used in industrial applications to control the internal flow of both compressible and incompressible fluids. A butterfly valve typically consists of a metal disc formed around a central shaft, which acts as its axis of rotation. As the valve's opening angle is increased from 0 degrees (fully closed) to 90 degrees (fully open), fluid is able to more readily flow past the valve. Characterizing a valve's performance factors, such as pressure drop, hydrodynamic torque, flow coefficient, loss coefficient, and torque coefficient, is necessary for fluid system designers to account for system requirements to properly operate the valve and prevent permanent damage from occurring. This comparison study of a 48-inch butterfly valve's experimental performance factors using Computational Fluid Dynamics (CFD) in an incompressible fluid at Reynolds numbers ranging approximately between 105 to 106 found that for mid-open positions (30-60 degrees), CFD was able to appropriately predict common performance factors for butterfly valves. For lower valve angle cases (10-20 degrees), CFD simulations failed to predict those same values, while higher valve angles (70-90 degrees) gave mixed results. (152 pages)

This thesis was written on behalf of SOMAS instruments AB. SOMAS develops, manufactures and markets valves. The mission was to reduce the wear between the disc edge and the seat in a butterfly valve that are used at high temperatures. This study investigated the possibility of using a surface treatment or coating that can reduce wear or if a new base material is better to use than the current steel 316 material. Possible materials, surface treatments and coatings were investigated and compared in a material study. In discussion with the company, four test pairs were chosen; • Steel 316 - Steel 316 • Steel 316 - Nitronic 60 • Nitronic 60 - Nitronic 60 • Steel 316 - Steel 316 with a surface coating of Tribaloy T-400 The wear behavior of the selected materials was investigated using a test rig at Karlstad University based on the method of block-on-ring. The machine spins a cylinder that corresponds to the seat against a block which in this case corresponds to the disc edge. The tests were carried out at room temperature, 250 ˚C and 500 ˚C. The cylinder was spinning at a speed of 100 rpm while the block pressed against with a load of 50 N. A profilometer, micro-hardness tester and scanning electron microscope (SEM) were used to investigate the wear. A comparison was made based on the volume of material removed from the blocks, the maximum wear depth of the blocks and the maximum wear depth of the cylinder. Wear mechanisms, chemical composition and hardness profiles were used to explain differences in results. The results were compared with the steel 316 to steel 316 solution. The Tribaloy T-400 showed good properties to reduce the wear at room temperature. Block made of Tribaloy T-400 showed no wear, instead steel from the cylinder had been adhered to the blocks. At higher temperatures, the amount of adhered material on the tribaloy T-400 increased, resulting in more wear at the surface of the cylinder than at room temperature. The wear on the cylinder was comparable to the wear of a steel cylinder that slid against a steel block. Nitronic 60 against nitronic 60 exhibited a significant reduction in wear compared with steel to steel at room temperature. At higher temperatures, nitronic 60 against nitronic 60 was the test pair that exhibited least wear. Nitronic 60 is recommended for further examination as a material in both the disc edge and the seat in a butterfly valve to be used at both room temperature and elevated temperatures.
Detta examensarbete skrevs på uppdrag från SOMAS instruments AB. SOMAS utvecklar, tillverkar och marknadsför ventiler. Uppdraget gick ut på att minska nötningen mellan spjällkanten och sätet i en vridspjällsventil som ska användas i höga temperaturer. Denna studie undersökte möjligheten det att använda en ytbehandling eller ytbeläggning som kan minska nötningen eller om ett nytt basmaterial är bättre att använda än det nuvarande materialet stål 316. Möjliga material, ytbehandlingar och ytbeläggningar undersöktes och jämfördes i en materialstudie. I diskussion tillsammans med företaget så valdes fyra stycken testpar; • stål 316 - stål 316 • stål 316 - nitronic 60 • nitronic 60 - nitronic 60 • stål 316 - stål 316 med en ytbeläggning av tribaloy T-400 Nötningsbeteendet hos de valda materialen undersöktes med hjälp av en testrigg på Karlstad universitet som bygger på metoden ”block-on-ring”. Maskinen snurrar en cylinder som motsvarar sätet mot ett block som i detta fall motsvarar spjällkanten. Testerna utfördes i rumstemperatur, 250 ˚C och 500 ˚C. Cylindern snurrade med en hastighet av 100 rpm medan blocket tryckte mot med en last på 50 N. En profilometer, mikrohårdhetstestare och svepelektronmikroskåp användes för att undersöka nötningen. En jämförelse gjordes baserad på volymen av det bortnötta materialet från blocken, maximala nötningsdjupet på blocken och maximala nötningsdjupet på cylindern. Slitagemekanismer, kemisk sammansättning och hårdhetsprofiler användes för att kunna förklara skillnader i resultaten. Resultaten jämfördes mot stål 316 mot stål 316. Tribaloy T-400 visade upp bra egenskaper för att kunna minska nötningen i rumstemperatur. Block gjorda av Tribaloy T-400 uppvisade ingen nötning, istället hade material från stål cylindern adderats på blocken. Vid högre temperaturer så ökade mängden adderat material på tribaloy T-400 vilket resulterade i att ytan på cylindern uppvisade mer nötning än i rumstemperatur. Nötningen på cylindern kunde jämföras med nötningen hos en stålcylinder som glidit mot ett stål block. Nitronic mot nitronic uppvisade vid rumstemperatur en stor minskning av nötning jämfört med stål mot stål. Vid högre temperatur var nitronic 60 mot nitronic 60 det test par som uppvisade minst nötning. Nitronic 60 rekommenderas för vidare undersökning som material i både spjällkanten och sätet i en vridspjällsventil som ska användas i både rumstemperatur och i höga temperaturer.

Nickel aluminum bronze (NAB) alloys are used in naval and maritime applications for their excellent corrosion resistance under the influence of seawater. One application involves the use of a NAB butterfly valve within a NAB fluid line to control fluid flow of seawater. Due to the chaotic environment, the corrosion rate of the NAB tubing downstream from the valve increases significantly. The disc angle at which the valve alters fluid flow causes an increase in the fluid velocity and an increase in the turbulence produced on the downstream side of the valve. These fluid conditions contribute to the increase in the corrosion rate of the NAB piping downstream from the valve. This thesis aims to characterize how the change in the disc angle of the butterfly valve causes a change in the erosion-corrosion rate of NAB downstream from the valve. A butterfly valve is simulated using orifice plates of varying diameters to mimic flow conditions at different disc angles. An orifice plate is a simple device with a hole in its center that is designed to restrict fluid flow across a fluid line. Under the same hydrodynamic conditions, the orifice produces nearly the exact same flow coefficients as the valve. At a volumetric flowrate of 0.00757 m^3/s a total of eight locations found along the liquid/metal interface produced pitting sites. The average passivation layer thickness is also measured.
Master of Science

O foco desta pesquisa é a análise computacional da cavitação em válvula borboleta utilizando o software comercial Ansys CFX versão 14. Dentre várias aplicações, a válvula pode ser utilizada no controle da vazão de água para lavagem de gases oriundos do processo de fabricação do aço num conversor LD. Foi estabelecido como parâmetros constantes de simulação, a pressão a montante e jusante respectivamente em 150 e 60 kPa e a temperatura de 80C. O objetivo deste trabalho é conhecer, através da simulação computacional, os ângulos em que a cavitação torna-se crítica na válvula borboleta, mapeando as áreas de cavitação, que será validada pelo equacionamento da válvula, de acordo com a norma da ISA. Será analisado o escoamento do fluído, priorizando a variável pressão e diferencial de pressão através da válvula, variando os ângulos do obturador de 10 em 10 graus, até o ângulo de 70. Em seguida, serão feitas novas simulações com as temperaturas de 50, 60, 70 e 90C, haja vista que, a vaporização da água está diretamente relacionada, não somente com a pressão, mas também com a temperatura do fluído. A escolha desta válvula para estudo dá-se pelo fato de ter uma alta recuperação de pressão a jusante, levando ao colapso as bolhas de vapor, quando a pressão se eleva acima da pressão de vapor da água, resultando no fenômeno físico denominado por cavitação, alvo de análise e mapeamento desta pesquisa. O regime de escoamento do fluído newtoniano é turbulento e utilizou-se a técnica de volumes finitos idealizada por Patankar, para resolução numérica, e o software comercial CFX versão 14 da Dinâmica de Fluidos Computacional. Foi utilizada a geometria e condições de contorno operacionais de uma válvula borboleta para investigar as regiões as quais ocorrem possibilidades de desgaste e focos de cavitação.
The focus of this study is a computational analysis of cavitation in butterfly valve using a commercial software named Ansys CFX version 14. Among several applications, the valve may be used in controlling water flow for gas washing originating from the washing process in a steelmaking converter LD. Therefore, the constant pressure upstream and downstream respectively at 150 and 60 kPa and de 80C , was established as constant simulation parameter. The purpose of this study is find out, using a computer simulation, which angles at the cavitation becomes critical in the butterfly valve, and mapping the areas of cavitation, which will be validated by the valve equation, according to ISA standards. Therefore, the flow of the fluid will be analyzed, prioritizing the variable and the differential constant pressure through the valve by varying the obturators angles from 10 to 10 degrees, until it comes to a 70 angle. To achieve this purpose, new simulations will be made with temperatures of 50, 60, 70 and 90 degrees, considering that the water vaporization is directly related to not only the pressure but also the temperature of the fluid. In this study, the butterfly valve was chosen because of its high downstream pressure recovery, leading to collapse of the vapor bubbles, when the pressure is elevated above the water vapour pressure, resulting in the physical phenomenon known as cavitation, which is the target analysis and mapping of this study. The Newtonians flow regime was found turbulent and to numerical solution was used the technique of finite volume designed by Patankar, by using commercial software CFX version 14.0 of Computational Fluid Dynamics. Was used both geometric and operational contour of a butterfly valve project to investigate in which part and conditions of a valve can occur potential wear and cavitations spots.

The thesis deals with the evaluation of the investment in the fast closing valve replacement in The dam Vranov using Computational fluid dynamics (CFD). The final effects of the fast closing valve replacement will be examined on three different types of valves with regard to the turbine output in operation zone and without the influence of water intake runner and turbine draft tube. The aim of the thesis is to theoretically evaluate alternatives of the fast closing valve replacement and define its basic characteristics and classifications.

The work deals with design solutions to the intake manifold modern contemporary internal combustion engines. Then describes the types of flow and structural design of ports, including the intake of their basic properties. The thesis also compare the results of the analysis and design optimization based on simulation of flow inlet port and measure the actual inlet port.

Proper aeration of cavitating hydraulic equipment can greatly reduce cavitation intensity, noise, and damage. This thesis quantifies the benefit, in terms of damage and noise, from aerating six inch butterfly valve. The incipient damage level of cavitation was obtained for both aerated and non -ae ra ted conditions. The level is defined as one pit per square inch of a soft aluminum test specimen per one minute of operation. A description of the cavitation pits that occurred plus where they appeared is presented. A graph showing the aerated and non-aerated limits of incipient damage is given along with a table showing the percent reduct ion of damage from aeration. A graph and table are also given depicting the reduction in noise. The proper location of aeration ports to allow natural aeration is outlined .

This master thesis deals with ignition systems which are used in cars vehicles with gas engines and also with setting of the best moment of ignition of gasoline-air mixture in cylinders of engine. Ways of gas injection at diesel engines and their control systems are also described in this thesis. Next chapter deals with control unit and describes main actions which are necessary for today’s motor vehicles. As illustration is used example of succession of actions which are necessary for calculation and setting regular value of pre-ignition. At the end is shown animation, which can be used for practice lessons in a subject Automobile Electric and Electronic Systems as a example. It will simplify understanding of described activities which are all accomplished by central control unit. For purposes of laboratory lessons is in this thesis also discussed measuring of engine performance with changes of parameter of central control unit.

This thesis is developed as a proposal for heating for a primary school and kindergarten in the region of Brno-countryside. For the insulated building, a combination of heating and air-conditioning is proposed. The concept is designed so that the air-conditioning preheats the exterior air and the heating system warms the incoming air to a comfortable temperature. For the required thermal performance, sources of heat (for gas and pellets) and a layout solution for the boiler room is designed. Drainage of combustion products is proposed for both solutions. The project solution is per the extent of the construction permit. The theoretical part is linked with the practical part through the condensation boilers, their function and division, and drainage of combustion products. The experiment for the given topic was conducted on the drainage of combustion products. The pressure loss of the reverse knob was determined in relation to the flow rate of air in the condensation boilers as this loss is essential in assessing the drainage of combustion products.

碩士
國立宜蘭大學
機械與機電工程學系碩士班
99
This research uses finite element method to do the appropriate analysis for the butterfly valve.The experiments are performed to obtain the test data for verification of the analytical results. The experiment and the analysis butterfly valve size is 101.6mm, graphite ring thickness is 2mm, 4mm and 5mm. Tests under the fixed torsion, using the hydraulic pressure, the air pressure pressurizes again in the rated range to the valve seat on, by the strain gauge which buries in advance gauges its strain capacity to use for to confirm the finite element analytical results. The results showed that the analytical strains are completely agreed with the experimental data for the 101.6mm butterfly valve subjected to the allowable pressure. When the graphite ring become thicker, the strain will be smaller.

碩士
國立宜蘭大學
機械與機電工程學系碩士班
101
The numerical method is used in the research to simulate the fluid field, fluid-structure interaction, and noise of eccentric butterfly valve. The fluid flow volume control tests are performed to verify the analytical results obtained from computational fluid dynamics (CFD). The opening of butterfly valve will start from 10% (9 degree) and increase 10% each analytical or experimental step till to 100% (90 degree). In each step, the flow coefficient (CV) can be calculated. The pressure, fluid vector and turbulence distribution will be observed from the post processing of CFD. In CFD analysis, K-Ɛ and Reynolds Stress Method (RSM) turbulent models are used and also judged to fit which opening. The pressure obtained from CFD will become the input loading on the structural analysis. In noise analysis, the fluid velocity distribution will become the source to study the noise (the sound level for ear will be from 750 Hz to 3000 Hz) produce from the butterfly valve. The results showed that the RSM turbulent model is suitable to the opening from 40% to 60% and K-Ɛ turbulent model is better in the opening of 70% to 100%. The test based on ANSI/ISA 75.02 Flow coefficient test will measure the CV values. The simulation results agree with that of experimental data except the singular point. The stress concentration obtained from the structural analysis is observed at the interface between the valve disc and axis. As though the stress do not reach the yielding point, there will have the opportunity to get the fatigue failure. The sound level of 44 dB is observed from the noise analysis with the opening of 80% to 100% with 750 Hz. The sound level between the inside tube and 1m outside of tube has a difference of around 22 dB.

碩士
國立臺灣大學
機械工程學研究所
90
Leakage has been a difficult problem to handle for butterfly valves in fire test. The environment of the fire test specification is a directly exposed to flame. The thermal stresses of valve, resulted from variation temperature gradients, is the major factor leading to leakage. The thermal stresses and the gaps generated on the valve are difficult to measure directly. The leakage obtained from experiments is found limited use and cannot provide any clues for improvement. The objectives of this research, therefore, set to analyse the possible causes of leakage in fire test and, accordingly, to find the basis of key design factors to improve fire seal. This research applies finite element analysis to obtain thermal stresses and deformations for the valve component, which are difficult to measure in fire test. Base on the result, causes of leakage are analysed. The analysis indicates that selections of the part material and seal mechanism are the keys to solve leakage problems of butterfly valve in fire test.

碩士
國立成功大學
水利及海洋工程學系專班
94
This thesis studied the characteristics of energy loss coefficient (kc) of butterfly valve in small degree of opening by experiment. The diameters of tested butterfly valves are 50 and 100 millimeters respectively. The static cubage test method was adopted in measuring discharge. 　　The results showed that the kc of 50 mm is much larger than 100 mm’s, especially in small degree opening. This revealed that kc varied with the structure, diameter and disc shape of a butterfly valve. In addition, kc decreased as opening degree increased. The kc would increase slightly only as the discharge decreased. 　　Other experimental results revealed that the kc decreased as Reynolds number increased, i.e., kc had negative correlation with Reynolds　number. The kc increased in accompanying with pressure coefficient increased. It meaned kc had positive correlation with pressure coefficient. The kc increased as the Froude number increased, i.e., kc had negative correlation with Froude number.

碩士
國立成功大學
機械工程學系
86
In a piping system, butterfly valves are often used as a flow controller to either modulate the flow throttling range or control the flow's on/off positions. Because butterfly valves are usually light-weighted and low cost, they have a wide range in size selection and possess a small flow resistance, therefore, they are widely accepted in many industrial applications. After a certain period of service, a butterfly valve and its downstream pipe wall may be damaged by erosion. The elimination or mitigation of this kind of erosion problem is actually the most important issue for a valve user. An experiment setup is used in this study to investigate the erosion problem. The water tunnel is 3 inches in diameter and the pipes are made by transparent PE for the ease of flow visualization and photograph purpose. At certain key positions, the pressure and flow vibration level are also measured to support the observation of possible erosion phenomena. The results indicate the most serious erosion problem may occur when the valve open angle is between 20-40 degrees. In this paper, five different valve disks are used to perform the tests, the results shows the model 5 have the smallest vibration level both on the valve stick and its downstream pipe wall under the critical valve opening angle. These results implies that a suitable buffer attached on the back side of disk surface near the orifice side could mitigate the erosion phenomena.

碩士
國立彰化師範大學
機電工程學系
100
In this study, computer-aided design (CAE) tool and finite element method (FEM) are applied to analyze performance of a double eccentric butterfly valve with metal seat. An experimental system was developed to measure the amount of valve leakage and the strain of the metal seat at various operation conditions with different pressures and temperatures where they can be drawn back to the design to improve the performance of the valve. Experimental results show that the higher pressure lead more leakage, and simultaneously the greater positive strain of the metal seat. The corresponding results to the analysis in FEM is that the strain of valve disc located in the back-end support rod is greater than that of the disc front contacted with the metal ring resulting in the dramatically decrease of the contact force which is the main factor of increasing the valve leakage. In situation of the high temperatures, the experimental results represent that the higher temperatures leads less valve leakage in case of the highest operation pressure, 300 psi. It indicates that the thermal deformation of the metal seat make the greater contact force with the disc to reduce valve leakage.

碩士
國立屏東大學
生態休閒教育教學碩士學位學程
108
This study is to realize and combine the teaching activities with the outdoor teaching places and what the influence for those elementary school students' learning is. It's analyzed about the difference between the learning achievement and experience value with the different background variables. It also analyzes both coherence and predictability. The objects of the study are the fourth graders in Tainan Tzu Chi Elementary private school, and they have a test on Google internet questionnaire. There are 118 students' questionnaires and the recovery percentage is 100%.The outdoor teaching place is in the Alexander Butterfly Farm in Rende in Tainan. 　　The study focuses on quantitative research, and assists with qualitative research. By using the SPSS statistics software and the result information of the questionnaires, and analyzing with descriptive statistics, independent sample t-test, independent sample one-way ANOVA, Pearson product-related correlation analysis, and multiple regression analysis, the result of significant level (α) is .05. Moreover, it gets the qualitative data from worksheet, personal sharing, and individual interview.Through the result of the study, there is some information as follows: First, there isn't any significant difference toward those students in outdoor teaching learning achievement about different insect interests, the number of the visit time and the feeling of the visit. Second, there isn't any significant difference toward those students in outdoor teaching experience value about different insect interests, the number of the visit time and the feeling of the visit. Third, there isn't any significant correlation about learning achievement and experience value toward those students in outdoor teaching. Fourth, there isn't any predictability about learning achievement and experience value toward those students in outdoor teaching. Fifth, through the qualitative data, students have positive attitude toward outdoor teaching by learning about the insect in the correlation places and assists the curriculums in class with deeply and widely learning. 　　According to the result of the study, it is suggested that education organizations could combine the students' curriculums with outdoor teaching activities in the future to make it have more vivid intension learning.