The Parametric Modeling of Local Resistance and Pressure Drop in a Rotary Ball Valve

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Dan Wang ◽  
Changqing Bai
Keyword(s):  
Pressure Drop ◽  
Flow Resistance ◽  
Analytical Formula ◽  
Resistance Coefficient ◽  
Parametric Modeling ◽  
Equivalent Model ◽  
Local Resistance ◽  
Operating Process ◽  
Valve Opening ◽  
Good Agreement

In this paper, a theoretical study of ball valves is carried out for investigating the local resistance and pressure drop of ball valves in operating process. An equivalent model of ball valves is proposed based on the inherent mechanism of the resistance loss, which can be divided into three equivalent throttling components: a thick orifice, two variable-opening eccentric orifice plates, and a Z type elbow. Through analysis of the flow resistance of the three components, a general parametric modeling of ball valves is presented for the flow resistance analysis, and then an analytical formula of pressure drop is demonstrated. The results obtained from the presented model are compared with the prior test data to validate this model, and good agreement is observed. Indicate that the presented model has high accuracy in predicting the resistance and pressure loss in various openings. The results show that the influences of thin orifice plates play an important role in the total flow resistance coefficient and pressure drop, especially in the small opening. The effects of thick orifice plates and the Z type elbow gradually increased as the valve opening rises and becomes significant when the opening is more than 70%.

Study on Resistance Characteristics of Trilobal Throttling Element in Narrow Annular Channel

2017 ◽  
Author(s):  
Wu Youguang ◽  
Li Weihua ◽  
Jia Haijun
Keyword(s):  
Experimental Data ◽  
Turbulence Model ◽  
Annular Channel ◽  
Resistance Coefficient ◽  
Local Resistance ◽  
Function Change ◽  
Local Resistance Coefficient ◽  
Fluent Software ◽  
The Relationship ◽  
Good Agreement

An experimental study was performed to investigate the resistance characteristics of the trilobal throttling element in narrow annular channel, while corresponding flow fields analyzed using Fluent software with RNG k-ε turbulence model based on the structural grid for the trilobal throttling element with different placket angle. A relationship between the packet angle θ and the local resistance coefficient ξ is obtained. Results show that the local resistance coefficient obtained by numerical simulation of the trilobal throttling element in narrow annular channel have a good agreement with the experimental data, and their relative error is less than 8%. This also fully proves that the RNG k-ε turbulence model is suitable for the simulation of the trilobal throttling element in the narrow annular channel. The local resistance coefficient of the trilobal throttling element in narrow annular channel increases with rising packet angle θ, and the relationship is similar to the power function change.

Numerical Study of Large Diameter Butterfly Valve on Flow Characteristics

2011 ◽  
Vol 236-238 ◽  
pp. 1653-1657 ◽  
Author(s):  
Xiao Dong Wang ◽  
Jing Liang Dong ◽  
Tian Wang
Keyword(s):  
Pressure Drop ◽  
Flow Resistance ◽  
Numerical Study ◽  
Large Diameter ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Numerical Approach ◽  
Resistance Coefficient ◽  
Butterfly Valve ◽  
Dimensional Simulation

A numerical approach was used to investigate the flow characteristics around a butterfly valve with the diameter of 2108 mm by the commercial computational fluid dynamics (CFD) code FLUENT6.3. The simulation was carried out to predict flow field structure, flow resistance coefficient, hydrodynamics torque and so on, when the large diameter butterfly valve operated at various opening degrees. The three-dimensional simulation results shown that there are vortexes presented near valve back region as the opening degree smaller than 40 degree; the flow resistance coefficient reduces rapidly with the increasing of opening degree and the resistance coefficient is quite small as the angle larger than 50 degree; the hydrodynamic torque reduces with the increasing of opening degree and the hydrodynamic torque is smaller than 20% of maximum torque; the torque ratio and the pressure drop ratio are reduce with the increasing of opening degree, the pressure drop ratio reduces rapidly as the opening degree is smaller than 50 degree.

scholarly journals DEM--CFD modeling and simulations of hydrodynamic characteristics and flow resistance coefficient in fixed-bed reactors

2021 ◽  
Author(s):  
Yaping Li ◽  
Le Xie ◽  
Yonghua Zhou ◽  
Chongwen Jiang ◽  
Hong Zhong
Keyword(s):  
Pressure Drop ◽  
Flow Resistance ◽  
Fixed Bed ◽  
Resistance Coefficient ◽  
Spherical Particles ◽  
Hydrodynamic Characteristics ◽  
Model Parameters ◽  
Large Set ◽  
Fixed Bed Reactors ◽  
Fixed Beds

The ability to predict void fraction, pressure drop, and flow resistance coefficient in fixed-bed reactors is significant to their optimal design. In this study, the discrete element method (DEM) is combined with computational fluid dynamics (CFD) to simulate the hydrodynamic characteristics of fixed-beds. A realistic random packing structure for fixed-beds with spherical particles was generated via the DEM method and then meshed using Ansys ICEM software for the CFD simulation. A grid independency study was performed to select appropriate grid model parameters. A large set of numerical experiments was conducted to investigate the hydrodynamic characteristics with respect to different inlet velocities and particle sizes, and the simulated pressure drop data were used to calculate the flow resistance coefficient. The output flow resistance coefficients agreed well with those calculated by the classical models in laminar and turbulent flow regimes, thereby indicating the accuracy and advantage of the proposed DEM–CFD approach.

scholarly journals Comparative analysis of regulating characteristics between air-ring flow regulating valve and center butterfly valve

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251943
Author(s):  
Shixian Wu ◽  
Heqing Liu ◽  
Yongping Chen
Keyword(s):  
Flow Resistance ◽  
Flow Characteristics ◽  
Maximum Velocity ◽  
Experimental System ◽  
Resistance Coefficient ◽  
Flow Coefficient ◽  
Pipeline System ◽  
Butterfly Valve ◽  
Abrasive Erosion ◽  
Valve Opening

In this study, a novel air-ring flow regulating valve was proposed to reduce the flow resistance caused by valve structural pressure drop in fluid transportation pipeline system. The regulating characteristics at different valve openings were analyzed by numerical method and the results were compared with the center butterfly valve which is most widely applied in fluid transportation pipeline system. Besides, an experimental system was designed to validate the numerical model in the present study. The results indicated that the simulation results agree well with experimental data. The resistance coefficient of the air-ring flow regulating valve is smaller than that of the center butterfly valve when the valve opening is greater than 67%, and the resistance coefficient is reduced by up to 100% as the valve is fully opened. Both valves maintain approximately equal percentage flow characteristics, the deviation in relative flow coefficient is small. In addition, the wall shear stress of the air-ring flow regulating valve is much smaller than that of the center butterfly valve at the same valve opening, and the maximum velocity in the pipeline system is always smaller than that of the center butterfly valve, which significantly reduces valve surface abrasive erosion and thus prolongs its service life.

scholarly journals Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Skeletal Structure

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3355
Author(s):  
Grzegorz Wałowski
Keyword(s):  
Pressure Drop ◽  
Porous Material ◽  
Total Pressure ◽  
Flow Resistance ◽  
Gas Flow ◽  
Gas Permeability ◽  
Resistance Coefficient ◽  
Skeletal Structure ◽  
Porous Bed ◽  
Total Pressure Drop

The hydrodynamic conditions resulting from the permeability of porous materials are based not only on the assessment of the gas flow through these materials, but also the losses related to the pressure energy in this flow. Flow resistance is a direct measure of this loss. The aim of this experimental research was to evaluate the flow resistance of the porous material in relation to the gas flow. The research was carried out on a material with a slit-porous structure. The tests were carried out on a system for measuring gas permeability under the conditions of gas bubbling through the char. The issue of the total pressure drop process in the porous bed was considered in the Reynolds number category. The coefficient of flow resistance for the char was determined and the value of this coefficient was compared with the gas stream, and an experimental evaluation of the total pressure drop on the porous bed was made. The novelty of this article is the determination of the tortuosity and the gas permeability coefficient for a solid of any shape—a rigid skeleton.

The effect of two-phase flow regime on hydrodynamics and mass transfer in a horizontal-tube gas-liquid reactor

1985 ◽  
Vol 50 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Andreas Zahn ◽  
Lothar Ebner ◽  
Kurt Winkler ◽  
Jan Kratochvíl ◽  
Jindřich Zahradník
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Flow Regime ◽  
Liquid Flow ◽  
Horizontal Tube ◽  
Liquid Holdup ◽  
Two Phase ◽  
Flow Rates ◽  
Type Relation ◽  
Good Agreement

The effect of two-phase flow regime on decisive hydrodynamic and mass transfer characteristics of horizontal-tube gas-liquid reactors (pressure drop, liquid holdup, kLaL) was determined in a cocurrent-flow experimental unit of the length 4.15 m and diameter 0.05 m with air-water system. An adjustable-height weir was installed in the separation chamber at the reactor outlet to simulate the effect of internal baffles on reactor hydrodynamics. Flow regime maps were developed in the whole range of experimental gas and liquid flow rates both for the weirless arrangement and for the weir height 0.05 m, the former being in good agreement with flow-pattern boundaries presented by Mandhane. In the whole range of experi-mental conditions pressure drop data could be well correlated as a function of gas and liquid flow rates by an empirical exponential-type relation with specific sets of coefficients obtained for individual flow regimes from experimental data. Good agreement was observed between values of pressure drop obtained for weirless arrangement and data calculated from the Lockhart-Martinelli correlation while the contribution of weir to the overall pressure drop was well described by a relation proposed for the pressure loss in closed-end tubes. In the region of negligible weir influence values of liquid holdup were again succesfully correlated by the Lockhart-Martinelli relation while the dependence of liquid holdup data on gas and liquid flow rates obtained under conditions of significant weir effect (i.e. at low flow rates of both phases) could be well described by an empirical exponential-type relation. Results of preliminary kLaL measurements confirmed the decisive effect of the rate of energy dissipation on the intensity of interfacial mass transfer in gas-liquid dispersions.

The Calculation Method and Experimental Research on Throttling Pressure Drop during Kill a Well

2012 ◽  
Vol 229-231 ◽  
pp. 495-498
Author(s):  
Hui Xin Liu ◽  
Xian Min Yang ◽  
Cheng Tao Li ◽  
Xiang Cheng
Keyword(s):  
Pressure Drop ◽  
Calculation Method ◽  
Engineering Practice ◽  
Exploration Process ◽  
Throttle Valve ◽  
Long Time ◽  
Valve Opening ◽  
Casing Pressure ◽  
The Relationship ◽  
Control Accuracy

There is a common problem during kill a well, which is how to quickly and accurately control the surface casing pressure according to the requirements for killing a well. A step-by-step exploration process is employed on operation sites. Continuously adjusting throttle valve to acquire surface casing pressure may lead to failure of kill operation because of its long time and low control accuracy. Obviously, if the calculation problems of throttling drawdown can be resolved,the relationship between drawdown and throttle valve opening can be found and the course of explorating can be converted into a straight course.Then the success rate of killing well can be improved. More importantly, this can make automatic controll of surface casing pressure possible. The paper built the calculation method of throttling pressure drop by theoretical analysis and verified the calculation method by adopting it into field test. The result has showed that the calculation method of throttling pressure drop coincides with experimental results and it can be used in engineering practice.

The Productivity of Horizontal Wells in an In-Line Development System in Fields with Oil Rims

2021 ◽  
Author(s):  
Dmitriy Alekseevich Samolovov ◽  
Artem Igorevich Varavva ◽  
Vitalij Olegovich Polyakov ◽  
Ekaterina Evgenevna Sandalova
Keyword(s):  
Numerical Experiments ◽  
Single Phase ◽  
Analytical Formula ◽  
Horizontal Wells ◽  
Flow Equation ◽  
Development Pattern ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Limited Applicability ◽  
Good Agreement

Abstract The study proposes an analytical method for calculating the productivity of horizontal wells in a line-drive development pattern in fields with oil rims. The paper presents an analysis of existing techniques and compares them with the results of detailed numerical experiments. It also shows the limited applicability of existing techniques. On the basis of the obtained solution of a single-phase flow equation for a line-drive pattern of horizontal wells, an analytical formula was obtained which more accurately describes the productivity of wells beyond the limits of applicability of existing methods. The resulting formula is in good agreement with the results of a detailed numerical experiment.

Torque Characteristics of a 122-Centimeter Butterfly Valve With a Hydro/Pneumatic Actuator

1981 ◽  
Vol 103 (3) ◽  
pp. 396-404 ◽  
Author(s):  
F. N. Lin ◽  
W. I. Moore ◽  
F. E. Lundy
Keyword(s):  
Hydraulic Resistance ◽  
Flow Resistance ◽  
Field Testing ◽  
Hydraulic Cylinder ◽  
The Other ◽  
Pneumatic Actuator ◽  
Butterfly Valve ◽  
Hydraulic Flow ◽  
Resistance Torque ◽  
Valve Opening

Actuating torque data from field testing of a 122-centimeter (48 in.) butterfly valve with a hydro/pneumatic actuator is presented. The hydraulic cylinder functions as either a forward or a reverse brake. Its resistance torque increases when the valve speeds up and decreases when the valve slows down. A reduction of flow resistance in the hydraulic flow path from one end of the hydraulic cylinder to the other will effectively reduce the hydraulic resistance torque and hence increase the actuating torque. The sum of hydrodynamic and friction torques (combined resistance torque) of a butterfly valve is a function of valve opening time. An increase in the pneumatic actuating pressure will result in a decrease in both the combined resistance torque and the actuator opening torque; however, it does shorten the valve opening time. As the pneumatic pressure increases, the valve opening time for a given configuration approaches an asymptotical value.

Numerical Analysis of Gas Turbine Inlet Fogging Nozzle Manifold Pressure Drop

2014 ◽  
Author(s):  
Hai Zhang ◽  
Qun Zheng ◽  
Mustapha Chaker ◽  
Cyrus Meher-Homji
Keyword(s):  
Pressure Drop ◽  
Gas Turbine ◽  
Flow Resistance ◽  
Research Effort ◽  
Water Injection ◽  
Injection Velocity ◽  
Injection Angle ◽  
Turbine Inlet ◽  
Area Of Concern ◽  
Inlet Duct

The air pressure drop over the nozzles manifolds of inlet fogging system and the flow resistance downstream of the nozzle array (manifold) have always been an area of concern and is the object of this paper. Fogging nozzles arrays (involving several hundred nozzles) are mounted on channels and beams, downstream of the inlet filters and affect the pressure drop. The water injection angle, nozzle injection velocities and the progressive evaporation of the water droplets evaporation all influence the inlet pressure seen at the gas turbine inlet. This paper focuses on a numerical simulation investigation of flow resistance (pressure drop) of inlet fogging systems. In this research effort, the inlet duct is meshed in order to compute the pressure drop over the nozzles frames in fogging and non-fogging conditions. First, the resistance coefficients of an air intake filter are obtained by numerical and experimental methods, and then the coefficients are used for the simulation of the inlet duct by considering the filter as a porous media. Effects of nozzle spread pattern and water injection pattern are then modeled. The results indicate that injection velocity and arrangement of nozzles could have significant effects on the pressure drop and intake distortion, which will affect compressor performance. This paper provides a comprehensive analysis of the pressure drop and evaporation of inlet fogging and will be of value to gas turbine inlet fogging system designers and users.

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