scholarly journals Numerical Investigation of Methodologies for Cavitation Suppression Inside Globe Valves

2020 ◽  
Vol 10 (16) ◽  
pp. 5541
Author(s):  
Jun-ye Li ◽  
Zhi-xin Gao ◽  
Hui Wu ◽  
Zhi-jiang Jin
Keyword(s):  
Cavitation Number ◽  
Common Phenomenon ◽  
Valve Seat ◽  
Valve Body ◽  
Working Temperature ◽  
Outlet Pressure ◽  
Cavitation Phenomenon ◽  
Installation Angle ◽  
Cavitation Intensity ◽  
Globe Valve

Cavitation inside globe valves, which is a common phenomenon if there is a high-pressure drop, is numerically investigated in this study. Firstly, the cavitation phenomenon in globe valves with a different number of cages is compared. When there is no valve cage, cavitation mainly appears at the valve seat, the bottom of the valve core, and the downstream pipelines. By installing a valve cage, cavitation bubbles can be restricted around the valve cage protecting the valve body from being damaged. Secondly, the effects of the outlet pressure, the working temperature, and the installation angle of two valve cages in a two-cage globe valve are studied to find out the best method to suppress cavitation, and cavitation number is utilized to evaluate cavitation intensity. Results show that cavitation intensity inside globe valves can be reduced by increasing the valve outlet pressure, decreasing the working temperature, or increasing the installation angle. Results suggest that increasing the outlet pressure is the most efficient way to suppress cavitation intensity in a globe valve, and the working temperature has a minimal effect on cavitation intensity.

New approach of suppressing cavitation in water hydraulic components

2016 ◽  
Vol 231 (21) ◽  
pp. 4022-4034 ◽  
Author(s):  
Zhang Zuti ◽  
Cao Shuping ◽  
Luo Xiaohui ◽  
Shi Weijie ◽  
Zhu Yuquan
Keyword(s):  
Pressure Distribution ◽  
Bubble Dynamics ◽  
Cloud Model ◽  
The Novel ◽  
Outlet Pressure ◽  
Cavitation Phenomenon ◽  
Throttle Valve ◽  
Novel Approach ◽  
Cavitation Intensity ◽  
Water Hydraulic

Cavitation frequently appears in high pressure water hydraulic components and leads to serious hydraulic erosions and horrible hydrodynamic noises. In this paper, a novel approach of suppressing cavitation was proposed, inducing the outlet pressure back to the orifice to improve the pressure distribution of throttle valves. In order to realize this approach, an optimized throttle valve chamber structure was designed. After that, the anticavitation performance of the valve was investigated. A theoretical cavitation cloud model was built based on bubble dynamics. In order to solve the mathematic cavitation model, the velocity field and pressure distribution of the novel throttle valve were simulated through Computational Fluid Dynamics(CFD). Combining the simulation results, the mathematic cavitation cloud model was solved through numerical calculations. Moreover, new indexes estimating cavitation intensity were proposed scientifically to investigate cavitation phenomenon. Then, the comparison of the novel throttle valve (with an innovative valve chamber) and traditional throttle valve in anticavitation performance was conducted under different conditions. Finally, the experiment about anticavitation performance was completed on the test rig. The calculation and experiment results indicated that the approach, inducing the outlet pressure back to the orifice, was effective in suppressing cavitation.

A Parametric Study of Hydrodynamic Cavitation Inside Globe Valves

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Zhi-jiang Jin ◽  
Zhi-xin Gao ◽  
Jin-yuan Qian ◽  
Zan Wu ◽  
Bengt Sunden
Keyword(s):  
Large Deviation ◽  
Fluid Velocity ◽  
Economic Loss ◽  
Hydrodynamic Cavitation ◽  
Geometrical Parameters ◽  
Piping System ◽  
Valve Body ◽  
Cavitation Intensity ◽  
Bending Radius ◽  
Globe Valve

Hydrodynamic cavitation that occurs inside valves not only increases the energy consumption burden of the whole piping system but also leads to severe damages to the valve body and the piping system with a large economic loss. In this paper, in order to reduce the hydrodynamic cavitation inside globe valves, effects of valve body geometrical parameters including bending radius, deviation distance, and arc curvature linked to in/export parts on hydrodynamic cavitation are investigated by using a cavitation model. To begin with, the numerical model is compared with similar works to check its accuracy. Then, the cavitation index and the total vapor volume are predicted. The results show that vapor primarily appears around the valve seat and connecting downstream pipes. The hydrodynamic cavitation does not occur under a small inlet velocity, a large bending radius, and a large deviation distance. Cavitation intensity decreases with the increase of the bending radius, the deviation distance, and the arc curvature linked to in/export parts. This indicates that valve geometrical parameters should be chosen as large as possible, while the maximal fluid velocity should be limited. This work is of significance for hydrodynamic cavitation or globe valve design.

Effects of Sleeve Parameters On Cavitation Control Performance in Steam Trap Valves

2021 ◽  
Author(s):  
Chang Qiu ◽  
Zhi-xin Gao ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian
Keyword(s):  
Power Systems ◽  
Optimization Design ◽  
Thermal Power ◽  
Orifice Diameter ◽  
Geometrical Parameters ◽  
Piping System ◽  
Cavitation Performance ◽  
Installation Angle ◽  
Steam Trap ◽  
Cavitation Intensity

Abstract The steam trap valve is used in thermal power systems to pour out condensate water and keep steam inside. While flowing through steam trap valves, the condensate water can easily reach cavitation, which may cause serious damage to the piping system. In this paper, in order to control cavitation inside steam trap valves, effects of sleeve parameters, including orifice diameter, installation angle and thickness, are investigated using a cavitation model. The pressure, velocity and vapor distribution inside valves are analyzed and compared for different sleeve geometrical parameters. The total vapor volumes are also predicted and compared. The results show that the sleeve parameters have a significant influence on the cavitation intensity and cavitation vapor distributions. Specifically, the orifice diameter of the sleeve has much larger effect on each aspect than that of other two geometrical parameters of the sleeve. The improved geometrical parameters of the sleeve are determined to suppress the cavitation inside the valve. The sleeve with smaller diameter orifices, higher installation angle (maximum 80°) and higher thickness is recommended in practice for better anti-cavitation performance. The work is of significance for cavitation control and the optimization design of steam trap valves.

Influence of the Wall Thickness on the Allowable and Failure Pressures of Two- and Tree-Way Globe Valve Bodies

2011 ◽  
Vol 488-489 ◽  
pp. 646-649
Author(s):  
Milan Opalić ◽  
Ivica Galić ◽  
Krešimir Vučković
Keyword(s):  
Internal Pressure ◽  
Wall Thickness ◽  
Design Method ◽  
Equivalent Plastic Strain ◽  
Strain Curve ◽  
Linear Motion ◽  
Valve Body ◽  
Failure Pressure ◽  
Critical Location ◽  
Globe Valve

A globe valve is a linear motion valve used to shut off and regulate fluid flow in pipelines. Depending on the number of process connections, they are produced as two‑ or three-way valves. The main valve component carrying the internal pressure is the valve body. For safe exploitation, the valves are designed with the allowable internal pressure taken into consideration. The aim of this paper is to investigate the influence of the wall thickness on the allowable and failure pressures of two- and tree-way globe valve bodies, DN50 and DN100 respectively. Twice-elastic-slope (TES) and the tangent‑intersection (TI) methods are used to obtain the plastic collapse pressures at the critical location which was determined (Fig. 1a and 1b) at the location where maximum equivalent plastic strain throughout the valve body thickness reaches the outer surface. Obtained values are used afterwards to calculate corresponding allowable pressures according to the limit design method, while the failure pressure at the same location was determined as the highest point from the load-maximal principal strain curve. Calculated allowable pressure values, for both valve bodies, are compared with the corresponding ones obtained using the EN standard.

Cavitation Intensity Measurement by Analysis of Pump Structure Oscillation: A New Parametric Method Approach

2008 ◽  
Author(s):  
Hadi Arjmandi Tash ◽  
Morteza Sadeghi ◽  
Mohammad T. Shervani Tabar ◽  
M. Mohammad Ettefagh
Keyword(s):  
Parametric Method ◽  
Axial Flow ◽  
Average Energy ◽  
Operating Conditions ◽  
Detection Methods ◽  
Computational Time ◽  
Hardware Complexity ◽  
Cavitation Phenomenon ◽  
Cavitation Intensity ◽  
Axial Flow Pump

One of the sources of instability in pumps is cavitation phenomenon. Cavitation in a pump can cause some undesirable effects, such as deterioration of the hydraulic performance (drop in head-capacity and efficiency curves), damage of the pump by pitting and erosion, structure vibration and resulting noise. Cavitation can appear within the entire range of operating conditions; therefore its occurrence inside a pump and its intensity must, by all means, be identified. In the present study, alternations in the velocity of an axial flow pump structure, for the first time used to investigate Cavitation. An average energy method for identification cavitation occurrence and measurement its intensity has been developed. This is called the Logarithmic Cavitation Intensity (LCI). To establish the pump cavitation conditions, a statistical analysis has been undertaken in a real-time and an LCI has been recommended as a proper criterion for defining the cavitation intensity. The results also showed the proposed method besides some other advantages comparing other detection methods, is feasible by simple hardware with low sampling frequency resulting in reducing the computational time as well as hardware complexity and cost.

scholarly journals Appearance of high submerged cavitating jet: The cavitation phenomenon and sono luminescence

2013 ◽  
Vol 17 (4) ◽  
pp. 1151-1161 ◽  
Author(s):  
Ezddin Hutli ◽  
Omer Alteash ◽  
Raghisa Ben ◽  
Milos Nedeljkovic ◽  
Vojislav Ilic
Keyword(s):  
Working Conditions ◽  
Injection Pressure ◽  
Cavitation Number ◽  
Effect Of Temperature ◽  
Cloud Cavitation ◽  
Cavitation Phenomenon ◽  
Jet Trajectory ◽  
Influencing Parameters ◽  
Jet Structure ◽  
Cavitating Jet

In order to study jet structure and behaviour of cloud cavitation within time and space, visualization of highly submerged cavitating water jet has been done using Stanford Optics 4 Quick 05 equipment, through endoscopes and other lenses with Drello3244 and Strobex Flash Chadwick as flashlight stroboscope. This included obligatory synchronization with several types of techniques and lenses. Images of the flow regime have been taken, allowing calculation of the non-dimensional cavitation cloud length under working conditions. Consequently a certain correlation has been proposed. The influencing parameters, such as; injection pressure, downstream pressure and cavitation number were experimentally proved to be very significant. The recordings of sono-luminescence phenomenon proved the collapsing of bubbles everywhere along the jet trajectory. In addition, the effect of temperature on sono-luminescence recordings was also a point of investigation.

scholarly journals Numerical Simulation Analysis of Cavitation Performance of Tandem Propeller

2018 ◽  
Vol 36 (3) ◽  
pp. 509-515 ◽  
Author(s):  
Xiaoxu Du ◽  
Zhengdong Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Cavitation Number ◽  
Hydrodynamic Characteristics ◽  
Turbulent Model ◽  
Cavitation Model ◽  
Cavitation Phenomenon ◽  
Cavitation Performance ◽  
Simulation Results ◽  
Good Agreement

The steady non cavitation hydrodynamic characteristics of CLB4-55-1 tandem propeller and the steady cavitation flows of NACA66 hydrofoil are numerically studied firstly based on the RANS equations of homogeneous multiphase using CFD theory, combined with the SST k-ω turbulent model and Z-G-B cavitation model. Numerical simulation results are in good agreement with the experimental results, which indicates that the numerical method is reliable and accurate. Then, the cavitation performance of the tandem propeller are numerical simulated and analyzed. The results show that the computational model can predict the cavitation performance of tandem propeller accurately. The cavitation performance of tandem propeller is nearly the same as single propeller, however, the cavitation phenomenon of back propeller is greater than the head propeller at certain advance coefficient and cavitation number. The cavitation phenomenon will disappear with the increase of the advance coefficient or the cavitation number.

Cavitation intensity monitoring in an axial flow pump based on vibration signals using multi-class support vector machine

2017 ◽  
Vol 232 (17) ◽  
pp. 3013-3026 ◽  
Author(s):  
Mohammad Taghi Shervani-Tabar ◽  
Mir Mohammad Ettefagh ◽  
Saeed Lotfan ◽  
Hamed Safarzadeh
Keyword(s):  
Support Vector Machine ◽  
Axial Flow ◽  
Support Vector ◽  
Cavitation Noise ◽  
Vibration Signals ◽  
Cavitation Phenomenon ◽  
Statistical Behavior ◽  
Cavitation Intensity ◽  
Axial Flow Pump ◽  
Flow Pump

The cavitation phenomenon, which is rampant in axial flow pumps, should be avoided due to its undesirable effects on the pump’s performance. Therefore, in this study the cavitation performance of an axial flow pump is monitored based on vibration signals. For this purpose, experimental vibration data is collected for five different levels of cavitation. Time-domain features are extracted based on statistical behavior of the measured signals. Considering the nonlinear and high-frequency nature of the cavitation noise in the signal, the second set of features including both time- and frequency-domain parameters are obtained based on statistical behavior of the first intrinsic mode function, via empirical mode decomposition combined with Hilbert Huang transform. Compensation distance evaluation technique is applied to pick the appropriate features. Multi-class support vector machine is trained for classification of the various levels of cavitation intensity. The results of testing the support vector machine algorithm show that the developed methodology can monitor the pump’s cavitation intensity in onsite operation with high accuracy.

scholarly journals Simulation Of The Process Of Cavitation Treatment Of Liquid Feed

2021 ◽  
Vol 24 (2) ◽  
pp. 16-26
Author(s):  
Elchyn Aliiev ◽  
Roman Maliehin ◽  
Vitalii Ivliev ◽  
Olha Aliieva
Keyword(s):  
Liquid Phase ◽  
Rational Design ◽  
Film Flow ◽  
Cavitation Number ◽  
Raw Material ◽  
Movement Speed ◽  
Technological Parameters ◽  
Cavitation Phenomenon ◽  
Liquid Feed ◽  
Operation Process

The same fractional composition and uniformity of distribution of raw material components of plant origin in the mixture are the main criteria for the liquid feed quality. This is ensured by the homogenisation and dispersion of feed components using cavitation treatment. The purpose of the study is to simulate the process of cavitation treatment of liquid feed with a rotary cavitation disperser-homogeniser and substantiate its rational design and technological parameters. The task is to create such a rotary cavitation disperser-homogeniser, which allows simultaneously performing technological processes of dispersion, emulsification, and homogenisation of mixture components in a liquid medium with higher productivity, quality, and lower energy consumption. As a result of modelling the action of a rotary cavitation disperser-homogeniser in the Star CCM+ software, the distributions and dynamics of velocities of the liquid phase of the mixture and the pressure and concentration of the gaseous phase of liquid in the diffuser are established, which indicates the presence of cavitation. This confirms the operability of the developed design and technological facilities for the preparation of liquid feed and indicates the expediency of further research to substantiate its technological parameters. As a result of numerical modelling of the operation process of a rotary cavitation disperser-homogeniser, the dependences of the maximum (max) and minimum (min) movement speed of the liquid phase of the mixture in the inlet Vin and in the diffuser Vrot on the rotor speed n, inlet diameter Din and the number of resonators Nhole are determined. The qualitative criterion for evaluating the cavitation phenomenon in the developed equipment is the maximum and minimum cavitation number Xmax and Xmin, which depends on the rotation speed of the rotor n, the inlet diameter Din and the number of resonators Nhole. The value of the cavitation number Xmin=0.08 and Xmax=0.57 is achieved at n=2725 rpm, Din=0.049 m, Nhole=48, which corresponds to a film flow of liquid with a stable separation of the cavitation cavity from the rest of the continuous flow (film cavitation)

HHC (Hitachi Hyper Valve): Corrosion Resistant, Withstands Erosion and Low CO Release

2004 ◽  
Author(s):  
Yoshihisa Kiyotoki ◽  
Mutuo Chigasaki
Keyword(s):  
Corrosion Resistance ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Base Alloy ◽  
Chemical Compositions ◽  
Valve Seat ◽  
Valve Body ◽  
Valve Disc ◽  
Metal Microstructure

In order to prevent valve performance deterioration by corrosion and wear against the seat (following, the valve-seat) of the valve-disc and the valve-body at fossil and nuclear power plants, a Co-base alloy is hard-faced onto the valve-seat. However, valve-seats deteriorate, for example, by corrosion, cracking and erosion. Moreover, the drift of the set point of the safety valves also occurs, by the phenomenon of Corrosion-Bonding. A valve-seat with excellent corrosion resistance, erosion toughness and mechanical toughness is sought. And, if possible, a low Co release rate material is preferred in nuclear power plants. Therefore, to improve valve performance, we manufactured a new valve named HHV with a valve seat, whose metal microstructure is different from that of conventional valve seats, within the range of chemical compositions of RCoCr-A (AWS). We also, evaluated the performance of the HHV Valve. We verified that HHV has improved valve performance. Moreover, we applied HHV under actual operating power plant conditions. The results show that HHV is superior to conventional valves in corrosion resistance, etc.

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