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.

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.

Numerical Analysis of Contraction Geometry Effects on Cavitation Choking in a Piping System

2019 ◽  
Author(s):  
Motohiko Nohmi ◽  
Shusaku Kagawa ◽  
Tomoki Tsuneda ◽  
Wakana Tsuru ◽  
Kazuhiko Yokota
Keyword(s):  
Static Pressure ◽  
Sudden Expansion ◽  
Piping System ◽  
Valve Body ◽  
Line System ◽  
Pipe System ◽  
Flow Fluctuation ◽  
Supply Pipe ◽  
Static Pressure Difference ◽  
Pipe Line

Abstract There is a contraction portion in the water supply pipe line system, and cavitation may occur in the contraction when the flow velocity is increased. Such a situation occurs widely in the throat of the fluid machineries and in the vicinity of the valve body of the valve. In operation of the valve, it is well known that a phenomenon occurs in which the flow rate does not increase even if the static pressure difference upstream and downstream of the valve is increased due to the growth of cavitation in the contraction, which is well known as choking . It is not clear what phenomena occurs when cavitation surge occurs in the pipe system in the situation where choking is occurring in the contraction. In this study, cavitation CFD was performed on pipes those have three different geometry contractions. It was revealed that choking occurred when cavitation occurred in any shape. Also, in the case with the sharp contraction part and the sudden expansion, the flow fluctuation at the upstream of the contraction is much weaker than that at the downstream, but in the contraction with the bent part where the centrifugal force acts on the flow, the flow fluctuation at the upstream was found to be strong.

Bolt Strength in Sectional Body Construction of Valves

2019 ◽  
Author(s):  
Bhaskar Shitolé
Keyword(s):  
Rigid Bodies ◽  
Bolted Joints ◽  
Terminal Point ◽  
Piping System ◽  
Valve Body ◽  
Section Modulus ◽  
Creep Characteristics ◽  
Body Construction ◽  
Minimum Requirements ◽  
Body Joints

Abstract ASME B16.34-2017 Section 6.4.2 provides requirements for valves with bolted body joints and threaded body joints. The section states that valves with bodies of sectional construction such that bolted or threaded body joints are subject to piping mechanical loads in addition to the pressure rating for which the valve is designed, shall satisfy the following requirements. For bolted joints, the requirement is a simple formula where the product of pressure rating class designation and ratio of area bounded by the effective outside periphery of a gasket or O-ring or other seal-effective periphery and total effective bolt tensile stress area are less than a certain constant. For bolts of strength less than 137.9 MPa, the value of constant reduces as a multiple of 50.76 times the bolt tensile strength in MPa required or provided in a sectional construction. Section 6.4.3 cautions that the minimum requirements of ASME B16.34 may fall short in scenarios due to valve design, special gaskets, high temperature service, creep characteristics etc. This paper reviews and studies this ASME B16.34 requirement which was triggered by failure of a valve with section body construction in the field. Traditionally valves have been considered as rigid bodies when analyzing a piping system for stresses, support loads, terminal point loads and deflections. The rigid modelling assumes the strength of the valve is much higher than an equivalent straight length of pipe. Some computer programs have a provision that permits modeling the valve as a multiple like 3- or 4-times pipe section modulus. This paper compares the strength of piping and valves based on inherent valve body thickness, body sectional bolting provided and strength of the equivalent piping flanges. The paper makes conclusions for the user to be aware of so that pre-emptive actions can be taken when using valves with sectional body construction.

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.

CFD Simulations and Experiments of Flow Fluctuations Around a Steam Control Valve

2006 ◽  
Vol 129 (1) ◽  
pp. 48-54 ◽  
Author(s):  
Ryo Morita ◽  
Fumio Inada ◽  
Michitsugu Mori ◽  
Kenichi Tezuka ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Three Dimensional ◽  
Control Valve ◽  
Piping System ◽  
Cfd Simulations ◽  
Valve Body ◽  
Side Load ◽  
Flow Fluctuations ◽  
Partial Opening ◽  
Attached Flow ◽  
High Pressure Region

Under certain opening conditions (partial opening) of a steam control valve, the piping system in a power plant occasionally experiences large vibrations. To understand the valve instability that is responsible for such vibrations, detailed experiments and CFD calculations were performed. As a result of these investigations, it was found that under the middle-opening (partial opening) condition, a complex three-dimensional (3D) flow structure (valve-attached flow) sets up in the valve region leading to a high pressure region on a part of the valve body. As this region rotates circumferentially, it causes a cyclic asymmetric side load on the valve body, which is considered to be the cause of the vibrations.

Experimental Study on Large Turbine HP-Valve’s Excitation Fault Caused by Steam’s Unsteady Flow and its Economic Solution

2014 ◽  
Vol 536-537 ◽  
pp. 1501-1509 ◽  
Author(s):  
Jie Wan ◽  
Jun Sheng Gu ◽  
Guo Rui Ren ◽  
Qian Guo ◽  
Zhi Hua Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Thermal Power ◽  
Economic Loss ◽  
Random Fluctuation ◽  
Variable Load ◽  
Steam Turbines ◽  
Operation Condition ◽  
Valve Body ◽  
Power Generating Unit ◽  
Unit Depth

In order to stabilize the uncertainty of large-scale new energy power’s random fluctuation in the grid, there is an increasing number of large thermal power generating unit needing to do deep variable load operation. However, the pattern of steam inlet on turbine’s part load has a very significant impact on the unit operation condition of safety, stability and economy. In this paper the HP-valve’s body vibration fault of large steam turbines caused by unsteady steam flow under partial arc admission operating at part of their full load is researched, and an economic solution based on analysis and diagnosis of fault mechanism is provided by designing of complex HP-valve opening sequence rules. This solution solves the safety problem of valve vibration and avoids the economic loss by using full arc admission or replacing the valve body equipment directly, which is of great effective and practical verified by units’s actual operating experiment. As a result, it demonstrates that the optimization of HP-valve iadmission mode can not only change the stress state of high pressure rotor and prevent its vibration caused by the force of unbalanced flow to improve the shafting stability of the unit when running with variable load, but also can improve the steam instability and solve the resulting vibration problem in HP-valve. And it is of great engineering practical value to improve high-power thermal power unit depth secure efficient load operation.

scholarly journals ANALISA PRESSURE DROP DENGAN PENAMBAHAN ZAT ADITIF CAIRAN COOLANT PADA PIPA SILINDER MENGGUNAKAN METODE EMPIRIS DAN METODE EKSPERIMEN

2018 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Irwan Setiawan ◽  
Nurrohman . ◽  
Hablinur Al Kindi
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Fluid Velocity ◽  
Flow Characteristics ◽  
Data Retrieval ◽  
Piping System ◽  
Problem Analysis ◽  
Calibration Data ◽  
Literature Study ◽  
Pipe Length

The flow of fluid through the pipe creates fluid friction with pipe walls causing pressure drop and fluid flow velocity affecting the use of energy to drain it. Pressure drop can be affected by several factors such as friction or friction factor, pipe length, pipe diameter and fluid velocity. In this research, it will analyze pressure drop on piping system based on friction, fluid flow characteristics, and fluid velocity. The analysis was done by using two methods, namely experimental method and empirical calculation method. The stages of this study consist of problem analysis, literature study, calibration, data retrieval, empirical data processing and experiments, validation, analysis of results and conclusions. Based on the results of empirical and experimental research, the lowest pressure drop in the experiment and empirical was the 12 LPM discharge copper pipe and the water coolant ratio is 0: 100. This means that the best material pipes used were copper pipes rather than steel and galvanized pipes. The results of the tests and experiments have been tested for validation. The validation value of empirical and experimental data measurement is 91%.

Experimental study of cavitation intensity using a novel hydrodynamic cavitation reactor

2019 ◽  
Vol 33 (9) ◽  
pp. 4303-4310 ◽  
Author(s):  
Hyunsoo Kim ◽  
Bonchan Koo ◽  
Seungho Lee ◽  
Joon Yong Yoon
Keyword(s):  
Experimental Study ◽  
Hydrodynamic Cavitation ◽  
Cavitation Intensity
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