Modelling incompressible flow in a pressure relief valve

1997 ◽  
Vol 211 (2) ◽  
pp. 83-93 ◽  
Author(s):  
J Francis ◽  
P L Betts
Keyword(s):  
Incompressible Flow ◽  
Flow Characteristic ◽  
Axisymmetric Flow ◽  
Separated Flow ◽  
Flow Patterns ◽  
Shear Layers ◽  
Relief Valve ◽  
Pressure Relief ◽  
Valve Disc ◽  
Pressure Relief Valves

Lift, blowdown and discharge of pressure relief valves depend ultimately on the flow structures generated within those valves. A report is made of an enquiry into the incompressible flow structure within such a valve. Commercial software is used to predict axisymmetric flow patterns inside a model of a real valve, and comparisons are made with the pressure distribution and force imposed on the real valve disc. The reliability of the simulation is further assessed using the oil-film technique to record reattachment lengths of separated shear layers. Results of the simulation are encouraging and have enabled flow regimes visible in the valve flow characteristic to be identified with the transition between separated flow patterns inside the valve.

Pressures beneath the disc of a compensated pressure relief valve for gas/vapour service

1997 ◽  
Vol 211 (4) ◽  
pp. 285-289 ◽  
Author(s):  
P L Betts ◽  
J Francis
Keyword(s):  
Shock Wave ◽  
Pressure Distribution ◽  
Compressible Flow ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Valve Disc

In this work, the pressure distribution was measured on the underside of a commercial valve disc ( in situ) when the relief valve was subject to choked compressible flow. The results indicate the limits of three-dimensional effects on the substantially axisymmetric flow. The results also show the position of the minimum section (throat) and shock wave; their behaviour with changing lift is seen to match that inferred from previous work.

Dynamic Behavior of Transportation Pressure Relief Valves Under Simulated Fire Impingement Conditions

1999 ◽  
Vol 122 (1) ◽  
pp. 60-65 ◽  
Author(s):  
A. J. Pierorazio ◽  
A. M. Birk
Keyword(s):  
Dynamic Testing ◽  
Test Facility ◽  
Time Varying ◽  
Relief Valve ◽  
Pressure Relief ◽  
Flow Rates ◽  
Depth Analysis ◽  
Pressure Relief Valves ◽  
Accident Conditions ◽  
Insight Into

This paper presents the results of the first full test series of commercial pressure relief valves using the newly constructed Queen’s University/Transport Canada dynamic valve test facility (VTF) in Maitland, Ontario. This facility is unique among those reported in the literature in its ability to cycle the valves repeatedly and to measure the time-varying flow rates during operation. This dynamic testing provides much more insight into valve behavior than the single-pop or continuous flow tests commonly reported. The facility is additionally unique in its simulation of accident conditions as a means of measuring valve performance. Specimen valves for this series represent 20 each of three manufacturers’ design for a semi-internal 1-in. 312 psi LPG relief valve. The purpose of this paper is to present the procedure and results of these tests. No effort is made to perform in-depth analysis into the causes of the various behaviors, nor is any assessment made of the risk presented by any of the valves. [S0094-9930(00)01201-4]

A contribution to an inviscid vortex-shedding model for an inclined flat plate in uniform flow

1977 ◽  
Vol 82 (2) ◽  
pp. 223-240 ◽  
Author(s):  
Masaru Kiya ◽  
Mikio Arie
Keyword(s):  
Flat Plate ◽  
Vortex Shedding ◽  
Separated Flow ◽  
Flow Patterns ◽  
Shear Layers ◽  
Visualization Technique ◽  
Time Intervals ◽  
Discrete Vortex ◽  
Kutta Condition ◽  
Vorticity Transport

Unsteady separated flow behind an inclined flat plate is numerically studied through the use of the discrete-vortex approximation, in which the shear layers emanating from the edges of the plate are represented by an array of discrete vortices introduced into the flow field at appropriate time intervals at some fixed points near the edges of the plate. The strengths of the nascent vortices are chosen so as to satisfy the Kutta condition at the edges of the plate. Numerical calculations are performed for a plate at 60° incidence impulsively started from rest in an otherwise stationary incompressible fluid, by systematically changing the distance between the location of the nascent vortices and the edges of the plate. The temporal changes in the drag force, the rate of vorticity transport at both edges of the plate and the velocity of the separated shear layers are given together with the flow patterns behind the plate on the basis of this model. The results of the computation show that the vortex street behind the plate inclines as a whole towards the direction of the time-averaged lift force exerted on the plate. It is also predicted from the calculations that the vortex shedding at one edge of the plate will not occur at the mid-interval of the successive vortex shedding at the other edge. The predicted flow patterns are not inconsistent with a few experimental observations based on the flow-visualization technique.

Steady-State Positions of a Pop Action Safety Valve

2011 ◽  
Author(s):  
Jean-Franc¸ois Rit ◽  
Pierre Moussou ◽  
Christophe Teygeman
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
Relief Valve ◽  
Pressure Relief ◽  
Working Pressure ◽  
Process Industries ◽  
Water Pipes ◽  
Upstream Pressure ◽  
Pressure Relief Valves ◽  
The Stability

Pressure relief valves in water pipes are known to sometimes chatter when the inlet pressure slightly exceeds the maximum allowable working pressure (MAWP) value. Though these devices are responsible for numerous fatigue issues in process industries, there is a relatively low number of technical publications describing well-established facts about them, especially for heavy fluids. The present study deals with the investigation of the stability of a pressure relief valve when a pressure drop device is arranged upstream. The valve is a simple spring device, with a 1″1/2 inlet diameter and a set pressure equal to 3 MPa. The 12% to 66% range of relative opening for this valve exhibit an unstable static equilibrium of the plug, designed to achieve the so called “pop action”; as soon as the pressure set point is reached, a runaway process leads to the full opening. The statically stable regimes were observed in former studies with respect to the upstream pressure and to the plug position, with a test rig arrangement which ensured an almost constant pressure upstream. In the present study, high pressure drop devices are arranged upstream, in order to stabilize the hydraulic regimes. It is found that the upstream pressure drop devices significantly enlarge the range of steady state plug positions and upstream pressures. Pressure and plug position measurements are shown with a time resolution lower than 2 ms. Comparison with hydraulic regimes of the former studies indicate that the presence of an upstream pressure drop modifies the plug balance. It is proposed that the arrangement of pressure drop device upstream may significantly reduce the risk of valve instability in water pipes.

scholarly journals Statistical Performance Evaluation of Spring Operated Pressure Relief Valve Reliability Improvements 2004 to 2014

2015 ◽  
Author(s):  
Holly L. Watson ◽  
Robert E. Gross ◽  
Stephen P. Harris
Keyword(s):  
South Carolina ◽  
The United States ◽  
Pressure Relief Valve ◽  
United States Department ◽  
Relief Valve ◽  
Pressure Relief ◽  
Maintenance Program ◽  
Operational Systems ◽  
Pressure Relief Valves ◽  
Improved Performance

The United States Department of Energy’s Savannah River Site (SRS) in Aiken, South Carolina, is dedicated to promoting site-level risk-based inspection (RBI) practices in order to maintain a safe and productive work environment. Inspecting component parts of operational systems, such as pressure relief valves (PRVs), is a vital part of SRS’s safe operating envelope. This paper is a continuation of a SRS program to minimize the risks associated with PRV failures. Spring operated pressure relief valve (SOPRV) test data accumulated over the past ten years resulted in over 11,000 proof tests of both new and used valves. Improved performance is seen for air service valves resulting from changes to the maintenance program. Although, statistically significant improvement was not seen for liquid, gas, or steam service valves, analysis shows that the overall probability of failure on demand is trending down. Current SRS practices are reviewed and the reasons for improved performance are explored.

The Design and Research of Automatic Micro-Pressure Relief Valves Used in Mine Rescue Cabin

2015 ◽  
Vol 752-753 ◽  
pp. 828-832
Author(s):  
Nian Yong Zhou ◽  
Yan Long Jiang ◽  
Lei Xu ◽  
Jun Li ◽  
He Xu Wang
Keyword(s):  
Fast Response ◽  
Pressure Relief Valve ◽  
Opening Pressure ◽  
Relief Valve ◽  
Pressure Relief ◽  
Advantages And Disadvantages ◽  
Sealing Performance ◽  
Pressure Relief Valves ◽  
Relief Rate ◽  
Mine Rescue

By analyzing the key technologies of pressure relief valve and comparing the advantages and disadvantages of existing products, liquid sealing automatic micro-pressure relief valve is designed with the properties of adjustable opening pressure, fast response rate, good sealing performance and long life, etc. Also, a reasonable mathematical model of liquid sealing automatic micro-pressure relief valve is developed, and the pressure relief valve’s opening pressure, reset pressure, relief rate and other key performance parameters is obtained. This work wil be helpful for the design and research of automatic micro-pressure relief valves used in mine rescue cabin.

Real-Time Simulated Pressure Relief Valves in Physical Hydraulic Circuits

2005 ◽  
Author(s):  
Tero Eskola ◽  
Heikki Handroos ◽  
Takao Nishiumi
Keyword(s):  
Hydraulic System ◽  
Main Idea ◽  
Dynamic Responses ◽  
Pressure Relief Valve ◽  
Design Parameters ◽  
Relief Valve ◽  
Pressure Relief ◽  
The Real ◽  
Pressure Relief Valves ◽  
On Line

The present paper deals with hardware-in-the-loop (HIL) simulation of hydraulic components and systems. The main idea is to develop hydraulics by using a simulation model of it as a part of the machine. The interface between the real and simulated parts is defined by means of pressures and flows. The proposed idea makes it possible to test a variety of design parameters of a hydraulic system or single component on-line while running the practical experimental machine. The method is demonstrated in its application to a single-stage pressure relief valve in a simple hydraulic circuit. The real valve is replaced in the circuit by a HIL simulator mimicking the dynamic behavior of the valve. Finally the dynamic responses of original pressure relief valve and the HIL simulator are compared.

Statistical Performance Evaluation of Soft (Elastomer) Seat Pressure Relief Valves

2013 ◽  
Author(s):  
Robert E. Gross ◽  
Stephen P. Harris
Keyword(s):  
South Carolina ◽  
Performance Evaluation ◽  
The United States ◽  
Probability Of Failure ◽  
United States Department ◽  
Relief Valve ◽  
Pressure Relief ◽  
On Demand ◽  
Pressure Relief Valves ◽  
Statistical Performance Evaluation

Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated pressure relief valves at the United States Department of Energy’s Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated pressure relief valves. These pressure relief valves are typically smaller and of lower cost than hard seat (metal to metal) pressure relief valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the pressure relief valve fails to perform its intended safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat valves. The research in this paper shows that the proportion of soft seat spring operated pressure relief valves failing is the same or less than that of hard seat valves, and that for failed valves, soft seat valves typically have failure ratios of proof test pressure to set pressure less than that of hard seat valves.

Instability of Pressure Relief Valves in Water Pipes

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
P. Moussou ◽  
R. J. Gibert ◽  
G. Brasseur ◽  
Ch. Teygeman ◽  
J. Ferrari ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Negative Pressure ◽  
Dynamic Instability ◽  
Pressure Sensors ◽  
Displacement Sensor ◽  
Relief Valve ◽  
Pressure Relief ◽  
Water Pipes ◽  
Spring Force ◽  
Pressure Relief Valves

Pressure relief valves in water pipes are known to sometimes chatter when the inlet pressure slightly exceeds the set pressure. While these devices are responsible for numerous fatigue issues in process industries, there is a relatively low number of technical publications covering their performance, especially in heavy fluid applications. The present study is intended as a contribution to the understanding of pressure relief valve dynamics, taking into account fluid-structure interactions. A series of tests were performed with a water relief valve in a test rig. Adjusting the set pressure of the valve to about 30 bars, an upstream pressure varying from 20 bars to 35 bars was imposed, so that the valve opened and the water flow varied from a few m3/h to about 80 m3/h. During the tests, the pipe was equipped upstream and downstream of the valve with static pressure sensors and a flowmeter, the disk lift was measured with a laser displacement sensor, and the spring force was recorded simultaneously. Several fluctuating pressure sensors were also installed in the inlet pipe. Static instability is investigated by comparing the spring force to the hydraulic force. Dynamic instability is observed and it is shown that the resonant behavior of the disk generates an apparent negative pressure drop coefficient at some frequencies. This negative pressure drop coefficient can trigger a dynamic instability in a manner similar to the negative damping effect in leakage-flow vibrations.

Reliability Testing of Pressure Relief Valves

2004 ◽  
Author(s):  
Robert E. Gross
Keyword(s):  
Test Results ◽  
Relief Valve ◽  
Pressure Relief ◽  
Data Set ◽  
System Service ◽  
Utility System ◽  
Pressure Relief Valves ◽  
Clean Air ◽  
The One ◽  
Time In Service

Following a brief description of pressure relief valves, this paper presents as-found set point test results for pressure relief valves that have been in process or utility system service. The paper examines the reliability of the relief valve to open at set pressure as a function of several key parameters, including time in service, fluid, size, and valve design (vendor). Although it may be that steam and water service valves are affected adversely by service conditions, this analysis is focused primarily on clean air/gas service. The probable correlation between fluid cleanliness and reliability is not being made, but will be considered in future studies. Valves that discharge outside allowable ASME tolerances are evaluated to determine possible causes of the deviation. Three failure case studies are presented. A final summary of test results indicates that valve reliability is not a strong function of time in service for the one-to-five year operating periods investigated. Additionally, this data set indicates that less than one percent (0.96%) of all valves pop tested at greater than 1.4 times tag set pressure.

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