Liquid Pipeline Location Specific Cyclic Pressure Determination

2018 ◽  
Author(s):  
Vlado Semiga ◽  
Aaron Dinovitzer ◽  
Sanjay Tiku ◽  
Geoff Vignal
Keyword(s):  
Pressure Range ◽  
Time History ◽  
Pressure Profile ◽  
Integrity Assessment ◽  
Cyclic Pressure ◽  
Pump Station ◽  
Pressure Time ◽  
Pipeline Segment ◽  
Time Histories ◽  
Discharge Pressure

In the majority of liquid pipelines, the pump station discharge pressure ranges are much greater than the pressure ranges experienced at the suction end of the downstream pump station. Consequently, the cyclic pressure induced fatigue damage accumulation rate is greater at the discharge end than at the suction end of a given pipeline segment. In completing an integrity assessment of a fatigue susceptible feature, assuming that the pump station discharge cyclic pressure profile applies to all features in the line segment is conservative. This conservative assumption can lead to un-necessary repairs, unintentional damage from over-prescribed maintenance, or inefficient decisions regarding maintenance action prioritization. The following paper presents the results of a Canadian Energy Pipeline Association (CEPA) initiative to develop a simple approach to define the cyclic pressure history at any point in a liquid pipeline segment based on the bounding discharge and suction pump station Supervisory Control and Data Acquisition (SCADA) pressure time history data. The approach was developed based on collected operating pipeline SCADA pressure time history data for line segments with intermediate measurement points which could be used to validate the developed model. The pressure time histories for all the locations were analyzed using a Rainflow cycle counting technique to develop pressure range spectra (i.e. histograms of pressure range events) and the cyclic pressure severity of each of the time histories was characterized by the Spectrum Severity Indicator (SSI). The SSI represents the number of annual 90MPa hoop stress cycles required to accumulate the same fatigue damage as the actual pressure spectrums. The technique presented in this paper illustrates how to infer the pressure range spectra or SSI at intermediate locations. The technique is shown to be a significant improvement (i.e. higher location specific accuracy) than either applying the discharge pressure spectrum or applying a linear interpolation between discharge and suction conditions in fatigue life assessments. The liquid pipeline cyclic pressure characterization technique presented in this paper will permit integrity assessment or severity ranking of features along a pipeline to be based on an accurate local pressure profile rather than an upper bound. This understanding will help to improve the accuracy of defect loading, one of the three main pillars in integrity assessment (i.e., loading, geometry, materials) for defects susceptible to cyclic loading (e.g., cracking, mechanical damage).

Experimental Investigation of Invar Edge Effect in Membrane LNG Tanks

2010 ◽  
Author(s):  
Mateusz Graczyk ◽  
Kjetil Berget ◽  
Joachim Allers
Keyword(s):  
Fluid Motion ◽  
Structural Response ◽  
Time History ◽  
Pressure Profile ◽  
Pressure Effects ◽  
Local Pressure ◽  
Temporal And Spatial Distribution ◽  
Containment System ◽  
Pressure Time ◽  
Time Histories

Sloshing, a violent fluid motion in tanks is of current interest for many branches of the industry, among them gas shipping. Although different methods are commonly combined for analyzing sloshing in LNG carriers, time histories of the pressure in the tanks are most reliably obtained by experiments. Very localized pressures may be important for the structural response of the tank containment system. Moreover, the typical pressure time history duration is similar to the structural natural frequency. Therefore, pressure measurements need to be performed with due account for temporal and spatial distribution. This requires a high sampling resolution both in time and space. Fine spatial resolution becomes especially important when local pressure effects are of interest, such as pressure profile passing a membrane corrugation of Mark III containment or Invar edge of No.96 containment. In this paper experimental approach applied by MARIN-TEK for analyzing sloshing phenomenon is presented. The focus is put on investigating effects of Invar edges. A transverse 2D model of a typical LNG carrier is used. Local pressure effects are investigated based on low filling level tests with different wall surfaces: smooth and with horizontal protrusions representing the surface similar to the No.96 containment system.

Experimental Investigation of Invar Edge Effect in Membrane LNG Tanks

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Mateusz Graczyk ◽  
Kjetil Berget ◽  
Joachim Allers
Keyword(s):  
Fluid Motion ◽  
Structural Response ◽  
Time History ◽  
Pressure Profile ◽  
Pressure Effects ◽  
Local Pressure ◽  
Temporal And Spatial Distribution ◽  
Containment System ◽  
Time Histories ◽  
Liquid Natural Gas

Sloshing, a violent fluid motion in tanks is of current interest for many branches of the industry, among them gas shipping. Although different methods are commonly combined for analyzing sloshing in liquid natural gas (LNG) carriers, time histories of the pressure in the tanks are most reliably obtained by experiments. Very localized pressures may be important for the structural response of the tank containment system. Moreover, the typical pressure time history duration is similar to the structural natural frequency. Therefore, pressure measurements need to be performed with due account for temporal and spatial distribution. This requires a high sampling resolution both in time and space. Fine spatial resolution becomes especially important when local pressure effects are of interest, such as pressure profile passing a membrane corrugation of Mark III containment or Invar edge of No. 96 containment. In this paper experimental approach applied by MARINTEK for analyzing sloshing phenomenon is presented. The focus is put on investigating effects of Invar edges. A transverse 2D model of a typical LNG carrier is used. Local pressure effects are investigated based on low filling level tests with different wall surfaces: smooth and with horizontal protrusions representing the surface similar to the No. 96 containment system.

Fuel-Air Ratio Determination From Cylinder Pressure Time Histories

1985 ◽  
Vol 107 (4) ◽  
pp. 252-257 ◽  
Author(s):  
J. C. Gilkey ◽  
J. D. Powell
Keyword(s):  
Time History ◽  
Operating Conditions ◽  
Cylinder Pressure ◽  
Pressure Time ◽  
Wide Range ◽  
Pressure Trace ◽  
Time Histories ◽  
High Bandwidth ◽  
Ratio Determination ◽  
Microprocessor Technology

Determining fuel-air ratio quickly over a wide range of engine operating conditions is desirable for better transient engine control. This paper describes a method based on cylinder pressure time history pattern recognition which has potential for providing such a high bandwidth measurement. The fact that fuel-air ratio has an effect on the shape of the cylinder pressure trace is well-known. It should therefore be possible to obtain the fuel-air ratio of an engine by examining the pressure trace if the engine speed, load, and EGR are known. The difficulty lies in separating the effects of unknown engine load, speed, and EGR from the fuel-air ratio effects. An algorithm was developed using a wide range of steady state experimental data from a single cylinder engine. Application of the algorithm requires the calculation of first, second and third moments of the cylinder pressure time history. Verification of the algorithm showed that the root mean square error in estimates were about 5 percent for fuel-air ratio and 3 percent for a combination of fuel-air and EGR. These results were obtained using a single pressure trace which yields a response time of 1.5 engine revolutions. The algorithm was also found to be relatively insensitive to the use of different fuels, errors in spark advance, and variations in relative humidity. Research is continuing to verify the accuracy under transient engine conditions. An operational count shows that this algorithm should be well within the limits of present microprocessor technology.

The Use of Plastic Cold Flow in the Development of an Externally Connected Transducer for Recording Pressure-Time Histories of Diesel Fuel Injection Phenomena and Its Application in Fault Diagnosis

1977 ◽  
Vol 99 (2) ◽  
pp. 274-278
Author(s):  
W. S. Heggie
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Dynamic Pressure ◽  
Time History ◽  
Diagnostic Techniques ◽  
Field Application ◽  
Cold Flow ◽  
Pressure Time ◽  
Time Histories ◽  
Diesel Fuel Injection

An investigation of possible methods for obtaining a pressure-time history of the diesel fuel injection cycle was conducted, with the object of producing a rugged externally connected pressure transducer. A resistance technique that discriminates against characteristics not directly associated with dynamic pressure was developed and the resulting principles incorporated into the design of a compact transducer [1]. In order to eliminate the necessity of cementing a resistance element directly to the high-pressure line, a technique using the cold flow of cured resin held captive in a steel enclosure was developed. This has resulted in an instrument of equal sensitivity and fidelity which may be installed in the field by personnel without specialized training. Diagnostic techniques applied to the analysis of diesel fuel injection health are described that are considered to have practical field application, using an externally connected transducer. No numerical measure is required, the method being based on comparison of fault signatures with a healthy master. The signature is considered to contain a definite quantity of criteria evaluated by a defined series of qualities resulting in a less nebulous approach than that of random comparison by superimposure. Nine of the most common diesel fuel injection faults are induced, checked for repeatability, and used as representative examples to illustrate the method.

Determination of the transfer function between the injected flow-rate and high-pressure time histories for improved control of common rail diesel engines

2016 ◽  
Vol 18 (3) ◽  
pp. 212-225 ◽  
Author(s):  
Alessandro Ferrari ◽  
Emanuele Salvo
Keyword(s):  
Transfer Function ◽  
Working Conditions ◽  
Flow Rate ◽  
Diesel Engines ◽  
Time History ◽  
Common Rail ◽  
Rail Pressure ◽  
Experimental Estimation ◽  
Pressure Time ◽  
Time Histories

Theoretical and experimental methodologies have been proposed and illustrated to determine the transfer function between the injected flow-rate and the rail pressure for common rail injection systems. An analytical transfer function has been calculated in the frequency domain, utilizing a previously developed lumped parameter model of the overall hydraulic layout of a common rail system. The predicted transfer function has been compared, in a Bode diagram, with an experimental estimation of the transfer function, based on the measured rail pressure and injected flow-rate time histories that were acquired at the hydraulic rig for different working conditions. The experimental estimation of the transfer function has been worked out by applying a selective spectral technique in order to reduce the effects of measurement noise on the rail pressure and injected flow-rate time histories. The accuracy of the model-derived transfer function has been improved significantly by integrating a pressure control system sub-model, which includes the action of the electronic control unit on the rail pressure time history through the pressure regulator, in the hydraulic model of the common rail circuit. Finally, the time histories of the rail pressure, predicted by means of the complete injection apparatus model, have been compared with the corresponding experimental traces at different working conditions and a very satisfactory agreement has in general been found. The methodologies proposed for the accurate evaluation of the transfer function between the injected flow-rate and the rail pressure time histories can be applied to diesel engines in order to implement innovative closed-loop strategies for the injected mass control.

Pipeline Corrosion Integrity Management by Direct Assessment

2015 ◽  
Author(s):  
Shailesh Javia
Keyword(s):  
Integrated Approach ◽  
Assessment Process ◽  
Regulatory Requirements ◽  
Integrity Assessment ◽  
Advantages And Disadvantages ◽  
Direct Assessment ◽  
Pipeline Segment ◽  
Integrity Management ◽  
Post Assessment ◽  
Pipeline Corrosion

Integrity management of pipelines is a systematic, comprehensive and integrated approach to proactively counter the threats to pipeline integrity. Pressure testing, in-line inspection and direct assessment methods are used to verify the integrity of a buried pipeline. The Paper Discuses Direct Assessment Methodologies for Hydrocarbon Non Piggable Pipelines. Advantages and Disadvantages of Direct Assessment methodology and DA Protocols. The DA process accomplishes this by utilizing and integrating condition monitoring, effective mitigation, meticulous documentation and timely structured reporting processes. DA is a structured, iterative integrity assessment process through which an operator may be able to assess and evaluate the integrity of a pipeline segment. TIME DEPENDENT THREATS INEVITABLY LED TO NUMEROUS FAILURES WITH A COMMON DEFINING MECHANISM OR SOURCE – CORROSION. This Paper will focus on internal, external and stress corrosion cracking direct assessment along with pre and post assessment, quality assurance, data analysis and integration, and remediation and mitigation activities. This paper will discuss some of the regulatory requirements for Pipeline Integrity Management System.

Second Paper: Deep Drawing and Free Forming Using a Water Hammer Technique

1964 ◽  
Vol 179 (1) ◽  
pp. 222-233 ◽  
Author(s):  
A. P. Vafiadakis ◽  
W. Johnson ◽  
I. S. Donaldson
Keyword(s):  
Deep Drawing ◽  
Time History ◽  
Water Hammer ◽  
High Rate ◽  
Pressure Time ◽  
Order Of Magnitude ◽  
History Of ◽  
Overall Efficiency ◽  
Initial Movement ◽  
Better Than

Earlier work on a water-hammer technique for high-rate forming of sheet metal has been extended to include work on deep drawing using lead plugs. A study of the pressure-time history of a deforming blank during its initial movement is reported. An assessment of the overall efficiency of the process has been made and is found to be about 50 per cent; this is an order of magnitude better than that found with comparable electro-hydraulic and explosive methods.

CO and H2O Time-Histories in Shock-Heated Blends of Methane and Ethane for Assessment of a Chemical Kinetics Model

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
O. Mathieu ◽  
C. R. Mulvihill ◽  
E. L. Petersen ◽  
Y. Zhang ◽  
H. J. Curran
Keyword(s):  
Chemical Kinetics ◽  
Laminar Flame ◽  
Combustion Process ◽  
Time History ◽  
Good Marker ◽  
Ignition Delay Times ◽  
Depletion Rate ◽  
Time Histories ◽  
Main Components ◽  
Detailed Kinetics

Methane and ethane are the two main components of natural gas and typically constitute more than 95% of it. In this study, a mixture of 90% CH4/10% C2H6 diluted in 99% Ar was studied at fuel lean (equiv. ratio = 0.5) conditions, for pressures around 1, 4, and 10 atm. Using laser absorption diagnostics, the time histories of CO and H2O were recorded between 1400 and 1800 K. Water is a final product from combustion, and its formation is a good marker of the completion of the combustion process. Carbon monoxide is an intermediate combustion species, a good marker of incomplete/inefficient combustion, as well as a regulated pollutant for the gas turbine industry. Measurements such as these species time histories are important for validating and assessing chemical kinetics models beyond just ignition delay times and laminar flame speeds. Time-history profiles for these two molecules were compared to a state-of-the-art detailed kinetics mechanism as well as to the well-established GRI 3.0 mechanism. Results show that the H2O profile is accurately reproduced by both models. However, discrepancies are observed for the CO profiles. Under the conditions of this study, the CO profiles typically increase rapidly after an induction time, reach a maximum, and then decrease. This maximum CO mole fraction is often largely over-predicted by the models, whereas the depletion rate of CO past this peak is often over-estimated for pressures above 1 atm.

CO and H2O Time-Histories in Shock-Heated Blends of Methane and Ethane for Assessment of a Chemical Kinetics Model

2017 ◽  
Author(s):  
O. Mathieu ◽  
C. Mulvihill ◽  
E. L. Petersen ◽  
Y. Zhang ◽  
H. J. Curran
Keyword(s):  
Gas Turbine ◽  
Chemical Kinetics ◽  
Laminar Flame ◽  
Combustion Process ◽  
Practical Interest ◽  
Time History ◽  
Good Marker ◽  
Ignition Delay Times ◽  
Time Histories ◽  
Detailed Kinetics

Methane and ethane are the two main components of natural gas and typically constitute more than 95% of it. In this study, a mixture of 90% CH4 /10% C2H6 diluted in 99% Ar was studied at fuel lean (ϕ = 0.5) conditions, for pressures around 1, 4, and 10 atm. Using laser absorption diagnostics, the time histories of CO and H2O were recorded between 1400 and 1800 K. Water is a final product from hydrocarbon combustion, and following its formation is a good marker of the completion of the combustion process. Carbon monoxide is an intermediate combustion species, a good marker of incomplete/inefficient combustion, as well as a regulated pollutant for the gas turbine industry. Measurements such as these species time histories are important for validating and assessing chemical kinetics models beyond just ignition delay times and laminar flame speeds. Time-history profiles for these two molecules measured herein were compared to a modern, state-of-the-art detailed kinetics mechanism as well as to the well-established GRI 3.0 mechanism. Results show that the H2O profile is accurately reproduced by both models. However, discrepancies are observed for the CO profiles. Under the conditions of this study, the measured CO profiles typically increase rapidly after an induction time, reach a maximum and then decrease. This maximum CO mole fraction is often largely over-predicted by the models, whereas the depletion rate of CO past this peak is often over-estimated by the models for pressures above 1 atm. This study demonstrates the need to improve on the accuracy of the HCCO reactions involved in CO formation for pressures of practical interest for the gas turbine industry.

Nonlinear Wave Crest Distribution on a Vertical Breakwater

2018 ◽  
Author(s):  
Valentina Laface ◽  
Giovanni Malara ◽  
Felice Arena ◽  
Ioannis A. Kougioumtzoglou ◽  
Alessandra Romolo
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Vertical Wall ◽  
Surface Elevation ◽  
Wave Crest ◽  
Height Distribution ◽  
Free Surface Elevation ◽  
Pressure Transducers ◽  
Pressure Time ◽  
Time Histories

The paper addresses the problem of deriving the nonlinear, up to the second order, crest wave height probability distribution in front of a vertical wall under the assumption of finite spectral bandwidth, finite water depth and long-crested waves. The distribution is derived by relying on the Quasi-Deterministic representation of the free surface elevation in front of the vertical wall. The theoretical results are compared against experimental data obtained by utilizing a compressive sensing algorithm for reconstructing the free surface elevation in front of the wall. The reconstruction is pursued by starting from recorded wave pressure time histories obtained by utilizing a row of pressure transducers located at various levels. The comparison shows that there is an excellent agreement between the proposed distribution and the experimental data and confirm the deviation of the crest height distribution from the Rayleigh one.

Sign in / Sign up

Export Citation Format

Share Document