Transient Flow Assurance for Determination of Operational Control of Heavy Oil Pipelines

2010 ◽  
Author(s):  
Victor Cabrejo ◽  
Mo Mohitpour
Keyword(s):  
Steady State ◽  
Dynamic Analysis ◽  
Heavy Oil ◽  
Transient Flow ◽  
Check Valve ◽  
Bubble Collapse ◽  
Operational Control ◽  
Rapid Reduction ◽  
Oil Pipeline ◽  
Pump Station

Most liquid pipelines design and operational control is based on steady state flow analysis. This neglects dynamic effects that occur as a result of occurrence of surges in a pipeline caused by rapid changes in pressure as a consequence of changes in the flow rate. A transient analysis of liquid pipelines on the other hand assures pipeline performance under all conditions (steady state and dynamic situations) including evaluating the following: • Impact from pump station start up, delivery restriction or shutdown (zero delivery); • Pump unit trip/failure; • Rapid mainline valve closures including Slam shut of a non-return (check) valve; • Effect of running the pipeline with minimum flow and maximum pump discharge pressure operating condition; • Variation in demand including rapid reduction/curtailment of delivery volumes; • Bubble collapse (the transition from slack-line to tight-line flow); • Unintentional changes in operational position of control valves; • Fluid property delivery conditions; • Liquid injection assessment; • Surge protection including pressure relief/control system evaluation; • Restart requirement to avoid slack-line conditions prevalent in hilly/mountainous parts right of way (ROW). Such a dynamic analysis would indicate whether liquid surges are of concern from design, as well as system operational conditions. It also would provide an evaluation of an automated control or potential automated strategies for overpressure protection. In this paper the dynamic analysis of liquid pipelines resulting in design and operational benefits will be described. Finally their benefits in application to a heavy oil pipeline facilities “Keystone” will be highlighted.

scholarly journals Pressure Analysis in the Draft Tube of a Pump-Turbine under Steady and Transient Conditions

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4732
Author(s):  
Jing Yang ◽  
Yue Lv ◽  
Dianhai Liu ◽  
Zhengwei Wang
Keyword(s):  
Steady State ◽  
Pressure Pulsation ◽  
Transient Flow ◽  
Draft Tube ◽  
Simulation Method ◽  
Wall Pressure ◽  
Pump Turbine ◽  
Steady State Condition ◽  
Transient Conditions ◽  
Pumped Storage

Pumped-storage power stations play a regulatory role in the power grid through frequent transition processes. The pressure pulsation in the draft tube of the pump-turbine under transient processes is important for safe operation, which is more intense than that in the steady-state condition. However, there is no effective method to obtain the exact pressure in the draft tube in the transient flow field. In this paper, the pressure in the draft tube of a pump-turbine under steady-state and transient conditions are studied by means of CFD. The reliability of the simulation method is verified by comparing the real pressure pulsation data with the test results. Due to the distribution of the pressure pulsation in the draft tube being complex and uneven, the location of the pressure monitoring points directly affects the accurate judgement of cavitation. Eight monitoring surfaces were set in the straight cone of the draft tube and nine monitoring points were set on each monitoring surface to analyze the pressure differences on the wall and inside the center of the draft tube. The relationships between the pressure pulsation value inside the center of the draft tube and on the wall are studied. The “critical” wall pressure pulsation value when cavitation occurs is obtained. This study provides references for judging cavitation occurrences by using the wall pressure pulsation value in practical engineering.

Transient flow behaviors of the check valve with different spool-head angle in high-pressure hydrogen storage systems

2022 ◽  
Vol 46 ◽  
pp. 103761
Author(s):  
Jianjun Ye ◽  
Zhenhua Zhao ◽  
Junxu Cui ◽  
Zhengli Hua ◽  
Wenzhu Peng ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrogen Storage ◽  
Transient Flow ◽  
Storage Systems ◽  
Check Valve ◽  
Pressure Hydrogen

scholarly journals Transient Flow Characteristic of High-Pressure Hydrogen Gas in Check Valve during the Opening Process

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4222
Author(s):  
Jianjun Ye ◽  
Zhenhua Zhao ◽  
Jinyang Zheng ◽  
Shehab Salem ◽  
Jiangcun Yu ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Flow ◽  
Transient Flow ◽  
Check Valve ◽  
Hydrogen Gas ◽  
Strong Impact ◽  
Hydrogen Flow ◽  
Hydrogen Systems ◽  
Pressure Hydrogen ◽  
Opening Process

In high-pressure hydrogen systems, the check valve is one of the most easy-to-damage components. Generally, the high-pressure hydrogen flow can generate a strong impact on the check valve, which can cause damage and failure. Therefore, it is useful to study the transient flow characteristics of the high-pressure hydrogen flow in check valves. Using dynamic mesh generation and the National Institute of Standards and Technology (NIST) real hydrogen gas model, a transient-flow model of the high-pressure hydrogen for the check valve is established. First, the flow properties of high-pressure hydrogen during the opening process is investigated, and velocity changes and pressure distribution of hydrogen gas flow are studied. In addition, the fluid force, acceleration, and velocity of the valve spool are analyzed quantitatively. Subsequently, the effect of the hydrogen inlet-pressure on the movement characteristic of the valve spool is investigated. The results of this study can improve both the design and applications of check valves in high-pressure hydrogen systems.

scholarly journals Research on the steady‐state operation optimization technology of oil pipeline

2020 ◽  
Vol 8 (11) ◽  
pp. 4064-4081
Author(s):  
Enbin Liu ◽  
Yong Peng ◽  
Yang Yi ◽  
Liuxin Lv ◽  
Weibiao Qiao ◽  
...  
Keyword(s):  
Steady State ◽  
Operation Optimization ◽  
Oil Pipeline ◽  
Steady State Operation

Unsteady natural convection in a cavity with internal heating and cooling

1984 ◽  
Vol 140 ◽  
pp. 135-151 ◽  
Author(s):  
John C. Patterson
Keyword(s):  
Steady State ◽  
Natural Convection ◽  
Numerical Solutions ◽  
Transient Flow ◽  
Scaling Analysis ◽  
Steady State Flow ◽  
Internal Heating ◽  
Sources And Sinks ◽  
Heating And Cooling ◽  
Unsteady Natural Convection

The problem of transient natural convection in a cavity of aspect ratio A < 1 driven by internal buoyancy sources and sinks distributed linearly in the horizontal and uniformly in the vertical is considered. Scaling analysis is used to show that a number of possible transient flow regions are possible, collapsing ultimately onto one of conductive, transitional, or convective steady-state flow regimes. A number of numerical solutions are obtained, and their relationships to the scaling analysis are discussed.

Ultrasonic measurement of self-loosening in bolted joints

2011 ◽  
Vol 226 (7) ◽  
pp. 1869-1884 ◽  
Author(s):  
MB Marshall ◽  
R Lewis ◽  
T Howard ◽  
H Brunskill
Keyword(s):  
Steady State ◽  
Ultrasonic Measurement ◽  
Bolted Joints ◽  
Catastrophic Failure ◽  
Interface Pressure ◽  
Rapid Reduction ◽  
Contact Conditions ◽  
Joint Integrity ◽  
Clamping Pressure ◽  
Insight Into

Self-loosening of bolted joints in response to vibration can lead to the catastrophic failure of a range of engineering components and structures. Many techniques employed to study this phenomenon focus on directly measuring the pre-load remaining in the bolt itself, and offer little insight into the behaviour of the clamped interface. In this study, a non-intrusive ultrasonic reflection-based technique is used to first characterize interface pressure in the joint, and then determine the rate at which relaxation occurs. A key advantage of the technique is that it does not require the modification of the contact conditions, and rather utilizes the spring-like behaviour of a rough surface interface when subject to ultrasonic excitation. A series of different bolt torques were investigated, along with the inclusion of both plain and spring washers under the bolt head. All test samples were subjected to an oscillating fixed–displacement vibration cycle. An initial rapid reduction in interface clamping pressure was observed, followed by a more steady-state period. Increasing bolt torque was seen to enhance joint integrity, whereas both the plain and spring washers showed little improvement. The spring washer was observed to extend the secondary steady-state phase of loosening, though as the majority of pre-load was removed prior to this period any change was largely unbeneficial.

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