The Effect of Water Hammer on Pressure Oscillation of Hydrogen Natural Gas Transient Flow

2014 ◽  
Vol 554 ◽  
pp. 251-255 ◽  
Author(s):  
Galadima Agaie Baba ◽  
Amin Norsarahaida
Keyword(s):  
Natural Gas ◽  
Transient Flow ◽  
Splitting Method ◽  
Control Valve ◽  
Pressure Oscillation ◽  
Water Hammer ◽  
Transient Pressure ◽  
Eigenmode Analysis ◽  
Flux Vector Splitting ◽  
Convex Closure

The unexpected closing of a control valve or pumping, which can be planned or accidental could lead to pressure oscillation commonly known as water hammer. Pressure waves oscillation in the fluid flow interaction leads to unsteady state phenomenon. Numerical computation on transient flow model of hydrogen natural gas mixture (HCNG) in a pipeline where different types of valves are considered for effective delivery and safety. Reduced order modeling (ROM) technique is employed in the transient analysis of high pressured HCNG in a short pipe. The flow is governed by a system of Euler equations that are discretized using the implicit Steger-Warming flux vector splitting method (FSM). Eigenmode analysis and the subsequent construction of ROM use only a few dominant flow eigenmodes. The boundary conditions are imposed using the closure law at the upstream and downstream of the pipeline. The effect of closure function is analyzed and the results are presented on different mass ratios and HCNG flow parameters. The transient pressure oscillations of HCNG at different closure functions are compared so as to test the best type of valve for HCNG transportation. The highest and lowest value of transient pressure wave occurs when instantaneous and convex closure law is considered, respectively.

scholarly journals Analysis of Water Hammer with Different Closing Valve Laws on Transient Flow of Hydrogen-Natural Gas Mixture

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Norazlina Subani ◽  
Norsarahaida Amin
Keyword(s):  
Natural Gas ◽  
Pressure Wave ◽  
Transient Flow ◽  
Water Hammer ◽  
Wave Profile ◽  
Maximum Pressure ◽  
Gas Mixture ◽  
Pressure Waves ◽  
Closing Time ◽  
Closure Laws

Water hammer on transient flow of hydrogen-natural gas mixture in a horizontal pipeline is analysed to determine the relationship between pressure waves and different modes of closing and opening of valves. Four types of laws applicable to closing valve, namely, instantaneous, linear, concave, and convex laws, are considered. These closure laws describe the speed variation of the hydrogen-natural gas mixture as the valve is closing. The numerical solution is obtained using the reduced order modelling technique. The results show that changes in the pressure wave profile and amplitude depend on the type of closing laws, valve closure times, and the number of polygonal segments in the closing function. The pressure wave profile varies from square to triangular and trapezoidal shape depending on the type of closing laws, while the amplitude of pressure waves reduces as the closing time is reduced and the numbers of polygonal segments are increased. The instantaneous and convex closing laws give rise to minimum and maximum pressure, respectively.

Numerical Solution of Transient Flow in Wind Tunnels

Volume 1 ◽  
2004 ◽  
Author(s):  
A. Nouri-Borujerdi ◽  
M. Ziaei-Rad
Keyword(s):  
Atmospheric Pressure ◽  
Transient Flow ◽  
Splitting Method ◽  
Wind Tunnels ◽  
Flux Vector ◽  
Governing Equations ◽  
One Dimensional ◽  
Flux Vector Splitting ◽  
Pass Through ◽  
Good Agreement

This paper deals with design and analysis of intermittent supersonic wind tunnels. System can be constructed by allowing air at atmospheric pressure to pass through a converging-diverging nozzle, a test section and a diffuser into a vacuum tank. The governing equations of compressible fluid flow have been solved numerically using flux vector splitting method to obtain running time under which it works at the design Mach number. The formulation has been tested on the theory of quasi one-dimensional compressible flow. The numerical results are in good agreement with the results of the theory.

scholarly journals The investigation of gas–liquid two-phase transient flow based on Steger–Warming flux vector splitting method in pipelines

2016 ◽  
Vol 8 (10) ◽  
pp. 168781401667253 ◽  
Author(s):  
Jin Jiang ◽  
You Fu ◽  
Lisheng Zhang ◽  
Yanhui Li ◽  
Weidong Ji ◽  
...  
Keyword(s):  
Transient Flow ◽  
Splitting Method ◽  
Flux Vector ◽  
Two Phase ◽  
Flux Vector Splitting

Numerical Integration of the AUSMV Scheme With a Dynamic Wellbore Temperature Model

2018 ◽  
Author(s):  
John Emeka Udegbunam ◽  
Kjell Kåre Fjelde ◽  
Dan Sui
Keyword(s):  
Dynamic Models ◽  
Drilling Fluid ◽  
Splitting Method ◽  
Isothermal Condition ◽  
Temperature Model ◽  
Two Phase ◽  
Transient Model ◽  
Flux Vector Splitting ◽  
Wellbore Temperature ◽  
Transient Models

The AUSMV scheme is a hybrid transient model derived from Advection-Upwind-Splitting Method (AUSM) and Flux Vector Splitting (FVS) method. The two-phase flow model was formulated under isothermal condition. This neglected the behavior of temperature during transient scenarios, for instance, unloading and drilling fluid circulation. In contrast to this assumption, wellbore temperature changes locally with time under such dynamic conditions. The numerical accuracy of the AUSMV scheme can be improved in two ways. The scheme can be reformulated by including energy equation in the system of governing conservation laws. This option, however, is computationally rigorous and expensive. A better alternative is to develop a separate dynamic temperature model that will calculate wellbore and formation temperatures. Then the two dynamic models — the AUSMV scheme and temperature model — are numerically coupled into a thermohydraulic simulator. The present work will include a brief introduction to the AUSMV scheme, followed by the description of the temperature model. In addition, how the two transient models are integrated will be presented. Simulation cases, demonstrating the improved modeling capability of the scheme for a drilling situation, will be shown.

A Comparative Study of Methane Combustion Characteristics with Different Additions in an Optical SI Engine

2021 ◽  
Author(s):  
Lin Chen ◽  
Xiao Zhang ◽  
Ren Zhang ◽  
Wanhui Zhao
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Power Output ◽  
High Speed ◽  
Propagation Speed ◽  
Pressure Oscillation ◽  
Methane Combustion ◽  
Natural Gas Engines ◽  
Auto Ignition ◽  
Flame Propagation Speed

Abstract Natural gas is a promising fuel for IC engines with minimal modification, whereas its low power output and slow flame propagation speed remain a challenge for automobile manufacturers. To find a method of improving the natural gas engines, methane combustion with different additions was comparatively studied. High-speed direct photography and simultaneous pressure were performed to capture detailed combustion evolutions. First, the results of pure methane combustion confirm its good anti-knock property, and no pressure oscillation occurs even there is an end-gas auto-ignition, indicating that high compression ratio and high boosting are effective ways to improve the performance of natural gas engines. Second, adding heavy hydrocarbons can greatly improve engines' power output, but engine knock should be considered if low anti-knock fuel was used. Third, as a carbon-free and gaseous fuel, hydrogen addition can not only increase methane flame propagation speed but reduce cyclic variations. However, a proper fraction is needed under different load conditions. Last, oxygen-enriched combustion is an effective way to promote methane combustion. The heat release becomes faster and more concentrated, specifically, the flame propagation speed can be increased by more than 2 times under 27% oxygen concentration condition. The current study shall give insights into improving natural gas engines' performance.

scholarly journals An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

2000 ◽  
Vol 123 (2) ◽  
pp. 418-428 ◽  
Author(s):  
Mark P. Wernet ◽  
Michelle M. Bright ◽  
Gary J. Skoch
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Transient Flow ◽  
Dynamic Pressure ◽  
Rotating Stall ◽  
Transient Pressure ◽  
Pressure Transducers ◽  
Stable Operating ◽  
Particle Imaging

Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in high-speed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

Investigation of a new shock damper system efficiency in reducing water hammer excess pressure due to the sudden closure of a control valve

2018 ◽  
Vol 26 (3) ◽  
pp. 258-266 ◽  
Author(s):  
Mohammad Bostan ◽  
Ali Akbar Akhtari ◽  
Hossein Bonakdari ◽  
Bahram Gharabaghi ◽  
Omid Noori
Keyword(s):  
Control Valve ◽  
Water Hammer ◽  
Excess Pressure ◽  
System Efficiency
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