A New Scenario in Probe Local Oxidation: Transient Pressure-Wave-Assisted Ionic Spreading and Oxide Pattern Formation

2007 ◽  
Vol 19 (18) ◽  
pp. 2618-2623 ◽  
Author(s):  
X. N. Xie ◽  
H. J. Chung ◽  
Z. J. Liu ◽  
S.-W. Yang ◽  
C. H. Sow ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Pressure Wave ◽  
Transient Pressure ◽  
Local Oxidation

Benchmarking the Dual and Compound Techniques-Based Branching Design Strategy Used for Upgrading of Pressurized Hydraulic Systems

2021 ◽  
Vol 143 (2) ◽  
Author(s):  
Waêl Ben Amira ◽  
Ali Triki
Keyword(s):  
Pressure Wave ◽  
Plastic Material ◽  
Conventional Technique ◽  
Steel Pipe ◽  
Low Density Polyethylene ◽  
Piping System ◽  
Low Density ◽  
Hydraulic Systems ◽  
Transient Pressure ◽  
Pipe Flow Model

Abstract Prior research has recognized that the compound- and dual-technique-based branching redesign measures, used as alternatives to the conventional technique-based one, were effective in upgrading steel pipe-based pressurized hydraulic systems. Principally, the compound technique used two different plastic material types for the short-penstock instead of the single material type utilized in the conventional technique. However, the dual technique is based on splitting the single penstock installed in the conventional technique into a set of dual subpenstocks placed at each connection of the main-piping system to hydraulic parts. This handling aimed at improving the conventional technique efficiency with regard to the tradeoff between the magnitude attenuation and period expansion effects of the transient pressure-wave signal. Accordingly, this study proposed a comprehensive comparison between the compound- and dual-technique-based branching strategy with particular focus on the tradeoff between the two last parameters. The plastic material types demonstrated in this study included the high- or low-density polyethylene. The application addressed a waterhammer maneuver initiated into a reservoir-steel-pipe-valve system. Numerical computations used the method of characteristics for the discretization of the 1D extended pressurized-pipe flow model, embedding the Kelvin–Voigt and Vitkovsky formulations. The finding of this study suggested that the high- or low-density polyethylene (HDPE–LDPE) setup of the compound technique is the most prominent protected system setup, providing an acceptable tradeoff between the attenuation of magnitude and the expansion of the period of pressure-wave oscillation.

scholarly journals Pressure Waves due to Rapid Evaporation of Water Droplet in Liquid Lead Coolant

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
S. E. Yakush ◽  
A. S. Iskhakov ◽  
V. I. Melikhov ◽  
O. I. Melikhov
Keyword(s):  
Steam Generator ◽  
Water Droplet ◽  
Pressure Wave ◽  
Coolant Flow ◽  
Boiling Water ◽  
Liquid Lead ◽  
Transient Pressure ◽  
Flash Evaporation ◽  
Steam Generator Tube ◽  
Water Steam

Flash evaporation of a superheated water droplet in heavy liquid metal coolant (lead) is considered, in application to the analysis of a lead-cooled fast reactor steam generator tube rupture accident. The model is based on thermodynamic equilibrium formulation for the expanding water-steam mixture and inviscid compressible formulation for the surrounding liquid lead, with the interface conditions determined from the solution of the Riemann problem. Numerical solution is performed in the spherically symmetric geometry using a conservative numerical scheme with a moving sharp interface. Transient pressure and velocity profiles in each phase are presented for the parameters typical of the steam generator tube rupture accidents, demonstrating the process of boiling water expansion and pressure wave formation in the coolant. The results obtained are compared with a simplified model which considers the volume-averaged parameters of boiling water droplets and considers coolant as an incompressible liquid. Good agreement between the full and simplified models is demonstrated. Impacts of coolant flow on structures caused by pressure wave propagation and subsequent coolant flow are discussed.

scholarly journals Research on an Lost Circulation Zone Location Method Based on Transient Pressure Wave

ACS Omega ◽  
2021 ◽  
Vol 6 (39) ◽  
pp. 25807-25818
Author(s):  
Ruida Zhang ◽  
Zhongxi Zhu ◽  
Chaofei Wang ◽  
Zhigang Guan
Keyword(s):  
Pressure Wave ◽  
Circulation Zone ◽  
Transient Pressure ◽  
Location Method ◽  
Lost Circulation

scholarly journals Scale Effects on Solid Rocket Combustion Instability Behaviour

2021 ◽  
Author(s):  
David R. Greatrix
Keyword(s):  
Numerical Model ◽  
Pressure Wave ◽  
Scale Effects ◽  
Combustion Instability ◽  
Pressure Rise ◽  
Transient Pressure ◽  
Solid Propellant Rocket ◽  
Burning Propellant ◽  
Solid Rocket ◽  
Propellant Rocket

The ability to understand and predict the expected internal behaviour of a given solid-propellant rocket motor under transient conditions is important. Research towards predicting and quantifying undesirable transient axial combustion instability symptoms necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. A numerical model incorporating pertinent elements, such as a representative transient, frequency-dependent combustion response to pressure wave activity above the burning propellant surface, is applied to the investigation of scale effects (motor size, i.e., grain length and internal port diameter) on influencing instability-related behaviour in a cylindrical-grain motor. The results of this investigation reveal that the motor’s size has a significant influence on transient pressure wave magnitude and structure, and on the appearance and magnitude of an associated base pressure rise.

scholarly journals Pressure Wave Transmission in a Fluid Contained in a Plastically Deforming Pipe

1974 ◽  
Vol 96 (4) ◽  
pp. 258-262 ◽  
Author(s):  
G. L. Fox ◽  
D. D. Stepnewski
Keyword(s):  
Plastic Deformation ◽  
Pressure Wave ◽  
Pipe Wall ◽  
Experimental Tests ◽  
Elastic Wave Velocity ◽  
Wave Transmission ◽  
Pressure Waves ◽  
Transient Pressure ◽  
Cooling Systems ◽  
Wall Deformation

The transmission of high pressure pulses through piping loops such as reactor cooling systems is usually studied with water hammer analysis techniques. Conventional wave analysis includes only elastic pipe wall deformation. However, plastic deformation of the pipe wall is effective in reducing the magnitude of transmitted pressure waves if the pressure is of sufficient magnitude to cause plastic yielding. This effect can be treated using a one-dimensional dynamic analysis by noting the similarity between the equations describing pressure wave induced plastic deformation in a solid bar and wave transmission causing plastic strain in a fluid filled pipe. The results of the analysis show that at fluid pressures less than the pipe yield pressure, waves are transmitted at elastic wave velocity; however, at pressures which exceed the pipe yield point, wave velocities are substantially reduced and the waves are dispersed. These results demonstrate that plastic deformation from transient pressure loading is limited to a relatively short length of piping near the source of the pressure pulse. The significance of this behavior with respect to reactor cooling systems is that pressures above those causing yield are not transmitted to primary loop components such as pumps and heat exchangers. The theoretical results are compared with experimental tests and show reasonable agreement.

The Initial Startup Wave Velocity in Isothermal Pipeline With Compressible Gelled Crude Oil

SPE Journal ◽  
2013 ◽  
Vol 19 (03) ◽  
pp. 418-424 ◽  
Author(s):  
Zhang Guozhong ◽  
Xiao Wentao ◽  
Liu Gang ◽  
Lan Hao
Keyword(s):  
Crude Oil ◽  
Wave Velocity ◽  
Flow Rate ◽  
Pressure Wave ◽  
Viscoplastic Fluid ◽  
Essential Difference ◽  
Constant Flow ◽  
Transient Pressure ◽  
Waxy Crude Oil ◽  
Constant Flow Rate

Summary The results of pipe-flow experiments show that the advancement velocity of pressure is considerably slower than the transient-pressure-wave velocity during the startup of pipeline with compressible gelled crude oil under constant flow rate. The startup wave velocity that dominates the advancement velocity of pressure in pipeline with compressible gelled crude oil was described and explained, and the essential difference between the startup wave velocity and the transient-pressure-wave velocity was also described in detail. The startup wave front marks the substantive commencement of breakdown of gel structure, and also indicates when the flow rate starts to become stable in the pipeline segments passed through during startup under constant flow rate, so it is a crucial factor affecting the calculation of startup pressure. In this paper, the efficient numerical formulas to compute the startup wave velocity were deduced on the basis of the analysis of 1D flow of viscoplastic media in elastic pipeline. The reliability of the formulae was verified by the well agreement between the calculated values and the results of pipeline startup experiments carried out with the N-Y gelled crude oil. These formulas facilitate scientific analysis for the safe and economical operation of pipeline transporting waxy crude oil. During the initial startup of pipeline with compressible gelled crude oil under constant flow rate, the startup wave velocity is considerably slower than the transient-pressure-wave velocity, decreases with the increase of the propagation distance and the gel strength of crude oil, and increases with the increase of startup flow rate (the volume elastic/plastic coefficient of gelled crude oil and the ratio of the wall thickness to the inside diameter of the pipeline). It is noticeable that the formulae deduced in this paper are not limited to the pipelines with gelled crude oil. They are also applicable to most kinds of pipelines transporting compressible viscoplastic fluid with strong structure.

scholarly journals Leak detection using cepstrum of cross-correlation of transient pressure wave signals

2017 ◽  
Vol 232 (15) ◽  
pp. 2723-2735 ◽  
Author(s):  
Niloufar Motazedi ◽  
Stephen Beck
Keyword(s):  
High Precision ◽  
Pressure Wave ◽  
Cross Correlation ◽  
Detection Method ◽  
Leak Detection ◽  
Transient Pressure ◽  
Computational Simulations ◽  
Straight Pipe ◽  
The Cross

A new leak detection method is proposed here which is based on the cepstrum of the cross-correlation of the pressure signals from two transducers. Computational simulations of leaks with different properties, size, position and shape, in a straight pipe and a T-Junction network were studied. The proposed method was successful in estimating leakages and the pipeline features with a high precision. For the results with a straight pipe, this method is considerably more accurate than using the cross-correlation leak detection method or the cepstrum method alone. However, the results obtained by cepstrum and cepstrum of cross-correlation for the T-Junction case were quite accurate, while cepstrum alone showed a slightly better precision.

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