Impact pressure distribution of an SC-CO2 jet used in rock breakage

Author(s):  
Yong Liu ◽  
Juan Zhang ◽  
Jianping Wei ◽  
Chenchen Wang ◽  
Jiawei Cui
2019 ◽  
Vol 20 (1) ◽  
pp. 209-218
Author(s):  
Yu Wang ◽  
Yaan Hu ◽  
Jinde Gu ◽  
Yu Peng ◽  
Yang Xue

Abstract In view of high water head and large discharge in the release structures of hydraulic projects, the inverted arch plunge pool has been put forward due to higher overload capability and stability. Impact pressure on the bottom is a serious concern in design safety precautions, however, the quantitative impact pressure distribution in the inverted arch plunge pool is not yet elucidated. In this study, a novel approach is presented to estimate the impact pressure of an inverted arch plunge pool. Impact pressure characteristics are experimentally investigated under different hydraulic conditions. The results detailed the effect of relative discharge coefficient and the deflection angle relative to the vertical central axis of the plunge pool bottom. The predicting formulas of impact pressure distribution are derived within small relative errors, and the proposed approaches have good applicability in three case studies. The achievements of this investigation are used to define issuance parameters relevant for engineering practice.


2018 ◽  
Vol 25 (s1) ◽  
pp. 29-35 ◽  
Author(s):  
Duje Veic ◽  
Wojciech Sulisz

Abstract The problem of impact pressure distribution on a monopole structure excited by irregular breaking waves is investigated. The analysis is performed by applying a numerical model that combines potential flow model with a Navier-Stokes/VOF solution. The temporal pressure distribution is analysed for two breaking wave cases characterized by the significant difference in the steepness of the wave front. The peak impact pressures are observed in the region below the overturning wave jet where the pressure increases rapidly resulting in a peak value of the slamming coefficient equal to Cs=2π. The vertical load distribution provided by the derived model is more realistic than a rectangular shape distribution applied in engineering practice. This is because the vertical load distribution strongly depends on breaking wave shape and it is difficult to uniquely approximate such a load distribution by a rectangle.


2020 ◽  
Author(s):  
Michael L. Kyburz ◽  
Betty Sovilla ◽  
Johan Gaume ◽  
Christophe Ancey

<p>In order to estimate avalanche loads on buildings and structures of various sizes and geometries,  practitioners are interested in recommendations or experimental data for a wide variety of obstacle geometries and sizes. Full-scale avalanche measurements are performed across the world since the late 1970s to increase knowledge about avalanche flow behaviour, including impact on structures. These structures are usually equipped with sensors to measure impact pressure, avalanche velocity and/or snow density. Modifying the structure profile is hardly possible because of high construction costs. To date, it has thus been possible to test and calibrate empirical relationships used in engineering only on a limited number of structures for which experimental data exist. We therefore aim to calibrate the drag coefficient and amplification factor for a broader range of obstacle shapes and sizes. In this context the drag coefficient generalizes the drag coefficient used in Newtonian fluid mechanics when computing the flow past an obstacle. The amplification factor reflects the snow load’s deviation from a hydrostatic-like pressure. To estimate these two parameters, we simulate how an avalanche interacts with differently sized and shaped obstacles using the Discrete Element Method (DEM). First, we test the DEM model’s capacity to reproduce full-scale pressure measurements performed on two different obstacles at the Vallée de la Sionne test site by comparing simulated and measured impact pressures. Second, we run new simulations involving other geometries and dimensions, for which no experimental data exist. Our results show that the pressure distribution depends not only on the obstacle geometry, but also on avalanche flow regime and snow properties. We eventually examine the pressure distribution for different generic geometries and avalanche scenarios. This analysis should ultimately help to improve extant engineering guidelines.</p>


2011 ◽  
Vol 109 ◽  
pp. 551-556 ◽  
Author(s):  
Qun Luo ◽  
Kai He ◽  
He Mao ◽  
Jiu Hua Li ◽  
Quan Chang Li ◽  
...  

This paper presents a numerical simulation approach to analyze high velocity waterjet characteristics and impact pressure. For the complexity of waterjet formation in air, multiphase mixture flow model is used, and the simulation is performed in FLUNET software. The simulation includes the hydrodynamic characteristics and pressure distribution of high velocity waterjet in air. The decay of pressure at different distance along centerline under different pump pressure is analyzed and the length of the initial region of waterjet is determined. In addition, the impact pressure of waterjet at different stand-off distance is also simulated, and the impact pressure distribution and its changing tendency with the stand-off distance are obtained. This paper provides theoretical parameters for waterjet incremental sheet metal forming.


2016 ◽  
Vol 10 (6) ◽  
Author(s):  
Abubakar Jibrin Abbas ◽  
Ghasem Ghavami Nasr ◽  
Amir Nourian ◽  
Godpower Chimagwu Enyi

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