scholarly journals Experimentally determined distribution of granular-flow characteristics in collisional bed load transport

2018 ◽  
Vol 180 ◽  
pp. 02061
Author(s):  
Václav Matoušek ◽  
Štěpán Zrostlík ◽  
Luigi Fraccarollo ◽  
Anna Prati ◽  
Michele Larcher

A series of laboratory experiments on turbulent open-channel two-phase flow in a form of intense bed load transport is reported. Measurements in a laboratory tilting flume included camera based imaging techniques to identify the structure of the flow at the local level. Obtained experimental distributions of two-phase flow related parameters - granular velocity, concentration, and temperature - across a collisional transport layer are discussed. The results are analysed together with additional measured quantities (discharges of mixture and grains, flow depth, bed slope etc). Our major goal is to evaluate the distribution of granular stresses across the transport layer with a special attention paid to the interface between the transport layer and the bed. Furthermore, comparisons are discussed between the experimental results and predictions produced by suitable kinetic-theory based models.

Equipment ◽  
2006 ◽  
Author(s):  
Marijus Seporaitis ◽  
S. Gasiunas ◽  
Raimondas Pabarcius

2021 ◽  
pp. 103813
Author(s):  
Dewei Wang ◽  
Shanbin Shi ◽  
Yucheng Fu ◽  
Kyle Song ◽  
Xiaodong Sun ◽  
...  

Data in Brief ◽  
2018 ◽  
Vol 16 ◽  
pp. 527-530 ◽  
Author(s):  
Abdalellah O. Mohmmed ◽  
Mohammad S. Nasif ◽  
Hussain H. Al-Kayiem

Author(s):  
Jorge Pinho ◽  
Patrick Rambaud ◽  
Saïd Chabane

The goal of this study is to understand the behavior of a safety relief valve in presence of a two-phase flow induced by cavitation, in which the mass flux tends to be reduced. Two distinct safety relief valves are tested: an API 2J3 type and a transparent model based on an API 1 1/2G3 type. Instead of using a spring, the design of both valves allows the adjustment of the disk at any desired lift. Tests are conducted with water at ambient temperature. Results show a similar influence of cavitation on the flow characteristics of both valves. The liquid pressure recovery factor FL, which is normally used to identify a choked flow condition in a control valve, is experimentally determined in a safety relief valve. The existence of a local minimum located at a height position L/D = 0.14 indicates in this position, a change on the flow characteristics of both valves. It is verified that the existence of a local minimum in the liquid recovery factor is related to the minimum cross section of the flow, which does not remain constant for every lift positions. Furthermore, it is remarked that in the case of the 2J3 safety valve, the blow down ring adjustment has significant influence on the location of the minimum cross sections of the flow.


Author(s):  
Feng Xiao ◽  
Mehriar Dianat ◽  
James J. McGuirk

A robust two-phase flow LES methodology is described, validated and applied to simulate primary breakup of a liquid jet injected into an airstream in either co-flow or cross-flow configuration. A Coupled Level Set and Volume of Fluid method is implemented for accurate capture of interface dynamics. Based on the local Level Set value, fluid density and viscosity fields are treated discontinuously across the interface. In order to cope with high density ratio, an extrapolated liquid velocity field is created and used for discretisation in the vicinity of the interface. Simulations of liquid jets discharged into higher speed airstreams with non-turbulent boundary conditions reveals the presence of regular surface waves. In practical configurations, both air and liquid flows are, however, likely to be turbulent. To account for inflowing turbulent eddies on the liquid jet interface primary breakup requires a methodology for creating physically correlated unsteady LES boundary conditions, which match experimental data as far as possible. The Rescaling/Recycling Method is implemented here to generate realistic turbulent inflows. It is found that liquid rather than gaseous eddies determine the initial interface shape, and the downstream turbulent liquid jet disintegrates much more chaotically than the non-turbulent one. When appropriate turbulent inflows are specified, the liquid jet behaviour in both co-flow and cross-flow configurations is correctly predicted by the current LES methodology, demonstrating its robustness and accuracy in dealing with high liquid/gas density ratio two-phase systems.


2014 ◽  
Vol 28 (2) ◽  
pp. 153-160
Author(s):  
Kenichi KATONO ◽  
Goro AOYAMA ◽  
Takuji NAGAYOSHI ◽  
Kenichi YASUDA ◽  
Koji NISHIDA

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