Visualization and Numerical Simulation of Exchange Flow in Density Different Gases

Buoyancy-driven exchange flows of helium-air through inclined a narrow tube was investigated. Exchange flows may occur following the opening of a window for ventilation, as well as when a pipe ruptures in a high temperature gas-cooled reactor. The experiment in this paper was carried out in a test chamber filled with helium and the flow was visualized using the smoke wire method. A high-speed camera recorded the flow behavior. The image of the flow was transferred to digital data, and the slow flow velocity, i.e. micro flow rate was measured by PIV software. Numerical simulation was carried out by the code of moving particle method with Lagrange method.

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Helium-Air Exchange Flow Rate Measurement Through a Small Opening

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2007-37008 ◽

2007 ◽

Author(s):

Motoo Fumizawa ◽

Hidenori Horiuchi

Keyword(s):

Flow Rate ◽

High Speed ◽

Flow Behavior ◽

Test Chamber ◽

Digital Data ◽

Cover Plate ◽

Vacuum Vessel ◽

Exchange Flow ◽

Counter Flow ◽

Mass Increment

Buoyancy-driven counter flows of helium-air were investigated through horizontal and inclined small openings. Counter flows may occur following a window opening as ventilation, fire in the room as well as a pipe rupture accident in a high temperature gas-cooled nuclear reactor [1]. The counter flows also occur following the fusion reactor accident of LOVA that takes place through the breaches of vacuum vessel penetration duct [2]. The experiment has carried out by a test chamber filled with helium and flow was visualized by the smoke wire method. The flow behavior has recorded by a high-speed camera with a computer system. The image of the flow was transferred to the digital data, thus the flow velocity was measured by PTV software. The mass fraction in the test chamber was measured by electronic balance. The detected data was arranged by the densimetric Floude number of the counter flow rate that derived from the dimensional analysis. The method of mass increment was developed and applied to measure the counter flow rate. By removing the cover plate placed on the top of the opening, the counter flow initiated. Air enters the test chamber and the mass of the gas mixture in the test chamber increased. The volumetric counter flow rate was evaluated from the mass increment data. In the case of inclination openings, the results of both methods were compared. The inclination angle for maximum densimetric Floude number decreased with increasing length-to-diameter ratio of the opening. For a horizontal opening, the results from the method of mass increment agreed with those obtained by other authors for a water-brine system.

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Study of Gas/Liquid Behavior Within an Aeroengine Bearing Chamber

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4007753 ◽

2013 ◽

Vol 135 (5) ◽

Cited By ~ 5

Author(s):

Budi Chandra ◽

Kathy Simmons ◽

Stephen Pickering ◽

Steven H. Collicott ◽

Nikolas Wiedemann

Keyword(s):

Film Thickness ◽

High Speed ◽

Flow Behavior ◽

Ambient Pressure ◽

Current Model ◽

Test Chamber ◽

Experimental Program ◽

Working Fluid ◽

Rotating Shaft ◽

Significant Difference

Aeroengine bearing chambers typically contain bearings, seals, shafts and static parts. Oil is introduced for lubrication and cooling and this creates a two phase flow environment that may contain droplets, mist, film, ligaments, froth or foam and liquid pools. Some regions of the chamber contain a highly rotating air flow such that there are zones where the flow is gravity dominated and zones where it is rotation dominated. The University of Nottingham Technology Centre in Gas Turbine Transmission Systems, is conducting an ongoing experimental program investigating liquid and gas flow behavior in a relevant highly rotating environment. Previously reported work by the UTC has investigated film thickness and residence volume within a simplified chamber consisting of outer cylindrical chamber, inner rotating shaft and cuboid off-take geometry (termed the generic deep sump). Recently, a more aeroengine relevant bearing chamber offtake geometry has been studied. This geometry is similar to one investigated at Purdue University and consists of a “sub-sump” region approached by curved surfaces linked to the bearing chamber. The test chamber consists of an outer, stationary cylinder with an inner rotating shaft. The rig runs at ambient pressure and the working fluid (water) is introduced either via a film generator on the chamber wall or through holes in the shaft. In addition to visual data (high speed and normal video), liquid residence volume within the chamber and film thickness were the two numerical comparators chosen. Data was obtained for a number of liquid supply rates, scavenge ratios and shaft rotation speeds. The data from the current model is compared to that from the earlier studies. The data shows that in contrast to the previously reported generic deep sump study, the residence volume of the curved wall deep sump (CWDS) designs is far less sensitive to shaft speed, liquid supply rate and scavenge ratio. The method of liquid supply only makes a significant difference at the lowest scavenge ratios. Residence volume data for the Nottingham CWDS is comparable, when appropriately scaled, to that for the Purdue design. The film thickness data shows that at the lower shaft speeds investigated the flow is gravity dominated whereas at higher shaft speeds shear dominates.

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Experimental and Numerical Simulation on Hydraulic Behavior of Molten Flow in the Lower Part in Reactor Core

Volume 5: Student Paper Competition ◽

10.1115/icone24-60572 ◽

2016 ◽

Author(s):

Kota Matsuura ◽

Hideaki Monji ◽

Susumu Yamashita ◽

Hiroyuki Yoshida

Keyword(s):

Numerical Simulation ◽

Liquid Film ◽

High Speed ◽

Nuclear Power ◽

Power Plants ◽

Flow Behavior ◽

Reactor Core ◽

Video Camera ◽

Working Fluid ◽

Simulation Code

In the decommissioning work of nuclear power plants, it is important to grasp the sedimentation place of molten materials. However, the technique to grasp exactly sedimentation place is not established now. Therefore, the detailed and phenomenological numerical simulation code named JUPITER for predicting the molten core behavior is developed. In the study, visualization experiment and numerical simulation were performed to validate the applicability of the JUPITER to the hydraulic relocation behavior in core internals. The test section used in this experiment simulated the structure of the core internals, such as a control rod and a fuel support piece, simply. The working fluid is water under the atmospheric pressure. The experiment uses a high-speed video camera to visualize the flow behavior. The behavior and the speed of the liquid film in a narrow flow channel is obtained. For the numerical analysis carried out prior to the experiment, the behavior of flow down liquid was shown. The typical behavior was also observed that the tip of a liquid film flowing down splits into.

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Study of Gas/Liquid Behaviour Within an Aeroengine Bearing Chamber

Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation ◽

10.1115/gt2012-68753 ◽

2012 ◽

Cited By ~ 2

Author(s):

Budi Chandra ◽

Kathy Simmons ◽

Stephen Pickering ◽

Steven H. Collicott ◽

Nikolas Wiedemann

Keyword(s):

Film Thickness ◽

High Speed ◽

Flow Behavior ◽

Ambient Pressure ◽

Current Model ◽

Test Chamber ◽

Experimental Program ◽

Working Fluid ◽

Rotating Shaft ◽

Significant Difference

Aeroengine bearing chambers typically contain bearings, seals, shafts and static parts. Oil is introduced for lubrication and cooling and this creates a two phase flow environment that may contain droplets, mist, film, ligaments, froth or foam and liquid pools. Some regions of the chamber contain a highly rotating air flow such that there are zones where the flow is gravity dominated and zones where it is rotation dominated. The University of Nottingham Technology Centre in Gas Turbine Transmission Systems, is conducting an ongoing experimental program investigating liquid and gas flow behavior in a relevant highly rotating environment. Previously reported work by Chandra et al [1, 2] has investigated film thickness and residence volume within a simplified chamber consisting of outer cylindrical chamber, inner rotating shaft and cuboid off-take geometry (termed the generic deep sump). Recently a more aeroengine relevant bearing chamber offtake geometry has been studied. This geometry is similar to one investigated by Chandra [3] at Purdue University and consists of a “sub-sump” region approached by curved surfaces linked to the bearing chamber. The test chamber consists of an outer, stationary cylinder with an inner rotating shaft. The rig runs at ambient pressure and the working fluid (water) is introduced either via a film generator on the chamber wall or through holes in the shaft. In addition to visual data (high speed and normal video), liquid residence volume within the chamber and film thickness were the two numerical comparators chosen. Data was obtained for a number of liquid supply rates, scavenge ratios and shaft rotation speeds. The data from the current model is compared to that from the earlier studies [1, 2, & 3]. The data shows that in contrast to the previously reported generic deep sump study, the residence volume of the curved wall deep sump (CWDS) designs is far less sensitive to shaft speed, liquid supply rate and scavenge ratio. The method of liquid supply only makes a significant difference at the lowest scavenge ratios. Residence volume data for the Nottingham CWDS is comparable, when appropriately scaled, to that for the Purdue design. The film thickness data shows that at the lower shaft speeds investigated the flow is gravity dominated whereas at higher shaft speeds shear dominates.

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Numerical Simulation of Behavior of Sand Particles during High-Speed Penetration with Particle Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.715.198 ◽

2016 ◽

Vol 715 ◽

pp. 198-202

Author(s):

Ryota Shimono ◽

Keiko Watanabe

Keyword(s):

Numerical Simulation ◽

High Speed ◽

Free Particle ◽

Particle Method ◽

Particle Methods ◽

Sand Particle ◽

Mesh Free ◽

Research Themes ◽

Macro Scale ◽

Sand Particles

The phenomena that occur during high-speed penetration of a projectile into sand particles are interesting subjects in engineering. The macro-scale research themes are the behavior of the ejected sand particles and the progress of the high-speed projectile, while the micro-scale research themes are the deformation and fragmentation of a single sand particle. Studies of these unique phenomena were conducted using both experiments and numerical simulation. Although accurate simulation of the behavior of sand particles during high-speed penetration is difficult because sand particles have characteristics of both fluids and solids, the reproducibility of the actual phenomena has improved in recent years with the development of particle methods. In our research, we conducted simulations of the phenomena using Smoothed Particle Hydrodynamics (SPH), which is a mesh-free, particle-based method. The results showed the possibility of accurate reproduction during high-speed projectile penetration into sand particles at the macro-scale.

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