Flame Stretching in a Room Model With Natural Vent

2009 ◽  
Author(s):  
W. K. Chow ◽  
S. S. Han ◽  
Y. Gao ◽  
H. Dong ◽  
Y. Huo ◽  
...  
Keyword(s):  
Short Note ◽  
Flame Length ◽  
Pool Fire ◽  
Scale Model ◽  
Ceiling Vent ◽  
Set Up ◽  
Room Model ◽  
Real Scale ◽  
Pool Sizes

Flame stretching in a room with a ceiling vent will be discussed in this short note. A real-scale model was constructed with a gasoline pool fire placed inside. Another pool fire of the same size and amount of fuel was burnt outside the model. Different pool sizes of diameters 0.07 m, 0.08 m, 0.11 m, 0.16 m and 0.2 m were set up. Volume of gasoline varied from 30 ml to 500 ml to give different burning durations. The flame lengths of the two fires were measured and compared. It is observed that the flame length of the pool fire inside the room was over 20% higher than that outside at the later stage of the fire.

Observations on Flame Stretching in a Room Model With Natural Vent

2008 ◽  
Author(s):  
W. K. Chow ◽  
C. K. Law
Keyword(s):  
Short Note ◽  
Flame Length ◽  
Pool Fire ◽  
Small Model ◽  
Ceiling Vent ◽  
Room Model

Flame stretching in a room with a ceiling vent will be discussed in this short note. A small model was constructed with a pool fire placed inside. Another pool fire of the same size and amount of fuel was burnt outside the model. The flame lengths of the two fires were measured and compared. It is observed that the flame length of the pool fire inside the model was higher than that outside. The value was even double at the later stage of the fire.

Scale Modeling Studies on Flame Stretching and Swirling in a Room With Natural Vents

2011 ◽  
Author(s):  
W. K. Chow ◽  
S. S. Han
Keyword(s):  
Side Wall ◽  
Fire Regimes ◽  
Pool Fire ◽  
Flame Height ◽  
Pool Fires ◽  
Scale Modeling ◽  
Modeling Studies ◽  
Long Time ◽  
Set Up ◽  
Room Model

Flame stretching and swirling in a room fire with natural vents will be studied with scale models in this paper. Experiments were carried out in two models of same size 18 cm by 15 cm by 15 cm with or without a movable wall. A total of 16 tests were carried out with different ceiling vent sizes and ventilation arrangement. Different propanol pool fires of diameters 0.11 m to 0.2 m were set up. Volume of propanol varied from 30 ml to 500 ml to give different burning durations. Two pool fires of same volume of fuel and diameter were used in each test, one put in the model and the other burnt outside. The flame lengths of the two fires inside and outside the room model were measured and compared. Two fire regimes under limited ventilation were observed in this scale modeling studies. Firstly, the pool fire inside the model burnt for a longer time with a taller flame when there is no ventilation provided to the model. At the later stage of the fire, the flame height inside the model stretched by over 20% taller than that for the pool fire outside the model. This fire scenario of having tall flame for a long time is very hazardous and should be considered in designing natural vents. Secondly, providing ventilation at the side wall of the model might induce swirling motion inside. Air will be supplied into the model to burn the pool fire faster with short duration. The flame swirled up to a tall height fast but not stretching up slowly as in the case with limited ventilation. The additional air intake flow can be taken as air pumping action.

scholarly journals Active Separation Control at the Pylon-Wing Junction of a Real-Scale Model

AIAA Journal ◽  
2019 ◽  
Vol 57 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Philipp Schloesser ◽  
Vitaly Soudakov ◽  
Matthias Bauer ◽  
Jochen Wild
Keyword(s):  
Scale Model ◽  
Separation Control ◽  
Real Scale

scholarly journals A Study on turbulence-combustion interaction and Sub-grid Scale model in the simulation of Methane pool fire using LES

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Mohammad Safarzadeh ◽  
Ghassem Heidarinejad ◽  
Hadi Pasdarshahri
Keyword(s):  
Pool Fire ◽  
Scale Model

scholarly journals A Scale Model of Tension Structures in Road Tunnels to Optimize the Use of Solar Light for Energy Saving

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Antonio Peña-García ◽  
Luisa-María Gil-Martín ◽  
Roberto Escribano ◽  
Antonio Espín-Estrella
Keyword(s):  
Energy Savings ◽  
Construction Materials ◽  
Electricity Consumption ◽  
Scale Model ◽  
Major Influence ◽  
Road Tunnels ◽  
Tension Structures ◽  
Materials Used ◽  
Set Up ◽  
New Equation

Shifting the threshold zone of road tunnels with semitransparent tension structures has shown itself to be an effective way of saving energy in regards to electricity consumption, maintenance, and construction materials used in the electrical lighting, thus lessening negative environmental impacts. Even though the shape of the tension structure has a major influence on energy savings, the optimal type of structure for each tunnel is often difficult to determine, because experiments using real tunnels are extremely expensive. It is thus necessary to find methods of doing this that are both reliable as well as economical. In this research study, three candidate structures were set up at the portal of a scale model of a real tunnel. The energy savings in each case were analyzed and compared. As a result, it was possible to formulate a new equation that calculates the energy savings in the threshold zone.

High Resolution Large Eddy Simulations to Evaluate Turbulence Properties Within a Real Helicopter Engine Combustor

2018 ◽  
Author(s):  
Charlie Koupper ◽  
Jean Lamouroux ◽  
Stephane Richard ◽  
Gabriel Staffelbach
Keyword(s):  
Gas Turbine ◽  
Turbulence Intensity ◽  
Numerical Scheme ◽  
Mesh Refinement ◽  
Large Eddy Simulations ◽  
Scale Model ◽  
Large Eddy ◽  
Set Up ◽  
High Level ◽  
The Impact

In a gas turbine, the combustor is feeding the turbine with hot gases at a high level of turbulence which in turns strongly enhances the heat transfer in the turbine. It is thus of primary importance to properly characterize the turbulence properties found at the exit of a combustor to design the turbine at its real thermal constraint. This being said, real engine measurements of turbulence are extremely rare if not inexistent because of the harsh environment and difficulty to implement experimental techniques that usually operate at isothermal conditions (e.g. hot wire anemometry). As a counterpart, high fidelity unsteady numerical simulations using Large Eddy Simulations (LES) are now mature enough to simulate combustion processes and turbulence within gas turbine combustors. It is thus proposed here to assess the LES methodology to qualify turbulence within a real helicopter engine combustor operating at take-off conditions. In LES, the development of turbulence is primarily driven by the level of real viscosity in the calculation, which is the sum of three contributions: laminar (temperature linked), turbulent (generated by the sub-grid scale model) and artificial (numerics dependent). In this study, the impact of the two main sources of un-desired viscosity is investigated: the mesh refinement and numerical scheme. To do so, three grids containing 11, 33 and 220 million cells for a periodic sector of the combustor are tested as well as centred second (Lax-Wendroff) and third order (TTGC) in space schemes. The turbulence properties (intensity and integral scales) are evaluated based on highly sampled instantaneous solutions and compared between the available simulations. Results show first that the duration of the simulation is important to properly capture the level of turbulence. If short simulations (a few combustor through-times) may be sufficient to evaluate the turbulence intensity, a bias up to 14% is introduced for the turbulence length scales. In terms of calculation set-up, the mesh refinement is found to have a limited influence on the turbulence properties. The numerical scheme influence on the quantities studied here is small, highlighting that the employed schemes dissipation properties are already sufficient for turbulence characterization. Finally, spatially averaged values of turbulence intensity and lengthscale at the combustor exit are almost identically predicted in all cases. However, significant variations from hub to tip are reported, which questions the pertinence to use 0-D turbulence boundary conditions for turbines. Based on the set of simulations discussed in the paper, guidelines can be derived to adequately set-up (mesh, scheme) and run (duration, acquisition frequency) a LES when turbulence evaluation is concerned. As no experimental counterpart to this study is available, the conclusions mainly aim at knowing the possible numerical bias rather than commenting on the predictivity of the approach.

scholarly journals Upscaling of a local model into a larger-scale model

Ocean Science ◽  
2019 ◽  
Vol 15 (2) ◽  
pp. 291-305
Author(s):  
Luc Vandenbulcke ◽  
Alexander Barth
Keyword(s):  
Data Transfer ◽  
Scale Model ◽  
Test Case ◽  
Western Basin ◽  
Nested Model ◽  
Upscaling Technique ◽  
Basin Scale ◽  
Online Exchange ◽  
Operational Systems ◽  
Set Up

Abstract. Traditionally, in order for lower-resolution, global- or basin-scale (regional) models to benefit from some of the improvements available in higher-resolution subregional or coastal models, two-way nesting has to be used. This implies that the parent and child models have to be run together and there is an online exchange of information between both models. This approach is often impossible in operational systems where different model codes are run by different institutions, often in different countries. Therefore, in practice, these systems use one-way nesting with data transfer only from the parent model to the child models. In this article, it is examined whether it is possible to replace the missing feedback (coming from the child model) by data assimilation, avoiding the need to run the models simultaneously. Selected variables from the high-resolution simulation will be used as pseudo-observations and assimilated into the low-resolution models. This method will be called “upscaling”. A realistic test case is set up with a model covering the Mediterranean Sea, and a nested model covering its north-western basin. Under the hypothesis that the nested model has better prediction skills than the parent model, the upscaling method is implemented. Two simulations of the parent model are then compared: the case of one-way nesting (or a stand-alone model) and a simulation using the upscaling technique on the temperature and salinity variables. It is shown that the representation of some processes, such as the Rhône River plume, is strongly improved in the upscaled model compared to the stand-alone model.

Some Experimental Results on Internal Fire Whirls in a Vertical Shaft

2013 ◽  
Author(s):  
Y. Gao ◽  
G. W. Zou ◽  
S. S. Li ◽  
W. K. Chow
Keyword(s):  
Full Scale ◽  
Pool Fire ◽  
Experimental Results ◽  
Vertical Shaft ◽  
Remote Site ◽  
Scale Modeling ◽  
Key Factor ◽  
Fire Whirl ◽  
Real Scale

Earlier studies on burning a pool fire in a vertical shaft model indicated that appropriate sidewall ventilation provision is a key factor for the onset of an internal fire whirl. Experiments on burning a pool fire inside a real-scale shaft model of 9 m tall were performed to further investigate the swirling motion. The full-scale modeling burning tests were carried out at a remote site in China. Four different ventilation openings were arranged. Results of onsetting of internal fire whirls for the four tests will be reported.

Semi-automatic calibration procedure for the vision-robot interface applied to scale model decoration

Robotica ◽  
1992 ◽  
Vol 10 (4) ◽  
pp. 303-308
Author(s):  
Luis Gonzaga Trabasso ◽  
Cezary Zielinski
Keyword(s):  
Three Dimensional ◽  
Robot Vision ◽  
Work Load ◽  
Calibration Procedure ◽  
Scale Model ◽  
Three Dimensional Objects ◽  
University Of Technology ◽  
Scale Models ◽  
Set Up ◽  
Small Work

SUMMARYA semi-automatic method for calibrating a robot-vision interface is presented. It puts a small work-load on the operator, requires a simple calibration jig and a solution of a very simple system of equations. It has been extensively used in an experimental robotic cell set up at Loughborough University of Technology, where various aspects of the manufacturing and the decoration of scale models are being investigated. As an extension of the calibration procedure, the paper also shows practical solutions for the problem of dealing with three dimensional objects using a single camera.

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