scholarly journals Smoke Obscuration Measurements in Reduced-Scale Fire Modelling Based on Froude Number Similarity

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3628 ◽  
Author(s):  
Wojciech Węgrzyński ◽  
Piotr Antosiewicz ◽  
Tomasz Burdzy ◽  
Mateusz Zimny ◽  
Adam Krasuski
Keyword(s):  
Froude Number ◽  
Similarity Criterion ◽  
Optical Filters ◽  
Optical Path Length ◽  
Full Scale ◽  
Fire Modelling ◽  
Smoke Layer ◽  
New Type ◽  
Geometrical Scale ◽  
Reduced Scale

A common method for investigating various fire- and smoke-related phenoma is a reduced-scale fire modelling that uses the conservation concept of Froude number as its primary similarity criterion. Smoke obscuration measurements were not commonly used in this approach. In this paper, we propose a new type of optical densitometer that allows for smoke obscuration density measurements on a reduced-scale. This device uses a set of mirrors to increase the optical path length, so that the device may follow the geometrical scale of the model, but that still measures smoke obscuration as if it were in full scale. The principle of operation is based on the Bougher-Lambert-Beer law, with modifications related to the Froude number-based scaling principles, to streamline the measurements. The proposed low-budget (< $1000) device was built, calibrated with a set of the reference optical filters, and used in a series of full- (1:1) and reduced-scale (1:4) experiments with n-Heptane fires in a small compartment. The main limitation of this study is the assumption that there is similar soot production in full- and reduced-scale fires, which may not be true for many Froude-number scaling applications. Therefore, it must be investigated in a case-by-case basis. In our case, the results are promising. The measured obscuration in the reduced-scale had a 10% error versus averaged measurements in full-scale measurements. Moreover, there were well represented transient changes of the smoke layer optical density during the combustion and after the smoke layer settled.

Spraying Experiments with a Model Stern Trawler

1998 ◽  
Vol 42 (04) ◽  
pp. 260-265 ◽  
Author(s):  
K. K. Chung ◽  
E. P. Lozowski ◽  
W. P. Zakrzewski ◽  
R. Gagnon ◽  
T. Thompson
Keyword(s):  
Statistical Analysis ◽  
Froude Number ◽  
Significant Wave Height ◽  
Flux Distribution ◽  
Full Scale ◽  
Scale Model ◽  
Spray Droplet ◽  
Towing Tank ◽  
Ship Speed ◽  
Longitudinal Distance

With a view to formulating vessel spraying and icing models, 22 spraying experiments were performed in the IMD/NRC towing tank using a 1:13 scale model of the stern trawler MT Zandberg. Neglecting the effect of wind drag on the spray droplet trajectories, an empirical spray flux equation for the scale Zandberg was derived, based on a statistical analysis of the spraying data. Using Froude number scaling, this model-scale equation was transformed into a full-scale spray flux equation. This spraying study shows that the total spray flux generated during ship/wave collisions depends on ship speed (Vs) and significant wave height (H1/3) according to V3⅓, H7⅓ while the spray flux distribution over the foredeck varies exponentially with longitudinal distance. Using this full-scale spray flux equation, a spray trajectory model, taking wind drag effects into account, was subsequently developed.

Deterministic–stochastic approach to compartment fire modelling

2008 ◽  
Vol 465 (2104) ◽  
pp. 1029-1041 ◽  
Author(s):  
V Bertola ◽  
E Cafaro
Keyword(s):  
Deterministic Model ◽  
Random Noise ◽  
Stochastic Approach ◽  
Fire Dynamics ◽  
Arbitrary Degree ◽  
Compartment Fires ◽  
External Perturbations ◽  
Fire Modelling ◽  
Smoke Layer ◽  
Suitable Potential

A generalized Semenov model is proposed to describe the dynamics of compartment fires. It is shown that the transitions to flashover or to extinction can be described in the context of the catastrophe theory (or the theory of dynamical systems) by introducing a suitable potential function of the smoke layer temperature. The effect on the fire dynamics of random perturbations is then studied by introducing a random noise term accounting for internal and external perturbations with an arbitrary degree of correlation. While purely Gaussian perturbations (white noise) do not change the behaviour of the fire with respect to the deterministic model, perturbations depending on the model variable (‘coloured’ noise) may drive the system to different states. This suggests that the compartment fires can be controlled or driven to extinction by introducing appropriate external perturbations.

EVALUATION OF THE EFFECT OF THE NEW TYPE JOINT METAL AND COUNTERMEASURES AGAINST ROCKING BY FULL SCALE SHAKING TABLE TESTS OF EDO-EPS EMBANKMENT

2019 ◽  
Vol 34 (0) ◽  
pp. 153-160
Author(s):  
Tsuyoshi NISHI ◽  
Mihiro TANI ◽  
Natsuki HAYASHI ◽  
Tatsuro KUBOTA ◽  
Hiroyuki KYOKAWA ◽  
...  
Keyword(s):  
Full Scale ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
New Type

Design Optimization and Safety Evaluation of Cross-Sea Bridge Barrier

2011 ◽  
Vol 97-98 ◽  
pp. 100-107
Author(s):  
Lei Fang ◽  
Liang Zhang ◽  
Shu Ming Yan ◽  
Ning Jia ◽  
Min Jing ◽  
...  
Keyword(s):  
Design Optimization ◽  
Impact Test ◽  
Safety Evaluation ◽  
Full Scale ◽  
Finite Elements Analysis ◽  
Acceptance Criteria ◽  
Analysis And Design ◽  
Bridge Safety ◽  
Study Results ◽  
New Type

By comprehensive analysis and design optimization of barrier structure parameters, a new type of beam-and-post steel barrier was invented according to impact test condition and acceptance criteria of cross-sea bridge barrier. Full-scale impact tests and finite elements analysis were conducted to do safty evalution of the barrier. The results show that, ASI value is 1.62 for test and that is 1.67 for FEA, THIV is 30.7km/h for test and that is 31.2km/h for FEA. Working width is 0.88m for test and that is 0.62m for FEA. Occupant risk evaluation index can meet the requirements of level B and the working width can meet the requirements of level W3. Both of tracking and posture of vehicles are well. The study results above show that safety performance of cross-sea bridge barrier can meet or exceed the acceptance criteria. FEA results are consistent with Full-scale impact test, which validate the reliability of FEA. cross-sea bridge barrier can meet the highest test level for beam-and-post steel barrier, which can defend the out-of-control vehicles effectively and help to ensure the bridge safety.

scholarly journals Full-scale and reduced-scale tests on smoke movement in case of car park fire

2013 ◽  
Vol 57 ◽  
pp. 35-43 ◽  
Author(s):  
István Horváth ◽  
Jeroen van Beeck ◽  
Bart Merci
Keyword(s):  
Full Scale ◽  
Smoke Movement ◽  
Car Park ◽  
Reduced Scale

Stability of Smoke Layer Under Sprinkler Water Spray

2005 ◽  
Author(s):  
C. F. Zhang ◽  
R. Huo ◽  
Y. Z. Li ◽  
W. K. Chow
Keyword(s):  
Sprinkler System ◽  
Full Scale ◽  
Operating Pressure ◽  
Water Spray ◽  
Smoke Layer ◽  
The Stability

Stability of smoke layer induced by a fire will be studied in this paper. A series of full-scale burning tests were carried out to study the interaction of the hot smoke layer with a sprinkler water spray. A new rig was built to give a smoke layer. The results show that the stability of a smoke layer will be disturbed by the discharged water spray. The operating pressure of the sprinkler system is a key point. When the smoke layer lost its stability, the dragging force acting on the smoke layer was found to be less than the buoyancy.

scholarly journals THE ECONOMIC VALUE OP A NEW BREAKWATER ARMOUR UNIT 'DOLOS'

1966 ◽  
Vol 1 (10) ◽  
pp. 50 ◽  
Author(s):  
E.M. Merrifield ◽  
J.A. Zwamborn
Keyword(s):  
Economic Value ◽  
Full Scale ◽  
Field Conditions ◽  
Test Results ◽  
Shore Protection ◽  
Wave Channel ◽  
New Type ◽  
Rubble Mound ◽  
The Stability ◽  
Made In

The Dolos, a new type of armour unit which closely resembles a normal ship's anchor, was developed and tried out under field conditions on the main breakwater of East London harbour. Since these full-scale Dolosse proved very successful, tests were made in a wave channel to compare the stability of Dolosse with other known types of armour blocks. The test results showed that the Dolos is outstandingly stable, and since manufacture and random placing of Dolosse offers no particular difficulties it is concluded that in many cases the use of Dolosse in armour layers may lead to more economical solutions for rubble mound breakwater and shore protection works.

scholarly journals Performance analysis of a new system for night cooling of buildings on a full scale office room - CFD study

2021 ◽  
Vol 2116 (1) ◽  
pp. 012106
Author(s):  
M Lança ◽  
P J Coelho ◽  
J Viegas
Keyword(s):  
Natural Ventilation ◽  
Concrete Slab ◽  
Full Scale ◽  
Energy Saving Potential ◽  
Air Supply ◽  
New Type ◽  
Computational Fluid Dynamics Cfd ◽  
The Difference ◽  
Night Ventilation ◽  
Indoor Conditions

Abstract Night natural ventilation systems have been receiving increased attention in recent years because of their energy saving potential and environmental protection when used in passive instead of active cooling. A recently proposed novel system for cooling the building concrete slab is studied numerically in the present work. It consists of a new type of a Suspended Ceiling (SC) with a peripheral gap between it and the walls, combined with the positioning of the air supply and extraction grilles between the ceiling slab and the SC. The system relies only on night ventilation as a means for cooling down the structure of the building. This study focuses on the use of Computational Fluid Dynamics (CFD) to predict the airflow and thermal performance of this strategy and it is applied to a full scale office room. The calculations show that a SC with a gap can reduce the difference between the average temperatures at the end of the heating and the end of the cooling periods by 25% compared with the case of a full covered slab room scenario (tight SC). CFD proved to be a useful and accurate tool to predict indoor conditions in buildings.

scholarly journals Pioneering Construction Materials through Prototypological Research

Biomimetics ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 56 ◽  
Author(s):  
Felix Heisel ◽  
Dirk E. Hebel
Keyword(s):  
21St Century ◽  
Paradigm Shift ◽  
Building Materials ◽  
Construction Materials ◽  
Full Scale ◽  
Sustainable Construction ◽  
New Materials ◽  
Specific Question ◽  
New Type ◽  
Architectural Research

The article at hand follows the understanding that future cities cannot be built the same way as existing ones, inducing a radical paradigm shift in how we produce and use materials for the construction of our habitat in the 21st century. In search of a methodology for an integrated, holistic, and interdisciplinary development of such new materials and construction technologies, the chair of Sustainable Construction at KIT Karlsruhe proposes the concept of “prototypological” research. Coined through joining the terms “prototype” and “typology”, prototypology represents a full-scale application, that is an experiment and proof in itself to effectively and holistically discover all connected aspects and address unknowns of a specific question, yet at the same time is part of a bigger and systematic test series of such different typologies with similar characteristics, yet varying parameters. The second part of the article applies this method to the research on mycelium-bound building materials, and specifically to the four prototypologies MycoTree, UMAR, Rumah Tambah, and Futurium. The conclusion aims to place the results into the bigger research context, calling for a new type of architectural research.

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