scholarly journals Optimization of an automated smoke control system in an industrial atrium

2019 ◽  
Vol 4 (1) ◽  
pp. 25-36
Author(s):  
Iman Mohamad Sharaf ◽  
Ghada El-Sawah
Keyword(s):  
Management System ◽  
Numerical Models ◽  
Systems Design ◽  
Pool Fire ◽  
Industrial Building ◽  
Smoke Control ◽  
Fire Control ◽  
Worst Case ◽  
Smoke Plume ◽  
Smoke Management

Pool fires are the most common hazard in many industrial applications. Therefore, automated fire control systems and occupational safety design codes and procedures are of major importance in industrial building systems design. Smoke is the main factor that causes deaths and casualties in fires. Thus, fire safety engineering (FSE) considers smoke management system as one of the most important factors. In this study, smoke generation during pool fire is numerically simulated to optimize the smoke management system. The smoke and temperature distributions inside a mechanically ventilated atrium are simulated using a computational fluid dynamic (CFD) transient model after initiating a diesel pool fire in the worst case scenario. Four numerical models are simulated and their results are compared to choose the model that optimizes smoke control. The models enable better approximations of the underlying physical phenomena in smoke transport for a single phase gas mixture. A velocity field approach is predicted using a turbulent standard k-ε model to study the domain with smoke plume. The ability to demonstrate and predict the flow field inside the atrium while the roof exhaust fans are operating is also investigated. The study aids in smoke management systems' design and helps to better understand of smoke plume behavior inside large spaces.

scholarly journals Assessing storm surge hazard and impact of sea level rise in the Lesser Antilles case study of Martinique

2017 ◽  
Vol 17 (9) ◽  
pp. 1559-1571 ◽  
Author(s):  
Yann Krien ◽  
Bernard Dudon ◽  
Jean Roger ◽  
Gael Arnaud ◽  
Narcisse Zahibo
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Numerical Models ◽  
Lesser Antilles ◽  
Adaptation Measures ◽  
Worst Case ◽  
Mitigation And Adaptation ◽  
The Impact

Abstract. In the Lesser Antilles, coastal inundations from hurricane-induced storm surges pose a great threat to lives, properties and ecosystems. Assessing current and future storm surge hazards with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave–current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique under present climate or considering a potential sea level rise. Results confirm that the wave setup plays a major role in the Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge – up to 100 % in some cases. The nonlinear interactions of sea level rise (SLR) with bathymetry and topography are generally found to be relatively small in Martinique but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.

scholarly journals Tsunamis from prospected mass failure on the Marsili submarine volcano flanks and hints for tsunami hazard evaluation

2020 ◽  
Vol 83 (1) ◽  
Author(s):  
G. Gallotti ◽  
F. Zaniboni ◽  
G. Pagnoni ◽  
C. Romagnoli ◽  
F. Gamberi ◽  
...  
Keyword(s):  
Numerical Models ◽  
Hydrothermal Activity ◽  
Hazard Evaluation ◽  
Medium Size ◽  
Tyrrhenian Sea ◽  
Submarine Volcano ◽  
Case Scenario ◽  
Worst Case ◽  
Tsunami Waves ◽  
Mass Failure

AbstractThe Marsili Seamount (Tyrrhenian Sea, Italy) is the largest submarine volcano in the Mediterranean Sea, located in the middle of the Marsili Basin, facing the Calabrian and Sicilian coasts on its eastern side, and the coasts of Sardinia on the opposite side. It has erupted in historical times, and its summit crest is affected by widespread hydrothermal activity. This study looks at mass failures taking place at different depths on the flanks of the volcano and estimates their associated tsunamigenic potential. Mass failure, tsunami generation, and propagation have been simulated by means of numerical models developed by the Tsunami Research Team of the University of Bologna. In all, we consider five cases. Of these, three scenarios, one regarding a very small detachment and two medium-sized ones (between 2 and 3 km3 failure volume), have been suggested as possible failure occurrences in the published literature on a morphological basis and involve the north-eastern and north-western sectors of the volcano. The two additional cases, one medium-sized and one extreme, intended as a possible worst-case scenario (volume 17.6 km3), affecting the eastern flank. Results indicate that small-volume failures are not able to produce significant tsunamis; medium-size failures can produce tsunamis which dangerously affect the coasts if their detachment occurs in shallow water, i.e., involves the volcano crest; and extreme volume failures have the potential to create disastrous tsunamis. In all the simulations, tsunami waves appear to reach the Aeolian Islands in around 10 min and the coasts of Calabria and Sicily in 20 min. This study highlights that there is a potential for dangerous tsunamis generation from collapses of the Marsili volcano and as a consequence a need to intensify research on its status and stability conditions. More broadly, this investigation should also be extended to the other volcanic seamounts of the Tyrrhenian Sea, since their eruptive style, evolution, and tsunamigenic potential are still poorly known.

scholarly journals Biased Information Passing Between Subsystems Over Time in Complex System Design

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Jesse Austin-Breneman ◽  
Bo Yang Yu ◽  
Maria C. Yang
Keyword(s):  
Complex System ◽  
System Design ◽  
Large Scale ◽  
Early Stage ◽  
Systems Design ◽  
System Level ◽  
Worst Case ◽  
Early Stage Design ◽  
Complex System Design ◽  
Biased Information

During the early stage design of large-scale engineering systems, design teams are challenged to balance a complex set of considerations. The established structured approaches for optimizing complex system designs offer strategies for achieving optimal solutions, but in practice suboptimal system-level results are often reached due to factors such as satisficing, ill-defined problems, or other project constraints. Twelve subsystem and system-level practitioners at a large aerospace organization were interviewed to understand the ways in which they integrate subsystems in their own work. Responses showed subsystem team members often presented conservative, worst-case scenarios to other subsystems when negotiating a tradeoff as a way of hedging against their own future needs. This practice of biased information passing, referred to informally by the practitioners as adding “margins,” is modeled in this paper with a series of optimization simulations. Three “bias” conditions were tested: no bias, a constant bias, and a bias which decreases with time. Results from the simulations show that biased information passing negatively affects both the number of iterations needed and the Pareto optimality of system-level solutions. Results are also compared to the interview responses and highlight several themes with respect to complex system design practice.

Vibration-Based SHM of Ordinary Buildings: Detection and Quantification of Structural Damage

2015 ◽  
Author(s):  
Alessio Pierdicca ◽  
Francesco Clementi ◽  
Diletta Maracci ◽  
Daniela Isidori ◽  
Stefano Lenci
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Residual Life ◽  
Numerical Models ◽  
Natural Aging ◽  
Real Structure ◽  
Industrial Building ◽  
Ground Acceleration ◽  
Earthquake Scenario ◽  
Structural Health

One of the most important issues in civil and in mechanical engineering is the detection of structural damages, which are defined as changes of material properties, of boundary conditions and of system connectivity, which adversely affect the system’s performances. The damage identification process generally requires establishing existence, localization, type and intensity of the damage. During its service life, a structure, besides his natural aging, can be subjected to earthquakes. These events may have a deep impact on building safety and a continuous monitoring of the structure health conditions, through Structural Health Monitoring (SHM) techniques, is necessary in many cases. Within this a background, the purpose of this work is to propose an integrated novel approach for the diagnosis of structures after a seismic event. The proposed monitoring system is based on recording the accelerations of the real structure during a seismic input, and the reintroduction of them into a numerical model, suitably tuned, in order to outline a possible post-earthquake scenario. This approach provides an estimation of the health of the building and of its residual life, and to detect and quantify the damage, some of the crucial aspects of SHM. Actually, we also get both online and self-diagnosis of the structural health. The technique is applied to a real structure, an industrial building liable of some seismic vulnerabilities. It it did not undergo an earthquake, so we have not recordered accelerations, and get them from a different numerical models subjected to the ground acceleration of a realistic earthquake.

scholarly journals Assessing storm surge hazard and impact of sea level rise in Lesser Antilles-Case study of Martinique

2017 ◽  
Author(s):  
Yann Krien ◽  
Bernard Dudon ◽  
Jean Roger ◽  
Gaël Arnaud ◽  
Narcisse Zahibo
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Numerical Models ◽  
Lesser Antilles ◽  
Adaptation Measures ◽  
Worst Case ◽  
Mitigation And Adaptation ◽  
The Impact

Abstract. In the Lesser Antilles, coastal inundations from hurricane-induced storm surges cause great threats to lives, properties, and ecosystems. Assessing current and future storm surge hazard with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave-current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique, under present climate or considering a potential sea-level rise. Results confirm that the wave setup plays a major role in Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge, up to 100 % in some cases. The non-linear interactions of sea level rise with bathymetry and topography are generally found to be relatively small in Martinique, but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles, and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.

Optimizing Low-Volume Road Network Performance Through Improved Management, Design, and Construction

2003 ◽  
Vol 1819 (1) ◽  
pp. 299-305 ◽  
Author(s):  
G. D. Van Zyl ◽  
M. G. Henderson ◽  
H. G. Fourie
Keyword(s):  
Management System ◽  
Road Network ◽  
Performance Monitoring ◽  
Systems Design ◽  
Western Cape ◽  
Road Management ◽  
Gravel Roads ◽  
Low Volume ◽  
Gravel Road ◽  
Design And Construction

The Provincial Administration of the Western Cape in South Africa is responsible for 18,900 km of proclaimed roads, of which 10,500 km are unsurfaced. A formal gravel road management system has been in operation since 1989 that assists in prioritizing projects for regraveling and upgrading gravel roads to surfaced standards. Because of fund limitations for upgrading gravel roads to surfaced roads, there is a need to optimize performance of the gravel road network and maximize use of knowledge and latest research results for southern Africa. Staff shortages and loss of in-house expertise made external assistance necessary to improve service to road users. Processes formalized, implemented, and planned for this purpose included ( a) upgrading the gravel road management system to quantify benefits, prioritize activities, and select maintenance and improvement measures; ( b) appointing consulting engineers in each district to help manage borrow pits, materials design, training, construction supervision and quality control, maintenance planning and control, and performance monitoring; ( c) communication about project priorities, construction programs, work methods, construction team performance, and activity costs; and ( d) development of an operational web-enabled system to manage all activities related to unsurfaced roads. Within 1 year, a remarkable difference in gravel road performance was observed without a significant reduction in productivity. Total transportation costs were lowered with only a marginal increase in agency costs. Continuous communication among system operators, design engineers, project managers, and construction teams is considered one of the most important aspects in optimizing performance of the Western Cape low-volume road network. This study highlights the most important changes in management, systems, design, and construction and the practical innovations responsible for the successes achieved as a potentially valuable aid to those involved with providing and maintaining low-volume roads.

scholarly journals Preliminary Study on Exhaust Efficiency of Smoke Management System in Tunnel Fires

2013 ◽  
Vol 52 ◽  
pp. 514-519 ◽  
Author(s):  
Qi-qi Xu ◽  
Liang Yi ◽  
Zhi-sheng Xu ◽  
De-xing Wu
Keyword(s):  
Management System ◽  
Smoke Management ◽  
Tunnel Fires ◽  
Preliminary Study

Numerical analysis of combined buoyancy-induced and pressure-driven smoke flow in complex vertical shafts during building fires

2016 ◽  
Vol 26 (6) ◽  
pp. 1684-1698 ◽  
Author(s):  
Yanqiu Chen ◽  
Xiaodong Zhou ◽  
Taolin Zhang ◽  
Zhijian Fu ◽  
Yuqi Hu ◽  
...  
Keyword(s):  
Heat Source ◽  
Control Systems ◽  
Systems Design ◽  
Research Approach ◽  
Smoke Control ◽  
Building Fires ◽  
Content Type ◽  
Smoke Flow ◽  
Significant Difference ◽  
Pressure Driven

Purpose – The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems. Design/methodology/approach – A total of 435 3-D fire simulations were conducted through NIST fire dynamics simulator to analyze thermal behavior of combined buoyancy-induced and pressure-driven smoke flow in complex vertical shafts, under consideration of influence of heat release rate (HRR) and locations of heat sources. This influence was evaluated through neutral pressure plane (NPP), which is a critical plane depicting the flow velocity distributions. Hot smoke flows out of shafts beyond the NPP and cold air flows into shafts below the NPP. Findings – Numerical simulation results show that HRR of heat source has little influence on NPP, while location of heat source can make a significant difference to NPP, particularly in cases of multi-heat source. Identifying the location of NPP helps to develop a more effective way to control the smoke with less energy consumption. Through putting an emphasis on smoke exhausting beyond the NPP and air supplying below the NPP, the smoke control systems can make the best use of energy. Research limitations/implications – Because of the chosen research approach, the research results may need to be tested by further experiments. Practical implications – The paper includes implications for the optimization of smoke control systems design in buildings. Originality/value – This paper fulfills an identified need to research the behavior of hot smoke in building fires and optimize the design of smoke control systems.

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