scholarly journals FDS MODELING OF THE FIRE-PREVENTING EAVES EFFECTIVENESS TO PREVENT THE FIRE SPREADING ON FACADE OF HIGH-RISE BUILDINGS

2021 ◽  
Vol 23 ◽  
pp. 39-45
Author(s):  
R. Yakovchuk ◽  
Ya. Ballo ◽  
A. Kuzyk ◽  
O. Kagitin ◽  
V. Kovalchuk
Keyword(s):  
Initial Conditions ◽  
Structural Parameters ◽  
Numerical Algorithms ◽  
Equation System ◽  
Navier Stokes ◽  
Design Parameters ◽  
Fire Prevention ◽  
Building Structures ◽  
Fire Dynamics ◽  
High Rise

Purpose. Applying FDS modelling to detect the influence of structural parameters of facade fire eaves, the effectiveness of fire prevention by vertical building structures in high-rise buildings.Methods. To calculate the temperature in the high-rise building model used Pyrosim computer system that serves as the user's shell application Fire Dynamics Simulator (FDS). This FDS system uses numerical algorithms to solve the complete Navier-Stokes differential equation system to determine temperature and other hazardous factors during a fire.Results. The results of FDS modelling during substantiation of constructive parameters of fire eaves, which protrude beyond the facade and located on the border of fire compartments along the contour of high-rise buildings with a nominal height of more than 73.5 m, are presented. Premises and substantiated the criteria for the destruction of external light openings (windows) as an integral factor in the spread of fire on the external vertical building structures of high-rise ПОЖЕЖНА БЕЗПЕКА40 Вісник ЛДУБЖД, №23, 2021buildings. A study of the effectiveness of the structural parameters of cornices and their impact on the effectiveness of fire prevention by vertical building structures under the same initial conditions of fire development. Constructed comparative dependences of distribution of temperatures of heating of a facade of the house. Also defined the duration of achievement of their critical values.Scientific novelty. The analysis of the data obtained as a result of FDS modelling under the same initial conditions and conclusions on the effectiveness of design parameters of fire facade cornices on the border of fire compartments and ways to further improve their design to prevent the spread of fire in high-rise buildings. These studies are aimed at their use by design institutions during the development of design parameters of fire eaves, which protrude beyond the facade and are located on the border of fire compartments along the contour of high-rise buildings, as well as to improve the regulatory framework for fire safety.

scholarly journals INVESTIGATION OF DESIGN PARAMETERS FACADE FIRE-FIGHTING EAVES FOR PREVENT THE SPREAD OF FIRES ON FACADE STRUCTURES OF HIGH-RISE BUILDINGS

Fire Safety ◽  
2021 ◽  
Vol 37 ◽  
pp. 16-23
Author(s):  
Ya. Ballo ◽  
R. Yakovchuk ◽  
V. Nizhnyk ◽  
O. Sizikov ◽  
A. Kuzyk
Keyword(s):  
Reference Conditions ◽  
Numerical Algorithms ◽  
Equation System ◽  
Fire Spread ◽  
Fire Fighting ◽  
Design Parameters ◽  
Fire Dynamics ◽  
High Rise ◽  
Building Facades ◽  
Fire Spreading

Purpose. The research based on FDS modeling aims to identify design parameters influence of the façade firefighting eaves at fire compartment border on the prevention of fire spreading in high-rise buildings.Methods. To calculate the temperature in high-rise building model Pyrosim computer system is used which serves as the user's shell application Fire Dynamics Simulator (FDS). This FDS system uses numerical algorithms to solve the complete Navier-Stokes differential equation system to determine the temperature and other hazardous factors during a fire.Results. This article deals with the results of using the FDS modeling to substantiate fire-fighting eaves design parameters, which are extended beyond the facade and are located at fire compartment border along the perimeter of high-rise buildings with a conventional height of more than 73.5 m. A comparative analysis of eaves' design parameters and their effect on the temperature distribution along the building facade during a possible fire was conducted. Comparative dependences of tempera-ture distribution on building facades were constructed, as well as their heating areas were determined.Scientific novelty. According to national and foreign regulations requirement analytical research and information sources on the of high-rise buildings design, fire safety requirements to the high-rise public buildings facades with a conventional height of more than 73.5 m were scientifically substantiated in terms of the requirements formation for limiting the fire spreading, smoke and building facades exterior constructions heating.Practical value. Obtained data was analyzed as a result of FDS modeling under the same reference conditions to provide a conclusion on facade fire-fighting eaves design parameters effectiveness at fire compartment border and further improvement ways of their construction and fire spread prevention in high-rise buildings.

Adaptive Control of a Base Isolated System for Protection of Building Structures

2005 ◽  
Vol 128 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Jing Zhou ◽  
Changyun Wen ◽  
Wenjian Cai
Keyword(s):  
Base Isolation ◽  
Controller Design ◽  
Structural Parameters ◽  
External Disturbance ◽  
Nonlinear Behavior ◽  
Residual Effect ◽  
Design Parameters ◽  
Building Structures ◽  
Active Protection ◽  
Bounded Disturbance

In this paper, we present two adaptive backstepping control algorithms for a second-order uncertain hysteretic structural system found in base isolation scheme for seismic active protection of building structures. The hysteretic nonlinear behavior is described by a Bouc–Wen model. The structural parameters and isolation parameters are all uncertain parameters. In the first scheme, there is no apriori information required from these parameters and the residual effect of the hysteresis is treated as a bounded disturbance. An update law is used to estimate the bound involving this partial hysteresis effect and external disturbance. In the second scheme, we further take the structure of the Bouc–Wen model describing the hysteresis into account in the controller design, if apriori knowledge on some parameters of the model is available. It is shown that not only is global stability guaranteed by the proposed controller, but also both transient and asymptotic performances are quantified as explicit functions of the design parameters so that designers can tune the design parameters in an explicit way to obtain the required closed loop behavior.

scholarly journals Effect of an oscillating time-dependent pressure gradient on Dean flow: transient solution

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Basant K. Jha ◽  
Dauda Gambo
Keyword(s):  
Pressure Gradient ◽  
Initial Conditions ◽  
Fluid Velocity ◽  
Outer Cylinder ◽  
Time Dependent ◽  
Navier Stokes ◽  
Dean Flow ◽  
Continuity Equations ◽  
Riemann Sum ◽  
Flow Formation

Abstract Background Navier-Stokes and continuity equations are utilized to simulate fully developed laminar Dean flow with an oscillating time-dependent pressure gradient. These equations are solved analytically with the appropriate boundary and initial conditions in terms of Laplace domain and inverted to time domain using a numerical inversion technique known as Riemann-Sum Approximation (RSA). The flow is assumed to be triggered by the applied circumferential pressure gradient (azimuthal pressure gradient) and the oscillating time-dependent pressure gradient. The influence of the various flow parameters on the flow formation are depicted graphically. Comparisons with previously established result has been made as a limit case when the frequency of the oscillation is taken as 0 (ω = 0). Results It was revealed that maintaining the frequency of oscillation, the velocity and skin frictions can be made increasing functions of time. An increasing frequency of the oscillating time-dependent pressure gradient and relatively a small amount of time is desirable for a decreasing velocity and skin frictions. The fluid vorticity decreases with further distance towards the outer cylinder as time passes. Conclusion Findings confirm that increasing the frequency of oscillation weakens the fluid velocity and the drag on both walls of the cylinders.

scholarly journals Numerical Modelling of Reinforced Concrete Slender Walls Subjected to Coupled Axial Tension–Flexure

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Element Model ◽  
Lateral Loading ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
High Rise ◽  
Ultimate Deformation ◽  
Axial Tension ◽  
Plastic Hinge Length

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.

Automatic Three-Dimensional Optimisation of a Modern Tandem Compressor Vane

2014 ◽  
Author(s):  
R. C. Schlaps ◽  
S. Shahpar ◽  
V. Gümmer
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Trust Region ◽  
Automatic Generation ◽  
Navier Stokes ◽  
Design Parameters ◽  
High Fidelity ◽  
Stall Margin ◽  
Design Choice ◽  
Multipoint Approximation

In order to increase the performance of a modern gas turbine, compressors are required to provide higher pressure ratio and avoid incurring higher losses. The tandem aerofoil has the potential to achieve a higher blade loading in combination with lower losses compared to single vanes. The main reason for this is due to the fact that a new boundary layer is generated on the second blade surface and the turning can be achieved with smaller separation occurring. The lift split between the two vanes with respect to the overall turning is an important design choice. In this paper an automated three-dimensional optimisation of a highly loaded compressor stator is presented. For optimisation a novel methodology based on the Multipoint Approximation Method (MAM) is used. MAM makes use of an automatic design of experiments, response surface modelling and a trust region to represent the design space. The CFD solutions are obtained with the high-fidelity 3D Navier-Stokes solver HYDRA. In order to increase the stage performance the 3D shape of the tandem vane is modified changing both the front and rear aerofoils. Moreover the relative location of the two aerofoils is controlled modifying the axial and tangential relative positions. It is shown that the novel optimisation methodology is able to cope with a large number of design parameters and produce designs which performs better than its single vane counterpart in terms of efficiency and numerical stall margin. One of the key challenges in producing an automatic optimisation process has been the automatic generation of high-fidelity computational meshes. The multi block-structured, high-fidelity meshing tool PADRAM is enhanced to cope with the tandem blade topologies. The wakes of each aerofoil is properly resolved and the interaction and the mixing of the front aerofoil wake and the second tandem vane are adequately resolved.

A Dynamic Model for the Design of Methanol to Hydrogen Steam Reformers for Transportation Applications

2004 ◽  
Vol 126 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Gregory L. Ohl ◽  
Jeffrey L. Stein ◽  
Gene E. Smith
Keyword(s):  
Response Time ◽  
Dynamic Model ◽  
First Principles ◽  
Initial Conditions ◽  
Design Parameters ◽  
Physical Parameters ◽  
Steam Reformer ◽  
Powerful Means ◽  
Steam Reformers ◽  
Transportation Applications

As an aid to improving the dynamic response of the steam reformer, a dynamic model is developed to provide preliminary characterizations of the major constraints that limit the ability of a reformer to respond to the varying output requirements occurring in vehicular applications. This model is a first principles model that identifies important physical parameters in the steam reformer. The model is then incorporated into a design optimization process, where minimum steam reformer response time is specified as the objective function. This tool is shown to have the potential to be a powerful means of determining the values of the steam reformer design parameters that yield the fastest response time to a step input in hydrogen demand for a given set of initial conditions. A more extensive application of this methodology, yielding steam reformer design recommendations, is contained in a related publication.

A Study of the Anchor Effect Based on Structural Parameters of Flexible Pressurized Anchor and Pressure from Surrounding Rock

2011 ◽  
Vol 71-78 ◽  
pp. 4634-4637
Author(s):  
Tian Lin Cui ◽  
Jing Kun Pi ◽  
Yong Hui Liu ◽  
Zhen Hua He
Keyword(s):  
Structural Parameters ◽  
Structural Features ◽  
Surrounding Rock ◽  
Design Parameters ◽  
Optimized Design ◽  
Anchor Effect ◽  
The Finite Element Method ◽  
Anchor System ◽  
New Type ◽  
Stress Relation

In order to optimize the design of flexible pressurized anchor, this paper gives a further analysis on structural features of the new type of flexible pressurized anchor and carries out a contact analysis on anchor system by using the finite element method. It calculates as well as researches the contact stress relation of interactional anchor rod and surrounding rock under the circumstance of anchoring, obtaining the law of all major design parameters of anchor rod structure and pressure from surrounding rock influencing the anchoring performance and arriving at the conclusion that the anchor rod is adapted to various conditions of surrounding rock. They not only serve as important references for optimized design and application of anchor rod, but also provide a basis for the experiment of new type of anchor rod.

An Automated CFD Design and Analysis Tool for Inlet-Bleed Systems

1998 ◽  
Author(s):  
Tom I-P. Shih ◽  
Yu-Liang Lin ◽  
Andrew J. Flores ◽  
Mark A. Stephens ◽  
Mark J. Rimlinger ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Incident Shock ◽  
Navier Stokes ◽  
Oblique Shock Wave ◽  
Design Parameters ◽  
Analysis Tool ◽  
Cfd Analysis ◽  
Circular Holes ◽  
Embedded Grids

Abstract A pre-processor was developed to assist CFD experts and non-experts in performing steady, three-dimensional Navier-Stokes analysis of a class of inlet-bleed problems involving oblique shock-wave/ boundary-layer interactions on a flat plate with bleed into a plenum through rows of circular holes. With this pre-processor, once geometry (e.g., hole dimensions and arrangement) and flow conditions (e.g., Mach number, boundary-layer thickness, incident shock location) are inputted, it will automatically generate every file needed to perform a CFD analysis from the grid system to initial and boundary conditions. This is accomplished by accessing a knowledge base established by experts who understand both CFD and the class of problems being analyzed. For experts in CFD, this tool greatly reduces the amount of time and effort needed to setup a problem for CFD analysis. It also provides experts with knobs to make changes to the setup if desired. For non-experts in CFD, this tool enables reliable and correct usage of CFD. A typical session on a workstation from data input to the generation of all files needed to perform a CFD analysis involves less than ten minutes. This pre-processor, referred to as AUTOMAT-V2, is an improved version of a code called AUTOMAT. Improvements made include: (1) multi-block structured grids can be patched in addition to being overlapped; (2) embedded grids can be introduced near bleed holes to reduce the number of grid points/cells needed by a factor of up to four; (3) grid systems generated allow up to three levels of multigrid; (4) CFL3D is supported in addition to OVERFLOW, two well-known and highly regarded Navier-Stokes solvers developed at NASA’s Langley and Ames Research Centers; (5) all files needed to run RONNIE for patched grids and MAGGIE for overlapped grids are also generated; and (6) more design parameters can be investigated including the study of micro bleed and effects of flow/hole misalignments.

scholarly journals Conducting experimental investigations of wind influence on high-rise constructions

2018 ◽  
Vol 33 ◽  
pp. 02067 ◽  
Author(s):  
Olga I. Poddaeva ◽  
Anastasia N. Fedosova ◽  
Pavel S. Churin ◽  
Julia S. Gribach
Keyword(s):  
Aerodynamic Drag ◽  
Experimental Investigations ◽  
Building Structures ◽  
High Rise ◽  
Aerodynamic Pressure ◽  
Stage Of Development ◽  
Wind Influence ◽  
Under Construction ◽  
Building Designs ◽  
The Impact

The design of buildings with a height of more than 100 meters is accompanied by strict control in determining the external loads and the subsequent calculation of building structures, which is due to the uniqueness of these facilities. An important factor, the impact of which must be carefully studied at the stage of development of project documentation, is the wind. This work is devoted to the problem of studying the wind impact on buildings above 100 meters. In the article the technique of carrying out of experimental researches of wind influence on high-rise buildings and constructions, developed in the Educational-research-and-production laboratory on aerodynamic and aeroacoustic tests of building designs of NRU MGSU is presented. The publication contains a description of the main stages of the implementation of wind tunnel tests. The article presents the approbation of the methodology, based on the presented algorithm, on the example of a high-rise building under construction. This paper reflects the key requirements that are established at different stages of performing wind impact studies, as well as the results obtained, including the average values of the aerodynamic pressure coefficients, total forces and aerodynamic drag coefficients. Based on the results of the work, conclusions are presented.

Computational Characterization of Passive Fluid Mixing in Microfluidics

Volume 3 ◽  
2004 ◽  
Author(s):  
Erik D. Svensson
Keyword(s):  
Stokes Equations ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Fluid Mixing ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Fluid Systems ◽  
Sensitive Dependence ◽  
Microfluidic Mixers

In this work we computationally characterize fluid mixing in a number of passive microfluidic mixers. Generally, in order to systematically study and characterize mixing in realistic fluid systems we (1) compute the fluid flow in the systems by solving the stationary three-dimensional Navier-Stokes equations or Stokes equations with a finite element method, and (2) compute various measures indicating the degree of mixing based on concepts from dynamical systems theory, i.e., the sensitive dependence on initial conditions and mixing variance.

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