scholarly journals About dependence of parameters of internal explosion on the device of safety designs in apertures of the protecting walls of the production and residential buildings

2018 ◽  
Vol 251 ◽  
pp. 02015 ◽  
Author(s):  
Vyacheslav Gorev
Keyword(s):  
Burning Rate ◽  
Small Volume ◽  
Residential Buildings ◽  
Unit Weight ◽  
Gas Explosion ◽  
Building Collapse ◽  
The Real ◽  
Explosion Pressure ◽  
Internal Explosion ◽  
Pressure Unit

Protection of buildings against consequences of gas explosion indoors by means of the safety designs (SD) is widespread. In a number of the regulating documents requirements to these designs are imposed. It agrees, the regulating documents are allowed to carry out calculation of system of protection against internal explosion by means of the safety designs. The key sizes determining the area of apertures of the blocked safety designs are: speed of explosive combustion, most allowed explosion pressure, unit weight (per acre) the safety designs and pressure of opening of the safety designs. Under pressure openings it is meant pressure with which communications of the safety designs with walls of the building collapse and the safety designs starts moving. Depth of seal of the safety designs in an aperture remains out of sight and is supposed what influences the end result a little. In the real article an attempt to deal with this question is made. As a result of the conducted researches it was established that depth of seal of the safety designs in an aperture has to be considered when calculating system of protection of buildings against internal explosion by means of the safety designs. Especially it is important for rooms of small volume of V0≤120 of m3. For the analysis of explosion in the production buildings it is necessary to consider the volume of these rooms and a possibility of increase in burning rate because of existence of barriers indoors.

Study on Numerical Simulation of Gas Explosion inside Compression Compartment of Gas Filling Station

2014 ◽  
Vol 962-965 ◽  
pp. 531-538 ◽  
Author(s):  
Yu Wang ◽  
Yun Yi Wu
Keyword(s):  
Numerical Simulation ◽  
Influence Factors ◽  
Unit Weight ◽  
Point Location ◽  
Gas Explosion ◽  
Ignition Point ◽  
Explosion Pressure ◽  
Propagation Behavior ◽  
Filling Station ◽  
Open Pressure

For the compression compartment safety design in gas filling station, hazards of gas explosion inside compression compartment should be assessed, and explosion energy as well as influence factors should be determined. In this paper, numerical simulation was adopted to build 3D model of compression compartment and simulate gas explosion pressure and flame propagation behavior under different ignition point location, open-pressure and weight of relief panels. The results show that the ignition point location relative to the location of the vent opening and relief panel’s characteristics is very important for gas explosion inside compression compartment. The nearer the ignition point location is away from the venting opening location, the smaller the caused explosion pressure will be. For the relief panel, explosion pressure is proportional with the open-pressure and the weight of relief panel. Besides the rational distribution of ignition source and the adoption of relief panel with less unit weight and relief pressure, the crushing material damage and secondary hazard of flame should also be noticed in order to mitigate the hazard of gas explosion.

scholarly journals Dynamic Characteristics of Gas Explosion and Its Mitigation Measures inside Residential Buildings

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Kang Cen ◽  
Bin Song ◽  
Ruiqing Shen ◽  
Yidong Zhang ◽  
Wuge Yu ◽  
...  
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Subsequent Treatment ◽  
Area Ratio ◽  
Mitigation Measures ◽  
Maximum Temperature ◽  
Gas Explosion ◽  
The Real ◽  
Explosion Process ◽  
Simulation Results

Currently, there is very limited understanding of a gas explosion process inside residential buildings. In this study, a numerical model of gas explosion in a residential building was developed using Computational Fluid Dynamics (CFD). The numerical simulations were performed for different gas cloud filling regions and equivalence ratios to identify the initial scenario, and the simulation results were compared with the real consequences of gas explosion. Additionally, the temporal and spatial evolvement characteristics of explosion overpressure and indoor temperature were analyzed. Furthermore, the effects of vent area ratio and the activation pressure of vent panels in the kitchen were investigated to propose effective mitigation measures for the gas explosions inside residential buildings. The results show that the simulation results reproduced by the CFD model are in good agreement with the real accident consequences. During the explosion process, the overpressure distribution in a room is almost uniform at the same moment and there exists little spatial difference. The maximum temperature can reach up to 1953°C, which can cause secondary fire accidents easily. The maximum flame speed is in the range of 34.3 m/s and 230.9 m/s. It indicates that gas explosion inside residential buildings is a typical deflagration process. When the vent area ratio is less than 0.3, the overpressure peaks decrease rapidly with the increase of the vent area ratio. However, when the vent area ratio is larger than 0.3, the overpressure peaks are almost independent on the vent area ratio. There is a proportional relationship between the overpressure peaks and the activation pressure of vent panels. These achievements provide reliable reference data for the accident investigation of gas explosion and subsequent treatment.

scholarly journals Internal explosion. Pressure peaks

2021 ◽  
Vol 263 ◽  
pp. 02041
Author(s):  
Vyacheslav Gorev ◽  
Evgeniya Chelekova
Keyword(s):  
Numerical Modeling ◽  
Small Volume ◽  
Pressure Change ◽  
Explosion Pressure ◽  
Scale Modeling ◽  
Gas Explosions ◽  
Internal Explosion ◽  
Pressure Dynamics ◽  
The Moment ◽  
Protective Structures

Internal emergency gas explosions occur at threatening intervals and cause significant destruction. The level of destruction indicates the imperfection of protection methods. Documents regulating the use of safety structures for the protection of buildings during an internal explosion are limited by the assignment of the area of openings covered by safety structures, without taking into account the properties of these structures, attachment methods and the rate of pressure increase during an explosion. The purpose of the work is to take into account as much as possible the influence of the properties of the protective structures, their attachment and the nature of the explosion on the dynamics of the explosion pressure change. The second goal is to obtain a methodology for converting the results of experimental results obtained on small volumes to determine the parameters of an explosion in conditions of large volume. The goals are achieved by the theory of dimensions and similarity using numerical modeling. The work revealed dimensionless complexes describing pressure dynamics both during opening of openings and at the moment of maximum power of energy release during explosion. Possibility of experimental scale modeling of processes of opening of safety structures is shown. In particular, it is shown that during an explosion in premises of a small volume (residential), the pressure during opening is more often critical.

Comparison of Ellipsoidal and Parabolic Mirror Systems in Fluorimetry and Room Temperature Phosphorimetry

1979 ◽  
Vol 33 (2) ◽  
pp. 166-170 ◽  
Author(s):  
G. L. Walden ◽  
J. D. Winefordner
Keyword(s):  
Room Temperature ◽  
Small Volume ◽  
Collection Efficiency ◽  
Parabolic Mirror ◽  
The Real ◽  
Real Value

The use of ellipsoidal and parabolic mirrors to increase the collection efficiency of sample luminescence is demonstrated for small volume samples. The results indicate that the real value of such systems is in the cases in which dilution to larger volumes is not desirable.

Mechanical impedances of lungs and chest wall in the cat

1992 ◽  
Vol 73 (2) ◽  
pp. 427-433 ◽  
Author(s):  
Z. Hantos ◽  
A. Adamicza ◽  
E. Govaerts ◽  
B. Daroczy
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Small Volume ◽  
Angular Frequency ◽  
Forced Oscillations ◽  
Amplitude Dependence ◽  
Volume Changes ◽  
The Real ◽  
Output Flow ◽  
Frequency Independent

In nine anesthetized and paralyzed cats, the mechanical impedances of the total respiratory system (Zrs) and the lungs (ZL) were measured with small-volume pseudorandom forced oscillations between 0.2 and 20 Hz. ZL was measured after thoracotomy, and chest wall impedance (Zw) was calculated as Zw = Zrs-ZL. All impedances were determined by using input airflow [input impedance (Zi)] and output flow measured with a body box [transfer impedance (Zt)]. The differences between Zi and Zt were small for Zrs and negligible for ZL. At 0.2 Hz, the real and imaginary parts of ZL amounted to 33 +/- 4 and 35 +/- 3% (SD), respectively, of Zrs. Up to 8 Hz, all impedances were consistent with a model containing a frequency-independent resistance and inertance and a constant-phase tissue part (G-jH)/omega alpha, where G and H are coefficients for damping and elastance, respectively, omega is angular frequency, and alpha determines the frequency dependence of the real and imaginary parts. G/H was higher for Zw than for ZL (0.29 +/- 0.05 vs. 0.22 +/- 0.04, P less than 0.01). In four cats, the amplitude dependence of impedances was studied: between oscillation volumes of 0.8 and 3 ml, GL, HL, Gw, and Hw decreased on average by 3, 9, 26, and 29%, respectively, whereas the change in G/H was small for both ZL (7%) and Zw (-4%). The values of H were two to three times higher than the quasistatic elastances estimated with greater volume changes (greater than 20 ml).

scholarly journals Analysis of repair works to remove the effects of structural failure after a gas explosion

2019 ◽  
Vol 284 ◽  
pp. 02002
Author(s):  
Aleksandra Bąk ◽  
Ryszard Chmielewski
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Technical Condition ◽  
Structural Elements ◽  
Structural Failure ◽  
Gas Explosion ◽  
Gas Explosions ◽  
Construction Supervision ◽  
Bearing Structure ◽  
Construction Works

The article presents the issues of repair works in a multi-family residential building, whose structural and non – structural elements have been damaged and destroyed by a gas explosion and the fire. Gas explosions in residential buildings constitute a small percentage of the total number of building disasters, however, due to the relatively large number of injured people, these incidents are very dangerous [1]. Moreover, the gas explosion often leads to significant material losses and fatalities. Proper assessment of the load-bearing structure after such incident requires an extensive knowledge of the behaviour of structures. The first authority, that issues a decision regarding further use is Construction Supervision Inspector. Until the demolition of the object is ordered, the next step is to provide expert report made by an authorized construction expert, whose aim is to assess the technical condition of the elements of the structure and to determine the scope of necessary repair works. Construction expert, who give such opinion during the assessment of objects immediately after such incident, often has limited access to structural elements, moreover these elements often are covered. Hence, the recommendations contained in these reports often do not include all of required construction works.

scholarly journals ‘Green’ obligations regarding new constructions and their impact on the real-estate market

2019 ◽  
Vol 13 (1) ◽  
pp. 560-566
Author(s):  
Simona Chirica
Keyword(s):  
Real Estate ◽  
Residential Buildings ◽  
Real Estate Market ◽  
Direct Impact ◽  
The Real ◽  
The Real Estate ◽  
Building Permits ◽  
Energy Dependency ◽  
The Real Estate Market ◽  
Electrical Vehicles

Abstract The fight for reducing green gas emissions and energy dependency requires the application of additional obligations for new constructions. From this perspective, starting from the 31st of December 2020 building permits for new constructions in the private sector shall be issued only if their energy consume is close to zero. Additionally, the recovery level of non-dangerous waste resulting from construction and demolition activities must reach until the 31st of December 2020 a percentage of minimum 70%. Also, with respect to residential and non-residential buildings, new and also buildings undergoing major renovation, the real-estate developers must take into consideration the obligations regarding the instalment of electrical recharging points for electrical vehicles. These additional obligations will have a direct impact upon the construction price and will certainly influence the real-estate market.

scholarly journals Burning Rate Enhancement Analysis of End-Burning Solid Propellant Grains Based on X-Ray Real-Time Radiography

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Wei Xianggeng ◽  
Bo Tao ◽  
Wang Pengbo ◽  
Ma Xinjian ◽  
Lou Yongchun ◽  
...  
Keyword(s):  
Burning Rate ◽  
Real Time ◽  
Solid Propellant ◽  
Burning Surface ◽  
Rocket Motor ◽  
Operating Pressure ◽  
Solid Rocket Motor ◽  
X Ray ◽  
The Real ◽  
Solid Rocket

Unexpected pressure rise may occur in the end-burning grain solid rocket motor. It is generally believed that this phenomenon is caused by the nonparallel layer combustion of the burning surface, resulting in the increase of burning rate along the inhibitor. In order to explain the cause of this phenomenon, the experimental investigation on four different end configurations were carried out. Based on the X-ray real-time radiography (RTR) technique, a new method for determining the dynamic burning rate of propellant and obtaining the real-time end-burning profile was developed. From the real-time images of the burning surface, it is found that there was a phenomenon of nonuniform burning surface displacement in the end-burning grain solid rocket motor. Through image processing, the real-time burning rate of grain center line and the real-time cone angle are obtained. Based on the analysis of the real-time burning rate at different positions of the end surface, the end face cone burning process in the motor working process is obtained. The closer to the shell, the higher the burning rate of the propellant. Considering the actual structure of this end-burning grain motor, it is speculated that the main cause of the cone burning of the grain may be due to the heat conduction of the metal wall. By adjusting the initial shape of the grain end surface, the operating pressure of the combustion chamber can be basically unchanged, so as to meet the mission requirements. The results show that the method can measure the burning rate of solid propellant in real time and provide support for the study of nonuniform combustion of solid propellant.

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