Chapter 6. A Review on Numerical Models for Coal and Gas Outbursts

2018 ◽  
pp. 191-214 ◽  
Keyword(s):  
Numerical Models ◽  
Coal And Gas Outbursts

scholarly journals Near-source characteristics of two-phase gas–solid outbursts in roadways

2020 ◽  
Author(s):  
Aitao Zhou ◽  
Meng Zhang ◽  
Kai Wang ◽  
Derek Elsworth
Keyword(s):  
Shock Waves ◽  
Numerical Models ◽  
Gas Flows ◽  
Far Field ◽  
Two Phase ◽  
Emergency Rescue ◽  
Source Characteristics ◽  
Basic Parameters ◽  
Significant Attenuation ◽  
Coal And Gas Outbursts

Abstract Coal and gas outbursts compromise two-phase gas–solid mixtures as they propagate as shock waves and flows from their sources. Propagation is influenced by the form of the outburst, proximity to source, the structure and form of the transmitting roadways and the influence of obstacles. The following characterizes the propagation of coal and gas outbursts as two-phase gas–solid flows proximal to source where the coupled effects of pulverized coal and gas flows dominate behavior. The characteristics of shock wave propagation and attenuation were systematically examined for varied roadway geometries using experiments and numerical models. The results demonstrate that the geometry of roadway obstructions is significant and may result in partial compression and sometimes secondary overpressurization in blocked and small corner roadways leading to significant attenuation of outburst shock waves. The shock waves attenuate slowly in both straight and abruptly expanding roadways and more significantly in T-shaped roadways. The most significant attenuation appears in small angle corners and bifurcations in roadways with the largest attenuation occurring in blocked roadways. These results provide basic parameters for simplifying transport in complex roadway networks in the far-field, and guidance for the design of coal and gas outburst prevention facilities and emergency rescue.

scholarly journals Near-source characteristics of two-phase gas-solid outbursts in roadways

2020 ◽  
Author(s):  
Aitao Zhou ◽  
Meng Zhang ◽  
Kai Wang ◽  
Derek Elsworth
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Numerical Models ◽  
Gas Flows ◽  
Far Field ◽  
Two Phase ◽  
Source Characteristics ◽  
Basic Parameters ◽  
Significant Attenuation ◽  
Coal And Gas Outbursts

Abstract Coal and gas outbursts compromise two-phase gas-solid mixtures as they propagate as shock waves and flows from their sources. Propagation is influenced by the form of the outburst, proximity to source, the structure and form of the transmitting roadways and the influence of obstacles. The following characterizes the propagation of coal and gas outbursts as two-phase gas-solid flows proximal to source where the coupled effects of pulverized coal and gas flows dominate behavior. The characteristics of shock wave propagation and attenuation are systematically examined for varied roadway geometries using experiments and numerical models. The results demonstrate that the geometry of roadway obstructions is significant and may result in partial compression and sometimes secondary overpressurization in blocked and small corner roadways leading to significant attenuation of outburst shock waves. The shock waves attenuate slowly in both straight and abruptly expanding roadways and more significantly in T-shaped roadways. The most significant attenuation appears in small angle corners and bifurcations in roadways with the largest attenuation occurring in blocked roadways. These results provide basic parameters for simplifying transport in complex roadway networks in the far-field, and guidance for the design of coal and gas outburst prevention facilities and disaster ventilation.

scholarly journals Near-source characteristics of two-phase gas-solid outbursts in roadways

2020 ◽  
Author(s):  
Aitao Zhou ◽  
Meng Zhang ◽  
Kai Wang ◽  
Derek Elsworth
Keyword(s):  
Shock Waves ◽  
Numerical Models ◽  
Gas Flows ◽  
Far Field ◽  
Two Phase ◽  
Emergency Rescue ◽  
Source Characteristics ◽  
Basic Parameters ◽  
Significant Attenuation ◽  
Coal And Gas Outbursts

Abstract Coal and gas outbursts compromise two-phase gas-solid mixtures as they propagate as shock waves and flows from their sources. Propagation is influenced by the form of the outburst, proximity to source, the structure and form of the transmitting roadways and the influence of obstacles. The following characterizes the propagation of coal and gas outbursts as two-phase gas-solid flows proximal to source where the coupled effects of pulverized coal and gas flows dominate behavior. The characteristics of shock wave propagation and attenuation are systematically examined for varied roadway geometries using experiments and numerical models. The results demonstrate that the geometry of roadway obstructions is significant and may result in partial compression and sometimes secondary overpressurization in blocked and small corner roadways leading to significant attenuation of outburst shock waves. The shock waves attenuate slowly in both straight and abruptly expanding roadways and more significantly in T-shaped roadways. The most significant attenuation appears in small angle corners and bifurcations in roadways with the largest attenuation occurring in blocked roadways. These results provide basic parameters for simplifying transport in complex roadway networks in the far-field, and guidance for the design of coal and gas outburst prevention facilities and emergency rescue.

Stochastic simulation of the spatio-temporal field of the average daily heat index in Southern Russia

2020 ◽  
Vol 82 ◽  
pp. 149-160
Author(s):  
N Kargapolova
Keyword(s):  
Heat Waves ◽  
Numerical Models ◽  
Heat Index ◽  
Real Field ◽  
Gaussian Field ◽  
The Real ◽  
Southern Russia ◽  
Weather Stations ◽  
Spatio Temporal ◽  
Temporal Field

Numerical models of the heat index time series and spatio-temporal fields can be used for a variety of purposes, from the study of the dynamics of heat waves to projections of the influence of future climate on humans. To conduct these studies one must have efficient numerical models that successfully reproduce key features of the real weather processes. In this study, 2 numerical stochastic models of the spatio-temporal non-Gaussian field of the average daily heat index (ADHI) are considered. The field is simulated on an irregular grid determined by the location of weather stations. The first model is based on the method of the inverse distribution function. The second model is constructed using the normalization method. Real data collected at weather stations located in southern Russia are used to both determine the input parameters and to verify the proposed models. It is shown that the first model reproduces the properties of the real field of the ADHI more precisely compared to the second one, but the numerical implementation of the first model is significantly more time consuming. In the future, it is intended to transform the models presented to a numerical model of the conditional spatio-temporal field of the ADHI defined on a dense spatio-temporal grid and to use the model constructed for the stochastic forecasting of the heat index.

Extending "the Shorted Port Method" for Calculation of S-Matrices, Using Reduced Numerical Models

2003 ◽  
Vol 59 (3-4) ◽  
pp. 10
Author(s):  
D. Yu. Kulik ◽  
S. L. Senkevich ◽  
Victor Ivanovich Tkachenko
Keyword(s):  
Numerical Models

Validation of Numerical Models Used for Designing the Composite Blade for ILX-27 Rotorcraft

2019 ◽  
Vol 2019 (4) ◽  
pp. 23-31
Author(s):  
Jakub Wilk ◽  
Radosław Guzikowski
Keyword(s):  
Epoxy Composite ◽  
Numerical Models ◽  
Experimental Studies ◽  
Strength Analysis ◽  
Laminate Glass ◽  
Composite Blade ◽  
Real Objects ◽  
Validation Procedure ◽  
Research Objects ◽  
Comparison Of The Results

Abstract The paper presents the validation procedure of the model used in the analysis of the composite blade for the rotor of the ILX-27 rotorcraft, designed and manufactured in the Institute of Aviation, by means of numerical analyses and tests of composite elements. Numerical analysis using finite element method and experimental studies of three research objects made of basic materials comprising the blade structure – carbon-epoxy laminate, glass-epoxy composite made of roving and foam filler – were carried out. The elements were in the form of four-point bent beams, and for comparison of the results the deflection arrow values in the middle of the beam and axial deformations on the upper and lower surfaces were selected. The procedure allowed to adjust the discrete model to real objects and to verify and correct the material data used in the strength analysis of the designed blade.

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