Experiments of highly transient thermo-fluid dynamic phenomena in He II induced by gas dynamic shock wave impingement

2002 ◽  
Author(s):  
H. Nagai
Keyword(s):  
Shock Wave ◽  
Fluid Dynamic ◽  
Gas Dynamic ◽  
Dynamic Phenomena

Gas-dynamic phenomena accompanying shock-wave interactions with the cooling plasma of a pulsed surface discharge

2011 ◽  
Vol 56 (8) ◽  
pp. 423-426 ◽  
Author(s):  
I. A. Znamenskaya ◽  
I. E. Ivanov ◽  
E. Yu. Koroteeva ◽  
D. M. Orlov
Keyword(s):  
Shock Wave ◽  
Surface Discharge ◽  
Wave Interactions ◽  
Gas Dynamic ◽  
Shock Wave Interactions ◽  
Dynamic Phenomena

Investigation of features of shock wave distribution in the rock massif at gas dynamic phenomena

2020 ◽  
pp. 234-243
Author(s):  
S.I. Skipochka ◽  
◽  
T.A. Palamarchuk ◽  
L.V. Prokhorets ◽  
V.P. Kurinnyi ◽  
...  
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Waves ◽  
Shock Wave Propagation ◽  
Rock Massif ◽  
Mining Operations ◽  
Technological Factors ◽  
Gas Dynamic ◽  
Methane Mixture ◽  
Dynamic Phenomena

When studying risk factors in coal mines, it is necessary, in the first place, to consider factors and properties of the rock massif occurred with the deepening of mining operations in the coal mines, and determine one of the main types of danger: risk of geodynamic phenomena. The geodynamic phenomena occur and develop under the influence of natural and technological factors. Natural factors determine the rock massif proneness of ato geodynamic manifestations or, in other words, its potential danger due to these phenomena. Occurrence of this danger depends on technological factors. Among the dangerous factors of underground coal production to which primarily belong the geodynamic phenomena, the main ones are gas-dynamic phenomena, which are the most complex by their nature and dangerous by consequences due to high dynamic power and release of great amount of gas during a short period of time. Their consequences can be accidents due to sudden gassing and blockage of workings by coal and rock, explosions of methane and coal dust, destruction of the roadway supports, damage of machines and mechanisms, equipment and devices. As the gas-dynamic phenomena in the rocks massif are accompanied by occurrence of various processes differed by their nature, therefore, risks caused by them should be taken into account at mining operations. When considering the gas-dynamic phenomena attention should be paid to the shock wave propagation, as it is one of the gas dynamic processes. Therefore, purpose of this research was to study specific features of the shock wave propagation in the rock massif in order to prevent dangerous consequences. In this article, the authors consider the processes which occur in the rock massif prone to dangerous gas-dynamic phenomena at the shock wave propagation. The methods of rock mechanics, mechanics of continuous media, gas and thermodynamics were used in the research. Analytical researches of processes and numerical analysis of the received results were carried out. It is shown that a sharp increase of thermodynamic parameters under the action of gas-dynamic phenomena can lead to occurrence of the shock waves. It is further established that an explosive air-methane mixture can be formed in cracks, cavities and pores of the face area. At opening the cavities and pores, cases of shock waves formation in air-methane mixture leading to its detonation are possible. Under adverse conditions, this phenomenon can lead to a fire in the roadway.

Effect of gas-dynamic phenomena on adsorption properties of coal in Krasnolimanskaya Mine

2018 ◽  
Vol 11 ◽  
pp. 46-55
Author(s):  
E.V. Ulyanova ◽  
◽  
V.A. Vasilkovskiy ◽  
O.N. Malinnikova ◽  
◽  
...  
Keyword(s):  
Adsorption Properties ◽  
Gas Dynamic ◽  
Dynamic Phenomena

scholarly journals Experimental performance comparison between circular and elliptical tubes in evaporative condensers

2021 ◽  
Author(s):  
Giuseppe Starace ◽  
Lorenzo Falcicchia ◽  
Pierpaolo Panico ◽  
Maria Fiorentino ◽  
Gianpiero Colangelo
Keyword(s):  
Heat Transfer ◽  
Experimental Approach ◽  
Fluid Dynamic ◽  
Major Axis ◽  
Performance Comparison ◽  
Operating Conditions ◽  
Condensation Temperature ◽  
Air Cooled Condensers ◽  
Reduced Scale ◽  
Dynamic Phenomena

AbstractIn refrigeration systems, evaporative condensers have two main advantages compared to other condensation heat exchangers: They operate at lower condensation temperature than traditional air-cooled condensers and require a lower quantity of water and pumping power compared to evaporative towers. The heat and mass transfer that occur on tube batteries are difficult to study. The aim of this work is to apply an experimental approach to investigate the performance of an evaporative condenser on a reduced scale by means of a test bench, consisting of a transparent duct with a rectangular test section in which electric heaters, inside elliptical pipes (major axis 32 mm, minor axis 23 mm), simulate the presence of the refrigerant during condensation. By keeping the water conditions fixed and constant, the operating conditions of the air and the inclination of the heat transfer geometry were varied, and this allowed to carry out a sensitivity analysis, depending on some of the main parameters that influence the thermo-fluid dynamic phenomena, as well as a performance comparison. The results showed that the heat transfer increases with the tube surface exposed directly to the air as a result of the increase in their inclination, that has been varied in the range 0–20°. For the investigated conditions, the average increase, resulting by the inclination, is 28%.

1D GAS-DYNAMIC SIMULATION OF SHOCK-WAVE PROCESSES VIA INTERNET

2009 ◽  
Author(s):  
K. V. Khishchenko ◽  
P. R. Levashov ◽  
M. E. Povarnitsyn ◽  
A. S. Zakharenkov ◽  
Mark Elert ◽  
...  
Keyword(s):  
Shock Wave ◽  
Dynamic Simulation ◽  
Wave Processes ◽  
Gas Dynamic

Underground operations in Internatsionalny mine rock mass susceptible to gas dynamic phenomena

2021 ◽  
pp. 76-80
Author(s):  
A. A. Vyunikov ◽  
◽  
S. G. Vorozhtsov ◽  
N. V. Khoyutanova ◽  
E. K. Pul ◽  
...  
Keyword(s):  
Rock Mass ◽  
Prediction Method ◽  
Test Site ◽  
Gas Release ◽  
Prevention Measures ◽  
Science Center ◽  
Gas Dynamic ◽  
Prediction And Prevention ◽  
Engineering Sciences ◽  
Dynamic Phenomena

Starting from 2019 extraction of diamond ore reserves from Internatsionalnaya pipe by Internatsionalny mine of ALROSA is carried out in complex geological and geomechanical conditions. Geodynamic situation is complicated by a few gas dynamic phenomena of different nature and scale recorded. The investigation results on gas release dynamics from dolomite rock mass during drivage of Spiral decline, in a test site on level.-802/-820 m in case of prediction and prevention measures undertaken to combat gas dynamic phenomena are presented. The dynamic characteristics of gas in outburst-hazardous dolomite rocks are calculated by the initial velocity of gas release. Efficiency of the current outburst hazard prediction method using facility MIG-Ts1 is proved. At the same time, it is necessary to perform additional studies to collect sufficient statistics and reliable data on gas release and gas pressure during drivage operations in the mine. The authors appreciate participation of Deputy CEO of VostNII Science Center, Doctor of Engineering Sciences, Professor V. S. Zykov, Doctor of Engineering Sciences, Professor A. V. Dzhigrin, Director of Research Center for Applied Geomechanics and Convergent Technologies in Mining at NUST MISIS College of Mining, Doctor of Engineering Sciences, Professor of the Russian Academy of Sciences V. A. Eremenko and Director of VNIMI’s Kemerovo Division, Candidate of Engineering Sciences P. V. Grechishkin.

On Difference Methods for Shock Wave Propagation in Variable Area Ducts Including Wall Friction

1973 ◽  
Vol 95 (2) ◽  
pp. 327-332
Author(s):  
R. H. Fashbaugh ◽  
A. Widawsky
Keyword(s):  
Shock Wave ◽  
Wave Attenuation ◽  
Fluid Dynamic ◽  
Finite Difference Methods ◽  
Wall Friction ◽  
Variable Cross ◽  
Viscous Effects ◽  
Cross Sectional ◽  
Basic Fluid ◽  
Difference Methods

Results are presented of an analytical study concerned with the prediction of the propagation of shock waves through air ducting systems. The solution is one-dimensional but is appropriate for ducts which have a variable cross-sectional area and includes attenuation due to viscous effects at the wall of the duct. Finite-difference methods are utilized to obtain an approximate solution to the basic fluid dynamic equations. Comparisons are given between analytical results and shock tube experimental data which validate the capabilities of the methods used to predict shock wave attenuation and the effect of duct area variation on shock strength.

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