Four-Dimensional Reconstruction of Leaked Gas Cloud Based on Computed Tomography Processing of Multiple Optical Paths Infrared Measurement

Currently, gas leakage source detection is conducted by the human senses and experience. The development of a remote gas leakage source detection system is required. In this research, an infrared camera was used to detect gas leakage. The gas can be detected by the absorption of infrared rays by the gas and the infrared rays emitted from the gas itself. A three-dimensional reconstruction of a leaked gas cloud was performed to identify the gas leakage source and the flow direction of the gas. The so-called four-dimensional reconstruction of the leaked gas cloud, i.e., reconstruction of three-dimensional images of a gas cloud varying with time, was successfully performed by applying the ART (Algebraic Reconstruction Techniques) method to the multiple optical paths of infrared measurement.

Galaxy Formation, Evolution and Rotation as a 4D Relativistic Cloud-World Embedded in a 4D Conformal Bulk: From String to Cloud Theory

The recent observation of the G2 gas cloud orbit around the galactic centre has challenged the model of a mere supermassive black hole that should have destroyed it. In addition, the Planck Legacy 2018 (PL18) release has preferred a positively curved early Universe with a confidence level exceeding 99%. In this study, the formation of a galaxy from the collapse of a supermassive gas cloud in the early Universe is modelled based on extended field equations as a 4D relativistic cloud-world that flows and spins through a 4D conformal bulk of an initial positive curvature considering the preference of the PL18 release. Owning to the curved background, this scenario of galaxy formation reveals that the core of the galaxy undergoes a forced vortex formation with a central event horizon leading to opposite vortices (traversable wormholes) that are spatially shrinking through evolving in the conformal time. It indicates that the galaxy and its core are formed at the same process where the surrounding gas clouds form the spiral arms due to the frame-dragging induced by the fast-rotating core. Further, the bulk conformal curvature evolution demonstrates the fast orbital speed of outer stars owing to external fields exerted on galaxies as they travel through conformally curved space-time. Accordingly, the G2 gas cloud that only faced the drag effects could be explained if its orbit is around the vortex but at a distance from the central event horizon. These findings could explain the fast orbital speed of outer stars where the galaxy formation and its core simultaneously could explain the formation of the supermassive compact galaxy cores with a mass of ~109 M⊙ at just 6% of the current Universe age and thus could resolve the black hole hierarchy problem.

Hazards Generated by an LNG Road Tanker Leak: Field Investigation of Vapour Propagation under Class B Conditions of Atmospheric Stability

The publication presents the results of a field test of 2–4 min releases of 96% LNG from a road tanker designed to carry the gas. The release was performed at a pressure of 5.9–6.1 atm at a discharge rate of 1.67–1.78 kg/s from a height of 0.75 m under class B conditions of atmospheric stability. Comparison of the obtained experimental results of the maximum concentrations and the simulation carried out with the EFFECS (11.2.0) software showed that the Gaussian gas model better describes the gas cloud propagation at most control points at this release intensity than the dense gas model. The dense gas model gave only slightly better results along the cloud propagation axis at close distances, not exceeding 25/30 m at ground level. It is shown that concentrations between 71% and 110% LEL are observed at the cloud visibility limit. The maximum value of the temperature drop, in the release axis, at a distance of 4 m amounts to ∆Tmax = 93.3 °C. This indicates that the cloud of the released LNG is almost entirely in the vapour state already in the short distance from the point of release, due to the turbulent outflow of the pressurised gas.

STUDY OF GAS FUEL LEAKAGE AND EXPLOSION IN THE ENGINE ROOM OF A SMALL LNG-FUELED SHIP

The engine fuel piping in LNG-fuelled ships’ engine room presents potential gas explosion risks due to possible gas fuel leakage and dispersion. A 3D CFD model with chemical reaction was described, validated and then used to simulate the possible gas dispersion and the consequent explosions in an engine room with regulations commanded ventilations. The results show that, with the given minor leaking of a fuel pipe, no more than 1kg of methane would accumulate in the engine room. The flammable gas clouds only exit in limited region and could lead to explosions with an overpressure about 12 mbar, presenting no injury risk to personnel. With the given major leaking, large region in the engine room would be filled with flammable gas cloud within tens of seconds. The gas cloud might lead to an explosion pressure of about 1 bar or higher, which might result in serious casualties in the engine room.

Dirty thunderstorms caused by volcano explosive eruptions in Kamchatka by the data of electromagnetic radiation

During volcano eruptions, so called dirty thunderstorms are the sources of electromagnetic radiation. They are caused by ash-gas clouds formed during explosive eruptions. Thunderstorm activity in an ash-gas cloud during volcano eruption is monitored by radio equipment. The VLF direction finder, located at Paratunka, monitors thunderstorm activity in the region of Kamchatka Peninsula including dirty thunderstorms accompanying explosive eruptions of Shiveluch and Bezymyanniy volcanoes. In the paper, we analyze records of electromagnetic radiation associated with dirty thunderstorms occurring during volcano eruptions from 2017 to 2020. During that period 24 eruptions of Shiveluch volcano and 5 eruptions of Bezymyanniy volcano occurred. Seventeen and three of them, respectively, caused dirty thunderstorms. Two-stage scenario of development is typical for all the dirty thunderstorms. The first stage lasts for 5–7 minutes and accompanies eruptive column development. However, if the eruption begins according to a smooth scenario, the first stage may be weak. The second stage lasts for 20–80 minutes and is associated with eruptive cloud formation and propagation. The intensity of this dirty thunderstorm stage depends on eruption power as well as on the interaction of an eruptive cloud during its propagation with the clouds of meteorological origin. Based on the obtained data, that is indicated by the increase of cloud-to-cloud stroke number.

Numerical modeling of open pit ventilation when varying the location of the dust and gas cloud

Research objective is to estimate the effect of bulk explosion location and the initial height of the dust and gas cloud on open-pit natural ventilation time and the level of air contamination of the upper edge of the open pit down the wind. Methods of research. Computer modeling of aerodynamics and gaseous component transfer in the 2D geometry is carried out with the COMSOL software. To calculate the aerodynamic characteristics, the approximation of the incompressible fluid with the standard k–ε turbulence model was carried out. Gaseous component distribution was modeled using the numerical solution to the convection-diffusion equation of contaminant transfer. Numerical experiments under the fixed initial concentration of the gaseous component and the speed of the incoming wind flow have been carried out for three locations of bulk explosions and six values of the initial height (from 70 to 420 m with a step of 70 m) of the dust and gas cloud. Research results and analysis. Spatial distributions of the model’s aerodynamic characteristics and contaminants gaseous component when reaching the maximum permissible concentration in the modeled area have been obtained. The estimated time of the open-pit natural ventilation and the dynamics of the open-pit upper edge air contamination dynamics down the wind have been analyzed. The complex and diversified nature of open pit ventilation for various locations of bulk explosions has been recorded. The undulating character of contaminant loss has been predicted (with different heights of peaks) conditioned by the presence of vortex formation in the open pit. Conclusion and scope of results. For the recirculation scheme of ventilation, the situations with the bulk explosion locations shifted to the windward edge of the open pit are the longest. It has been shown that the reduction in the dust and gas cloud lift does not always ensure the reduction in the contamination level at the upper edge of the open pit down the wind.

Numerical Simulation of Leakage and Diffusion Process of LNG Storage Tanks

To investigate the evolution process of LNG (Liquefied Natural Gas) liquid pool and gas cloud diffusion, the Realizable k-ε model and Eluerian model were used to numerically simulate the liquid phase leakage and diffusion process of LNG storage tanks. The experimental results showed that some LNG flashed and vaporized rapidly to form a combustible cloud during the continuous leakage. The diffusion of the explosive cloud was divided into heavy gas accumulation, entrainment heat transfer, and light gas drift. The vapor cloud gradually separated into two parts from the whole “fan leaf shape”. One part was a heavy gas cloud; the other part was a light gas cloud that spread with the wind in the downwind direction. The change of leakage aperture had a greater impact on the whole spill and dispersion process of the storage tank. The increasing leakage aperture would lead to 10.3 times increase in liquid pool area, 78.5% increase in downwind dispersion of methane concentration at 0.5 LFL, 22.6% increase in crosswind dispersion of methane concentration at 0.5 LFL, and 249% increase in flammable vapor cloud volume. Within the variation range of the leakage aperture, the trend of the gas cloud diffusion remained consistent, but the time for the liquid pool to keep stable and the gas cloud to enter the next diffusion stage was delayed. The low-pressure cavity area within 200 m of the leeward surface of the storage tank would accumulate heavy gas for a long time, forming a local high concentration area, which should be an area of focus for alert prediction.

Galaxy Formation and Rotation as a 4D Relativistic Cloud-World Embedded in a 4D Conformal Background: A Cloud Theory

The recent observation of the G2 gas cloud orbit around the galactic centre has challenged the model of a mere supermassive black hole at the centre of our galaxy which should have destroyed it. In addition, the Planck Legacy 2018 (PL18) release has preferred a positively curved early Universe with a confidence level exceeding 99%. In this study, the collapse of a large gas cloud in the early Universe to form a galaxy is modelled based on extended field equations as a 4D relativistic CloudWorld that flows and spins through a 4D independent conformal background of an initial positive curvature considering the preference of the PL18 release. Owning to the curved background, this scenario of galaxy formation indicates that the core of the galaxy undergoes a forced vortex formation with a central event horizon leading to opposite traversable wormholes that are spatially shrinking through the conformal time. It reveals that the galaxy and its core are formed at the same process where the surrounding gas clouds form the spiral arms due to the frame-dragging induced by the fast-rotating core. Accordingly, the G2 gas cloud that only faced the drag effects could be explained if its orbit is around the wormhole but at a distance from the central event horizon. The formation of the galaxy and its core simultaneously could explain the formation of the supermassive compact galaxy cores with a mass of ~109 M⊙ at just 6% of the current Universe age and could resolve the black hole hierarchy problem.