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

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8483
Author(s):  
Tomasz Węsierski ◽  
Robert Piec ◽  
Małgorzata Majder-Łopatka ◽  
Bernard Król ◽  
Wiktor Gawroński ◽  
...  
Keyword(s):  
Discharge Rate ◽  
Temperature Drop ◽  
Atmospheric Stability ◽  
Ground Level ◽  
Field Investigation ◽  
Dense Gas ◽  
Maximum Value ◽  
Propagation Axis ◽  
Class B ◽  
Gas Cloud

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.

scholarly journals A 3D study on the amplification of regional haze and particle growth by local emissions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Wei Du ◽  
Lubna Dada ◽  
Jian Zhao ◽  
Xueshun Chen ◽  
Kaspar R. Daellenbach ◽  
...  
Keyword(s):  
Atmospheric Stability ◽  
Ground Level ◽  
Particle Growth ◽  
Chemical Compositions ◽  
Size Distributions ◽  
Aerosol Composition ◽  
Regional Haze ◽  
Haze Formation ◽  
Beijing China

AbstractThe role of new particle formation (NPF) events and their contribution to haze formation through subsequent growth in polluted megacities is still controversial. To improve the understanding of the sources, meteorological conditions, and chemistry behind air pollution, we performed simultaneous measurements of aerosol composition and particle number size distributions at ground level and at 260 m in central Beijing, China, during a total of 4 months in 2015–2017. Our measurements show a pronounced decoupling of gas-to-particle conversion between the two heights, leading to different haze processes in terms of particle size distributions and chemical compositions. The development of haze was initiated by the growth of freshly formed particles at both heights, whereas the more severe haze at ground level was connected directly to local primary particles and gaseous precursors leading to higher particle growth rates. The particle growth creates a feedback loop, in which a further development of haze increases the atmospheric stability, which in turn strengthens the persisting apparent decoupling between the two heights and increases the severity of haze at ground level. Moreover, we complemented our field observations with model analyses, which suggest that the growth of NPF-originated particles accounted up to ∼60% of the accumulation mode particles in the Beijing–Tianjin–Hebei area during haze conditions. The results suggest that a reduction in anthropogenic gaseous precursors, suppressing particle growth, is a critical step for alleviating haze although the number concentration of freshly formed particles (3–40 nm) via NPF does not reduce after emission controls.

Geotechnical Investigation, Field Load Test and Analysis of Full-Scale Bored Pile

2015 ◽  
Vol 813-814 ◽  
pp. 1126-1130
Author(s):  
G. Kesavan ◽  
S.S. Chandrasekaran
Keyword(s):  
Tamil Nadu ◽  
Ground Level ◽  
Maximum Load ◽  
Field Investigation ◽  
Complex Problem ◽  
Load Test ◽  
Bored Pile ◽  
Economical Design ◽  
Pile Load Test ◽  
A Site

The maximum load carrying capacity of bored piles is a complex problem because it is a function of a number of factors, these factors include methods of soil exploration, ground water condition, types of grading of concrete, quantity and quality of concrete. The knowledge of Geotechnical test is important for the most economical design of the piles. This paper describes some important aspects of field investigation, design and construction of in-situ bored pile foundation, field pile load test of experience gained from the construction of the pile at a site in Aathoor in Tamil Nadu, India. The site was fully sandy soil from existing ground level. The design of bored pile under axial compression was done using Empirical formula, pile load test and by using PLAXIS 2D software. Results were compared with vertical load and settlement in this site.

scholarly journals CFD Analysis of Indoor Chlorine Gas Dispersion Storage: Temperatures, Wind Velocities and Ventilation Effects Studies

2016 ◽  
Vol 16 (1) ◽  
pp. 1
Author(s):  
M. Safakar ◽  
S. Syafiie ◽  
R. Yunus
Keyword(s):  
Ground Level ◽  
Dense Gas ◽  
Human Beings ◽  
Potential Health ◽  
Gas Dispersion ◽  
Indoor Space ◽  
Hazardous Chemical ◽  
Chlorine Gas ◽  
Different Temperatures ◽  
Wind Velocities

The Chemical products factories encounter inherent environmental risks in the process. The indoor release of hazardous chemical gases that are heavier than the air is nowadays a special subject for scrutiny because the dense clouds of the gas have a tendency to insist on the ground level or near the human breath level, causing fatal injuries or other potential health threats to human beings. In this study, a computational fluid dynamics (CFD) code FLUENT was employed in order to model the accidental indoor dispersion of a dense gas (chlorine) from a small undetected leak in an indoor industrial environment. Furthermore, the effects of different temperatures, wind velocities and ventilation on diffusion of chlorine are investigated in this paper. Results of the simulations represented that the chlorine gas dispersion would behave like the liquid and currents on the floor. It was also found that the chlorine concentration above the ground level increased slowly. Showing the effects of various temperatures and wind on spreading the dense gas will help to better identify the potential risks. In this research, the effects of the environmental situations with the release and spread of chlorine in the indoor space were meticulously investigated.

Assessing Peak-To-Mean Ratios of Odour Intensity in the Atmosphere near Swine Operations

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 224
Author(s):  
Qiang Zhang ◽  
Xiaojing Zhou
Keyword(s):  
Atmospheric Stability ◽  
Ambient Air ◽  
Noticeable Effect ◽  
Stability Class ◽  
Odour Source ◽  
Class B ◽  
Swine Operations ◽  
Measurement Session ◽  
Averaging Time

Odour in the atmosphere is usually characterized by an intermittent time series of high peaks and periods of low (or zero) concentrations. The peak-to-mean ratio (PMR) is commonly used to estimate short-term peaks from long-term averages to assess the odour impact. The objective of this study was to quantify the peak-to-mean ratio of odour intensity (PMR_OI) in the atmosphere near swine operations. Fifteen human assessors (sniffers) were trained to use an 8 point odour intensity scale to measure odour intensity in the ambient air near two swine operations. In each measurement session, the sniffers were placed 0° (in the direction of wind), 30°, and 45° from the wind directions at 100, 500, and 1000 m from the swine operations to sniff odour in the air every 10 s for 30 min. The results showed that odour in the atmosphere was intermittent. The intermittency (% of time when odour was detected) increased with the averaging time and decreased with the distance from the odour source and the direction from the wind. The measured intermittency ranged from 13% to 85%. The PMR_OI increased with the averaging time, the distance from the source, and the direction from the wind. In the wind direction, the largest difference in PMR_OI between 1 and 30 min averaging times was 68% (2.5 vs. 4.2), which occurred at 1000 m from the odour source under stability class B. The average PMR_OI increased from 1.5 at 100 m to 3.5 at 1000 m. Atmospheric stability had a noticeable effect on PMR_OI. At 1000 m, the 30 min PMR_OI decreased from 4.2 at stability class B (unstable) to 2.4 at E (slightly stable).

scholarly journals Approaches for predicting wind turbine hub-height turbulence metrics

2021 ◽  
Author(s):  
Hannah Livingston ◽  
Nicola Bodini ◽  
Julie K. Lundquist
Keyword(s):  
Wind Turbine ◽  
Control Strategies ◽  
Atmospheric Stability ◽  
Ground Level ◽  
Atmospheric Measurements ◽  
Large Variability ◽  
Near Surface ◽  
Energy Applications ◽  
Main Driver ◽  
Surface Measurements

Abstract. Hub-height turbulence is essential for a variety of wind energy applications, ranging from wind plant siting to wind turbine control strategies. Because deploying hub-height meteorological towers can be a challenge, alternative ways to estimate hub-height turbulence are desired. In this paper, we assess to what degree hub-height turbulence can be estimated via other hub-height variables or ground-level atmospheric measurements in complex terrain, using observations from three meteorological towers at the Perdigão and WFIP2 field campaigns. We find a large variability across the three considered towers when trying to model hub-height turbulence intensity (TI) and turbulence kinetic energy (TKE) from hub-height or near-surface measurements of either wind speed, TI, or TKE. Moreover, we find that based on the characteristics of the specific site, atmospheric stability and upwind fetch either determine a significant variability in hub-height turbulence or are not a main driver of the variability in hub-height TI and TKE. Our results highlight how hub-height turbulence is simultaneously sensitive to numerous different factors, so that no simple and universal relationship can be determined to vertically extrapolate turbulence from near-surface measurements, or model it from other hub-height variables when considering univariate relationships. We suggest that a multivariate approach should instead be considered, possibly leveraging the capabilities of machine learning nonlinear algorithms.

scholarly journals Turbulence characteristics in grassland canopies and implications for tracer transport

2009 ◽  
Vol 6 (8) ◽  
pp. 1519-1537 ◽  
Author(s):  
E. Nemitz ◽  
B. Loubet ◽  
B. E. Lehmann ◽  
P. Cellier ◽  
A. Neftel ◽  
...  
Keyword(s):  
Atmospheric Stability ◽  
Ground Level ◽  
Canopy Turbulence ◽  
Wind Component ◽  
Tracer Transport ◽  
Frequency Distributions ◽  
Plant Parts ◽  
Eddy Diffusivities ◽  
Hotwire Anemometry ◽  
Turbulence Parameters

Abstract. In-canopy turbulence is a required input to study pollutant cycling and chemistry within plant canopies and to link concentrations and sources. Despite the importance of grasslands worldwide, most previous work has focused on forests and crops. Here, turbulence parameters in a mature agricultural grassland canopy were measured with a combination of a small ultrasonic anemometer, hotwire anemometry and a radon (Rn) tracer technique, as part of a measurement to study ammonia (NH3) exchange with grassland. The measurements are used to derive vertical profiles of basic turbulent parameters, for quadrant-hole analysis of the two-parametric frequency distributions of u'−w' and to derive in-canopy eddy diffusivities as input for models of in-canopy tracer transport. The results are in line with previous measurements on taller canopies, but shows increased decoupling between in-canopy flow and above-canopy turbulence. The comparison of sonic anemometry and Rn measurements implies that Lagrangian time-scales must decrease sharply at the ground, with important implications for estimating the magnitude of ground-level and soil emissions from concentration measurements. Atmospheric stability above and within the canopy has little influence on the standard deviation of vertical wind component inside the canopy. Use of the turbulence parameters in an analytical Lagrangian framework, which is here validated for heat transfer, suggests that measured in-canopy profiles of NH3 are consistent with a ground-level source, presumably from senescent plant parts, which is recaptured by the overlying canopy.

scholarly journals An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

2011 ◽  
Vol 11 (12) ◽  
pp. 5719-5744 ◽  
Author(s):  
W. R. Sessions ◽  
H. E. Fuelberg ◽  
R. A. Kahn ◽  
D. M. Winker
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Atmospheric Stability ◽  
Vertical Wind Shear ◽  
Ground Level ◽  
Naval Research ◽  
Plume Rise ◽  
Hotspot Detection ◽  
Transport Pathways ◽  
Thermal Buoyancy

Abstract. The Weather Research and Forecasting Model (WRF) is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem) allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia. One of the most important aspects of simulating wildfire plume transport is the height at which emissions are injected. WRF-Chem contains an integrated one-dimensional plume rise model to determine the appropriate injection layer. The plume rise model accounts for thermal buoyancy associated with fires and local atmospheric stability. This paper describes a case study of a 10 day period during the Spring phase of ARCTAS. It compares results from the plume model against those of two more traditional injection methods: Injecting within the planetary boundary layer, and in a layer 3–5 km above ground level. Fire locations are satellite derived from the GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA) and the MODIS thermal hotspot detection. Two methods for preprocessing these fire data are compared: The prep_chem_sources method included with WRF-Chem, and the Naval Research Laboratory's Fire Locating and Monitoring of Burning Emissions (FLAMBE). Results from the simulations are compared with satellite-derived products from the AIRS, MISR and CALIOP sensors. When FLAMBE provides input to the 1-D plume rise model, the resulting injection heights exhibit the best agreement with satellite-observed injection heights. The FLAMBE-derived heights are more realistic than those utilizing prep_chem_sources. Conversely, when the planetary boundary layer or the 3–5 km a.g.l. layer were filled with emissions, the resulting injection heights exhibit less agreement with observed plume heights. Results indicate that differences in injection heights produce different transport pathways. These differences are especially pronounced in area of strong vertical wind shear and when the integration period is long.

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