Flammable gas cloud build up in a ventilated enclosure

Ivings, M.J.; Gant, Simon; Saunders, Caroline; Pocock, D.J.

doi:10.1016/j.jhazmat.2010.08.020

Cited by 13 publications

(6 citation statements)

References 4 publications

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“…The ideal gas law is used to evaluate the density evolution due to the compressible nature of the flow. For the dispersion subsonic flow regime, the SST k-has been validated by (Li et al, 2016), in which a natural gas dispersion in a room was simulated using SST k-model and validated against the experimental data obtained by (Ivings et al, 2010). The choice to perform a steady-state analysis is justified by the fact that, in real cases, the detection time of the safety sensors is so long that the flammable cloud transient formation and growth cannot be properly detected; it is highly plausible that the alarm signal is given only after the final cloud configuration is reached.…”

Section: Turbulence Modelsmentioning

confidence: 99%

Comparison of CFD Numerical Approaches for the Simulation of Accidental Gas Release in Energy Applications

Pappalardo¹,

Moscatello²,

Uggenti³

et al. 2020

Proceedings of the 30th European Safety and Reliability Conference and 15th Probabilistic Safety Assessment and Management Conf

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Oil & Gas plants are risk-relevant complex facilities for the presence of toxic, flammable and pressurized fluids. Risk assessment is mandatory to guarantee plant sustainability and compliance with directives. For offshore plants characterized by congested spaces, semi-empirical models for accident consequence simulation often result in risk overestimation. This could be avoided through Computational Fluid Dynamics (CFD), which guarantees more accurate results. Complex phenomena and geometries, however, entail large computational efforts that force limiting the number of simulations to explore the accident scenarios. This calls for new approaches able to model and simulate complex congested geometries in affordable time, while achieving keeping the required accuracy of the results. In this context, a novel CFD model based on ANSYS Fluent, named SBAM (Source Box Accident Model), has been proposed by the research group of the SEADOG lab in Politecnico di Torino with the aim of simulating complex environments with good accuracy and reduced computational cost. In this work, the results provided by the SBAM model on an accidental high pressure flammable gas release in a platform, are compared with those provided by other tools and models available in the market, and widely used in industrial applications, such as FLACS developed by Gexcon US and KFX developed by DNV-GL.

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Section: Turbulence Modelsmentioning

confidence: 99%

Comparison of CFD Numerical Approaches for the Simulation of Accidental Gas Release in Energy Applications

Pappalardo¹,

Moscatello²,

Uggenti³

et al. 2020

Proceedings of the 30th European Safety and Reliability Conference and 15th Probabilistic Safety Assessment and Management Conf

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“…There are very limited studies about the evaluation of ventilation for gas turbines in gas leak based on the former standard. 19 Instead, ISO 21789 was adopted because of its popularity and applicability for gas turbines, and the criteria stated in the standard was used for the assessment in this study.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the effectiveness of ventilation for gas turbine generator set safety

Dai

Gao

Li³

2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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Increasing global warming problems appeal to the employment of clean power generation machineries such as gas turbines. Gas turbine is gas-fired engine which is usually enclosed in an acoustic enclosure for higher reliability and lower operating noise. However, it may face the risk of fuel gas accumulation inside the package which can be extremely dangerous. For the safety of a gas turbine generator set, proper ventilation system is crucial to prevent it from danger by diluting the potential leaked gas. Inspired by the significance of ventilation, this paper aims to present and propose study for the assessment of the effectiveness of ventilation for gas turbine packages in worst-case gas leak. A 2 MW ZK2000 gas turbine was chosen for the study. Method of assessment was introduced and numerical studies by Computational Fluid Dynamics (CFD) were adopted, including both transient and steady state analysis. Aiming to figure out the conditions for worst-case gas leak, the location of leak that may cause the most dangerous gas accumulation was obtained by identifying the poorly ventilated regions within the enclosure. After that, the leak rate was estimated that just to trigger the gas detector at the ventilation outlet according to ISO 21789. Worst-case gas leak simulations were performed in cold engine situation because of the possibility analysis of gas leak. The results at standard conditions show great compliance with the limited value in the code thus indicates that the capability of the current ventilation design. Effect of dilution was studied with various ambient temperatures and ventilation flow rates. One of the key findings is that the flow uniformity has the major impact on enhancing dilution of gas cloud. Structures improvements within enclosure and operation instructions were suggested for the safety of gas turbine unit in the event of gas leak.

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“… 28 − 30 CFD is widely used in gas explosion experiments, especially the LES simulation method, which has a high degree of matching with the experimental results. 31 − 33 Ivings et al 34 determined that the volume fraction of flammable gas largely depends on the release rate of flammable gas and ventilation rate. Wang et al 35 simulated the leakage and diffusion law of natural gas in the tunnel based on FLUENT and proposed the emergency accident ventilation for different pipeline pressures and leak sizes.…”

Section: Introductionmentioning

confidence: 99%

“…The experimental research results indicated that an obvious secondary explosion pressure occurs at L/D = 3.5. The experiment is often restricted by factors such as personnel safety and high cost; numerical simulation has unique advantages in visualization and reducing research costs, especially in destructive experiments. − CFD is widely used in gas explosion experiments, especially the LES simulation method, which has a high degree of matching with the experimental results. − Ivings et al determined that the volume fraction of flammable gas largely depends on the release rate of flammable gas and ventilation rate. Wang et al simulated the leakage and diffusion law of natural gas in the tunnel based on FLUENT and proposed the emergency accident ventilation for different pipeline pressures and leak sizes.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Natural Gas Leakage and Explosion Characteristics

Cai

Liu

et al. 2022

ACS Omega

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Frequent occurrence of indoor natural gas explosion accidents seriously threatens the safety of people and property. To determine the law of indoor natural gas leakage and explosion hazards, based on experiment and simulation, the nature of natural gas explosion, the distribution law of natural gas volume fraction, flame propagation, temperature, and shock wave overpressure were studied. The results show that the flame structure can be divided into three zones, i.e., preheat zone, reaction zone, and product zone. OH + CO ⇔ H + CO 2 is the main exothermic reaction in the combustion process. The overall distribution law of natural gas volume fraction shows that the higher the position, the greater the volume fraction, and the closer the distance to the leak source at the same height, the greater the volume fraction, and the natural gas volume fraction of the hose falling off is the largest under different leakage conditions. The difference in the wrapping structure of the kitchen package has a significant impact on the diffusion distribution of natural gas. The flame development goes through five stages of ignition, slow burning, detonation, slow burning, and extinguishing. The indoor temperature reaches about 1400 °C. Although the simulated value of shock wave overpressure is larger than the experimental value, the relationship between overpressure and distance is expressed by Y = A + B * ln( X + C ). This study can provide certain technical support for natural gas accident rescue. The research can provide certain technical support for natural gas accident rescue and can also be used for accident investigation to form the determination procedure and method of leakage location and leakage amount.

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Flammable gas cloud build up in a ventilated enclosure

Cited by 13 publications

References 4 publications

Comparison of CFD Numerical Approaches for the Simulation of Accidental Gas Release in Energy Applications

Comparison of CFD Numerical Approaches for the Simulation of Accidental Gas Release in Energy Applications

Assessment of the effectiveness of ventilation for gas turbine generator set safety

Experimental and Numerical Study of Natural Gas Leakage and Explosion Characteristics

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