• Journal of the Korean Society of Safety
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• v.6 no.2
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• pp.31-36
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• 1991

Quenching effects of acetylene and hydrogen into oxygen detonation by using detonation arrester ［DA］are studied in this paper. The experiments were carried out in cylinderical shock tube. 5m long, 30mm dia., with stolchlometric ratio ［SR］of each gas and 10-l20$\mu$ Cell Size of brass and Stainless Steel of DAs were installed in it To clarify arresting ability correlation with initial pressure, Pi, critical thickness, Tct, and shapes of supporting panel of DA are also investigated It is found that ­detonation velocities has most dependency on Pi, it shows notable changes around 0.5kgf/$\textrm{cm}^2$ for hydrogen, 0.15kgf/$\textrm{cm}^2$ for acetylen respectively, ­DA can be safety device able to arrest shock wave of detonation, ­over Tct flame transmission might be only the factor has to be considered, ­acetylene seems to be much more stronger detonation characteristics than hydrogen because of reaction heat.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.153-157
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• 2003

Supersonic and hypersonic aircrafts must pass wide range of speed to reach high speed region. But for existing engines the most efficient operating speed ranges are decided according to their flying speed, so an engine which mixes several engines like TRJ (Turbo Ramjet) and ARJ (Air Turbo Ramjet) has been planed. This mixed type engine has inefficiency that more than two engines must be installed simultaneously, but the pulse detonation engine (PDE) that uses detonation wave has a strong point that it can operate in all speed range with single engine. This paper deals with the simulation of the pulse detonation engine which uses hydrogen peroxide $(H_2O_2)$ mono propellant. Hydrogen peroxide is low-cost propellant, and it is reacted without oxidizer. Comparison between $H_2-O_2$ mixture with $H_2O_2$ mono propellant about thrust, pressure, temperature and velocity shows that $H_2O_2$ is a very useful propellant.

• Journal of Korean Society of Disaster and Security
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• v.16 no.1
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• pp.61-70
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• 2023

This study presents an analytical study of investigating the effect of shock waves generated by the hydrogen detonation and damage to structures for the safety evaluation of hydrogen storage facilities against detonation. Blast scenarios were established considering the volume of the hydrogen storage facility of 10 L to 50,000 L, states of charge (SOC) of 50% and 100%, and initial pressures of 50 MPa and 100 MPa. The equivalent TNT weight for hydrgen detonation was determined considering the mechanical and chemical energies of hydrogen. A hydrogen detonation model for the converted equivalent TNT weight was made using design equations that improved the Kingery-Bulmash design chart of UFC 3-340-02. The hydrogen detonation model was validated for overpressure and impulse in comparison to the past experimental results associated with the detonation of hydrogen tank. A parametric study based on the blast scenarios was performed using the validated hydrogen detonation model, and design charts for overpressure and impulse according to the standoff distance from the center of charge was provided. Further, design charts of the three-stage structural damage and standoff distance of adjacent structures according to the level of overpressure and impact were proposed using the overpressure and impulse charts and pressure-impulse diagrams.

• Advances in aircraft and spacecraft science
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• v.10 no.3
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• pp.203-222
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• 2023

The detonation combustion is a supersonic combustion process follows on shock wave oscillations in detonation tube. In this paper numerical studies are carried out combined effect of blockage ratio and spacing of obstacle on detonation wave propagation of hydrogen-air mixture in pulse detonation combustor. The deflagration to detonation transition of stoichiometric (ϕ=1)fuel-air mixture in channel has been analyzed for effect of blockage ratio (BR)=0.39, 0.51, 0.59, 0.71 with spacing of 2D and 3D. The reactive Navier-Stokes equation is used to solve the detonation wave propagation mechanism in Ansys Fluent platform. The result shows that fully developed detonation wave initiation regime is observed near smaller vortex generator ratio of BR=0.39 inside the combustor. The turbulent rate of reaction has also a great significance role for shock wave structure. However, vortices of rapid detonation wave are appears near thin boundary layer of each obstacle. Finally, detonation combustor demonstrates the superiority of pressure gain combustor with turbulent rate of reaction of 0.6 kg mol/m3 -s inside the detonation tube with obstacle spacing of 12 cm, this blockage enhanced the turbulence intensity and propulsive thrust. The successful detonation wave propagation speed is achieved in shortest possible time of 0.031s with a significance magnitude of 2349 m/s, which is higher than Chapman-Jouguet (C-J) velocity of 1848 m/s. Furthermore, stronger propulsive thrust force of 36.82 N is generated in pulse time of 0.031s.

• Journal of computational fluids engineering
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• v.15 no.4
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• pp.67-75
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• 2010

Hydrogen safety is one of important issues for future public usage of hydrogen. When hydrogen is released in a compartment, the occurrence of detonation must be prohibited. In order to evaluate the possibility of DDT (Deflagration to Detonation Transition) in the compartment with the hydrogen release, sigma-lambda criteria which were developed from experimental data are commonly used. But they give a little conservative results because they do not consider the detailed geometrical effect of the compartment. This is the main reason of the need to mechanistic combustion model for evaluation of hydrogen flame propagation and acceleration. In this study, sigma-lambda criteria and combustion model were systematically applied to evaluate a possibility of DDT in a IRWST compartment of APR1400 nuclear power plant during a hypothetical accident. A combustion model in an open source CFD code OpenFOAM has been applied for analyses of hydrogen flame propagation. The model was validated by evaluating the flame acceleration tests conducted in FLAME facility. And it was applied to evaluate the characteristics of a hydrogen flame propagation in the IRWST compartment of APR1400.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.1989-1998
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• 1995

Characteristics of the flame propagation for normal and abnormal combustion in hydrogen premixture in a cylindrical constant-volume combustion chamber are studied numerically. A detailed hydrogen oxidation kinetic mechanism, mixture transport properties and a model describing spark ignition process are used. The calculated pressure-time history of the stable deflagration wave propagation agrees well with the experiment. The ignition of the premixture in the unburned gas, initiated by the hot spot, causes a transition from deflagration to detonation under some initial temperature and pressure. Under the initial conditions with high temperature and pressure, excessive ignition energy initiates a strong blast wave and a detonation wave that follows. The chemical reaction in the detonation wave is much more vigorous than that in the deflagration wave and the peak pressure in the detonation wave is much higher than the equilibrium value.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.169-174
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• 2014

Detonation propagation studies is recently getting more attention in these days for its feasibility in aerospace application. Another motivation for this study is the safety concern in industries, since the detonation can cause failure to the mechanical components particularly when the flame accelerates within a pipe or tubes. In this study we numerically simulated a Moderately unstable detonation case with various grid systems and fluid dynamic length scales and have compared in the contents. Moderately Unstable detonation case was selected for this study and detailed Hydrogen-Air Reaction Mechanisms proposed by Jachimowski was used in this study with N2 as inert species.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1423-1430
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• 2017

Detonation cell width is an important parameter in hydrogen explosion assessments. The experimental data on gas detonation are statistically analyzed to establish a universal method to numerically predict detonation cell widths. It is commonly understood that detonation cell width, ${\lambda}$, is highly correlated with the characteristic reaction zone width, ${\delta}$. Classical parametric regression methods were widely applied in earlier research to build an explicit semiempirical correlation for the ratio of ${\lambda}/{\delta}$. The obtained correlations formulate the dependency of the ratio ${\lambda}/{\delta}$ on a dimensionless effective chemical activation energy and a dimensionless temperature of the gas mixture. In this paper, support vector regression (SVR), which is based on nonparametric machine learning, is applied to achieve functions with better fitness to experimental data and more accurate predictions. Furthermore, a third parameter, dimensionless pressure, is considered as an additional independent variable. It is found that three-parameter SVR can significantly improve the performance of the fitting function. Meanwhile, SVR also provides better adaptability and the model functions can be easily renewed when experimental database is updated or new regression parameters are considered.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.11
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• pp.1094-1103
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• 2008

A fuel specific detonation wave in a pipe propagates with a predictable wave velocity. This internal detonation wave speed determines the level of flexural wave excitation of pipes and the possibility of resonant response leading to a large displacement. In this paper, we present particular solutions of displacements and the resonance conditions for internally loaded pipe structures. These analytical results are compared to numerical simulations obtained using a hydrocode(multi-material blast wave analysis tool). We expect to identify potential explosion hazards in the general power industries.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.4
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• pp.548-559
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• 2015

We performed a numerical simulation based on the two-dimensional (2-D) unsteady Euler's equation with a single-step Arrhenius reaction model in order to investigate the detonation wave front propagation of an Argon (Ar) diluted oxy-hydrogen mixture ($2H_2+O_2+12Ar$). This simulation operates in the detonation frame of reference. We examine the effect of grid size and the performance impact of integrated quantities such as mass flow. For a given set of baseline conditions, the minimal and maximum grid resolutions required to simulate the respective detonation waves and the detonation cell structures are determined. Tertiary shock wave behavior for various grids and pre-exponential factors are analyzed. We found that particle fluctuation can be weakened by controlling the mass flow going through the oblique shock waves.