• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.99-105
• /
• 2004

The effects of pressure on combustion characteristics of the conical flameholder were investigated experimentally in the pressure range from 0.11 ㎫ to 0.40 ㎫. The result shows that the total equivalence ratio of lean limit becomes lower as the combustor inlet pressure rises and NOx emission is proportional to the pressure to the 0.5th power.

• Corrosion Science and Technology
• /
• v.3 no.6
• /
• pp.257-261
• /
• 2004

Leaking of fuel gas in a building creates flammable atmosphere and gives rise to explosion. Observations from accidents suggest that some explosions are caused by quantity of gas significantly less than the lower explosion limit amount required to fill the whole confined space, which might be attributed to inhomogeneous mixing of the leaked gas. The minimum amount of leaked gas for explosion is highly dependent on the degree of mixing in the building. This paper proposes a method for estimating minimum amount of flammable gas for explosion assuming Gaussian distribution of flammable gas.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.5 no.5
• /
• pp.97-103
• /
• 1997

Effects of fuel injection timing on the lean misfire limit of a sequential MPI SI engine has been investigated. To investigate the interaction of injection timing and intake flow characteristics, so called axial stratification phenomena, 4 kinds of different intake swirl port of the same combustion chamber geometry have been teated in a single cylinder engine test bench. And 2 kinds of fuel, gasoline and compressed natural gas(CNG), were used to see the effect of liquid fuel vaporization. Result shows that combination of port swirl and injection timing governs the lean misfire limit and lean misfire limit envelopes remain almost the same for a given ratio regardless of engine speed. It is also found that two phase flow has some effects on lean misfire limit.

• Journal of the Korean Institute of Gas
• /
• v.9 no.3 s.28
• /
• pp.9-14
• /
• 2005

To estimate the explosion characteristics of converted gas, the study was examined into effects of altering oxygen concentration and adding hydrogen. From the result of the experiment, as the concentration of converted gas and hydrogen were increased at $21\%$ oxygen concentration, the lower explosion limit was low. Minimum explosion oxygen concentration was $6\%$. Maximum explosion pressure of converted gas was $4.61 kg_f/cm^2$, now Maximum explosion pressure rising velocity was $130.75 kg_f/cm^2/s$ at converted gas concentration $40\%$. Also, minimum ignition energy was 0.13 mJ at converted gas concentration $50\%$.

• Journal of the Korean Institute of Gas
• /
• v.14 no.2
• /
• pp.1-6
• /
• 2010

The strength safety of high pressure gas cylinder has been analyzed by using a finite element method. In this study, the internal gas pressures of a steel bombe include a service charging pressure of $9kg/cm^2$, high limit charging pressure of $18.6kg/cm^2$, high limit of safety valve operation pressure $24.5kg/cm^2$, and hydraulic testing pressure of $34.5kg/cm^2$. The computed FEM results indicate that the strength safety for a service charging pressure of $9kg/cm^2$ and high limit charging pressure of $18.6kg/cm^2$ is safe because the stress of a gas cylinder is within yield strength of steel. But the stress for a hydraulic testing pressure of $34.5kg/cm^2$ sufficiently exceeds the yield strength and remains under the tensile strength. If the hydraulic testing pressures frequently apply to the gas cylinder, the bombe may be fractured because a fatigue residual stress is accumulated on the lower round end plate due to a plastic deformation. The computed results show that the concentrated force in which is applied on a skirt zone does not affect to the lower round end plate, and the most weak zone of a bombe is a middle part of a lower round end plate between a bombe body and a skirt for a gas pressure. Thus, the FEM results show that the profile of a lower round end plate is an important design parameter of a high pressure gas cylinder.

• Journal of the Korean Institute of Gas
• /
• v.12 no.2
• /
• pp.1-6
• /
• 2008

For the safety design and operation of many gas process, it is necessary to know certain explosion limit, flash point, autoignition temperature (AIT) and minimum oxygen concentration of handling substances. Also it is necessary to know explosion limit at high temperature and pressure. In this study for the safe handling of hydrogen, explosion limit and AIT of combustion properties for hydrogen were investigated. By using the literatures data, the lower and upper explosion limits of hydrogen recommended 4.0 vol% and 77.0 vol%. Also the AIT of hydrogen with ignition sources recommended $400^{\circ}C$ at the electrically heated crucible furnace (the whole surface heating) and recommended $640^{\circ}C$ at the local hot surface. The new equations for predicting the temperature and the pressure dependence of the explosion limits of hydrogen are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Journal of the Korean Institute of Gas
• /
• v.11 no.4
• /
• pp.59-63
• /
• 2007

The purpose of this paper is to find optimum vent port of the booth for gas explosion experiment. Also, it is to understand the safety of the booth for explosion experiment which is installed to let the trainees for legal education which is managed by IGTT(Institute of gas technology training) blow the riskiness of explosion. Since the booth for gas explosion experiment is a confined space, we used the exhaust model for indoor explosion. As the result, it was safety calculated when the amount of leaking gas was close to the maximum of explosion limit on the explosion experiment.

• Nuclear Engineering and Technology
• /
• v.53 no.10
• /
• pp.3286-3297
• /
• 2021

The released hydrogen can be ignited even with weak ignition sources. This emphasizes the importance of the hydrogen flammability evaluation to prevent catastrophic failure in hydrogen related facilities including a nuclear power plant. Historically numerous attempts have been made to determine the flammability limit of hydrogen mixtures including several diluents. However, no analytical model has been developed to accurately predict the limit concentration for mixtures containing radiating gases. In this study, the effect of H₂O and CO₂ on flammability limit was investigated through a numerical simulation of lean limit hydrogen flames. The previous flammability limit model was improved based on the mechanistic investigation, with which the amount of indirect radiation heat loss could be estimated by the optically thin approximation. As a result, the sharp increase in limit concentration by H₂O could be explained by high thermal diffusivity and radiation rate. Despite the high radiation rate, however, CO₂ with the lower thermal diffusivity than the threshold cannot produce a noticeable increase in heat loss and ultimately limit concentration. We concluded that the proposed mechanistic analysis successfully explained the experimental results even including radiating gases. The accuracy of the improved model was verified through several flammability experiments for H₂-air-diluent.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.4
• /
• pp.11-17
• /
• 2011

In order to see flame behavior in the annular reverse gas turbine combustor, sector combustion test was performed. Ignition test by using torch ignition system was carried out at various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with constant air mass flow rate. In test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity. Test result shows that lean blow out limits are increased with air velocity. The highest blow out limit was found at the combustor inlet velocity of 65 m/s.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.153-159
• /
• 2010

In order to see the flame behavior in the annular reverse gas turbine combustor, sector combustion test was performed. Ignition test by using torch ignition system was carried out at the various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with constant air mass flow rate. In the test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity. Test result shows that lean blow out limits are increased with air velocity. The highest blow out limit was found at the combustor inlet velocity of 65m/s.