수소-산소 가연혼합물의 스파크 점화에너지 측정을 위한 기초연구

Abstract

The international community continues to make various efforts to solve the climate change problem and create a sustainable society. One of the various efforts, carbon neutrality, was presented. In response, the domestic government also suggested the first direction to expand the use of hydrogen to practice carbon neutrality. However, in the case of hydrogen, the flammable range (4% to 75%) is very wide and the ignition energy (0.017mJ) is also very low, so the risk of explosion is higher than other fuels. In particular, when hydrogen and oxygen are mixed, it has a wider combustible range (4% to 95.2%) and lower ignition energy (0.0012mJ) than conventional hydrogen fuel. However, studies on the measurement of the ignition energy of hydrogen-oxygen combustible mixtures are few and insignificant. Therefore, in this study, the ignition energy of the hydrogen-oxygen combustible mixture was measured. In order to measure the ignition energy of combustibles, an ignition source for igniting the combustibles is required, and the spark ignition energy of a hydrogen-oxygen combustible mixture is measured through a spark ignition device most widely used to measure ignition energy among various ignition sources. In order to measure the ignition energy through the spark ignition device, the breakdown voltage value must be measured first. In this study, the breakdown voltage according to the gap condition and the hydrogen volume percentage was measured. It was found that the breakdown voltage increased as the gap increased and the hydrogen volume percentage decreased. In addition, spark ignition energy was calculated through the measured breakdown voltage. The minimum ignition energy of the hydrogen-oxygen combustible mixture was measured in two ways. The first method is to measure the extinguishing distance for each hydrogen volume percentage of the hydrogen-oxygen combustible mixture through a relational expression between the extinguishing distance and the minimum ignition energy. The second method is a method of estimating the minimum ignition energy through a probability basis based on the ignition energy measured in this study. The minimum ignition energies of each measured hydrogen-oxygen combustible mixture were measured to be 2.23μJ and 3.10μJ. There was a difference between the minimum ignition energy of hydrogen-oxygen combustible mixtures measured through experiments and the minimum ignition energy of known hydrogen-oxygen combustible mixtures. This is determined to be due to the difference in the material, thickness, and hydrogen volume percentage of the electrode.