이중연료 엔진의 배기 시스템에서 발생하는 폭발사고에 관한 수치 해석

Abstract

Air pollutants emissions from ships are regulated according to the International Maritime Organization (IMO), and the method of using liquefied natural gas (LNG) as fuel is used to comply with Tier III related to nitrogen oxides and sulfur oxides emission regulations. Dual fuel engines comply with environmental regulations and are used for economic advantages, and the ratio of dual fuel engines to newly built ships is increasing. In dual fuel engines, there is a possibility of an explosion accident in the exhaust system due to leakage of unburned residual gas from the inside of the cylinder. Therefore, the explosion relief valve (ERV) is being installed to respond to such accidents. In this study, to analyze the explosion accidents occurring in the exhaust system using numerical analysis, the gas flow in the exhaust valve was modeled using user-defined functions (UDFs), and explosion accidents occurring in the exhaust system were implemented using the partially premixed combustion (PPC) model. The results of without the ERV, the temperature increased to 2493 K and the pressure increased to 7.5 bar, and the pressure results with one small or one medium ERV exceeded the allowable pressure of the exhaust system of 4.0 bar. As the results of numerical analysis by installing two small ERVs, the temperature increased to 2200 K and the pressure increased to 3.2 bar, which did not exceeded the allowable pressure of 4.0 bar. Through these results, it was confirmed that it was appropriate to install two ERVs in order to apply to explosion accidents occurring in the exhaust system. Finally, it was possible to analyze the explosion accidents occurring in the exhaust system using numerical analysis, and it could be used to select the specifications of the ERV. In addition, it was possible to save the cost of performing an explosion test, and it was expected that it could be used to predict the outcome of an explosion accident occurring under the actual engine operating conditions.