Analisa Kegagalan pada Pipa Elbow di Turbocharger Lokomotif Kereta Api dengan Simulasi CFD dan Analisa Laju Korosi

Abstract

Erosion is one of the significant problems in turbocharger elbow components on diesel locomotives, mainly due to the exhaust gas flow containing solid particles such as soot. This study aims to analyze the erosion phenomenon in turbocharger elbows using the Computational Fluid Dynamics (CFD) approach and predict the service life of components based on thickness reduction data due to corrosion. Simulations were performed to capture turbulent flow patterns, pressure distributions, particle trajectories, and erosion rates at various operating conditions. Simulation conditions were set with exhaust gas flow rates of 0.8 g/s and 1.3 g/s, temperatures of 300 °C and 700 °C, and flow velocities of 15 m/s, 30 m/s and 45 m/s, which represent the operating parameters of a diesel engine. In addition, a fishbone diagram was applied to identify factors causing erosion, including particles in the exhaust gas, flow characteristics, material elbow, geometry, and engine operating conditions. The results obtained were the highest erosion rate occurring on the outer side of the elbow bend, in accordance with the turbulent flow pattern that directs solid particles to that area. The pressure distribution and particle trajectory also confirmed the critical areas that experienced particle impacts. The erosion rate values obtained were then compared with component thickness measurement data after two years of use, which were used to verify the elbow life prediction. The simulation results showed that the highest erosion rate was 0.272 mm/year and the lowest was 0.027 mm/year with a remaining life of 9.2 years. The erosion rate value is close to the thickness measurement results that occur at a flow rate of 1.3 g/s with a speed of 30 m/s which obtained an erosion rate of 0.108 mm/year with an error of 3.74% compared to a speed of 45 m/s which reached an error of 158.92%.