Numerical Study of Gas Flow and Solid Particle Erosion in the Fuel Gas Distribution Octopus Pipe of a Gas Turbine

Abstract

The Fuel Gas Distribution Octopus Pipe is a critical component of the Siemens V94.2 gas turbine operated at PLTGU Muara Tawar, responsible for distributing fuel gas to the burners in premix mode.  This study aims to analyze the gas-flow characteristics and to predict the erosion rate using a Computational Fluid Dynamics (CFD) approach. Numerical simulations were performed on the 16Mo3 manifold pipe geometry using the Realizable k–? turbulence model and the Oka erosion prediction model. The operating parameters were varied in terms of gas flow velocity and solid-particle mass flow rate. The results show that the primary erosion mechanism is dominated by inertial impaction, in which particles with a Stokes number greater than 0.1 are unable to follow the gas streamlines in elbow regions and tend to impact the outer elbow wall. Quantitatively, increasing gas velocity significantly raises the maximum erosion rate. At 52.85 m/s, the maximum erosion rate is predicted to be 5.56 × 10^-8 kg/m²·s, increasing to 1.83 × 10^-7 kg/m²·s at 70.47 m/s (field condition), and reaching 3.30 × 10^-7 kg/m²·s at 88.09 m/s. Increasing the solid-particle mass flow rate also increases the erosion rate in an approximately linear manner, from 1.77 × 10^-7 kg/m²·s to 2.28 × 10^-7 kg/m²·s as the particle mass flow rate increases from 1.31 × 10^-7 kg/s to 1.69 × 10^-7 kg/s.