IMPROVING THE RELIABILITY OF A DUAL-FUEL MARINE DIESEL ENGINE TURBOCHARGER NOZZLE RING BASED ON THERMOMECHANICAL AND GAS-DYNAMIC MODELING
https://doi.org/10.33815/2313-4763.2026.1.32.006-019
Abstract
The article focuses on improving the reliability of the Napier NT1-10 turbocharger nozzle ring used in the Wärtsilä W6L34DF dual-fuel marine diesel engine as part of a gas carrier's power plant. The relevance of this study is driven by the widespread adoption of medium-speed dual-fuel (DF) engines on liquefied gas carriers, as well as the high failure rate of turbocharger nozzle rings caused by thermomechanical loading and solid particle erosion. The methodological framework of the study comprises three-dimensional geometric modeling within the AutoCAD environment and numerical simulation using the cloud-based CAE platform SimScale: CFD analysis (OpenFOAM) to evaluate gas-dynamic processes in the flow passage, and finite element analysis (Code_Aster) to analyze static and thermomechanical stresses. The simulation results revealed that the zones of maximum stress are concentrated in the blade-to-root and casing-to-support transition areas. Based on the identified patterns, a modernized design is proposed: rounded geometric transitions (fillets) are introduced in the critical zones, which significantly reduces peak thermomechanical stress concentrations and lowers the risk of fatigue crack initiation without altering the gas-dynamic flow characteristics or the component's mounting arrangement. Conclusions: A modernized nozzle ring design featuring rounded transitions in critical zones is proposed. Re-simulation confirmed a substantial reduction in peak stress concentrations with no degradation of gas-dynamic flow characteristics and no modifications to the component's mounting arrangement. The applied approach — combining 3D geometric modeling in AutoCAD, CFD analysis, and thermomechanical analysis within the cloud-based SimScale platform — provides a comprehensive structural life assessment and can be utilized to improve other components of marine power plants.
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