Gas Turbine Propulsion Systems for Naval Vessels: Energy Flow Calculation Methodology and HighPressure Rotor CFD Simulation

Abstract

This paper addresses the modernization of naval propulsion systems through the adoption of gas turbine technology, with emphasis on thermodynamic calculation methodology and rotor flow simulation. The study is centred on the Rolls Royce gas turbine, employed in naval propulsion applications and covers all thermodynamic states from atmospheric air intake through the two-stage compression process, combustion chamber, high-pressure and lowpressure turbine stages, to the power turbine exhaust. Key parameters, including mass flow rates, stage temperatures, pressure ratios, stage power outputs, and overall thermal efficiency (η = 0.337), are systematically derived using polytropic compression relations and energy balance equations. In the second part of the paper, a 3D model of the gas turbine high-pressure rotor is developed in SolidWorks and subjected to CFD flow simulation. Three rotational speed regimes are analysed, 500 rad/s, 750 rad/s, and 1000 rad/s, with corresponding inlet boundary conditions of temperature, pressure, and velocity. The simulation results reveal total pressure drops across the rotor of 1.1%, 1.64%, and 2.3% respectively, consistent with increasing energy extraction at higher rotational speeds. Convergence of total pressure at both rotor inlet and outlet confirms numerical stability across all cases. The results provide a quantitative basis for performance assessment and design optimisation of naval gas turbine rotors.