Thermal and Fluid Analysis of a Low-Bypass Turbofan Engine

Abstract

Low-bypass turbofan engines play a central role in aircraft propulsion: they generate thrust both from the cooler bypass stream and the hot core jet, which lets them remain efficient over a wide span of flight regimes. Predicting their behaviour accurately is, however, far from straightforward, since thermodynamic energy conversion, compressible-flow effects, and component-level losses are strongly coupled. This paper develops a physics-based numerical framework for the thermal and fluid evaluation of such an engine. The cycle is built on steady-flow relations derived from the first and second laws of thermodynamics together with the relevant energy-transfer equations. The engine is treated as a sequence of control volumes — intake, compressor, combustor, turbine, and nozzle — so that performance can be evaluated under different operating conditions. MATLAB is used to numerically solve the governing equations and iterate over key design variables. Outputs include specific thrust, thrust-specific fuel consumption (TSFC), propulsive efficiency, fuel-to-air ratio, and station-wise entropy generation. A simplified three-dimensional geometry is constructed in SolidWorks to define the surface boundaries, while CFD and thermal simulations are run in SimScale to capture local flow and temperature behaviour. The combined results provide a structured framework that links thermodynamic, geometric and numerical analysis, and they highlight the trade-offs between specific thrust, propulsive efficiency, and irreversibility as the bypass ratio is varied.