Comparative Analysis of Analytical and Computational Thermal Models for the Free Double Piston Engine

Abstract

Effective thermal management is essential to ensure the performance, reliability, and longevity of advanced propulsion systems. The Free Double Piston Composite Cycle Engine (FDP-CCE) introduces a novel propulsion architecture that combines the efficiency of conventional piston engines with the structural configuration of turbofans. However, the elimination of crankshafts and the adoption of air lubrication systems introduce significant thermal challenges, particularly due to high temperatures in the combustion chamber and cylinder walls. This study presents the development of a computational thermal management tool aimed at evaluating and optimizing cooling strategies for the FDP-CCE. The tool couples an analytical heat transfer model with bypass air cooling to improve heat dissipation and maintain controlled temperature distribution across critical engine components. A parametric analysis is performed to investigate the effects of various material properties and bypass air heat transfer coefficients on overall thermal efficiency. The analytical and computational models produced similar results, validating the simplified 0D-1D model and enabling its use in further development due to its reduced computational cost. The findings contribute to the advancement of next-generation propulsion systems by providing a foundation for the integration of effective thermal control in composite cycle engines.