Performance Prediction of a Two-Stroke Aviation S.I. Engine by Means 0D/1D Thermo-Fluid Dynamic Simulation Code

Two-stroke engines represent an attractive solution for aviation industry applications (UAVs, VTOL aircraft, and ultralight aircraft) due to their compact size, high power-to-weight ratio, reduced number of moving parts, and the ability to operate with different fuels. This work presents a 0D/1D methodology for simulating the gas exchange, combustion, and unsteady flow of a two-stroke aviation engine. The scavenging and combustion processes, as well as the unsteady flow within the induction and exhaust systems, are investigated using a 0D/1D modeling approach. This study is motivated by the need to assess the accuracy of such models in predicting engine performance. For this purpose, the thermo-fluid dynamic code GASDYN has been applied and enhanced. The proposed 0D model is embedded into a 1D fluid-dynamic code for simulating the entire engine system. To characterize the baseline configuration, which includes tangential ports that facilitate a loop-scavenging process, computed results are compared with available experimental data from a conventional two-stroke spark ignition engine used in aviation applications. Validation was carried out under operating conditions representative of UAV operation at different speeds and full load. The final goal of this study is to modify the exhaust system geometry to increase the maximum power of the same engine architecture. Satisfactory results were achieved, demonstrating that the proposed approach can be applied to design and optimize two-stroke engines with a high degree of accuracy and reduced computational costs.