Design and Performance Evaluation of Low Bypass Micro Turbofan Engine Based on Micro Gas Turbine

In this research, a low bypass micro turbofan engine was developed using a micro turboprop engine. The development process included 1D design, airfoil and rig design, fabrication, and testing. The design target of the low bypass micro turbofan engine was determined based on core engine specification and cycle analysis. To augment thrust, a micro turboprop engine with 15 kW class shaft power was used. The Fan module was designed based on pressure ratio and mass flow rate determined from the cycle analysis. For 1D design of fan, calculation process considering compressibility of air was executed. With design parameters from 1D design, the meridian and airfoil shape design of fan module were conducted by using blade shape design program. To ensure stable approaching airflow in front of the fan, a bellmouth was designed and attached to the fan module. Performance prediction and verification process of the fan module were conducted through CFD and FEM analysis. Several design modifications were made to achieve the target performance and ensure structural stability. After the design process, the parts, including the fan module, were fabricated and assembled into the engine system. Engine system tests were conducted under different configurations, including with and without the bellmouth and varying core engine exhaust duct directions. Test results showed distinct differences in performance characteristics, including thrust and specific fuel consumption(SFC). With the application of the bellmouth and a rear-facing exhaust duct thrust increase of 14 % and 20 % were observed, respectively. These modifications allowed the engine to achieve the target performance.