| Summary: | 碩士 === 中華大學 === 機械與航太工程研究所 === 92 === High speed rotating machinery operating under thermal cycles is superior to traditional batteries from the point of view for power density. Micro gas turbine is a system device that supplies power and propulsion; it can be served as not only the electric generator or the propulsive power of MAV and UAV, but more probably the supplier for those portable electronics-computers, PDA, cell phones, GPS receivers that demand high power density. This study takes the MIT micro-gas turbine engine as a vehicle. We analyze thermodynamics properties for the system and make subsystem description. First we design a micro compressor, simulating the aerodynamic performance for its flow field and the proper ignition location when compressed air entering the combustion chamber. Then we analyze the heat transfer performance and the effect to cycle thermal efficiency of a Swiss-roll recuperator. Finally is the comparison between our analysis results and the MIT micro-gas turbine engine experimental data. Numerical analysis shows the pressure ratio of designed compressor is 1.9 at the design point of 600000rpm. The isentropic efficiency is 46.3% because of pressure loss before fluid entering rotor flow passages from ambient air and the higher temperature ratio of air resulting from higher rotational speed at low-pressure ratio. The simulation of combustion chamber shows in three different inlet pressure conditions the ignitor should just the same locate at about 8mm to 9mm downstream the outlet of diffuser vanes. The cycle thermal efficiency of both MIT micro-gas turbine and self-designed condition apparently upgrades with additional recuperation. Heat regeneration cycle has advantages when it comes to gas turbine system with low-pressure ratio.
|
|---|
