Design And Experiment Technique Researches Of High Load Micro Radial Turbine

Micro turbine engine can be used as propulsion system of low-cost micro aerial weaponsplatform because of its high power density and high thrust-weight ratio. Micro radial inflow turbine isthe core component of micro turbine engine. The high flow capacity and high single-stage load is thefuture developmental direction. The design technique research on micro radial inflow turbine withhigh flow capacity and single-stage load is important to improve the turbine performance and microengine performance. This paper studied the design techniques of micro turbine engine by numericalsimulation and experimental means, including the following aspects:1. The comprehensive performance comparison between micro radial turbine and axial turbinewas carried out. Based on the MTE-D micro turbine engine environment, the aerodynamicperformance and size differences of single-stage micro axial turbine and radial turbine was comparied,under the high flow rate and high power state. Based on the current design technique level of microengine components, the micro turbine type selection rule was summaried, which could be used toguide the turbine type selection for centimeter-level micro turbine engine.2. The design framework of micro radial inflow turbine rotor with high flow and high load wasbuilt. For the radial turbine rotor with the dimameter of30~100mm, the influences of leaf angledistribution, wheel diameter ratio, import flow angle, and impeller axial width on turbine performancewere studied. The preliminary design principles and selection laws of these design parameters weresummaried. The micro radial turbine rotor of MTE-D micro engine was designed. At the design point,the turbine drop pressure ratio was2.25, the flow rate was0.42kg/s, and the efficiency was0.82.3. Based on the MTE-D micro engine, the design techniques of micro vane nozzle wasresearched and improved. The influences of leaf angle distribution, meridional channel shape, bladenumber and other key design factors on nozzle performance were studied. The research determined abetter leaf angle distribution, defined the design principles of the meridional channel shape, andchoiced the best relative axial width and blade number. The design of micro vane nozzle for MTE-Dmicro engine was completed. Its flow rate was0.4kg/s, and the total pressure recovery coefficient was0.97.4. A new test facility for centimeter-level micro compressor and turbine was built. The test rigcould be used for full speed test of centrifugal compressor and long duration thermal test of radialinflow turbine. The facility had separate compressor path and turbine path. The power match at different speed and flow conditions could be achieved easily by adjusting compressor and turbineoperating condition individually to meet the need of impeller characteristics. In order to accuratelymeasure the impeller efficiency, the optical torque sensor with measurement accuracy of1%wasdesigned.5. By this self-built test rig for micro compressor and turbine, the cold and thermal tests of amicro radial turbine rotor designed in this paper with a diameter of78mm were completed, and partimpeller characteristics of this turbine were obtained. The test results verified the accuracy of thenumerical simulation. The micro radial turbine rotor and micro vane nozzle designed in this paperwere used in MTE-D micro turbine engine, and the engine ground test was completed. The engineachieved the design speed, and the thrust was more than120N. The ground test results furtherverificated the design technology for micro radial inflow turbine obtained by this paper.