Dept of Power Engineering,Nanjing Univ.of Aeroniautics and Astronautics,Nanjing,210016;Dept of Power Engineering,Nanjing Univ.of Aeroniautics and Astronautics,Nanjing,210016;Dept of Power Engineering,Nanjing Univ.of Aeroniautics and Astronautics,Nanjing,210016