1. Gas Turbine Institute, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China e-mail:
2. Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, PA 15213
3. Gas Turbine Institute, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China
4. Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, AL 35899 e-mail: