1. Center for Innovation in Gas Research and Utilization (CIGRU), Center for Alternative Fuels, Engines and Emissions (CAFEE), Computational Fluid Dynamics and Applied Multi-Physics Center, Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506, USA
2. Department of Applied Physics and Electronics, Umea University, 90187 Umea, Sweden
3. Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education of China, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China