1. School of Architecture and Urban Planning, Lanzhou Jiaotong University, Gansu 730070, P.R. China
2. Key Laboratory of Railway Vehicle Thermal Engineering, Lanzhou Jiaotong University, Ministry of Education, Lanzhou 730070, P.R. China
3. Department of Mechanical Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, P.R. China