Numerical Simulation Study of Three-Dimensional Flow Field on Roots- Type Power Machine Based on Dynamic Mesh Technique

Xiao Yanjun*, Liu Yuxiang, Wang Dayuan, Li Chunxia
School of Mechanical Engineering, Hebei University of Technology, Tianjin, 300000, P.R. China.

© 2015 Yanjun et al

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the School of Mechanical Engineering, Hebei University of Technology, Tianjin, 300000, P.R. China; Tel: +86-13388007288; E-mail:


Expander which drives an electromotor to generate electricity is the core of low-temperature waste heat recovery equipment. At present, domestic expanders on waste heat recovery system mostly arise from exploration, research and improvement on the existing models of screw expanders and scroll expanders, which have complex structures and high costs. For overcoming the shortcomings mentioned above, a new roots-type power machine is researched and designed. In this paper, the working fluid of low pressure waste heat is stimulated according to both the different operating conditions and the different intake and exhaust pressure and flow, and the changing process of internal flow field is simulated over the time period using dynamic mesh technique when the power machine is in rotating work. Besides, the pressure field, velocity field and graph of mass flow rate are analyzed with the simulation results, thus obtaining the conclusion of optimum operating conditions of the roots-type power machine to guide selection method in practice, that is, selecting appropriate roots-type power machines according to different types of waste heat in industrial production. These efforts can therefore provide strong theoretical guidance and foundation for the subsequent engineering practice of waste heat recovery system on roots-type power machine, and can have a profound impact on further recovery and utilization of low-grade energy.

Keywords: Dynamic mesh, industrial low-temperature waste heat, numerical simulation, roots-type power machine, the optimum operating conditions.