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

Expander who drives a electromotor to generate electricity is the core of low-temperature waste heat recovery equipment. At present, domestic expanders on waste heat recovery system mostly come from exploration, research and improvement on the existing models of screw expanders and scroll expanders, which has complex structures and high costs. Against the shortcomings above, we researched and designed a new roots-type power machine. In this paper, we simulated the working fluid of low pressure waste heat according to both the different operating conditions and the different intake and exhaust pressure and flow, and simulated the changing process of internal flow field over time period using dynamic mesh technique when the power machine is in rotating work. Besides, we analyzed the pressure field, velocity field and graph of mass flow rate with the simulation results, thus reaching the conclusion of the 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. Moreover, these efforts will provide strong theoretical guidance and foundation for the subsequent engineering practice of waste heat recovery system on roots-type power machine, and have a profound impact on further recovery and utilization of low-grade energy.