道路清扫车外文翻译

附录Ⅱ；Numericalstudyonparticle；headforastreetvacuumswee；BofuWu*,JinlaiMen,JieChe；SchoolofMechanicalEnglis；ABSTRACT；Thepurposeofthispaperist；Keywords:Pickuphead;Part；

1.Introduction；Cu

附录Ⅱ

Numerical study on particle removal performance of pickup

head for a street vacuum sweeper

Bofu Wu *, Jinlai Men, Jie Chen

School of Mechanical English Shanghai Jiao TongUniversity，Shanghai,200240,China

ABSTRACT

The purpose of this paper is to investigate the particle removal performance of pickup head for a street vacuum sweeper numerically. An integrated 3D numerical model was constructed based on particle suction process in computational fluid dynamics (CFD) software. The airflow through the pickup head was treated as a continuum, while particles were modeled as dispersed phase. The Reynolds stress model (RSM) and discrete particle model (DPM) were chosen in order to predict the air and particles flow accurately. The numerical simulation results show that the sweeper-traveling speed and the pressure drop across the pickup head have great effects on the particle removal performance. The removal efficiency of particles increases with the lower sweeper-traveling speed or the higher pressure drop, and small size particles have higher grade efficiency than that of large size particles under the same operating conditions. Moreover, the removal mass flow rate of particles increases with the higher sweeper-traveling speed. Therefore, a trade-off should be considered among high removal efficiency, low energy consumption, and high removal mass flow rate. Through the

numerical simulation, the effectiveness of street vacuum sweeper for removing particles from road surface is evaluated, and an optimal operating condition is obtained. Besides, more information is generated to better understand the particle suction process of the pickup head.

Keywords: Pickup head; Particle removal performance ;CFD ;Sweeper-traveling speed Pressure drop

1.Introduction

Currently, there is a widespread concern over the pollution of particle matter. Dust and silt are the major sources of particle matter pollution, the removal of which therefore attracts considerable attention [1]. Street sweeping is typically practiced to

remove the accumulation of dust and silt from road surface to improve aesthetics, public healthy, and storm water quality, so it is considered as an effective pollutant control practice for many local authorities [2,3]. Pickup head is the key component of street vacuum sweeper, which is designed to pick up particles efficiently from road surface and send them to dust collection hopper smoothly. The particle removal performance of the pickup head is the most important index for a street vacuum sweeper.

Many researches have been performed on estimating the particle removal performance of street sweeping. For example, a study by Chang et al. [4] evaluated the effectiveness of street sweeping and washing for controlling ambient total suspended particles by experiments, which indicated that the street sweeping and washing process was effective at removing dust and silt from urban roads. However, some researchers such as Vaze and Chiew [5] considered that the contribution of street sweeping to environmental quality was not very clear, and may have an adverse impact because street sweepers did not pick up smaller size particles effectively. Kang