纯吸吸尘与卷吸吸尘仿真对比分析

本研究基于计算流体力学软件FLUENT对纯吸式吸尘与龙卷风卷吸式吸尘进行了对比分析,旨在探明纯吸式与卷吸式在流场特征上的差异。通过对同一离地高度的吸尘口对比中发现,在近地面位置,纯吸式吸尘在吸尘口覆盖区域内有一个速度峰值,而卷吸式吸尘在吸尘罩覆盖区域内及覆盖区域外各有一个速度峰值,呈现双峰特性;在吸尘罩覆盖区域外的近地面,随着远离吸尘罩轴心,卷吸式吸尘气流速度降低较慢,而纯吸式吸尘气流速度降低较快。通过对不同离地高度的吸尘口对比中发现,随着吸尘口离地高度的增加,纯吸式吸尘近地面气流速度下降较快;而卷吸式吸尘近地面气流速度下降较慢。因此,充分利用卷吸式的近地面气流速度在吸尘口覆盖区域外降低较慢的特性,可实现大范围吸尘;充分利用随着吸尘口离地高度增加,卷吸式近地面平均速度降低较慢的特性,可实现远距离吸尘。

Similarity and Difference of Direct/Tornado Suction Modes of Road Sweeper:A Simulation Study

The flow-fields of street vacuum sweeper,operating in direct and/or tornado suction modes,were mathematically formulated with realizable k-ε turbulence model,theoretically analyzed and numerically simulated with FLUENT software.The influence of the suction-mode and suction port height on the radial velocity/pressure distributions and sweeping area was investigated.The simulated results show that the suction-mode and port-height have a major impact.To be specific,the direct and tornado modes have the radial velocity distributions with single-peak and double-peak,and have the radial pressure distributions with a valley and a peak,respectively.When it comes to effective sweeping area,the tornado-mode outperforms the direct-mode,because the vertical velocity profile(the sweeping area) is higher(wider) than(that) of direct-mode and because atmospheric pressure has a less strong impact.We suggest that the simulated results be of some technological interest in road-sweeper design.