微型车转向不稳的诊断与排除

微型车,尤其是国产微型车上时常出现转向不稳的故障,由于它比较隐蔽,而且比较缠手,时常给司机师傅造成困难。下面就多年积累的些许经验简单的分析一下。故障现象 1.转向盘抖动国产微型车车型小,速度较快,转向也比较灵活轻便。但如果不注意日常的保养和维修,极易出现这样或那样的问题,而转向盘抖动在行驶过程中常会发生。这种现象的出现一般与汽车的速度快慢有关。即随车速的不断提高加快,手感转向盘抖动的现象就越加明显;反之随车速的逐渐降低减慢,这种现象也随之减轻或消失。转向盘抖动这种故障在短时间内不影响使用,但也要及时处理解决。因为不加修理。

Unsteady Tip Clearance Flow in an Isolated Axial Compressor Rotor

The paper investigates effects of operating conditions, tip clearance sizes and external unsteady excitations on the unsteady tip clearance flow in an isolated axial compressor rotor by unsteady 3D Navier-Stokes simulations. The results show that the unsteady tip clearance vortex takes a periodic flow behavior in the rotor tip region. With the decrease of the flow coefficient, the unsteady tip clearance vortex is enhanced and its frequency becomes lower. A larger tip clearance size can cause bigger unsteady fluctuation amplitude and a lower fluctuation frequency of the tip clearance vortex at the near stall operating condition. The unsteady excitation with the natural frequency of the tip clearance vortex can enhance the unsteadiness of the tip clearance vortex and improve the overall rotor performance. The frequency of the unsteady tip clearance vortex is independent of external unsteady excitations with different frequencies.