非对称矩形蜗室内气流特性的实验研究

Experiment Investigation of the Airflow Characteristic in a Non-symmetric Square Volute

采用激光多普勒速度测量系统对 3种运行工况下后弯离心通风机非对称矩形蜗室内 1 80°子午流面上气流流动特性进行了实验测量 ,分析了测量流面不同位置处速度的分布特点 ,以及改变转速后 ,蜗室前壁、中间和后壁区径向速度及合成速度的分布。结果表明 ,蜗室中间的主流速度在不同转速下均呈抛物线型分布 ;蜗室前壁区的涡流区随转速的提高逐渐缩小最后消失 ,该处主流速度向抛物线型分布发展 ;后壁区的垂直方向气流几乎不受转速的影响。

Measurement of the three dimensional velocity is made on the 180° cross section of a non symmetric square volute for three working conditions.The distribution of the vertical and main flow velocity in the front,middle and back area of the cross section is analyzed with the working speed varied.The results clearly document that the curves of vertical and main velocity in the middle area of the volute are parabolic at all running speeds.The vortex flow in the front area is gradually reduced and disappears with increasing the running speed.The curve of the main velocity in the area tends to be parabolic.The vertical flow in the back area holds low speed,adverse,and is hardly influenced by the running speed.The results will be a great help to the optimization design of the air duct in internal combustion engines. Key words: Volute,LDV system,Main velocity,Flow characteristic