离心风机叶片扩压器内部流场的试验研究

利用激光多普勒测速仪(LDV)测量了离心风机叶片扩压器的内部流场。试验中，分别在大流量和小流量两个工况下对离心风机叶片扩压器的内部流场进行了详细的测量，由测量结果分析了叶片扩压器流道中前侧板侧、中间和后侧板侧三个回转面上气流速度的矢量分布和等值线分布，以及气流从扩压器的叶片凹面到凸面、从扩压器的进口到出口的流动特性。结果表明在扩压器喉部附近靠近扩压器凹面的局部区域，速度的方向会向叶片凸面发生较大角度的偏转；随着流量的增大，该区域将会向叶片扩压器的下游及流道宽度方向发展。

Experimental Investigation on the Flow Field in Vaned Diffuser of a Centrifugal Fan

An Experimental investigation on the flow fi el d in vaned diffuser of a centrifugal fan has been conducted using Laser Doppler Velocimeter (LDV). The experimental configuration consists of a shrouded backswe pt impeller, a vaned diffuser and a scroll. The three-dimensional velocity fiel d in vaned diffuser are obtained in several measurement planes perpendicular to the axis of impeller. The analysis of the distribution of velocity vector and ve locity contour in the those planes on two off-design operating condition shows that the low velocity locates at the convex side of the diffuser as the influenc e of the boundary layer and secondary flow. The direction and magnitude of the v elocity are changed suddenly near the diffuser inlet and throat at the concave s ide of the diffuser. Velocity oscillation, which deteriorate at higher flow rate , are greater at the upstream of the throat than those at the downstream of the throat.