Experimental Investigation on Velocity Fluctuation in a Vaned Diffuser Centrifugal Pump Measured by Laser Doppler Anemometry

Turbulent flow, mainly originating from the rotor-stator interaction (RSI), is closely associated with normal and safe operation of centrifugal pump. In current research, to clarify turbulent flow in pump a vaned diffuser, non-intrusive LDA (Laser Doppler Anemometry) system applied measure velocity pulsation signals at different regions when operates various rates. Time frequency domain analysis methods are combined investigate signals, distribution around volute tongue region reconstructed twenty measuring points. Results show that spectrum characterized by discrete components blade passing its higher harmonics, it caused RSI between impeller diffuser. For points spiral diffusion sections, due significantly reduced effect, shows an evident difference comparison not always dominant frequency. The amplitudes RMS* (root mean square velocity) values proves position rate affect pulsations. As observed high developed downstream diffuser channel for all measured