A HIGH-RESOLUTION PIV ANALYSIS ON GUIDE VANE INLET REGION OF A DIFFUSER PUMP

摘要

The latest PIV system is applied to quantitative analysis of the rotor-stator region within a diffuser pump. Fine optical setup closely concerned with PIV performance was arranged for the accurate PIV measurement of high-speed complex flow. Four different kinds of revolutions(1000, 1500, 2000 and 2500 rpm) were selected as experimental condition. A 1k x1k high-resolution CCD camera(Megaplus, Kodak) and Nd-Yag dual pulsed laser(120mJ) were used. Optimized cross correlation identification to obtain velocity vectors was implemented by direct calculation of correlation coefficients. The various parameters were represented quantitatively at the rotor and stator interaction region. A centrifugal diffuser pump was used and its maximum speed reached up to 3000rpm. The test model was a single stage, horizontal shaft pump with a vaned diffuser. The impeller was semi-closed type and had 10 backward blades with a discharge angle of 32.5 degree. The inlet and outlet radius of the guide vane were 160mm and 250mm, respectively. For illuminating the flow field, a air cooled Nd-Yag dual-pulsed laser was used and the measuring size was 74mm(H) x 85mm(V). For the purpose of flow visualization, the measuring sections of the apparatus were made of transparent acryl plate. Tapping water(7℃) was used as working fluid and tracer particles were PVC(average diameter is 110 μm).