Design parameters affecting the performance of the IRRI-designed axial flow pump

Date

1984

Abstract

The effects of the following design parameters on the performance of the axial flow pump were studied, namely, impeller vane discharge angle, diffusion vane angle, clearance between the impeller and the stator casing and shape of inlet approach. The cost comparison between a single-stage and the two-stage pump was made. The impeller vane discharge angle determined the head-capacity characteristics of the pump. These characteristic varied directly with the value of the discharge angle whose design value could vary from 15 ° to 30 ° depending on the desired head-capacity characteristic. The performance of the pump was not sensitive to the change in diffusion vane angle. The optimum vane angle was 47.21 ° and variations as great as ± 5° had no noticeable effect on the pump performance. The optimum clearance between the impeller and the stator casing was dictated by the deflection of the pump shaft. A 3.82 mm clearance was found optimum for an axial flow pump with 20 cm diameter of impeller. A fishtail-shaped inlet approach gave a much higher pumping efficiency than an oblique-shaped approach. The head and BHP input of a two-stage pump was found to be twice that of a single-stage pump at the same capacity at the best efficiency point. It was cheaper to use a single-stage pump at lifts 2.0 meter and below than a two-stage pump and at 2.5 meter lift if the opportunity cost of capital was 40 percent. At 30 percent opportunity cost of capital, the two-stage pump had less cost. A 3.0 m lift and above the cost of pumping was cheaper using the two-stage pump.

Document Type

Master Thesis

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 995 1984 A2 A33

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