원심펌프 성능에 관한 실험적 연구 (II) = Experimental Study on the Performance of Centrifugal Pump (II)

다국어 초록 (Multilingual Abstract)

This work is to investigate effect of operating characteristics of pump according to the rotational speed of pump and the change of flow rate when centrifugal pump operates with the condition that regulated flow, head, revolution number, and specific speed are respectively 0.7 ㎥/min, 8 m, 1750 rpm, 180 (m, ㎥/min, rpm). The pump used in the experiment doesn't have a guide vane and directly connects with outside rim so that the rotational speed of volute pump in spiral or volute casing increase by 100 rpm from 1450 until it reaches 1750. The results of the relationship of Q-H, Q-L, Q-η and the dimensionless performance features such as head coefficient, power coefficient and efficiency are as follows;
(1) According to the increase of evolution number, the head and power increase up to the square or cube of the evolution number. At the same evolution number, the power is increased according to the flow. In time of standard operation, the head has a stable feature in the early stage of flow increase from the segment point.
(2) The pump's highest efficiency shows 52% with flow rate 0.17㏄/min and head 4.7 m in time of 1450 rpm and 50% with flow 0.18㎥/min and head 6.7 m in the pump's highest rotational speed of 1750 rpm.
(3) In each rotational speed, curve of efficiency, head and power is different. Meanwhile, the dimensionless performance valuables show a line irrespective of rotational speed. As flow coefficient increases, power coefficient increases and head coefficient decreases. When the flow coefficient is 0.08, it reaches the maximum efficiency 52%.