빗물펌프장의 수력학적 과도현상에 관한 연구

Abstract

In this study, a field test was conducted to study the water hammer, which is a hydraulic transient phenomenon occuring at a rainwater pumping station. The drainage pump subject to the field test was a vertical shaft two floor mixed flow pump with a pump bore of 2,000 mm and a motor power of 1,320 kW. To test the hydraulic transients phenomenon of the drainage pump, the pressure sensors were installed on the pump discharge side and the outlet of the check valve. In the electrical transient test, the voltage, current, and the power facter of the motor were measured using a power meter. The measured pressure and electrical values were stored in a data acquisition system. A field test for water hammer phenomenon that occur when starting and stopping the drainage pump were conducted in cases where the electric butterfly valve was throttled and when it was full open. As a result of the field test, it was analyzied that the method of cutting off the power of the drainage pump after significantly throttling the electric butterfly valve can reduce the flow velocity in the discharge pipe, but the effect of increasing the pressure of the drainage pump appeared greater. It was observed that the flap valve closed before the check valve when the power to the drainage pump was shut off, and when the flap valve closed abruptly 1 second before and after, slamming occurred. This may cause the valve disk and the valve seat to be damaged by the impact, therefore, caution is required.