Unsteady Flow Characteristics of a 1000 MW Nuclear Power Plant Main Pump

To analyze in depth the flow field inside a 1 000 MW nuclear power plant main pump,numerically simulated was the main pump by using the commercial computational software CFD with the pressure fluctuation characteristics of the pump in question being obtained.The research results show that the pressure fluctuation inside the pump assumes a periodic change and the frequencies influenced by the impeller blades on the fluid are those integral number times of the rotational speed frequency f=24.2 Hz and of its harmonic waves.The amplitude of the pressure fluctuation inside the impeller increases gradually from the leading edge to the trailing edge of the blades while that in the guide blades decreases gradually from the leading edge to the trailing edge.The change in the volute of the pump is relatively small.Under different operating conditions,the amplitude of the pressure fluctuation is minimum at the rated-load operating condition but maximum under the operating condition at a smallest flow rate.The more deviates from,the rated flow rate,the worse the pressure fluctuation.