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Experimental study and numerical calculation of water hammer effect of closing valve of ball type regulating valve |
CHEN Yafei, GU Weiguo, WANG Dezhong, XU Rui |
Shanghai Jiao Tong University, Shanghai 200240, China |
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Abstract With respect to the water hammer phenomenon caused by the rapid closing of the ball type regulating valve in the pressurized water reactor nuclear power plant, both experimental method and numerical calculation were used to study the water hammer effect of the closed valve, and the influence of the closing speed on the water hammer impact waveform was analyzed. The results indicate that with the closing of valve, the pre-valve pressure increases first and then decreases, and the post-valve pressure first decreases and then increases. The pre-valve pressure peak and the post-valve pressure valley are reached almost simultaneously, which are accompanied by pressure fluctuations that decay rapidly over time. The water hammer effect of the closing valve has a stronger impact on the pipeline before the valve. In addition, the positive pressure before the valve and the negative pressure after the valve will produce a resultant force, which causes a greater water hammer impact on the valve body structure. When the valve closing time increases from 3 s to 5 s, the water hammer impact force can be reduced and the water hammer impact waveform can be changed as well. Based on the classical water hammer equation and characteristic line method, the calculation software was independently developed, and a set of numerical calculation methods for quickly analyzing the transient performance of valve closing and water hammer impact effects was established. By comparing the experimental data, the reliability of the software was verified. The calculation software can predict the valve closing dynamic process and pipeline water hammer phenomenon, which can support related practical engineering applications.
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Received: 20 November 2019
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