Prototype Monitoring of Cavitation in Valve Culvert of Qianwei Shiplock

Abstract

AbstractThe working condition of water valve is an important sign of the success for navigation lock design, and the valve cavitation characteristics and suppression technology is the key technical challenge in the design of high head navigation lock, in the view of the “flat bottom & top spreading” with the condition of “less project quantities, convenient construction” simple type corridor with the head of 19 m in Qianwei ship lock, the method of combining the physical model test and prototype observation are both adopt to this research. Through the physical model test, the cavitation position, cavitation characteristics and the effect of natural ventilation on cavitation suppression are comprehensively determined by analyzing the change law of cavitation noise intensity from several cavitation noise sensors under different opening conditions during the opening process, also the visual observation of flow state and auditory observation. Prototype observation focuses on the effect of self-aerated technology of valve lintel. When the air pipe outside the value lintel position is closed, there are evident in the cavitation pulse signal, and the maximum strength can reach to 182Pa, the “crackling” of cavitation collapse could be clearly felt at the top of the value, occasionally with 2–3 times slight “muffled thunder”, The results show that the valve section has stronger cavitation during the opening process of value. On the contrary, when self-aerated of valve lintel was realized, the maximum ventilatory capacity was 0.169 m3/s, which was close to the 0.170 m3/s calculated by the physical model in the design stage, and no cavitation pulse signal was detected among the valve wells on both sides, and the process line was “stable” with the maximum noise intensity only about 10 Pa, no sound of cavitation collapse was heard at the top of the valve section during the whole valve opening process. The comparison of value steeve vibration also verifies the effect of self-aerated technology of valve lintel at the same times. The results show that self-aerated technology of valve lintel can significantly inhibit the cavitation of valve segment of this form.