Effect of Aeration on the Cavitation Characteristics of the Control Valve in Hydro-Driven Ship Lifts

Abstract

In hydro-driven ship lifts, plunger valves and fixed cone valves are the most suitable structures for achieving accurate flow control under a wide range of flow conditions. In order to inhibit cavitation in these valve structures, experiments were conducted in which forced aeration was applied before the valve. The cavitation phenomena and aerated flow regime were observed through a transparent glass pipe, and the cavitation noise characteristics were recorded using a hydrophone. The test results show that aeration can reduce the valve working cavitation number, albeit to a limited degree (<5%). Based on the sound velocity theory of aerated flow and the experimental results, the relationship between the aeration concentration and the cavitation inhibition efficiency was obtained. When the aeration concentration is approximately 0.1%, cavitation can be significantly inhibited via forced aeration before the valve. Once the aeration concentration reaches 0.9%, the cavitation inhibition efficiency becomes saturated. The research results presented in this paper provide a reference for the cavitation inhibition of industrial valves.

Keywords

• aeration concentration
• wall pressure
• cavitation number
• cavitation noise
• ship lift