Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Study on Cavitation Phenomenon of Marine High-speed Propeller
Lien Yang and Xing Zheng
College of Shipbuilding Engineering, Harbin Engineering University
Harbin, Heilongjiang, China
cavitation phenomenon of real ship can be predicted according to theresults of uniform flow test in a cavitation cylinder. These cognitions put
forward a series of topics to researchers, such as: 1) what is themechanism of cavitation? 2) Does cavitation have scale effect? 3) How
does cavitation produce propeller denudation and how to prevent it? 4)
How does cavitation affect the performance of propeller? 5) How does
the non-uniformity of stern flow field affect the generation of cavitation?
6) How to predict the generation process of propeller cavitation (so as tobetter design the propeller to meet the actual demand)? These problems
have not been really solved, and solutions to a certain extent have been
carried out in industry and academia.

ABSTRACT
Cavitation can be classified as gasification cavitation, vaporization
cavitation and quasi cavitation. Cavitation produced by propeller can befurther divided into vortex cavitation, vesicular cavitation, sheet
cavitation and cloud cavitation. Vaporization cavitation phenomenon ofhigh-speed hydrofoils and marine propeller placed in a numerical poolwith free surface is studied by numerical simulation. Based on thepressure reduction coefficient and cavitation number at the section ofpropeller blade at a certain immersion depth, the occurrence mechanismof cavitation is discussed, as well as the influence of cavitation on thedenudation and hydrodynamic performance of propeller.

In this paper, the vaporization cavitation is mainly discussed, and two
typical numerical experiments are set up: 1) a high-speed hydrofoil isplaced in a numerical pool with free surface, and a certain understandingof the cavitation generation mechanism is obtained; 2) A high-speed
marine propeller is placed in a numerical tank with free surface, and a
new innovative propeller design process is given. Engineers can use thisprocess to design the propeller better and more efficiently in the whole
ship design cycle.

KEY WORDS: Marine propeller; hydrofoil; cavitation; denudation;vibration; two phase flow.

INTRODUCTION
As early as the late 19th century, it was found that the propeller design
at the stern of a ship could not reach the initial propeller design speed
and main engine design power in actual operation. During that period,
some engineers (Barnaby, 1897) tried to modify the propeller design formany times, and finally solved such problems only after the propeller
disk ratio increased by a certain proportion. The main reason for suchproblems that do not reach the expected speed is the cavitation of thepropeller.

The study of cavitation mechanism shows that cavitation is actually ageneral term, which can be divided into gasification cavitation,vaporization cavitation and quasi cavitation. The so-called gasification
cavitation refers to that the gas originally dissolved in water escapes into
the gas core existing in water by diffusion through the interface due todepressurization or supersaturation, and grows to the scale visible to thenaked eye. Vaporization cavitation refers to explosive vaporization ofliquid molecules due to depressurization to the so-called saturated steampressure. Water vapor enters the gas core through the interface andmakes it expand visible. Quasi cavitation refers to the gas core thatoriginally existed in water in various ways. Although there is no escapeof any water vapor or gas, it will expand to the visible scale when theexternal pressure decreases. Vaporization cavitation always appears
when the pressure is less than or at least equal to the saturated vapor
pressure of water (𝑝𝑣 ), and the growth process is rapid. Gasification
cavitation and quasi cavitation can occur when the pressure is greater
than, equal to or less than the water saturated vapor pressure, and thegrowth process is slow. This paper mainly discusses vaporization
cavitation. For vaporization cavitation, there are the so-called primarycavitation and vanishing cavitation.

The trend of ship development in the last 20 years of the 20th century(Sheng and Liu, 2004) is as follows: 1) the main engine of high-speed
ship is developing towards high speed and high power, and the main
engine is directly connected with the propeller. Cavitation is often
inevitable on the propeller of this kind of ship, so it promotes the researchand development of the so-called cavitation propeller or all cavitation
propeller. 2) When the ship is large, the main engine power is higher andthe propeller load is increasing. Due to the non-uniformity of the flow
field at the stern of this kind of ship, the cavitation on the propeller isgenerated from time to time, resulting in the denudation damage of theblade, which is often accompanied by strong tail vibration. Therefore,
the cavitation problem is becoming more and more important and has
attracted more and more attention of many scholars, so as to further
improve the understanding of the cavitation mechanism and seek thelaws and methods to avoid cavitation on the propeller.
Studies have shown that some concepts in the past are wrong, such asthat cavitation can be avoided by conventional design method, and theThe generation of all cavitation involves the factor that there is a gas corein the liquid. Someone has conducted such a test to measure whether the3303