CAVITATION EROSION PREVENTION BY AIR INJECTION
Model tests in cavitation tunnels show that air injection into the cavities through outlets at the duct surface is an efficient method of protecting a propeller duct against cavitation erosion damage. As long as the rate of air supply does not exceed what is necessary to prevent erosion, there is no significant reduction of propulsive efficiency or increase of vibrations. Referring to the case tested a tanker with ducted propeller of 8 m diameter, operating at 100 revs. per min, will require a rate of air supply of about 14 cu m per min., normal air. Further model tests demonstrate the feasibility of reducing or preventing cavitation erosion on the blades of a conventional (non-ducted) propeller by injecting air into the propeller disc through tubes protruding from the skeg ahead of the propeller. The exact positioning of the tube outlets is in this case very important. Available full scale experience with air injection on ducted propellers generally confirm model test results. There is some indication that the tests in combination with the scaling law applied in the paper to some extent overestimates necessary rates of air supply.
- Paper presented at SNAME (Gulf Section) Spring Meeting and Star Symposium: Merchant & Naval Design, The Past in Review The Future in Forecast, Houston, April 25-28, 1979.
Society of Naval Architects and Marine Engineers601 Pavonia Avenue
Jersey City, NJ USA 07306-2907
- Huse, E
- Publication Date: 1979
- Features: References;
- Pagination: 18 p.
- TRT Terms: Air injection systems; Cavitation (Mechanics); Cavitation erosion; Cavitation noise; Ducted propellers; Erosion; Measurement; Noise; Propellers; Vibration
- Uncontrolled Terms: Noise measurement
- Old TRIS Terms: Air injection; Cavitating propellers; Erosion damage; Model testing; Propeller induced vibration
- Subject Areas: Environment; Marine Transportation; Vehicles and Equipment;
- Accession Number: 00189646
- Record Type: Publication
- Source Agency: Society of Naval Architects and Marine Engineers
- Files: TRIS
- Created Date: Apr 25 1979 12:00AM