Cold spray coating and repair of propellers: surface treatment, overhaul, and repair
Moilanen, Henri (2020)
2020
Konetekniikan DI-ohjelma - Master's Programme in Mechanical Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2020-11-09
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202009287138
https://urn.fi/URN:NBN:fi:tuni-202009287138
Tiivistelmä
The thesis work studies the use of cold spray thermal spray method for coating and repairing marine propellers. The main areas of interest are protecting the propeller from corrosion by utilizing a cold sprayed barrier coating and the repair of cavitation damage on the propeller blade using cold spray. The use of cold spray is evaluated by a literature review on the coating materials, by analysing the cost of cold sprayed coatings and by comparing cold spray to alternative methods.
Theory part of the thesis discusses propellers, materials used for propeller manufacturing and the cold spray method. Main types of propellers, propeller repair and maintenance procedures and a typical propeller manufacturing process are discussed in Chapter 2. Operating conditions affecting propeller design and material selection such as corrosion, cavitation and impact loading and biological fouling are discussed in Chapter 3. Currently used propeller materials, possible alternative propeller materials and interesting coating and repair materials are discussed in Chapter 4. Chapter 5 discusses the operating principle of cold spray method, commercially available cold spray equipment, the spraying process from manufacturing standpoint and the economics of cold spray.
The case study on the propeller coating and repair is discussed in Chapter 6. The case study consists of analysing propeller coating costs, predicting the financial saving potential and net present value of the propeller as a function of propeller size by using a MATLAB script. The feasibility of using cold spray for propeller repair is also discussed based on a qualitative comparison of the cold spray method against the alternative repair methods.
Last chapters discuss the uncertainties and risks associated with coated propellers and cold sprayed repairs as well as future research topics.
Theory part of the thesis discusses propellers, materials used for propeller manufacturing and the cold spray method. Main types of propellers, propeller repair and maintenance procedures and a typical propeller manufacturing process are discussed in Chapter 2. Operating conditions affecting propeller design and material selection such as corrosion, cavitation and impact loading and biological fouling are discussed in Chapter 3. Currently used propeller materials, possible alternative propeller materials and interesting coating and repair materials are discussed in Chapter 4. Chapter 5 discusses the operating principle of cold spray method, commercially available cold spray equipment, the spraying process from manufacturing standpoint and the economics of cold spray.
The case study on the propeller coating and repair is discussed in Chapter 6. The case study consists of analysing propeller coating costs, predicting the financial saving potential and net present value of the propeller as a function of propeller size by using a MATLAB script. The feasibility of using cold spray for propeller repair is also discussed based on a qualitative comparison of the cold spray method against the alternative repair methods.
Last chapters discuss the uncertainties and risks associated with coated propellers and cold sprayed repairs as well as future research topics.