A master thesis from Aalborg University
Optimum Design of Propeller Boss Cap Fins (PBCF) by Model Scale Numerical Evaluation
Author(s)
Term
4. term
Education
Publication year
2021
Submitted on
2021-05-28
Pages
102 pages
Abstract
Implementation of Propeller Boss Cap Fins (PBCF) have presented great mitigation capabilities towards the induced hub vortex downstream of shipping propulsion systems, which implies an increased propeller efficiency. This project investigates the design and optimisation process of PBCF for a specified Controllable Pitch Propeller (CCP), achieved through a model-scale steady-state 3D RANS analysis in the software STAR-CCM+. The numerical model is validated against empirical data both with a rudder attached and at open water conditions, where satisfactory results justified the further utilisation of the model. From a thorough literature study a basis for the geometrical composition of the PBCF were formulated and analysed through the numerical model. By investigating different hydrofoils it was found the NACA 4412 yielded the greatest result. An individual optimisation procedure for each parameter were conducted, which concluded that the span height, circumferential and axial position were the most influential parameters. From the optimum measure of each parameter the optimised PBCF was achieved, which yielded an increase in efficiency of minimum 1.0 % for a wide range of ship speeds. For varying advance ratios an efficiency improvement between 0.59 % and 1.19 % was found. Pressure contour comparisons concluded that the induced hub vortex was completely destroyed.
Keywords
PBCF ; Propeller ; Propeller Boss Cap Fins ; CFD ; RANS ; Boss Cap Fins ; Optimisation ; Numerical ; 3D
Documents
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