Anti-Ventilation Plate Optimization: A collaboration between Chalmers University of Technology, Pennsylvania State University, and Volvo Penta

Abstract

With the increasing electri cation within the boating industry, problems associated with low energy-dense batteries arise. With the desire to increase mileage while reducing battery size, the need to save energy is larger than ever before. This has led to an extensive demand of minimizing the overall resistance of each part used within a boat's schematic; in this case, a sterndrive powered by an electric outboard motor. This project investigatd ways to optimize hydrodynamic performance of the anti-ventilation plate, which prevents surface air from being drawn into the system's propeller. The objective of this project was to generate and analyze a number of innovative antiventilation plate (AVP) design concepts through objective engineering practices which would supply Volvo with data and ideas for further considerations on future development. This project required a thorough understanding on outboard engine anatomies, boat design, hydrodynamic understanding of planing hulls, and computational uid dynamics. This knowledge was attributed to the team's independent research and close contact with industry experts and supervisors. The study further considered the identi cation of customer needs and the idea generation process; where these processes were supplemented by the team's initial research, ultimately allowing them to generate a multitude of unique features and concepts. Pugh-matrices were used to score the generated features against the proposed customer needs, where the leading features were then combined into feasible concepts. These combinations were then screened, utilizing another Pugh-matrix, where the lowest scoring concepts were eliminated. This was done to reduce the abundance of concepts down to a more manageable amount in order to analyze and develop further. For these concepts, they were then attached to the provided hull and sterndrive and simulations were carried out at speeds 10 and 12.5 m=s. The results showed that the team's leading concept was concept H, which was an AVP with a variable sweep system that had an airfoil cross-section. This concept performed best in terms of the most important metrics, total resistive forces and a trim angle near the determined optimum. However, concepts utilizing other features performed well regarding other metrics, and the conclusion is that for further development, combinations of these features should be analyzed at a variety of different conditions.