Gas Injected Liquid Lubrication System

Over 90% of world trade is carried by ocean going marine vessels, making the shipping industry a major element of the world economy. In Australia, the shipping industry annually contributes about $9 billion directly and $11.8 billion indirectly to the national gross domestic product (GDP). However, the shipping industry is one of the larger contributors to the total emissions both globally and domestically. As reported, shipping-related emissions are one of the major contributors to global air pollution, especially in coastal areas. A previous assessment found that over 70% of ship emissions have been detected up to 400 km inland, and significantly contribute to air pollution in the vicinity of harbours. This is particularly highlighted in Australia where many residential areas are located in the vicinity of ports. Examples include Ports Botany, Jackson, Newcastle and Kembla which are located within the Greater Metropolitan Region (GMR) of NSW and provide berthing and loading/unloading facilities for international shipping. The mechanism of air lubrication such as the Marine Gas Injected Liquid Lubrication System (GILLS) has proven to reduce drag and consequently fuel consumption which reduces the emission of CO2 and toxic pollutants. The GILLS uses a novel technique to inject air that creates bubbles on ship hulls. This method reduces shear wall stress by mixing air inside the boundary layer. This project aims to develop reliable and efficient computer models to demonstrate the effectiveness of the GILLS for various conditions. This will enable the application of this technology for commercial vessels. The key project activities include:1.Review of current literature to identify research undertaken on the effects of microbubbles on ship fuel efficiency and anti-biofouling. The team will engage with Bureau Veritas to incorporate key technology validation requirements into the scope of the risk assessment and simulation activities. The findings from the literature review will be used to develop a software simulation model of the GILLS to mimic the bubble distribution on the specific ferry based on key maritime operating assumptions (Action by Harwood and AMC/Macquarie).2.Develop a computer model for simulating the effects of bubbles on drag reduction for a well-characterised scenario and validate the model against the published data (e.g. Kumagai et al 2015). The required inputs on GILLS and its concept will be provided by Harwood (this is essential for the model development). This step includes creating the computational algorithm and identifying the optimum numerical and physical models for bubble flows. It will create a reliable efficient modelling platform for large scale simulations (Action by AMC/Macquarie).3.Harwood Marine will design and develop GILLS technology and mixing chambers and install it onto ferry 1. Sea trials of the operation of the GILLS technology on ferry 1 will be conducted prior to data collection. After the successful sea trials, cameras and appropriate data collection systems will be installed onto ferry 1 and ferry 2 (Harwood Marine) to collect the required data. These include some measurements on the fuel consumption and drag forces for a specific ferry with and without GILLS to provide essential data and inputs for the computer model. The recorded data and measurements will be shared with AMC/Macquarie team for computational modelling (Action by Harwood).4.Conduct computational modelling to study the impact of the installation of the GILLS device on a specific ferry. In this stage, the CAD model for the ferry will be first provided by the partner, allowing to build the geometrical model and mesh. Then, a comprehensive parametric study will be conducted to map the effects of different influencing parameters such as ferry velocity, bubble size, and pressure. Such comprehensive data will provide detailed information on how the GILLS affects drag reduction for a realistic case. The GILLS