The Study On The Marine Diesel Engine Combustion Process Optimization Of Wing-Assisted Ships

With the rapid development of the world economy, the energy and environment issue has drawn wide concern from the international community. Under this circumstance, wing-assisted technology arouses people’s attention once again and achieves rapid progress. When adopting wing-assisted system onboard, the main engine can work in power derated condition, then partial load deteriorates combustion quality, thus reducing the economy and power performance of the main engine. In order to improve the economy and power performance of the main engine, it is necessary to do some study on the wing-assisted ships’marine diesel engine combustion process.This thesis selects a multi airfoil with high aerodynamics characteristics as the research object, and chooses a76,000dwt Panamax bulk carrier as target ship. First, it conducts wind tunnel equipment on the model of the airfoil and figure out lift coefficient and resistance coefficient under different wind attack angle. And then, based on the aerodynamics characteristics and experiment data, compute the maximum wind assist force the target ship can acquire under different specific wind angle. Second, it builds the mathematical model of the ship, the main engine, the propeller and the wing, and then figures out the main parameters of the target ship’s main engine (including revolving speed, torque, effective power, and cyclic fuel volume) under wind assist force. Third, it builds the entire machine model of the target ship main engine, and then explore the law of the effect on the power and economy performance caused by fuel injection timing and injection duration. Finally, it conducts the optimized match computing of fuel injection timing and injection duration in partial load, so as to realize combustion process optimization of the main engine in partial load condition.Through the study on the combustion process optimization, conclusions can be drawn as follows. First, the change of practical wind can cause large change of the wind assist force. It leads to large change of marine diesel engine’s working condition and negative effect on its performance. Cascade the wind assist force will benefits the stable of the main engine’s working condition. Second, fuel injection timing and injection duration of marine diesel engine have significant effect on the economy and power performance. Both enlarging the fuel injection timing and shortening injection duration to a certain degree can amplify the maximum combustion pressure and the output power of the marine diesel engine. Third, the optimum match of fuel injection timing and injection duration can be acquired by simulation, thus realizing the optimization of marine diesel engine combustion process on wing-assisted ship and provide some theory basis of designation and management of such engines.