Study Of Analytical Method On The Real-time Characteristic Of The Engine Room Ventilation In The Sail-assisted Ship

Now that energy-saving and emission-reduction has become a focus of economic development in china, even in the whole world, shipping industry needs take some actions for this. COSCO has undertaken the "sail-assisted navigation" project, aiming at reducing the oil consumption of the M/E by installing the sails on vessel driven by diesel engine by using the wind energy at sea to supply the thrust for ship to cut down the shipping cost and achieve the goal of energy-saving and emission-reduction. Against the ground of this project, expounding for the particularity of the sail-assisted vessel, the E/R ventilation system should have the real-time characteristic, but the real-time E/R ventilation has not been studied deeply before. Therefore, this paper works over the E/R ventilation system of the sail-assisted vessel, studies on the analytical method on the real-time characteristic of ventilation, elaborates the process of solving the real-time characteristic equation of E/R ventilation, and makes use of the equation on the typical vessel to get the real-time ventilatory volume in the E/R.Firstly, this paper presents the conventional solving methods on the E/R ventilation characteristic with the analysis of the advantages and disadvantages of each method, together with the particularity of the sail-assisted ship, then the selected solving method is optimized and made more accurate, after which comes the mother equation on the E/R ventilation real-time characteristic. Secondly, the two main influence factors on the real-time characteristic of the E/R ventilation, that is, sail thrust and outboard temperature, are picked up. Through the analysis of the relationship between each factor and the real-time ventilatory volume respectively, the sail thrust and outboard temperature as the input variable are put into the mother equation and the solving equation of the E/R ventilation real-time characteristic in the wind-assisted ship as the result. Then, using the solving equation on the typical ship "wenzhuhai" vessel, the relationship between the wind direction, wind velocity and the sail thrust by the software of FLUENT comes out, then taking the wind direction and wind velocity as the input value, making the three-dimensional surface fitting of the real-time characteristic equation in the software of MATLAB. This paper chooses the typical course, dividing the whole course into 7 segments according to the wind condition, outputing the image of the real-time ventilatory volume at the different segment in the MATLAB, then compared with the common ventilatory volume, providing data to support the real-time control.Employing the analytical method above, according to the detailed data of the sail-assisted ship and the variety of the ocean wind, the fitting real-time ventilatory volume in E/R can be obtained through the solving equation of the E/R ventilation real-time characteristic. This real-time characteristic provides the theory foundation for the design of the E/R ventilation system on the sail-assisted ship.