船舶SCR系统陶瓷催化-过滤器烟气正向流动状态仿真与结构优化

为提高陶瓷催化-过滤器的工作性能,对陶瓷过滤器形状与过滤速度之间的关系进行研究,对不同止端直径的陶瓷过滤器内烟气正向流动状态进行仿真,计算不同止端直径下的外表面径向速度数据方差。仿真结果表明:锥形陶瓷过滤器的外表面径向速度沿轴向分布比烛状的更为均匀,当止端直径为40 mm时,速度波动最小,更有利于烟气的正向均匀流动。此外,对引射器和陶瓷过滤器的结构进行改进优化,运用Fluent软件和数据拟合方法对延长引射器扩张段和增加速度突增部分的陶瓷厚度2种方案进行分析,结果表明两种优化方法各有利弊,所以决定将两种优化方法结合使用。

The Simulation and Optimization of Structure of the Ceramic Catalytic-filter for SCR system of Ship

To improve the performance of ceramic catalytic filter, the relation between the shape and the speed of filtration velocity is researched; the simulation of the forward flow state of gas inside the catalytic filter in different dead end diameter is performed. And the variance of the radial velocity between different dead end diameter of the outer surface is obtained. The simulation results show that the distribution of the outer surface radial velocity along the axial in conical filter is more uniform compared with candle-shaped filter. when the dead end having a diameter of 40mm, the speed fluctuation is least, a diameter of 40mm is more beneficial to the positive uniform flow of the gas. Then the structure of the ceramic catalytic-filter and ejector are optimized. The schemes of increasing the thickness of the ceramics where the speed increases sharply and prolonging the ejector are analyzed by the method of data fitting through FLUENT software. The results show that both optimization methods have advantages and disadvantages. So, it is decided to use the dual structure optimization method of increasing the thickness of the ceramic and prolonging the ejector.