船用SCR系统的设计与数值优化

针对某型船用柴油机满足IMO Tier III标准的要求,设计了两型16种SCR反应器,采用数值模拟的方法研究了结构参数对反应器内气体流动的影响。结果表明在30°~45°区间较小的过渡角及较长的过渡段有利于气流的均匀分布;长径比在0.3~3之间变化时,随长径比增加,入口截面的均匀性指数先减小后增加,而中间截面则持续增加后趋于平缓。选取过渡角30°,长径比2.43的圆型SCR反应器研究了喷射参数对于尿素溶液喷射效果的影响,结果表明喷孔与轴线的角度在30°~60°时液滴平均行程随角度的减小而增加,有利于溶液的蒸发,同时喷射点应尽量远离壁面。

Design and Optimization of Marine SCR System

In order to satisfy IMO TierIII standard for a marine diesel engine, two series(16 types) of SCR reactors were designed. Based on numerical method, the effect of structure parameters on flow distribution in the reactors was inverstigated. The results show that smaller angle of inlet cone, which changes between 30° and 45°, is beneficial to the uniform distribution of flow. While with the increase of length-diameter ratio, which changes between 0.3 and 3, the index of flow uniformity decreases firstly and then increases for the inlet section. However, for the middle section, the index of flow uniformity increases and levels off. The cylindrical SCR reactor with 30° angle of inlet cone and 2.43 length-diameter ratio was chosen as the optimized model. Based on this model, the effect of spray parameters on spray process of adeblue solution was investigated. The results show that with the decrease of the angle between the spray hole and the axis, which varies between 30° and 60°, the mean route of droplets increase, in favour of evaporation. Meanwhile, the location of the spray hole should keep away from the tube wall.