融合CFD与PI控制的船舶柴油机SCR脱硝系统设计与分析

选择性催化还原技术对氮氧化物脱除具有显著效果，是当前最广泛使用的脱硝处理技术。本文从介观角度出发，采用CFD方法建立了船用SCR脱硝系统的物理模型，分析了SCR脱硝系统的反应机理，并通过用户自定义函数将PI控制算法融合进介观系统模型中，摒弃传统控制模型中的均匀分布假设，实现了介观尺度上的非均匀喷氨控制。仿真测试结果表明：船用SCR脱硝系统的气体分布呈现严重非均匀性；融合介观尺度上PI控制算法后，不仅可改善系统的非均匀性，还可提高系统的整体脱硝率、降低系统的氨逃逸量。本研究为宏观控制与介观机理建模的融合提供了新的研究思路。

SCR-DeNOx System Design and Analysis for a Marine Diesel Based on CFD and PI algorithm

Selective Catalytic Reduction technology has a significant effect on the removal of nitrogen oxides and therefore is widely used in denitrafication systems. In this paper, a mechanism model of a certain marine SCR denitrafication system is established with CFD method, which is from mesoscopic point of view. And then, reaction mechanisms of the SCR denitrafication system is analyzed. The PI algorithm is integrated into the CFD model by user-defined function, in which the homogeneous hypothesis for the mixed gases adopted in traditional control models is abandoned. Simulation results show that the gas distribution in the marine diesel SCR denitrification system presents a high non-uniformity; that with the PI algorithm in the CFD model, not only the non-uniformity of the system is significantly deduced, but also the denitrafication rate and the ammonia slip of the overall system are improved. This provides a new research idea for the fusion between macroscopic control and the mesoscopic models.