As an important part of high-pressure SCR system in a marine diesel, vaporizer/mixer is a vital place to improve the spray atomization of urea solution, the formation of reduction agent and the effective mixing of multiple components well. In this paper, vaporizer/mixer of high-pressure SCR (HP-SCR) system in a marine diesel engine was selected as the research subject, then I establish a three-dimensional model of the mixer by CFD and simulate the chemical reaction fluid dynamic by Fluent, and then its major design properties of pressure loss, flow velocity and species concentration uniformity, NH₃/NOx deviation as well as sensitiveness of diesel load were studied. According to characteristics of vaporizer/mixer of high-pressure SCR system, working performances of vaporizer/mixer installed without and with flow-guiding plates were compared and analyzed, and mixing effects of five flow-guiding plates were also evaluated in the paper. It is found that both the vaporizer/mixers which are installed with the centralized curved plates and irregular trapezoidal plates can meet the needs of design requirements of HP-SCR system, and the vaporizer/mixer installed with the irregular trapezoidal plates is superior to other structural flow-guiding plates. In addition, compared with vaporizer/mixer without flow-guiding plate, the maximum pressure loss of the vaporizer/mixer installed with irregular trapezoidal plates is only increased by 126 Pa, but its NH₃ concentration uniformity in the outlet is increased by 8.1 %, and the sensitiveness efficiency of diesel load is decreased to 0.1 %, which adapts to the various working conditions of high-pressure SCR system in the low-speed marine diesel.

作为船用柴油机高压SCR系统的重要组成部分，汽化器/混合器对于改善尿素溶液的喷雾雾化，还原剂的形成以及多种组分的有效混合至关重要。本文以船用柴油机高压SCR（HP-SCR）系统的汽化/混合器为研究对象，然后通过CFD建立混合器的三维模型并模拟了化学反应液的动力学。通过Fluent，然后确定其主要设计特性：压力损失，流速和物质浓度均匀性NH ₃研究了/ NOx偏差以及柴油负荷的敏感性。根据高压SCR系统汽化混合器的特点，对不带导流板和带导流板的汽化混合器的工作性能进行了比较分析，并对5个导流板的混合效果进行了评价。结果发现，既可以安装集中弯曲板的蒸发器/混合器，也可以安装不规则梯形板的混合器，都可以满足HP-SCR系统的设计要求，并且安装不规则梯形板的蒸发器/混合器要优于其他结构。导流板。此外，与不带导流板的蒸发器/混合器相比，安装有不规则梯形板的蒸发器/混合器的最大压力损失仅增加了126 Pa，₃出口浓度均匀度提高了8.1％，柴油负荷的灵敏度降低到0.1％，适应了低速船用柴油机高压SCR系统的各种工况。