发动机催化转化器结构优化及CFD模拟

为提高发动机催化转化器内部流体的流动均匀性,同时减小其压力损失,通过改进传统催化转化器的入口管和扩张管结构,并在扩张管内加装优化设计的新型导流装置,设计一种新型催化转化器结构。通过利用CFD软件分别对传统和新型催化转化器进行二维建模和流场对比分析,讨论新型扩张管和导流装置以及载体孔密度对催化转化器内部速度和压力分布的影响,并验证优化后的催化转化器结构的可行性和优越性。结果表明:相比传统催化转化器,优化后的新型催化转化器的载体前端具有较高的流动均匀性和较低的压力损失。在不同入口速度和载体孔密度条件下,新型催化转化器载体入口端部的流动均匀性系数分别均在0.94和0.95以上,同比分别高于传统催化转化器约5.2%~10.9%和4.9%~8.8%,且其平均压力损失同比分别下降约5.2%~7.4%和5.2%~6.9%,可见新型催化转化器能有效提高载体的利用率和使用寿命。

Structural optimization and CFD simulation of engine catalytic converter

In order to improve the flow uniformity of the fluid in the engine catalytic converter and reduce the internal pressure loss,a new catalytic converter model is designed by improving the inlet tube and expansion tube structure of the traditional catalytic converter,and installing a new diversion device optimal designed in the expansion tube.The two-dimensional model and flow field analysis of the traditional and new catalytic converters are performed by using CFD software,and the effect of the new expansion tube,diversion device and carrier pore density on the internal velocity and pressure distribution of the catalytic converter is discussed,and then the feasibility and superiority of the optimized catalytic converter structure is verified.The result shows that the new catalytic converter model has the better flow uniformity and lower pressure loss than the traditional catalytic converter.Under the conditions of different inlet speeds and carrier pore densities,the flow uniformity coefficient at the carrier inlet of the new catalytic converter is above 0.94and 0.95respectively,which is about 5.2%~10.9%and 4.9%~8.8%higher than that of the traditional catalytic converter,and its average pressure loss is about 5.2%~7.4%and 5.2%~6.9%lower than that of the traditional catalytic converter respectively,which shows that the new catalytic converter can effectively improve the utilization and service life of the carrier.