Study on the influence of optimization of internal flow channel structure of urea injector on injection uniformity
Publish Time: 2025-04-09
As a key component in the selective catalytic reduction (SCR) system, the design of its internal flow channel structure directly affects the injection uniformity of urea, which is related to the conversion efficiency and exhaust emission quality of the entire SCR system. This paper aims to explore the influence of optimization of the internal flow channel structure of urea injector on injection uniformity, and provide theoretical basis and practical guidance for improving the performance of SCR system.The main function of urea injector is to accurately and evenly inject urea solution into the exhaust pipe and fully mix it with the exhaust gas so as to convert nitrogen oxides (NOx) into harmless nitrogen and water under the action of SCR catalyst. However, in practical applications, the uniformity of urea injection is often affected by many factors, among which the design of the internal flow channel structure of the injector is a crucial link.The design of the flow channel structure directly affects the flow path, flow velocity distribution and injection form of the urea solution. A reasonable flow channel structure can keep the urea solution in a stable flow state during the injection process, avoid the occurrence of adverse phenomena such as eddy currents and turbulence, and thus improve the uniformity of injection. On the contrary, unreasonable flow channel structure may lead to uneven flow and injection angle deviation of urea solution during injection, which seriously affects the conversion efficiency of SCR system.In order to optimize the internal flow channel structure of urea injector, researchers usually adopt a method combining numerical simulation and experimental verification. By simulating and analyzing the internal flow field of the injector through computer fluid dynamics (CFD) software, the flow of urea solution can be observed intuitively, the injection uniformity can be predicted, and the flow channel structure can be optimized accordingly. At the same time, the effect of the optimized injector in practical application is verified by experiment, and the design scheme is further adjusted and improved.In the process of optimizing the flow channel structure, it is necessary to comprehensively consider multiple factors, such as flow channel shape, size, surface roughness, etc. By adjusting these factors, the flow path and flow velocity distribution of urea solution can be changed, so as to achieve the purpose of improving injection uniformity. For example, the use of a gradually contracting and expanding flow channel shape can keep the urea solution at a stable flow rate during the injection process, avoiding uneven injection caused by sudden changes in flow rate; the reasonable setting of the flow channel size can ensure that the urea solution is fully expanded during the injection process to form a uniform injection surface; reducing the surface roughness of the flow channel can reduce fluid resistance and improve injection efficiency.After the optimization of the urea injector, its injection uniformity has been significantly improved. This not only improves the conversion efficiency of the SCR system, reduces NOx emissions in the exhaust gas, but also effectively extends the service life of the catalyst. At the same time, the optimized injector also has better adaptability and stability, and can maintain stable injection performance under different working conditions.In summary, the optimization of the internal flow channel structure of the urea injector has a significant impact on the injection uniformity. By reasonably designing the flow channel structure, the injection uniformity of urea can be effectively improved, thereby improving the overall performance of the SCR system. Therefore, in future research and development, the optimization research on the internal flow channel structure of the urea injector should continue to be strengthened to provide a more efficient and reliable solution for automobile exhaust treatment.
