SCR UNIFORMITY EVALUATION METHOD AND IMPACT STUDY

With the increasingly stringent requirements for NOx emission and NH3 leakage in China's diesel engine pollutant emission standards, it is of great practical importance to study the gas velocity uniformity and NH3 distribution uniformity at the front end of Urea-SCR carriers. To study the gas velocity and NH3 distribution at the front end of SCR carrier, a method is proposed to accurately evaluate the velocity uniformity and NH3 distribution uniformity, and the method is written into Star-CCM+ Report Manager to simulate and calculate the uniformity index, and an SCR single-point conversion efficiency test is conducted to verify the accuracy of the method. By comparing the uniformity index calculated by simulation with the experimentally measured conversion efficiency, the results show that the method can accurately evaluate the front-end gas velocity and NH3 distribution uniformity of SCR carriers, and provide a reference for the study of front-end gas velocity and NH3distribution of Urea-SCR carriers for diesel engines. Finally, the above uniformity evaluation method was used to simulate the factors influencing the front-end velocity uniformity of SCR carriers, and the results showed that the lower the exhaust flow rate and the lower the temperature, the better the front-end velocity uniformity of SCR carriers.