尿素喷射量对SCR催化箱内温度场影响的试验研究

在发动机台架上,通过转动SCR催化箱内呈一字形布置热电偶的测量段,在稳态工况下对沿轴向多个截面内的温度场进行了测量,研究氨氮比对SCR催化箱内温度场分布规律的影响。结果表明:在试验条件下,当氨氮比小于1时,随着氨氮比的增加,催化箱内各截面温度分布的均匀性降低,而当氨氮比大于1,排气温度较低时,氨氮比的增加对催化箱内温度的分布几乎没有影响,而排气温度较高时,催化箱内温度分布的均匀性随氨氮比的增加而变差;随着氨氮比的增加,催化剂入口截面平均温度逐渐降低,而催化剂内各截面平均温度因反应放热大于散热损失而逐渐升高,且催化剂后端温度高于前端温度。

Influence of Urea Injection Quantity on Temperature Field of SCR Catalyst Container

The temperature fields of multiple cross sections along the axis were measured under steady condition on the engine test bench by revolving the in-line distributed thermocouples in SCR catalyst container and the influence of ammonia-nitrogen ratio (A/N ratio) on the temperature field distribution of SCR catalytic container was studied.The results show that the uniformity of temperature distribution deteriorates with the increase of A/N ratio at A/N ratio of less than 1.When A/N ratio is beyond 1,the increase of A/N ratio has little influence on the temperature distribution at low exhaust temperature,but the uniformity of temperature distribution becomes worse with the increase of A/N ratio at high exhaust temperature.With the increase of A/N ratio,the average temperature of SCR entrance section decreases,the average temperature of each cross section in the catalyst gradually increases because the heat release of reaction is greater than the heat loss and the catalyst temperature of the rear end is higher than that of the front end.