Evolution Characteristics of Diesel Particles Under Cooling Condition
柴油机排气微粒冷却演变特性的实验研究

Experimental research on the evolution characteristics of diesel particles under the cooling conditions has been carried out. The results showed that the cooling of the exhaust had important effect on the mass concentration of the diesel particles in the exhaust. The main cause that resulted in the change of the particle mass concentration was the condensation of gaseous hydrocarbon on the particle surface or existing in the form of liquid drop. The cooling of the exhaust promoted the increasing of the particle dimension and the decreasing of the particle numbers, especially for the smaller particles below 0.1 ?m. The cooling temperature of the exhaust had important effect on the evolution of diesel particles. After exhaust cooling, the volume concentration of diesel particles between 0.1 ?m and 1.0 ?m exhibited a tendency of decreasing. Moreover, exhaust velocity also had effect on the evolution of the diesel particles. The number concentration and volume concentration of the diesel particles between 0.1 ?m and 1.0 ?m decreased along with the decreasing of the exhaust velocity.