Objective  In this paper, experiments are carried out to investigate the effects of water spray on the soot removal of diesel engine flue gas.

  Method  A Dekati low pressure impactor (DLPI) is used to sample smoke soot in a flue. The sampling gun is wrapped in a heating belt and the temperature is controlled to prevent the condensation of wet flue gas after spraying and maintain the same state of soot in the flue. First, the uniformity of flue gas concentration is measured by a flue gas analyzer to verify that the flue gas distribution is basically uniform, and the sampling time is determined by DLPI. The soot purification efficiency under different diesel engine loads and different water spray volumes is then measured and compared.

  Results  The results show that the efficiency of soot removal can reach 50%. Under the same spray rate, the soot removal efficiency of the diesel engine under 100% load is higher than that under 50% load. When the spray rate reaches a certain value, the efficiency of soot collection and purification may reach the extreme value. Under 50% load, the contact time between water spray and soot is longer, and the agglomeration effect of small particles is more obvious than under 100% load.

  Conclusion  The measurement results show that water spray can effectively reduce the soot emissions of diesel engines.