Coking Characteristics And Inhibition Methods Of Stirling Engine Fuel Nozzle

As an external combustion engine,Stirling engine has been paid more and more attention by the domestic and Foreign Research Institute for its advantages of multi fuel,no noise,little pollution and high efficiency.When the diesel fuel is used as fuel,the fuel nozzle is placed in the combustion chamber,and the influence of heat radiation causes serious coking,which seriously affects the fuel atomization and fuel efficiency,as well as the reliability of the work.Therefore,nozzle coking has become one of the bottleneck problems that affect the reliability of the engine.The first analysis of the diesel oil composition and nozzle coking material.The results show that the nozzle located near the outer surface,the coking mechanism with metal surface catalytic performance for coking,coke is mainly amorphous carbon and chromium oxide grains from the position of far away nozzle is a large number of fibrous carbon distribution.Coking swirler produces located inside the orifice on,there may be two reasons,one is the thermal oxidation of coking,performance of amorphous carbon in the channel,the other is a metal catalytic coke,fuel and the wall surface of the metal atom catalyzing the formation of fibrous carbon and gradually grown.The method of adding coking inhibitor is put forward according to the thermal oxidation coking of nozzle surface.A laboratory simulation method was established.Through the treatment of diesel oil,the inhibition rate of coking can reach more than80%,which further proves that the thermal oxidative coke occupies a large proportion in the total amount of coking.The results show that the inhibition rate of coking at two heat flux densities of TJU-1 and TJU-2 is about 50%,and the inhibition effect is good.A coating with a thickness of 1.2?m was prepared by using TiCrAlN inert material to catalyze the coking of metal wall.The experimental results show that the coating has good effect on suppressing coking.The bench test shows that the continuous operating time of the engine nozzle increases from 200~300h to over1500 h after coating treatment.