Aiming at the problem of nozzle clogging caused by the sediment produced by selective catalytic reduction (SCR) system

and the problems of high back pressure in nozzle pipeline and uneven atomization spray caused by the sediment

an anti sediment clogging nozzle was designed and developed. The structure and working principle of the nozzle were introduced. The stable injection pressure of the nozzle can be set by adjusting the locking amount between the nozzle core and the screw sleeve. The maximum opening of the nozzle core could be mechanically limited

which can effectively avoid the problems of uneven atomization spray of urea and the escape of NH3. The opening and closing characteristics of the nozzle core and the mass flow rate characteristics of the orifice section were analyzed theoretically. The results show that when the nozzle is clogged by sediment

the nozzle core opening will increase with the increase of the pressure inside the nozzle

and the nozzle orifice radial section area and mass flow rate also increase

which not only effectively improves the discharge rate of sediment inside the nozzle

but also reduces the risk of sediment condensation outside the orifice. The numerical simulation of the atomization spray characteristics of the nozzle was carried out by using the fluid simulation software Fluent. The influence of different nozzle core openings and taper angles on the orifice radial section area

orifice section velocity distribution and orifice section mass flow rate characteristics of the nozzle was further studied. Finally

the atomization spray effect and opening pressure accuracy of the nozzle was verified by test. The test results show that the atomization spray effect of the nozzle is satisfactory

and the droplet distribution is relatively uniform. And at each stable injection pressure

the nozzle can be stably opened

and the opening pressure accuracy is ± 5%.