关键词: 气冷喷油杆;一维非稳态换热;燃油结焦;燃油进口参数;数值模拟;加力燃烧室

Abstract: In order to investigate the fuel deposition rate and deposit thickness in an air-cooled injector under actual working conditions, a one-dimensional unsteady heat-fluid-solid coupled heat transfer and fuel deposition model along the axial direction of the injector was proposed. Distributions of both injector wall and fuel temperature, deposition rate and relative deposit thickness were obtained. Effects of both inlet fuel temperature and mass flow rate on deposition characteristics were studied and compared with a non-air-cooled fuel injector. Results show that the fuel temperature increases along the axial direction, and the wall temperature reaches its peak at the bottom of the injector. For the air-cooled injector, the deposition rate and deposit thickness first increase and then decease along the axial direction under the basic condition. The maximum deposition rate is 26μg/(cm²·h), corresponding to a relative deposit thickness of 0.6%. For the non-air-cooled injector, there are two deposition peak areas respectively located at the front and bottom of the injector. Peak values of deposition rate are 398μg/(cm²·h) and 807μg/(cm²·h) respectively, corresponding to relative deposit thicknesses of 8% and 15%. With a fixed inlet mass flow rate, the deposition rate increases significantly as increasing the inlet temperature, and the total deposit mass shows an exponential growth trend. With a fixed inlet temperature, the deposition rate just increases slightly with the increase of inlet mass flow rate, and total deposit mass increases linearly. Compared with the non-air-cooled injector, both wall and fuel temperature can be reduced greatly with the air-cooled one, thus the deposit formation can be significantly inhibited.

Key words: Air-cooled fuel injector;One-dimensional unsteady heat transfer;Fuel deposition;Fuel inlet parameters;Numerical simulation;Afterburner