Research Of The Surface Quality Of Injection Hole And Fuel Injection Characteristics Based On Micro-hole Machining Parameters

With the continuous upgrading of the automobile industry,the gradually strict requirements for the nozzle processing in the automobile manufacturing field lead the orifice diameter getting smaller.Laser drilling technology,as a mature processing technology,effectively solve the difficulties of traditional cutting tools in micro-hole processing.In this paper,the fuel injection characteristics of laser drilling and orifice were studied through the roughness,and the effects of laser drilling parameters on surface roughness and surface roughness on fuel injection of nozzle were studied respectively.Firstly,the influence of laser drilling processing parameters on surface roughness was studied.The surface quality of hole wall under different laser power,pulse frequency and defocusing amount was carried out through the laser drilling experiments on Cr12Mo1V1 sample.The roughness of the inner surface was measured by the topography and characterized by the arithmetic mean deviation Ra of the profile.Based on the experimental data of wall roughness under different laser processing parameters,the relationships between inner wall roughness and laser processing power,pulse frequency were obtained.A prediction model of roughness was established by generalized regression neural network(GRNN).Through the GRNN prediction model,the precise prediction of the surface roughness of the hole wall under the given processing parameters was realized.Furthermore,the influence of laser processing parameters on the roughness was analyzed and the conclusion based on the experiment was supplemented.Finally,the nonlinear relationships between inner wall roughness and the power,the pulse frequency,the defocusing amount were studied.The effect of hole wall roughness on the near-field injection characteristics was studied.The fuel injection process was simulated by CFD numerical simulation.Firstly,the parameterization of the wall roughness was characterized by parametric modeling,and the injection characteristics of fuel injection under different roughness conditions were obtained by the simulation model.Based on the simulation results,the relationships between the surface roughness and the penetration distance,the spray cone angle were investigated.Finally,the experimental verification of the simulation model was carried out.The fuel injection experiments were applied to the nozzle holes machining by picosecond laser.The near-field fuel injection states under different hole wall roughness were obtained,and the test results obtained from the experiments were analyzed.At the same time,by comparing the penetration distance and the atomization cone angle obtained from the experiment and the simulation,it was proved that the simulation results are basically consistent with the actual results,thus verifying the accuracy of the simulation model.