带同轴引气激光制孔中的气动特性分析

Aerodynamic Characterization in Laser Hole Making with Coaxial Air Induction

针对锥形激光加工器在航空发动机热部件冷却孔加工过程中的吹渣效果,研究了射流冲击孔板附近的流场特性及其影响因素。针对同轴高压气体撞击带盲孔平板的射流结构,采用数值模拟方法,分析了不同进气压力p_(int)(0.2~1.5 MPa)、射流间距H/De(3.6,5.6,7.6)和冲击角度α(30°,45°,60°,90°)对盲孔附近气体动力学性能的综合影响。研究结果表明,当H/De为3.6时,随进气压力的增大,盲孔附近的气体动力学性能呈现先逐步提高后剧烈下降的趋势,较好工作压力为1 MPa;当射流间距H/De达到5.6及以上时,适当地增大喷嘴压力可以提高盲孔附近气流的气动水平,但提升有限。随着冲击角度α减小,盲孔内流出质量流量逐渐增大,α为30°时较垂直射流提升约11倍,但在冲击表面上气体的剪切流动随冲击角度减小逐渐变弱。

For the slag-blowing effect of a conical laser processor in the cooling hole machining process of aeroengine hot parts,the flow field characteristics near the jet impinging on the aperture plate and its influencing factors are investigated.For the jet structure of coaxial high-pressure gas impinging on a flat plate with blind holes,numerical simulation methods are used to analyze the comprehensive effects of different inlet pressures p_(int)(0.2—1.5 MPa),jet spacing H/De(3.6,5.6,7.6)and impact angleα(30°,45°,60°,90°)on the gas dynamics performance near the blind holes.The results show that when H/De is 3.6,with the increase of inlet pressure,the gas dynamics performance near the blind orifice shows a tendency of gradual improvement followed by a drastic decrease,and the better working pressure is 1 MPa;when the jet spacing H/De reaches 5.6 and above,the aerodynamic level of the gas flow near the blind orifice can be improved by appropriately increasing the nozzle pressure,but the enhancement is limited.As the impact angleαdecreases,the outflow mass flow rate in the blind hole gradually increases,and whenαis 30°,it is about 11 times higher than that of the vertical jet,but the shear flow of the gas on the impact surface becomes weaker as the impact angle decreases.