考虑弹性变形的光敏树脂风洞模型设计方法

Design Method for Photosensitive Resin Wind Tunnel Model Considering Elastic Deformation

为减小光敏树脂刚度较低引起的模型变形对风洞气动力试验数据的影响,提出一种考虑弹性变形的光敏树脂风洞模型设计方法。采用气动弹性数值计算的方法对光敏树脂模型在空气动力作用下的变形进行预测,基于数值计算的变形修正模型的原始外形,获得树脂模型的制造外形,使制造外形的模型在气动力作用下变形后的外形与原始外形相同,从而消除树脂模型弹性变形的影响。基于该方法和大展弦比机翼剖面刚性不变形假设设计出6套F4模型的制造外形,通过快速成形设备进行制造,并在FL-21跨声速风洞中进行验证试验。试验数据表明,在设计点时,4#、5#、6#模型的升力系数CL与国外风洞数据吻合较好,1#、2#、3#和5#模型的俯仰力矩系数Cmy与国外风洞数据吻合较好;在非设计点时,模型的CL和Cmy与国外数据偏差较大;同国外风洞试验雷诺数的差异使阻力系数比国外风洞试验的阻力系数大。因此,在设计点时考虑弹性变形的方法可以明显改善光敏树脂风洞模型的气动力试验数据精度。

A method for designing photosensitive resin wind tunnel model considering elastic deformation is presented to reduce the effect of model deformation caused by low stiffness of photosensitive resin on aerodynamic force experiment data in wind tunnel.Numerical calculation method for aeroelasticity is used to predict the model deformation under aerodynamic force and the original model shape is modified on the basis of the numerically calculated deformation,thereby the manufacture shape of resin model is obtained,so that the shape of model after deformation under aerodynamic force is same as the original model shape,thus eliminating the effect of photosensitive resin elastic deformation.Six F4 model manufacture shapes are designed on the basis of this method and the hypothesis that the airfoil of large aspect ratio wing is rigid.Six models are manufactured by using rapid prototyping equipment and tested in FL-21 transonic wind tunnel.Test data show that at design point,lift coefficients CL of 4#,5# and 6# models are in good agreement with the data of three foreign wind tunnels,and so are the pitch moment coefficients Cmy of 1#,2#,3# and 5# models;at off-design points,CL and Cmy are quite different from the foreign data;drag coefficients Cd are greater than foreign wind tunnel results because of Reynolds number Re difference between this test and foreign wind tunnel tests.So,at design point,this method can obviously improve the aerodynamic force data precision of photosensitive resin wind tunnel model.