Wind Tunnel Aerodynamic Coefficients Evaluation of RP Models based on Layer’s Thickness Affect

Nowadays, rapid prototyping (RP) methods are widely used to produce wind tunnel testing models where layer thickness is important parameter that affects aerodynamic characteristics of such wind tunnel models. This paper describes the affects of layer thickness on aerodynamic coefficients for constructed wind tunnel testing of models produced via rapid prototyping technology. Three models were evaluated, where these models were fabricated from ABSi by fused deposition method (FDM). The layer thickness applied, was 0.178mm, 0.254mm and 0.33mm. The surface roughnesses for each model were respectively 25μm, 63μm and 160μm (RZ) that was determined by PERTHOMETER2. A wing-body-tail configuration was chosen for the actual study. Testing covered the Mach range of Mach 0.3 to Mach 1.2 at an angle-of-attack range of -4° to +16° at zero sideslip. Coefficients of normal force, axial force, pitching moment, and lift over drag are shown at each of these mach numbers. Results from this study show that layer thickness does have effect on the aerodynamic characteristics: in general the data differ between the three models by fewer than 6%. The layer thickness does have more effect on the aerodynamic characteristics when mach number is decreased and had most effect on the aerodynamic characteristics of axial force and its derivative coefficients.

کلیدواژه ها:

Aerodynamic characteristics ، fused deposition method ، layer thickness ، Rapid prototyping ، surface roughness