Research On Visualization Technology Of Aircraft Icing Based On CFD Computing

Aircraft icing refers to the phenomenon of icing on the surfaces of the wings,engine intakes,tails,sensors,and other components when the aircraft is flying under icy weather conditions.The icing of the aircraft will affect the aerodynamic and handling performance of the aircraft,and even lead to a flight accident in severe cases.Therefore,relevant researchers have carried out research on the phenomenon of aircraft icing.At present,the most common method is the numerical calculation method based on CFD.The results generated by numerical calculation methods are often large in data volume and are not intuitive.Visualization is required so that relevant researchers can discover the information hidden in the data.However,the current visualization software lacks visualization functions specially designed for aircraft icing.It can statically display ice shape and water droplet trajectories,and cannot distinguish multiple ice shapes.In this regard,this thesis uses the relevant algorithms in computer graphics to study the visualization of aircraft icing.The main contents are as follows:(1)The process of aircraft icing and the common types of icing were investigated,the research status and visualization methods of aircraft icing at home and abroad were investigated,and the relevant methods in computer graphics are introduced,which are used for the subsequent visualization work of the thesis.The work provides theoretical support.(2)Aiming at the problem of dynamically displaying the growth of two-dimensional ice shape,the two-dimensional ice shape data at different time points calculated based on CFD under the same icing conditions were analyzed,and the ice shape data at the intermediate time points were complemented by interpolation method.Aiming at the problem that the ice shape curve is rough due to the sparse data points after the ice shape grows,a spline curve is used to smooth the ice shape,and a method for constructing the control points of the piecewise third-order Bezier curve is proposed.Finally,a smooth two-dimensional ice growth animation is generated according to the CFD calculation results,which solves the problem that the ice shape can only be displayed statically.(3)Aiming at the problem of dynamically displaying the impact and splashing process of water droplets,a method of generating 3D dynamic animation based on 2D static data is proposed,and the 3D model of the wing is constructed by the ear cutting method;the motion trajectory of water droplets is analyzed to determine the impact of water droplets.The speed and impact direction,and the splash speed of the water droplet is calculated according to the conservation of energy.Finally,the splash and impact animation of the water droplet motion is obtained,which solves the problem that the impact trajectory of the water droplet can only be displayed statically.(4)Aiming at the problem that the current icing visualization can only display the shape of the ice,and cannot distinguish multiple ice types,a method for extracting a single ice shape model is proposed by analyzing the difference between the shape after the growth of the ice shape and the original shape.In order to distinguish the ice shape and improve the realism of the ice shape,a GPU-based ray tracing algorithm is used to draw the ice shape,and a BVH tree is constructed to accelerate the calculation of the intersection of rays and fragments in the GPU;according to the characteristics of different ice shapes,Adjust the parameters in the ray tracing algorithm to realize the distinction of various ice types.The final experiment shows that the above method can perform highquality real-time rendering of a single ice shape,and realize the distinction of three ice shapes.