The Novosibirsk State Technical University (NETI) has developed a method for numerical simulation of the processes of icing of the aerodynamic surfaces of an aircraft. The results of the work can be applied in the design of anti-icing systems and the assessment of the aerodynamic characteristics of the aircraft.
"Icing of aircraft in flight is a serious safety problem", noted Maxim Gorbachev,Candidate of Technical Sciences, Associate Professor, the head of the Department of Technical Thermophysics,NSTU-NETI. Water vapor is always present in the atmospheric air and at low temperatures in certain flight conditions, the process of formation of an ice edge on the surface of the aircraft may occur. In this case, the resulting ice layer changes the structure of the flow around the aerodynamic surfaces, reduces the lift of the wing, negatively affects the efficiency of the control system, causes a loss of thrust, an increase in the turbulent track, and also leads to an increase in the weight of the aircraft.
"The development of anti-icing systems is a rather difficult task. Flight tests are not a reliable tool because it is difficult to determine the location of icing clouds in advance. It is more efficient to use simulation techniques to understand the various mechanisms of ice formation and de-icing. In the field of icing modeling, the main goal is to understand the physics of ice formation, to try to predict the shape of ice growths based on flight conditions and environmental conditions. To do this, it is necessary to calculate the trajectories of droplets and determine the deposition coefficient on the aerodynamic surfaces under consideration, "said Maxim Gorbachev.
Modeling of the dynamics of the ice layer growth on the profile surface was carried out iteratively and consisted of the following stages: the field of velocities, pressures, air density (and other parameters) near the aerodynamic profile under consideration was calculated (for this, the system of differential equations was solved); the trajectories of movement and precipitation of water droplets on the surface were calculated according to the known velocity field; the shape of the formed ice was calculated.
Based on the data obtained, it was concluded that the presence of an aerodynamic profile of an ice structure on the surface reduces the lifting force by more than 30% and increases the drag by more than 20% (depending on the initial parameters).
As a result of the studies, the results of modeling the flow around the surface of the aerodynamic profile were presented and the results of the dynamics of icing were obtained. The developed methodology was tested in the context of two-dimensional and three-dimensional problems. Scientists plan to conduct parametric studies of the influence of the initial parameters on the dynamics of ice formation, as well as develop recommendations for preventing or reducing ice formation.
The technique of numerical simulation of the icing process can be used in the design of anti-icing systems, assessment of aerodynamic characteristics of various aircraft, including UAVs, as well as in the design of wind turbines, tower cranes, bridges and other engineering structures.
Earlier, NSTU-NETI developed a computational model showing how hail impacts affect the composite parts of the aircraft.