Experts from the Perm National Research Polytechnic University (PNIPU) proposed a method to test the effectiveness of protecting small unmanned aerial vehicles (UAVs) from icing. socialbites.ca was informed about this by the press service of the scientific institution.
Small drones are widely used in search and rescue operations, aerial photography and surveillance of areas. However, their operation in sub-zero temperatures and high humidity is complicated by ice forming on the drone wings.
Due to their limited size, UAVs cannot use anti-icing systems used in passenger and cargo aviation. That’s why drones rely on a method called “overthrottle,” which sharply increases rotor speed for a short period of time. PNIPU scientists suggested that the process of ice destruction during “overthrottle” affects the stiffness of the wings and the geometry of their design.
To study these processes, technicians built a setup containing an air cooling tube in which the temperature could be maintained from -30 °C to +25 °C. Inside there is an electric motor that rotates the propeller of the aircraft under study.
A high-speed camera records the experimental process at speeds of up to 960 frames per second. A cloud of cooled liquid droplets is sprayed using a nozzle and fed into a container under the pressure of a compressor.
The sensor system allows you to evaluate vibration at various icing levels and obtain instantaneous humidity, pressure and temperature values. Using special software, researchers control the operating mode of the electric motor and the power of the cooling chamber, receive and record signals from measuring equipment.
Perm Polytechnic experts tested the device by placing a propeller in a pipe and covering the pipe with ice for two minutes at a rotation speed of 5000 rpm and a temperature of -10 °C.
Then the rotor speed was increased to 7000 rpm. The ice accumulation on the propeller blade, whose properties had changed, was eliminated, but ice remained on the other three blades. Final removal of ice from the remaining blades occurred after a rotation speed of 11500-12000 rpm was reached.
Scientists suggested that local heterogeneity of properties changes the properties of ice adhesion to the blade, so the ice melts on it at a slower rate.
“Controlled changes in the properties of the fan surface can reduce the energy consumption for “gas refilling” during flight and, as a result, increase its maximum duration,” said the candidate of technical sciences, a researcher at the High Performance Center. Associate professor at the Department of Aviation Information Technology Systems socialbites.ca. to their engines” told PNRPU Nikolay Sazhenkov.
Previously in Russia developed Installation for testing experimental aviation fuel.