Hanesh H. Method of hub losses reducing of pushing air propellers with tandem blades of small UAV

Thesis for the degree of Philosophy Doctor in the specialty 134 - Aviation and and Space-rocket technology. - National Aviation University of the Ministry of Education and Science of Ukraine; Kiev, 2021. The thesis is devoted to solving the scientific and applied problem of increasing the efficiency of propellers with tandem blades row. The dissertation work is an integral part of the research carried out at the National Aviation University and is aimed at improving the parameters and characteristics of propellers of unmanned aerial vehicles in a wide range of operating conditions. The work was carried out in accordance with the Concept of the State Target Scientific and Technical Program for the Development of the Aviation Industry for 2021-2030, approved by the Cabinet of Ministers of Ukraine on 11.11.2020, and the European Program for Scientific Research in Aviation until 2024 "Cllean Sky - 1" and "Cllean Sky - 2 "approved in 2008. The aim of the study is to increase the efficiency of propellers with double-row blades by reducing the level of sleeve losses. The object of research is UAV propellers with tandem blades row. The subject of research is the characteristics of propellers with tandem blades row.The work uses modern theoretical, numerous and experimental research methods. The theoretical part of the work is based on the application of the methods of gas dynamics, the theory of the boundary layer, turbulent jets and wakes, the theory of propellers. To study the structure and characteristics of three-dimensional flows, the methods of numerical gas dynamics are applied and implemented in the commercial software product ANSYS. With the help of experimental research methods, the approbation and verification of the obtained theoretical dependencies, solutions and results of numerical modeling were carried out. The reliability of the results obtained is ensured by the correct application of the mathematical apparatus for solving the set scientific tasks and is confirmed by a good agreement of the results of the calculated research based on the results of physical experiments.