ISSN 1068-7998, Russian Aeronautics, 2019, Vol. 62, No. 3, pp. 448–454. © Allerton Press, Inc., 2019. Russian Text © The Author(s), 2019, published in Izvestiya Vysshikh Uchebnykh Zavedenii, Aviatsionnaya Tekhnika, 2019, No. 3, pp. 89–94. 448 AERO- AND GAS-DYNAMICS OF FLIGHT VEHICLES AND THEIR ENGINES Study of Jet Propagation and Prevention of Jet Reattachment to the Nacelle during Jet Engine Thrust Reversal A. S. Mikhailov a , S. R. Nasyrov b , T. R. Samerkhanov b , and A. V. Kosterin a, * a Tupolev Kazan National Research Technical University, ul. Karla Marksa 10, Kazan, 420111 Tatarstan, Russia b Kazan (Volga region) Federal University, ul. Kremlevskaya 18, Kazan, 420008 Tatarstan, Russia *e-mail: 89030621520@mail.ru Received May 27, 2019; in final form, July 12, 2019 Abstract—Complex variable function theory methods are used to study the jet propagation and prevention of jet reattachment to the nacelle during jet engine thrust reversal for reverser cascades with constant and variable blade angles. Results obtained are compared with experimental data. DOI: 10.3103/S1068799819030127 Keywords: thrust reversal, reverser jet, complex variable function theory methods, reverser cascades with variable blade angles. Recently, the problem of creating short-landing aircraft is of importance. This is due to climate change and the modern political situation in the world. Weather anomalies become more frequent, and this makes runways unsuitable for safe landing of aircraft. The runway may be destroyed as a result of malicious intent, which also poses a threat to the safety of the aircraft landing. The main method to reduce the landing run under the conditions of a slippery and destroyed runway is the jet engine thrust reversal. The main limitation in using engine thrust reversal for braking an aircraft during a landing run is getting jets from the reverser device and foreign objects from the runway surface at the engine inlet. Ingress of reverser jets leads to a change in the velocities and temperatures fields at the engine inlet, which can cause a compressor surging and engine shutdown. This limitation leads to the fact that the reversal is turned off long before the full stop of the aircraft. The reduction of the landing run speed, at which the reverser jets ingress the engine, is achieved by optimizing the design of the deflection elements of the reverser in order to change the reverser jet propagation boundaries. Reducing the speed of the landing run, at which the reversal should be turned off, drastically reduces the length of the run and increases safety under slippery runway conditions. Reducing the length of the landing run for transport aircraft and special purpose aircraft will allow the use of short landing sites with any coverage. The main reason for the ingress of reverser jets on the engine inlet is the effect of reverser jet reattachment to the nacelle (the Coanda effect). Study and prevention of jet reattachment to the engine nacelle is the subject of the paper. Jet flows were considered in detail in [1, 2]. The ingress of exhaust gases at the engine inlet was studied in [3–6]. Mathematical modeling of the interaction of a jet and a solid surface was considered in [7], the flow of liquid in the reverser channel was investigated in [8, 9]. There are integral methods for estimating the mode of beginning the reverser jet reattachment to the nacelle in the flow [4, 5], requiring the use of complicated hardware and software. Of interest is the problem of using a more accessible mathematical tool, which at the initial design and in the conditions of rough calculations would allow describing the pattern of the jet reattachment with a prescribed accuracy. Let us consider a mathematical model of the gas flow at the outlet of the reverser cascade with variable blade angles. The method of replacing the reverser cascade with a permeable segment was used in theoretical studies [8, 9].