# TsAGI Science Journal, Issue 7, Year 2014

**NOZZLE THRUST AUGMENTATION UNDER DIMENSIONAL CONSTRAINTS**

*S. A. Takovitskii*

*The problem of designing axisymmetric supersonic nozzles is considered. In order to increase the jet thrust under dimensional constraints, the use an internal nozzle insert is proposed. The insert is located near the exit section outside the region of aerodynamic interference with the nozzle edge. The insert shape profiling and estimation of the thrust characteristics are performed by a direct optimization method. The research is performed within the framework of the Euler model for inviscid flow.*

**KEY WORDS: ***supersonic nozzle, jet thrust, optimization, internal insert*

**METHODOLOGY AND EXAMPLES OF NUMERICAL INVESTIGATIONS OF BODIES WITH DUCTS AT SUPERSONIC FLOW VELOCITIES**

*N. V. Voevodenko** & A. A. Gubanov*

*The problem of computing the aerodynamic performance of high-speed flying vehicles (FVs) with airbreathing jet engines is considered. An efficient, stable, rapid, robust, and informative computational instrument is required in investigations aimed at improving airframe design. A numerical method based on the hypersonic small-disturbance theory and the Godunov—Kolgan method is used in this study as the basic instrument in calculating the flow fields and total aerodynamic performance of a FV. In order to calculate the air inlet performance (mass flow rate coefficients, momentum components, etc.), the numerical results for the flow parameters at the entrance of the air inlet are used. The contribution of the engine air inlets to the total aerodynamic performance of the FV is determined by the momentum theorem. The results are compared with the experimental data and computational results using a Reynolds-averaged Navier—Stokes code. The performance of an axisymmetrical body with two air inlets is calculated.*

**KEY WORDS: ***high-speed flying vehicle with air-breathing jet engine, numerical investigations, momentum theorem*

**INTERFERENCE CONCEPT OF AERODYNAMIC DESIGN OF EFFECTIVE HYPERSONIC CONFIGURATIONS**

*Yu. I. Lobanovsky*

*An interference concept of aerodynamic design of hypersonic flying vehicles is presented, which makes it possible to develop some new configurations for efficient hypersonic flight. Wind tunnel tests of configurations designed on the basis of these principles with a volume coefficient typical for vehicles operating on a cryogenic fuel are performed at Mach numbers *M = * 7–10 and Reynolds numbers of the order of several million and provide the maximum lift-to-drag ratio *(

*L/D*)

*=*

_{max}*M*5.7–5.6, which is 10–30% higher than that of currently available aerodynamic configurations. In contrast to known configurations, the lift-to-drag ratio of the new configurations does not decrease with increasing Mach number. At

*> 7 and full-scale Reynolds numbers, the lift-to-drag ratio of such configurations in cruising flight can reach*(

*L/D*)

_{max}≈ 7. The aerodynamic characteristics of the proposed configurations at low and moderate supersonic speeds are similar to those of typical combinations of a body with a low-aspect-ratio wing.**KEY WORDS: ***hypersonic vehicle, wing, body, volume, waverider, lift, drag, lift-to-drag ratio, flow modes*

**INTERACTION OF A SUPERSONIC JET HEAVY LOADED BY PARTICLES WITH A SOLID BODY**

*G. V. Molleson & A. L. Stasenko*

*The purpose of this work is to develop the physicomathematical model and numerical code for investigation of a monodisperse supersonic flow impinging on a solid axisymmetric body in the case of the large initial mass fraction of particulates. In such flows, a chaotic layer which can be described by the diffusion model arises on the surface of the body in flow. Several variants of the radial distribution of the particle concentration at the nozzle entrance are investigated (these distributions depend on the particulate kinetics in the mixing chamber and serve as a separate problem). The influence of particle substance and dimensions on the flow gas thermodynamics is investigated for a large range of initial values of the particle mass density.*

**KEY WORDS: ***gas-dynamic acceleration of microparticles, recovery coefficients of the velocity components, compressed layer, rotation of the bounced particles, chaotic particles and their diffusion, flux densities of mass, momentum and energy of the phases*

**FUEL CONSUMPTION MINIMIZATION FOR AGRICULTURAL AIRCRAFT CONDUCTING SPRAYING**

*S. N. Suprunenko,** & L. T. Tang*

*A problem of fuel consumption minimization for agricultural aircraft conducting spraying of chemicals in a horizontal flight is considered. The problem is formulated as an optimal control one to be solved by variational methods, with particular regard to the nonstationarity of aircraft full mass during flight and to the complexity of an engine’s fuel consumption characteristics. A technique, proposed to determine the optimal solution, is based on an idea of making small improvements to the well-known quasi-stationary solution corresponding to an assumption of equality between the engine thrust and the aerodynamic drag. Illustrations of numerical computations fulfilled for the agricultural airplane PZL M-15 (Soviet-Poland design) show that in the case of sufficiently intensive spray-mass expenditure the proposed optimal solution can noticeably raise the fuel saving.*

**KEY WORDS: ***agricultural aviation, aerial application, flight regime optimization, variational calculus*

**EXPERIMENTAL INVESTIGATION OF THE AEROGASDYNAMICS OF A VECTORED-THRUST NOZZLE**

*G. N. Lavrukhin,** E. B. Skvortsov, & V. A. Talyzin*

*The results of the flow visualization and investigation of the aerogasdynamics characteristics of a turbofan engine nozzle with a thrust-vector control are presented. Some peculiarities of the flow and alteration of the nozzle characteristics with jet deflection are founded.*

**KEY WORDS: ***turbofan, nozzle, thrust vectoring, subsonic flow, thrust losses, thrust vector angle*

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