This paper presents the results of theoretical studies on rocket/space hardware aerogas dynamics obtained from 2016 to 2020 at the Department of Aerogas Dynamics and Technical Systems Dynamics of the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine along the following lines: rocket aerodynamics, mathematical simulation of the aerogas thermodynamics of a supersonic ramjet vehicle, jet flows, and the hydraulic gas dynamics of low-thrust control jet engines. As to rocket aerodynamics, computational methods and programs (CMPs) were developed to calculate supersonic flow past finned rockets. The chief advantage of the CMPs developed is computational promptness and ease of adding wings and control and stabilization elements to rocket configurations. A mathematical simulation of the aerogas thermodynamics of a supersonic ramjet vehicle yielded new results, which made it possible to develop a prompt technique for a comprehensive calculation of ramjet duct flows and generalize it to 3D flow past a ramjet vehicle. Based on marching methods, CMPs were developed to simulate ramjet duct flows with account for flow past the airframe upstream of the air inlet, the effect of the combustion product jet on the airframe tail part, and its interaction with a disturbed incident flow. The CMPs developed were recommended for use at the preliminary stage of ramjet component shape selection. For jet flows, CMPs were developed for the marching calculation of turbulent jets of rocket engine combustion products with water injection into the jet body. This made it possible to elucidate the basic mechanisms of the effect of water injection, jet–air mixing, and high-temperature rocket engine jet afterburning in atmospheric oxygen on the flow pattern and the thermogas dynamic and thermalphysic jet parameters. CMPs were developed to simulate the operation of liquid-propellant low-thrust engine systems. They were used in supporting the development and ground firing tryout of Yuzhnoye State Design Office’s radically new system of control jet engines fed from the sustainer engine pipelines of the Cyclone-4M launch vehicle upper stage. The computed results made it possible to increase the informativity of firing test data in flight simulation. The CMPs developed were transferred to Yuzhnoye State Design Office for use in design calculations.

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Theoretical studies on rocket/space hardware aerogas dynamics

Aimed at determining the maximum allowable pressure in the combustion chamber causing no flow separation in the air intake device, numerical simulation of the throttling process in a ramjet engine was carried out. Calculations were made in two formulations: with local and global time steps. When comparing results obtained using these approaches, the possibility was found to determine the air intake device throttling characteristics without losing the accuracy at the initial stages of designing the ramjet engines with introduction of the local time step. The non-stationary model created the basis for selecting the optimal integration step to minimize computational resources. The flow pulsations period was evaluated for the event of a surge. These pulsations frequencies were registered in the extremely low frequency range.

Numerical simulation of throttling processes in the ramjet engine

This paper suggests the verification and calibration method of thermal imagers that consists in comparison of temperature readings obtained by contact and thermal imaging method. The experimental setup has been developed to confirm the reliability of the proposed method. The main element of experimental setup is an emitting surface in the form of rectangular plate that measures 330×200×4 mm. The plate is covered with paint which emissivity factor is not less than 0,96. The paper presents the results of temperature field calculations on the plate emitting surface. The temperature field of the plate emitting surface has been determined by the contact method using chromel-alumel thermocouples and thermal imaging method. As a result of the obtained temperature values analysis, it has been concluded that if the plate emitting surface temperatures close to 50 °C, the heat exchange of the plate with the ambient air plays a significant role. The air heaters are applied in order to reduce the heat flows dissipation from the plate emitting surface into the environment. The heaters are two aluminum-magnesium alloy plates attached to the end face of the emitting surface. The metal heat exchangers – coils are installed on the surfaces of the plates and connected by hoses to the liquid thermostat. One of the plates heats the air flowing around the emitting surface, and another one prevents the emission thermal expansion into the environment. As a result of heaters application, the heat exchange intensity of a plate radiating surface with environment decreases. Moreover, recommendations about the choice of heaters sizes have been given. The main advantages of the method proposed are the following: ensuring high isothermic of the emitting surface throughout the height of the plate; accuracy of the temperature maintaining at a given level; reducing the device transition time to steady-state regime.

Improvement of methods and means of thermal imagers verification and calibration

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Non-equilibrium high speed air flow over spherical blunt bodies

Gas-dynamic features of the flow field over a model of an integrated hypersonic flying vehicle

The purpose of this work is to examine stream parameters in circuits of hypersonic facilities and to determine the degree of influence of non-equilibrium physical and chemical processes using numerical modeling of real gas flow and heat transfer For numerical modeling, the work employs the well-known ANSYS Fluent software and the HSFlow program (development of TsAGI) supplemented by a physicochemical module Axisymmetric Navier-Stokes equations for viscous heat-conducting gas are solved in combination with the equations of chemical kinetics and oscillatory mode energy relaxation Calculations were performed for the flow field in the nozzles and test sections of two facilities: T-122M (without a model) and VAT-104 with a model of a cylinder in the test section Results were compared with the results of calculations that employed a simplified model of real air properties where only equilibrium excitation of oscillatory degrees of freedom of oxygen and nitrogen molecules was considered

Sergey Valer'evich Chernov

Papers

Non-equilibrium high speed air flow over spherical blunt bodies

Gas-dynamic features of the flow field over a model of an integrated hypersonic flying vehicle

Numerical simulation of real air flow and heat exchange in hypersonic wind tunnels