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Методика проведення чисельного дослідження камери імпульсного детонаційного двигуна

The subject of research in this article is the process of detonation propagation in the chamber of a pulse detonation engine. Experimental research on detonation engines is a complex and expensive process that requires high-speed, high-precision equipment to obtain high-quality reliable results. Therefore, to conduct preliminary research, numerical experiment methods using mathematical simulation tools should be used. This work analyzes the possibility of applying known calculation models to study the detonation propagation process in the chamber of a pulse detonation engine. The task: to study the influence of the application of existing calculation models on the accuracy of numerical simulation of the detonation process; analyze the use of existing calculation models for the study of the detonation propagation process. The main method used in this work is the method of mathematical simulation using CFD technologies. The following results were obtained. The work considered the application of various turbulence models, chemical transition models, solvers and mesh sizes in modeling processes in the chamber of a pulse detonation engine. The application k-ε and k-ω turbulence models and their modifications are considered. The closest to the real result is obtained when applying k-ω model turbulence with SST modification. Generalized modification of this model averages the parameters on the front of the detonation wave, which leads to the destruction of the structure of the front. Taking into account the peculiarities of the processes occurring at the front of the detonation wave, the eddy-dissipation concept method will be better for modeling chemical transition, compared to the finite-rate method. Using the finite-rate method shows instantaneous combustion at the front of the detonation wave. This leads to a sharp increase in the parameters at the detonation front with its further separation from the main flow. To obtain a qualitatively reliable result of the parameters at the front of the detonation wave, cell dimensions of no more than 1/16 mm should be used. The application of the eddy-dissipation concept method with k-ω SST turbulence model allows obtaining the closest results to the experimental data. The deviation of pressure and velocity values obtained during modeling does not exceed 5% from their actual values. The temperature deviation does not exceed 10%. This is determined by the selected kinetic scheme of chemical transitions. All considered models and methods affect only the structure and development of the detonation wave front. There are no significant differences in the values of the parameters along the front (in the Taylor zone). Conclusion. The obtained results are of practical importance for the design and research of detonation engines. The use of the proposed calculation models will allow conducting numerical experiments for the pulse detonation engine chamber with sufficient accuracy, in comparison with experimental data.

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RESULTS OF DESIGN AND THEORETICAL STUDIES OF LV PRESSURIZATION SPRAYERS PARAMETERS

The pressurization system of the fuel tanks of launch vehicles is one of the important and critical subsystems of the pneumatic-hydro supply system. The pressurization system is designed to create the necessary pressures in the fuel tanks in order to ensure their required values at the engine inlets (both during launch and during operation  in  specified   modes),  as well as to ensure the strength and stability of the tanks during the flight of launch vehicles. These systems determine the configuration and appearance of launch vehicles, their energy characteristics and operating conditions. At the same time, the pressurization system is functionally interconnected with the operation of many other subsystems of the pneumatic-hydraulic supply system (refueling of fuel components, control systems, fuel consumption control systems, units of a liquid-propellant rocket propulsion system, etc.).
 One of the main functional elements of the pressurization system is the atomizer. The atomizer is designed to introduce pressurization gas into the tank in such a way that its speed and direction provide the required pressure and gas temperature distribution in the free volume of the tank, without causing unacceptable heating of the tank structure and fuel component, as well as possible disturbances (vibrations, etc.) .
 On the example of specific launch vehicles on high- and low-boiling fuel components, a generalizing review of the pressurization system sprayers developed in the Yuzhnoye State Design Office (YSDO) was carried out, as a result of which the authors determined and described in detail: their design features, requirements, classification, and the procedure for their development. The possibilities and tools for modeling the parameters of atomizers are shown. The experimental data of some of the developed atomizers are presented. Promising directions for the development of pressurization systems are outlined, which in the future will allow the development of highly efficient systems with optimal parameters.

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FORECASTING THE SERVICEABILITY OF THE RUBBER CORRUGATED SLEEVE OF THE DOCKING NODES OF THE LAUNCH VEHICLE'S THERMOSTATIC CONTROL SYSTEM

One of features of objects of spacerocket technique there is the reliable providing of capacity of the different systems, aggregates, mechanisms on the draught of great while of storage and exploitations for making of elements of that various materials are used. A rubber corrugated sleeve of a three-unit design with three structural elements, each of which is in different stress-deformed states, is used for the connecting nodes of the thermostatic control system. Since rubber as a structural material, having a number of advantages (low density, high elasticity and flexibility, low hardness, competitive price, etc.) compared to metal structural materials, over time quickly loses its technical characteristics, it was of interest to investigate the possibility of ensuring the operability of a rubber corrugated sleeve as a part of the connecting nodes of the thermostatic control system during the warranty period of storage and operation. The reason for this is the aging of rubber over time under the influence of many different factors activated by mechanical stress. Due to the fact that rubber is subject to the principle of temperature-time superposition, predicting the service life of the rubber corrugated sleeve was carried out using the method of accelerated climatic tests at elevated temperature. The testing modes were established according to the total curves for the unknown part of the sleeve, as it is found in the largest stress-strained steel. Pobudov's summation crookedness was based on Arrhenius' victories. The methodology was given to stimulate the sum curve. Testing at a special stand confirmed the conservation of the robotic capacity of the humic sleeve and the jointing on the length of the 15-point operational term with a margin coefficient of 1.5  

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