The ideal thermodynamic cycle of a detonation engine is substantiated and a method of computing the engine parameters is presented. In the ideal cycle the processes of gas compression and expansion are adiabatic. It is shown that low thermodynamic effectiveness of the detonation engine can be explained by significant wave losses of the total pressure in the shock wave and the entropy increase. The advantage of the engine in comparison with other thermal machines is the capability of obtaining a high value of absolute energy of the gas flow to do the work of gas expansion. While analyzing the thermodynamic cycle it is assumed, like in the gas turbine engine theory, that the characteristics of gas condition are determined by the parameters of stagnation subsonic flow in the sections corresponding to the beginning and the end of the processes making up the cycle. Heat supply downstream of the shock wave takes place in the subsonic flow in a constant-pressure process. Consideration of the cycle with stagnation parameters significantly simplifies its analysis and gives a fuller picture of its energy. A formula for calculating the coefficient of thermal efficiency of the ideal cycle of a detonation engine is presented as a function of the specific speed of propagation of the stabilized shock wave. It is shown that the ideal thermodynamic cycle of a detonation engine is described by two adiabatic curves, an isothermal curve determining huge wave losses, and two isobaric curves. The work of gas expansion in a detonation engine can be implemented both for obtaining the moving force of a vehicle and in industry, e. g., for metal hardening and cutting, production of high-hardness artificial diamonds, geophysical investigation.

Formulas of gas dynamic calculation of detonation parameters in variable cross-section ducts are presented and a design detonation diagram is given. The diagram shows the detonation characteristics of super-compressed detonation and under-compressed detonation as the function of shock wave specific speed depending on the intensity of temperature of the ideal gas in a subsonic one-dimensional flow behind the shock wave propagating in a chemically active air-fuel mixture and on the ratio of geometrical expansion (convergence) of the duct. The propagation of a stationary shock-wave the static pressure of which in the output cross-section of the expanded duct is equal to atmospheric pressure is referred to as design detonation. This means that all the energy of the shock wave at the output of the duct can be converted into polytropic work function of gas expansion in a detonation engine. Otherwise, if the flow takes place in the mode of overexpansion due to the separation of the compressive shock wave inside the duct or in the case of insufficient expansion part of the shock wave energy will be lost. The total impulse equation for a geometrically expanding duct is solved by replacing the integral describing the thrust force with the average integral value of the curve of the static pressure acting on the side wall of the expanding duct. The frictional force is neglected due to its insignificant value. It is shown that the presence of an insufficiently compressed shock wave is not possible as the shock wave moving at the supersonic speed in the convergent duct will be decelerated to the sonic speed. To stabilize it additional heat should be supplied to transform the convergent duct behind the compressive shock wave into a semi-permanent cross-section duct wherein thermal crisis stabilizing the shock wave can be achieved. The minimum value of the detonation pipe diameter of 50 mm is substantiated. Below that value sharp reduction of combustion efficiency takes place. The results of the work can be used for the computation of detonation engine thermodynamic cycle parameters.

The article substantiates the necessity of designing an optimal gas generator of a gas turbine engine. The generator is to provide coordinated joint operation of its units: compressor, combustion chamber and compressor turbine with the purpose of reducing the period of development of new products, improving their fuel efficiency, providing operability of the blades of a high-temperature cooled compressor turbine and meeting all operational requirements related to the operation of the optimal combustion chamber including a wide range of stable combustion modes, high-altitude start at subzero air and fuel temperature conditions and prevention of the atmosphere pollution by toxic emissions. Methods of optimizing the parameters of coordinated joint operation of gas generator units are developed. These parameters include superficial flow velocities in the boundary interface cross sections between the compressor and the combustion chamber, as well as between the combustion chamber and the compressor turbine. The effective efficiency of the engine thermodynamic cycle is the optimization target function. The required depth of the turbine blades cooling is a functional constraint evaluated with account for calculations of irregularity and instability of the gas temperature field and the actual flow turbulence intensity at the blades’ inlet. We carried out theoretical analysis of the influence of various factors on the gas flow that causes changes in the flow total pressure in the channels of the gas generator gas dynamic model, i.e. changes in the efficiencies of its units. It is shown that the long period (about five years) of the engine final development time, is due to the necessity to perform expensive full-scale tests of prototypes, in particular, it is connected with an incoordinate assignment in designing the values of the flow superficial velocities in the boundary sections between the gas generator units. Designing of an optimal gas generator is only possible on the basis of an integral mathematical model of an optimal combustion chamber.

The article shows the necessity of matching joint functioning of the compressor and the combustion chamber at the stage of designing a gas generator to provide the turbine operability and specifies the formula for the calculation of the superficial flow velocity downstream the compressor as a matching parameter which, if its value is provided, prevents gas temperature field instability downstream of the combustion chamber and correspondingly prevents the damage of the turbine blades.

Безопасность в техносфере, №5 (сентябрь-октябрь) Синтетические красители применяются прак-тически во всех отраслях промышленности [1]. С их применением осуществляют окрашивание природ-ных и синтетических волокон, бумаги, дерева, кожи и других материалов. Мировое производство синте-тических красителей составляет порядка 1 млн т в год. Кроме того, в связи с появлением на рынке новых красящих соединений остается актуальной проблема разработки мероприятий, направленных на обеспе-чение пожарной безопасности объекта защиты. Но без сведений о пожароопасных свойствах органиче-ских красителей это невозможно.В главе 13 ФЗ-№123 «Технический регламент о требованиях пожарной безопасности» для обеспече-ния пожарной безопасности на объектах необходимо создание систем предотвращения пожара, чтобы ис-ключить возникновение горючей среды и источника зажигания, которые становятся причиной пожара. В ст. 49 [2] предлагаются способы исключения образо-вания горючей среды: применение негорючих веществ и материалов; ограничение массы и (или) объема го-рючих веществ и др. Одна из главных проблем исполь-зования данных способов -отсутствие сведений о веществе. Таким образом, разработка универсального метода прогнозирования пожароопасных свойств ве-ществ позволит решить сложившуюся проблему. Та-кой подход позволит проводить анализ свойств уже исследованных веществ с целью прогнозирования пожароопасных свойств, которыми обладают новые соединения либо еще не синтезированные, что даст возможность на основе полученных данных разраба-тывать мероприятия, направленные на обеспечение пожарной безопасности объектов защиты.Задача создания и развития новых информаци-онных технологий, обеспечивающих многократное ускорение процесса обработки информации, пред-ставляет практический интерес. К таким технологи-ям можно отнести системы на базе моделирования, включающие молекулярные дескрипторы и искус-ственные нейронные сети. Поэтому для решения по-ставленной задачи предлагается использовать метод прогнозирования пожароопасных свойств веществ на основе молекулярных дескрипторов и искусствен-ных нейронных сетей. Ранее этот метод применялся нами [3,4,5, 6] и успешно себя зарекомендовал. При прогнозировании пожароопасных свойств веществ не требуется существенных временных и материаль-ных затрат, а также отсутствуют трудности, пред-ставленные на рис. 1 и связанные с прогнозировани-ем пожароопасных свойств веществ [7].