Not adiabatic temperature of combustion gas-air mixture

© Published under licence by IOP Publishing Ltd. In the present work was carried out thermodynamic analysis, the purpose of which was to determine the formula for calculating the temperature of combustion gas-air mixture in non-adiabatic conditions

Equation of fluctuations frequency of gas in the devices such as capacity-tube

© Published under licence by IOP Publishing Ltd. In this paper highlights gas oscillations in the devices consisting of a combustion chamber and a narrow tube for the outflow of combustion products. Considering the sound velocity gradient in the tube. The resulting equation of fluctuations frequency of gas in the test device with any geometrical parameters

Conditions for exciting the maximal gas vibration amplitude in a combustion chamber of the Helmholtz resonator type

In this paper, we present the results of calculating conditions for gas vibration excitement, sound pressure frequency and level as a function of mixture composition, geometric burner parameters and the resonator throat with constant capacity. We estimate in quantity the parameters influencing a vibration combustion process in the Helmholtz resonator with the inlet multichannel burner which result in the maximum possible gas vibration amplitude value. © 2012 Allerton Press, Inc

A mathematical model of vibration combustion in a tube with sudden cross-section change

The theoretical study of vibration combustion using a model of the pulsejet engine was carried out. The frequencies and amplitudes of gas vibrations that were calculated by the energy method are well agreed with experimental data. © Allerton Press, Inc. 2007

Effect of supplementation of water vapor to the environmental characteristics of the combustion of propane-air mixture

© Published under licence by IOP Publishing Ltd. To improve the efficiency of combustion of fuel gas and air can be used additive steam. The article presents the results of an experimental study of the influence of water vapor on the combustion of propane-butane mixture with air. Combustion mixture produced in a modified Bunsen burner. Studies carried change of steam temperature of 180 to 260 degrees Celsius, and the change of the specific volume steam in the composition of the fuel mixture. Influence steam on combustion was estimated by the change of temperature of heating the quartz tube. It has been established that the increase of the steam temperature and increasing the specific volume of the heated vapor in the composition of the gaseous fuel increases the temperature of combustion

Acoustic gas oscillations in coaxial tubes

© Published under licence by IOP Publishing Ltd.Pulsating combustion is one of the possible solutions to improve energy efficiency of combustors that use hydrocarbon fuels. In this paper analysis of gas oscillations in coaxial tubes is provided. An influence of geometric parameters of the combustion chamber and the resonance tube on the installation frequency is considered

Pulsating combustion of gas fuel in the combustion chamber with closed resonant circuit

In the combustion chambers of the pulsation of gas flow oscillation greatly accelerate heat dissipation to the walls of the combustion chamber and improve combustion efficiency as compared with a uniform combustion mode. This allows you to effectively solve a number of problems of industrial power, including an environmentally friendly combustion products. Significant drawback of such systems-the emitted noise exceeding the permissible requirements. One solution to this problem-the separation of the resonance tube into 2 parts connected at the output to the interference of sound waves. The results of theoretical studies pulsating combustion technical mixture of propane in the system, consisting of a combustion chamber and two resonance tubes forming a closed resonant circuit. Resonators have a variable length. Calculations have shown that under certain oscillation of the resonator length to the first resonant frequency of the system is achieved by reducing SPL more than 15 dB. For oscillations at a second resonant frequency is the complete elimination of noise while maintaining intense oscillations in the combustion chamber. © Published under licence by IOP Publishing Ltd

Frequencies of gas oscillations in a pipe with a concentrated heat source

It is known that the location of the heat source significantly affects the frequency of acoustic oscillations in the channels. The case of a step change in the sound speed is investigated. In this article, linear distribution of sound speed in hot gas is considered. The well-known equations are used to calculate frequencies of the gas oscillations. The analysis shows that the movement of the flame from the down up in an open tube causes a nonmonotonic change in the resonant frequency. The calculation results are in good agreement with the experimental data

Combustion instability control in the model of combustion chamber

An experimental study of the influence of external periodic perturbations on the instability of the combustion chamber in a pulsating combustion. As an external periodic disturbances were used sound waves emitted by the electrodynamics. The purpose of the study was to determine the possibility of using the method of external periodic perturbation to control the combustion instability. The study was conducted on a specially created model of the combustion chamber with a swirl burner in the frequency range from 100 to 1400 Hz. The study found that the method of external periodic perturbations may be used to control combustion instability. Depending on the frequency of the external periodic perturbation is observed as an increase and decrease in the amplitude of the oscillations in the combustion chamber. These effects are due to the mechanisms of synchronous and asynchronous action. External periodic disturbance generated in the path feeding the gaseous fuel, showing the high efficiency of the method of management in terms of energy costs. Power required to initiate periodic disturbances (50 W) is significantly smaller than the thermal capacity of the combustion chamber (100 kW). © Published under licence by IOP Publishing Ltd

Получение низкозастывающего дизельного топлива для надёжной работы техники в районах Крайнего Севера и Арктики

In the Republic of Sakha (Yakutia) there are many winter roads for transportation of food and essential goods. As a rule, vehicles are running on a diesel fuel on such roads. Despite the difficulties in operating diesel vehicles under extremely low temperatures, diesel vehicles are much more powerful and economical than gasoline ones. Problems with start and operation of a diesel engine are associated with low-temperature properties of diesel fuel. The process involved in refining oil to create a winter class diesel fuel is expensive and complex because paraffinic hydrocarbons must be removed.Therefore, today it is important to produce winter classes of diesel fuel by compounding a pour point depressant and a summer class of fuel. When using additives, problems arise with the choice of their concentration. Those limits that the manufacturer recommends in real life show a negative result.There is no wide range of those additives in Yakutia so the authors chose for experiments Dewaxol additives that diminish sedimentation during fuel transportation. So, during the study of the impact of Dewaxol additive, that contained amides and imides of mono- and dicarboxylic acids on the diesel fuel, it was considered how, at various concentrations of the additive and the heating temperature of fuel, the cloud point decreases, and sedimentation stability improves. The least squares method has allowed describing optimal concentration of pour point depressant. The study resulted in the conclusion that the fuel with a high content of depressant-dispersant additive has the best sedimentation stability.В Республике Саха (Якутия) функционирует множество автозимников для перевозки продовольствия и товаров первой необходимости. Как правило, по таким дорогам ездят автомобили, работающие на дизельном двигателе. Несмотря на трудности в эксплуатации дизельной техники при экстремально низких температурах, дизельная техника намного мощнее и экономичнее бензиновой. Проблемы с запуском и работой дизельного двигателя связаны с низкотемпературными свойствами дизельного топлива. Процесс переработки нефти для создания зимнего сорта дизельного топлива сопровождается большими затратами и сложной технологией, потому что необходимо удалить парафиновые углеводороды.Поэтому сегодня актуально производство зимних сортов дизельного топлива путём компаундирования депрессорной присадки и летнего сорта топлива. При использовании присадок возникают проблемы с выбором их концентрации. Те пределы, которые рекомендует производитель, в реальной жизни показывают отрицательный результат.В Якутии отсутствует широкий спектр таких присадок, поэтому авторы остановили свой выбор для проведения экспериментов присадках Dewaxol, которые уменьшают отложения при перевозке топлива. В ходе изучения воздействия присадки Dewaxol, в составе которой были амиды и имиды моно- и дикарбоновых кислот, на дизельное топливо было рассмотрено, как при различных концентрациях присадки и температуре нагрева топлива снижается температура помутнения и улучшается седиментационная устойчивость. Метод наименьших квадратов позволил описать оптимальную концентрацию депрессорной присадки. В результате исследования выяснилось, что наилучшей седиментационной устойчивостью обладает топливо с высоким содержанием депрессорно-диспергирующей присадки