CALCULATION OF HEAT TRANSFER INTENSITY OF GAS FUEL COMBUSTION PRODUCTS

Link for citation: Mrakin A.N., Afanaseva  O.V., Kuleshov O.Yu. Calculation of heat transfer intensity of gas fuel combustion products. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 5, рр.109-115.  The relevance of the research is determined by the modern trend in the field of thermal power engineering and heat engineering for the transition from traditional gaseous fuel (methane) to the use of hydrogen, methane-hydrogen mixtures, as well as thermochemical conversion gases. Switching to new non-design fuel is justified by considerations of reducing the negative impact on the environment and increasing the thermal efficiency of fuel combustion plants. In this case, the use of fuels with a composition different from the design one will affect the heat transfer processes. The main aim: carrying out a comparative analysis of indicators of the intensity of radiant and convective heat transfer of combustion products of non-design fuels, such as hydrogen, methane-hydrogen mixture and thermochemical conversion gases. As an assumption in the formulation of the problem and objectives of the study, the constancy of the heat release power in the apparatus due to changes in the amount of fuel burned was taken. Objects: heat exchange surface of a fire-tube hot water boiler. Methods: carrying out numerical calculation using traditional approaches to determine the indicators of the intensity of heat transfer in the system «combustion products – metal wall of the pipe of thermal power plants». We also used the relations tested earlier by other authors to calculate the thermophysical parameters of gas mixtures. Results. According to the results of the performed comparative calculations, we can conclude that the transition from the use of conventional fuel (natural gas/methane) to its thermochemical conversion gases under the considered conditions has almost no effect on the integral heat transfer performance. To a greater extent, this transition is caused by changes in the intensity of heat transfer for products of combustion of hydrogen and methane-hydrogen mixture, which will affect the operation of thermal power and heat technological installations. At the same time, it is necessary to conduct additional research on the combustion kinetics of thermochemical methane conversion gases, their thermophysical properties, etc., because the hardware design, type of the catalyst used and operating parameters of the process will affect the composition of obtained synthesis gas

Simulation of high-speed interaction between impactor and layered-spaced design involving explosive

In this paper we present calculating and experimental study of high-speed interaction between explosive content, protected by layered-spaced design, and the cermet impactor in wide speed range. An experimental technique and mathematical model of during the behavior of explosives, protected by layer-spaced design, by with high-speed impact. The process of the interaction between the cermet impactor and element of the protective design is customized and depends on the materials of the interacting bodies, the speed and angle of impact

High-speed impact of the metal projectile on the barrier containing porous corundum-based ceramics with chemically active filler

The paper presents a calculation-experimental study on high-speed interaction of the metal projectile with a combined barrier made of porous corundum-based ceramics filled with chemically active composition (sulfur, nitrate of potash) in the wide range of speeds. A mathematical behavior model of porous corundum-based ceramics with chemically active filler is developed within the scope of mechanics of continuous media taking into account the energy embedding from a possible chemical reaction between a projectile metal and filler at high-speed impact. Essential embedding of inlet heat is not observed in the considered range of impact speeds (2.5 … 8 km/s)

Calculation and experimental study on high-speed impact of heat-resistant coating materials with a meteoric particle

The given article presents the conducted calculation and experimental study on destruction of heat-resistant coating material of an aircraft in the process of high-speed interaction of the steel spherical projectile. The projectile is imitating a meteoric particle. The study was conducted in the wide range of velocities. The mathematical behavioral model of heat-resistant coating under high-speed impact was developed. The interaction of ameteoric particle with an element of the protective structure has especially individual character and depends on impact velocity and angle, materials of the interacting solids

Special features of high-speed interaction of supercavitating solids in water

Special features of material behavior of a supercavitating projectile are investigated at various initial velocities of entering water on the basis of the developed stress-strain state model with possibility of destruction of solids when moving in water and interacting with various underwater barriers with the use of consistent methodological approach of mechanics of continuous media. The calculation-experimental method was used to study the modes of motion of supercavitating projectiles at sub- and supersonic velocities in water medium after acceleration in the barrelled accelerator, as well as their interaction with barriers. Issues of stabilization of the supercavitating projectile on the initial flight path in water were studied. Microphotographs of state of solids made of various materials, before and after interaction with water, at subsonic and supersonic velocities were presented. Supersonic velocity of the supercavitating projectile motion in water of 1590 m/s was recorded

Experimental and theoretical research of the interaction between high-strength supercavitation impactors and monolithic barriers in water

The article describes experimental and theoretical research of the interaction between supercavitating impactors and underwater aluminum alloy and steel barriers. Strong alloys are used for making impactors. An experimental research technique based on a high-velocity hydro-ballistic complex was developed. Mathematical simulation of the collision the impactor and barrier is based on the continuum mechanics inclusive of the deformation and destruction of interacting bodies. Calculated and experimental data on the ultimate penetration thickness of barriers made of aluminum alloy D16T and steel for the developed supercavitating impactor are obtained

Intrusion features of a high-speed striker of a porous tungsten-based alloy with a strengthening filler in a steel barrier

The complex problem of increasing the penetrating power of strikers based on highly porous tungsten composites is considered by improving their strengthening properties by alloying the hardening components under high-speed collision conditions. Using the method of liquid-phase sintering, we fabricated samples of strikers based on a porous WNiFeCo alloy (tungsten + nickel + iron + cobalt), alloyed with tungsten carbide with cobalt (WCCo8) and titanium-tungsten carbide (TiWC). Dynamic tests of the strikers from the developed alloys were carried out at the collision velocity with a steel barrier of the order of 2800 m/s. The penetration depth of the striker based on a porous WNiFeCo alloy doped with tungsten carbides is 30% higher than the penetration depth of a striker of a monolithic WNiFe-90 alloy (tungsten + nickel + iron with a tungsten content of 90%)

Professional liability insurance of dentists as the form of social-legal defense

The article is devoted to the problems of the Medical professional liability insurance in Russia. Medical organizations or government are responsible for medical professional liability insurance

Changing the PH value of herbal decoctions for determining the optimum storage conditions

The purpose of the study is to find out which degree of purification water is less affected by various environmental conditions to determine the optimal temperature regimes for storage of decoctions.Цель исследования - выяснить, вода какой степени очистки меньше подвержена влиянию различных условий внешней среды и определить оптимальные температурные режимы хранения отваров

Мониторинг потребительского отношения населения к лекарственным средствам

Objective. Comparative analysis and monitoring of the population’s attitude to medicines through an assessment of their consumer qualities by visitors of pharmacies.Materials and Methods. Conducted two sociological survey thru the original questionnaires in 2002 and 2015 among pharmacy customers. Each survey included 380 respondents living in the cities of Central Russia. During the interviews, respondents were asked, among other things evaluate the 13 influencing their choice of consumer qualities of medicines. Six of these qualities characterize the pharmaceutical features and merchandising options are seven parameters of medicines. Statistical analysis used a set of indicators of variation statistics, ranking, rank correlation.Results. Ratings of consumer qualities of medicines are obtained for the studied years and changes in the whole period of monitoring. We have identified the priority characteristics of medicines which are essential for consumers, in particular: efficiency, clear information on the package, low cost, minor side effects, convenient way to receive.Conclusion. The revealed features of consumer attitudes to medicines should be taken into account pharmaceutical workers in information and consultative dealing with pharmacies visitors.Цель исследования – сравнительный анализ и мониторинг отношения населения к лекарственным средствам на основе оценки их потребительских качеств посетителями аптек.Материалы и методы. Проведены два социологических опроса по оригинальным анкетам в 2002 и 2015 гг. среди посетителей аптек. В каждом опросе приняли участие по 380 респондентов, проживающих в городах Центральной России. В ходе опросов респондентам предлагалось среди прочего оценить 13 влияющих на их выбор потребительских качеств лекарственных средств. Шесть этих качеств характеризуют фармацевтические особенности и семь – являются товароведческими параметрами лекарственных средств. Для статистической обработки использован комплекс показателей вариационной статистики, ранжирование, ранговая корреляция.Результаты. Получены рейтинги потребительских качеств лекарственных средств за исследуемые годы и их изменения в целом за период мониторинга. Определены приоритетные характеристики лекарственных средств, имеющие существенное значение для потребителей, в частности: эффективность, понятная информация на упаковке, низкая стоимость, незначительные побочные действия, удобный способ приема.Заключение. Выявленные особенности потребительского отношения к лекарственным средствам должны учитываться фармацевтическими работниками в информационно-консультативном общении с посетителями аптек