Initiation of Ignition of Highly Fuel Particles in The Flow of High Temperature Medium

An approximate analytical solution of ignition of the fuel porous particles has been brought. The impact of thermal radiation on the characteristics and conditions of the ignition has been considered. The verification of the solution has been obtained by comparing the calculated characteristics (delay time of ignition and the ignition temperature) with similar values obtained using the previously derived formulas

Numerical Modeling of Conjugate Thermogravitational Convection in a Closed System with a Radiant Energy Source in Conditions of Convective-Radiative Heat Exchange at the External Boundary

Mathematical modeling of conjugate natural convection in a closed rectangular cavity with a radiant energy source in conditions of convective-radiative heat exchange at the external boundary was conducted. The radiant energy distribution was set by the Lambert’s law. Conduction and convection processes analysis showed that the air masses flow pattern is modified slightly over the time. The temperature increases in the gas cavity, despite the heat removal from the one of the external boundary. According to the results of the integral heat transfer analysis were established that the average Nusselt number (Nu[av]) increasing occurs up to [tau]=200 (dimensionless time). Further Nu[av] has changed insignificantly due to the temperature field equalization near the interfaces "gas – wall"

Influence of air Gap Between the Transformer of Resistance and Object of Monitoring on Temperature Measurement Error

In operation the description of the developed heattransfer model in thermotransformers of resistance (RTD) in the conditions of air gap between surfaces of the sensor and object of measurement is provided. Research of influence of thickness of air gap on the relative error of temperature measurement by platinum, copper and nickel thermotransformers of resistance in the ranges of temperatures corresponding to each type is executed. Dependences of minimum necessary duration of heating up of sensors on the taken temperatures are received

Numerical Research of Steam and Gas Plant Efficiency of Triple Cycle for Extreme North Regions

The present work shows that temperature decrease of heat rejection in a cycle is necessary for energy efficiency of steam turbine plants. Minimum temperature of heat rejection at steam turbine plant work on water steam is 15°C. Steam turbine plant of triple cycle where lower cycle of steam turbine plant is organic Rankine cycle on low-boiling substance with heat rejection in air condenser, which safely allows rejecting heat at condensation temperatures below 0°C, has been offered. Mathematical model of steam and gas plant of triple cycle, which allows conducting complex researches with change of working body appearance and parameters defining thermodynamic efficiency of cycles, has been developed. On the basis of the model a program of parameters and index cycles design of steam and gas plants has been developed in a package of electron tables Excel. Numerical studies of models showed that energy efficiency of steam turbine plants of triple cycle strongly depend on low-boiling substance type in a lower cycle. Energy efficiency of steam and gas plants net 60% higher can be received for steam and gas plants on the basis of gas turbine plant NK-36ST on pentane and its condensation temperature below 0°C. It was stated that energy efficiency of steam and gas plants net linearly depends on condensation temperature of low-boiling substance type and temperature of gases leaving reco very boiler. Energy efficiency increases by 1% at 10% decrease of condensation temperature of pentane, and it increases by 0.88% at 15°C temperature decrease of gases leaving recovery boiler

Terms and Characteristics of Homogeneous Ignition of Coal-Water Particles Coated with a Water Film

The problem of coal-water fuel ignition of particles in a high-temperature heating has been solved numericallyin the framework of a two-layer model of "coal-water". The basic characteristics of the integrated ignition has been shown. The influence of the vaporization process of the water film on the ignition conditions has been shown

Alcohol consumption as a factor causing risks for population health (Russian research re-view)

Our review comprises medical and sociological research conducted over the last 20 years and dedicated to examining reasons and consequences of alcohol consumption in the Russian Federation. We detected that this research covered a wide range of issues starting from analyzing social contexts of alcohol consumption, microsocial, psychological, and biological factors causing alcohol-associated behavior in specific population groups, and then moving on to examining prevalence and gravity of medical and economic consequences which alcohol consumption usually leads to. We dwell on research results which explain reasons for alcohol consumption in various social and age population groups. We also describe different approaches to risk assessment procedure, assessment techniques and criteria applied for characterizing risks. We give concrete data on this bad habit prevalence in a number of the RF regions as well as data on medical-demographic losses caused by alcohol consumption. It is shown that the issue is recognized at the federal level and a number of political and administrative steps are taken to minimize it. We stress the necessity of closer cooperation between experts, authorities, and population in the process of solving tasks aimed at making our society healthier. We also reveal that risk-communication as a dialogue model is replaced with an information model; and the absence of "feedback" from risk recipients doesn't allow to adequately adjust information flows or to assess their efficiency. In our opinion, the most important task is to build up relevant risk-communications in the society as they will provide searching for most efficient dialogue techniques in the risk-communication system on alcohol addiction reasons and consequences. New risk-communication technologies should make for better risk awareness among population, above all among young people, as well as for creation of persistent attitude towards giving up alcohol as self-preserving behavior

Thermal conditions for stopping pyrolysis of forest combustible material and applications to firefighting

Five models describing heat transfer during evaporation of the water sprayed over the forest to stop fires and to cool down the pyrolysis of the bio- top layer are established and investigated by a parametric approach. It aims to improve the understanding of the behavior and the properties of the forest combustible material (FCM). A mathematical description of FCM surfaces (needles of pine and fir-tree, leaves of birch) is established. The characteristic time td to cool down the FCM layer below the temperature of the onset of the pyrolysis is the important parameter investigated in the present work. The effective conditions were determined allowing to reach the shortest td time and the lowest consumption of e.g. water to be dropped.SCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe