Home – Home – Jornals – Contemporary Problems of Ecology 2016 number 4

This paper presents the results of structuring surface temperatures in the Northern hemisphere for the period of modern climate changes. Main idea of the proposed classification is the geographic conditionality of the phase modulation of the temperature signal. The criterion is the consistency, namely, phasing of the temperature oscillations in certain geographic areas. We believe that changes in the synchronization modes of climatic processes during changing climate lead to transformations of the spatial structure of the temperature field because of transition of the system to the new state. The temperature series are represented as phase-modulated oscillations. External and internal disturbances, having influenced on the climate system, form a complicated modulation of the phase, and it is partly corresponded to these ones. Initial temperature space of 818 series is structured into 17 regional clusters, where the temperature changes occur synchronously. Properties of the resulting clusters and their compliance with the known climatic classifications are discussed. The classifying algorithm affords ground for the researchers to choose the degree of differentiation of the investigated field depending on the task. The phase modulation indices were evaluated, to identify manifestations of the external forcing in the surface temperature. Inconsistency of the indices to those in the case of the harmonic phase modulation allows quantifying the role of the regional climate-factors for each class. Modulation, which is the closest to the harmonic one, was found in the area of the North Atlantic thermohaline conveyor. During the study of the climate change, the proposed approach can be used as an analytical framework on any spatial scale, only by data on the surface temperature, and with predetermined level of detalisation. Searching synchronization in nonlinear chaotic systems may become one of the perspective ways to optimize the predictive models.

This paper presents the analysis results of the space-time structure of temperature and precipitation extreme indices. Four indicators were chosen to represent temperature indices, and four indicators, to study precipitation indices. For calculating the indices we used daily data for 75 meteorological stations in Western Siberia for the period 1961-2013. The period under study was divided into two intervals: 1961-1990 and 1991-2013 for assessing the trends. The results show the statistically significant decrease in the frequency of cold days and nights for the period 1991-2013 as compared to the period 1961-1990 at some stations. Conversely, we found a slight increase of warm extreme temperatures. The tendencies of extreme precipitation indices indicate a high irregular distribution in Western Siberia. Results show negative trends for all extreme indices of precipitation only in the northern part of the territory considered. The study shows here a decrease in the number of days with precipitation of different intensity by 1-2 days. The south territory is characterized by a growth of precipitation indices by 1-2 days. The results show that precipitation extreme indices mainly insignificantly change in the average from period to period. This may be due, in part, to a sparse observational network, especially north of 60 degrees latitude, which confirms the need to optimize it. Most optimally this problem can be solved through the use of autonomous automatic measuring systems. Using the principal component analysis, we found that the temperature indices have a relatively high synchronicity in changes on the studied territory. This fact may be due to the contribution of large-scale processes. On the other hand, the analysis of the extreme precipitation shows inconsistency in its changes within the territory. This may confirm that local factors over different parts of the selected area impact significantly the formation of precipitation.

In this study, the research of spatiotemporal changes of meridional circulation cells over the Siberian sector in the Northern hemisphere was carried out using reanalysis data over two time intervals: the period of intensive global warming 1976-1998 and the period of its slowdown 1999-2014. It was revealed that the most significant changes are observed in winter season in the beginning of XXI century: almost complete disappearance of the polar cell and intensification of Hadley and Ferrell cells was revealed. Tendencies in the changes of advective and eddy meridional heat fluxes and their relationship with stream function were also obtained and analyzed. Thus, there is the intensification of eddy circulation and the increase of the number of its centers in all months over the period of global warming weakening. It leads to meridional circulation development, strengthening of blocking processes, and, therefore, to the decrease of meridional heat fluxes in the Siberian sector in the beginning of XXI century.

Variations in the potential gradient of the electric field in the surface air layer during the passage of cumulonimbus clouds (Cumulonimbus, Cb) are investigated. More than 450 cases with Cb were reviewed. The method of selection of the structural elements, according to the potential gradient variations caused by the passage of Cb, was suggested. The formalization of the selected variations was carried out and the main types of the electric field potential gradient changes were identified. The parameters characterizing the potential gradient variation and its structural elements were defined for each type of the potential gradient variations. Interrelations between the features of the potential gradient variation types and characteristics of different origin Cb at different development stages were described.

The paper presents the principles of measuring the precipitation characteristics imaging and analyzing precipitation particle shadows. The method of precipitation type determination is described. It is based on microstructure characteristics measurements using the optical precipitation gauge. The measurements of the size and velocity ratios for rain and snow precipitation particles are presented.

Earlier, a method of restoration of a profile of atmospheric turbulence has been proposed by the authors in two intersecting laser beams, creating laser guide stars. Results of further development of this method are given in the present article. In particular, for Kolmogorov turbulence, the integral equation with a sharp kernel like delta function, which allows restoring a high-altitude profile more simply and more exactly, than in the initial version of a method, is constructed. Data of numerical experiment shows a good restoration of a profile of real turbulence up to heights of 10 km.

The 12-year aerosol studies along the route of the Russian Antarctic Expeditions in the East Atlantic and the Southern Ocean are summarized. We analyzed the spatial distribution (with 5^o latitudinal step), seasonal (November/April) variations, and interrelations between aerosol optical and microphysical characteristics. It is shown that the latitudinally average variations in aerosol parameters in the East Atlantic exceed one order of magnitude. The lowest (maximal) values are observed near Antarctica (in tropical zone): aerosol optical depth (0.5 μm) varies from 0.02 to 0.5, number concentrations of small particles (d = 0.4-1 μm) vary in the range 0.8-19 cm^-3, concentrations of large (d > 1 μm) particles vary in the range 0.04-2.2 cm^-3, and aerosol and black carbon mass concentrations vary in ranges 0.5-14 μg/m³ and 0.026-0.7 μg/m³, respectively.

The paper presents the results of complex observations of the atmosphere boundary layer dynamics carried out at the site of IAO SB RAS in September 2013 with the use of remote sensing, aerosol and Doppler lidars. The structure of aerosol and wind fields in the period of internal waves buoyancy and the low-level jet streams in the boundary layer are examined.

The paper presents the results of investigation of temporary changes in the vertical structure of aerosol fields in the mountain valley of Lake Baikal, in the presence of sources of smoke, from both remote and local forest fires. Measurements were carried out using the LOSA-M2 lidar, located on the east coast of Lake Baikal, during the expeditions of 2013 and 2015, when extremely high values of aerosol content in the troposphere caused by forest fires were observed. There is a significant difference between the space-time structures of the smoke aerosol from local forest fires in the basin of the lake, from the case when the impurity sources are located at a considerable distance.

Results of experimental investigations of the atmospheric internal waves (AIW) in the boundary layer of atmosphere on the base of wind velocity measurements by a Stream Line pulsed coherent Doppler wind lidar developed by Halo Photonics are presented in this paper. The measurements were carried out in 2015 on the east and on the west shores of Lake Baikal. A total of 7 cases of AIW events have been revealed. On the western shore of Lake Baikal it is always happening in presence of one or two (in 5 of 6 cases) narrow jet flows at heights of approximately 200 and 700 m. The period of the wave component oscillation of the wind velocity vector was 9 min in four cases of the AIW, in two cases it was equal to approximately 18 and 20 minutes, and 6.5 min in one case. The amplitude of oscillations of the horizontal wind velocity components was about 1 m/s, and the amplitude of the vertical wind component oscillations was three times less. In most cases, internal waves were observed for 45 min (5 trains with a period of 9 min). Only once the duration of the existence of AIW was about 4 hours.

The technique for retrieval of lidar profiles of vertical ozone distribution accounting for temperature and aerosol corrections is described. The range of lidar signal detection is from 5 to 18 km. The vertical ozone profiles measured over Tomsk with a differential absorption lidar of the Siberian Lidar Station in 2015 are compared with the profiles retrieved from ESA MetOp satellite data.

The paper discusses results of the analysis of vertical profiles of the normalized structure characteristic of air temperature C_T² in the atmospheric boundary layer under conditions of daytime convection. The experimental data have been obtained with Volna-4M acoustic Doppler radar (sodar) (Akademgorodok, Tomsk, Russia). The profiles were auto-normalized to the value of C_T² at the height H = 100 m. The results obtained in daytime (11:00-16:00 Local Time) in the warm period (July-August) of 2015 have been analyzed. The shape of the sodar vertical profiles of C_T² has been compared with results by other authors. The presence of a break in the C_T² profile at heights of 60-80 m can be noticed.

The physical basis for generation of magnitomultipol (MM) radiation in the region of 250-900 nm is suggested, as well as the mechanism of two-dimensional inverse relationship between the energies of Shtar effect at the low-frequency electric dipole and Zeeman effect on high-frequency magnetic multi-pole vibration-rotation transitions, combined with lower status in the V-scheme. The mechanism sets the rate of self-molecules in the “electron-ion” ensemble at MM, prepared in a weak magnetic multipole transition. Ensemble in the form of many cylindrical “solenoid-resonator” generates radiation in the MM-accumulation time on the threshold of the diamagnetic power between states of the prepared transition.

This paper is an introduction to the Special Issue of the Journal. Here, a brief historical delineation of the problem of studying interfaces between adjacent ecosystems (ecotones) was done. The high biodiversity of ecotones and their vulnerability to natural and anthropogenic impacts, including invasions of alien species, were noted. It was supposed that there was no contradiction between the ecotone and river continuum concepts. The important ecological role of amphibiotic animals and plants in interactions and functioning of the adjacent ecosystems was emphasized. The problem of studying the quantitative parameters of fluxes of matter and energy between ecosystems in conjunction with their qualitative parameters (the elemental and biochemical composition) was mentioned.

Routs of aquatic allochthonous inputs (aquatic subsidies) to detrital food webs were studied, as well as the aquatic subsidies influence on the formation of the functional and taxonomic structure of soil invertebrate communities in coastal ecosystems. The study took place in the coastal zone of an oxbow lake of the Pra river in the Oksky Reserve. The obtained results indicated the strong dependence of soil animals in the coastal habitats on aquatic subsidies. The isotopic analysis showed that aquatic resources enter soil food webs not only via predators feeding on flying insects or aquatic prey, but also via saprophages decomposing organic debris of aquatic origin. The contribution of water subsidies to the energy balance of soil invertebrates decreased rapidly with the increasing distance from the lake. The fraction of ‘water carbon’ in the tissues of collembolans and saprophages was already negligible at a few meters from the water edge. The dependence of predatory invertebrates on the water resources could be traced at somewhat greater distance (tens of meters).

The substance flow across the water-air boundary on the floodplain lake Kholodnoye (Saratov Oblast) is generally formed by the Culicomorpha (76.1 %) and accounts for 0.35 g/m² of the lake area per year. The energy flow amounts to 1.87 kcal/m², and its most part accounts for the second half of summer and autumn. Annual removal of biogenic elements: 0.18 g/m² for carbon, 0.04 g/m² for nitrogen, 0.004 g/m² for phosphorus. The greatest contribution to flows of substance and energy is brought by large species of midges, as well as phantom midges and medium-sized midges which produce several generations within a year and reach high abundance at a larval stage. Other floodplain lakes of the Volga river with similar biotopical features and species composition of amphibiotic insects are characterized by a quantitatively similar level of exchange processes with adjacent land ecosystems across the water-air boundary.

In this article, the emergence of insects from a floodplain lake of the small Usman river in the Usman forest (Voronezh Oblast) was analyzed. The abundance and frequency of occurrence of 103 species from 7 orders were estimated. Widespread and dominant species and groups ( Chaoborus flavicans (Mg.) (Diрtera), Cloeon inscriрtum (Bgtss.), C. diрterum (L.) (Ephemeroptera) and Scirtes hemisphaericus (L.) (Coleoptera)) were defined. For the vegetative period, the abundance of emerging insects accounted for 1795.5 ± 174.0 ind/m² of the water surface; their biomass amounted to 6756 ± 607.5 mg/m². The extent of the removal of biomass was measured in weight and energy units. Also, the removal of carbon, nitrogen, phosphorus, and essential fatty acids through the emergence of insects to floodplain terrestrial ecosystems was estimated.

Two methods of estimation of the emergence and transfer of biomass of blood-sucking mosquitoes (Diрtera, Culicidae) were compared. It was found that the phenological and quantitative data obtained by the hydrobiological method (using an aquatic net and a dipper) and by using cone-shaped traps were different. Nevertheless, the general characteristics of the studied processes were similar. The results of the hydrobiological method showed that the total value of the annual transfer of biomass by Culicidae accounted for 3.157 g wet weight/m² per year. According to the data obtained by using cone-shaped traps, the total value amounted to 3.457 g wet weight/m² per year.

The taxonomic composition, seasonal dynamics, and emergence intensity of Chironomidae adults that emerged from mountain oligotrophic lake Oiskoe (the Western Sayan, Southern Siberia) were established. The value of annual emergence of chironomid adults averaged 0.42 g wet weight m² in the lake area and approached the value of potential emergence which was calculated based on the estimation of zoobenthos secondary production. For the first time, fatty acid composition and the contents of essential omega-3 polyunsaturated fatty acids (PUFA) were compared between the larvae and adult stages of chironomids. The PUFA content per wet weight unit in adults was more than 7-fold higher as compared to that in larvae. The PUFA flux per lake area unit resulting from the chironomid emergence accounted for 1.752 mg/m x y, that is more than 10 times lower than the global estimation of axport through the amphibiotic insect emergence. Calculations showed that the PUFA flux brought with the chironomid emergence per land unit of the studied mountain territory was very low as compared to that for other landscapes. However, the calculated flux per land unit within the first 15 m of the shoreline was much higher and similar to that in productive landscapes.

Due to long-term monitoring of the abundance and spatial distribution of 18 widespread species of Odonаta, we estimated their contribution to the export of aquatic resources to the Barabinsk forest-steppe ecosystem. Annual emergence of Odonаta varied from 0.8 to 4.9 g/m² of the land area and from 2.3 to 13.3 g/m² of the water area, which is 4-5 times more as compared to that of Diрtera. The general flux of organic matter from water to terrestrial ecosystems remains relatively stable (6-fold interannual variability) irrespective of large interannual variations in the abundance of separate species (e. g., 42-fold interannual variability of Libellula quadrimaculata ). The metal content in 9 Odonаta species was defined. The export of metals provided by odonates decreases in the row K > Na > Mg > Ca > Fe > Zn > Cu > Mn > Pb > Ni > > Cr > Cd. Thus, odonates appeared to be quantitatively and qualitatively important providers of aquatic resources to the forest-steppe landscape of Western Siberia.

The qualitative composition and quantitative characteristics of the syrton allochthonous fraction in one of the rivers of the Russian Far East were examined. It was assumed that the revealed daily dynamics of the terrestrial invertebrates drift was determined by the specifics of their daily migrations on land. A counterargument to the theory of the zoobenthos night drift strategy as a way to avoid drift-feeding predators was suggested.

Beavers act as important agents which regulate the transfer of matter and energy from land to water and vice versa. Nevertheless, despite many examples of regulation of energy and matter flows by beavers, we cannot extrapolate the obtained results and get an overall picture of the beavers’ role as regulators of ecosystem processes. This can be explained by the strong contextual dependency of the results of beavers’ habitat-forming activity and by changes in the animals’ behavior after re-populating the habitat area. The peculiarities of the beavers’ influence on the habitat were analyzed on the example of small rivers which were recently populated by beavers and small rivers where beavers had already been living for 60-80 years.

Microcosm experiments showed that beavers’ vital activity products (BVAP) promoted the increase of nitrogen (N) and phosphorus (P) concentration, the decrease of the N / P ratio in water, the increase of the number and biomass of bacterial plankton. In these conditions, the number and biomass of small-sized Ceriodaphnia dubia Richard and large-sized Daphnia (Ctenodaphnia) magna Straus, which lived separately in microcosms, raised. The cohabitation of these cladocerans in microcosms under the BVAP influence resulted in a more intensive increase in the number and biomass of Daphnia magnа . The similar cohabitation without the BVAP influence led to the predominance of Ceriodaphnia dubia . Bioassay showed that the fertility of Ceriodaphnia dubia decreased in the water which was heavily populated with Daphnia mаgnа under the BVAP influence. It was suggested that the vital activity products of large-sized Daphnia species inhibit the fertility of small-sized Cladocera species. This fact, along with the high competitiveness of large cladoceran species under conditions of a high level of nutrition, determined the forming of the zooplankton communities in beaver ponds, which were characterized by the high number and biomass and the low uniformity.

Fatty acid (FA) contents and compositions in pectoral muscles of 18 species of birds from Novosibirsk, Volgograd, and Yaroslavl oblasts were studied. Three groups of birds that had significantly different FA compositions were distinguished based on multivariate statistical analysis: Passeriformes, Columbiformes, and a group of waterfowl and waterbird species (Charadriiformes, Anseriformes, Podicipediformes, and Ciconiiformes). The highest content of physiologically important docosahexaenoic fatty acid (22:6 n- 3, DHA), which is considered as a marker of aquatic food, was surprisingly found in the biomass of Passeriformes which are terrestrial feeders, rather than in the biomass of waterfowls and waterbirds. It was suggested that Passeriformes species have an ability to synthesize large quantities of DHA from short-chain -3 fatty acids, which is rare among animals.

Fully developed turbulent pipe flows of power-law fluids are studied by means of direct numerical simulation. Two series of calculations at generalised Reynolds numbers of approximately 10000 and 20000 were carried out. Five different power law indexes n from 0.4 to 1 were considered. The distributions of components of Reynolds stress tensor, averaged viscosity, viscosity fluctuations, and measures of turbulent anisotropy are presented. The friction coefficient predicted by the simulations is in a good agreement with the correlation obtained from experiment. Flows of power-law fluids exhibit stronger anisotropy of the Reynolds stress tensor compared with the flow of Newtonian fluid. The turbulence anisotropy becomes more significant with the decreasing flow index n. An increase in apparent viscosity away from the wall leads to the damping of the wall-normal velocity pulsations. The suppression of the turbulent energy redistribution between the Reynolds stress tensor components observed in the simulations leads to a strong domination of the axial velocity pulsations. The damping of wall-normal velocity pulsations leads to a reduction of the fluctuating transport of momentum from the core toward the wall, which explains the effect of drag reduction.

The algorithm for calculation of dynamic compliance of multilayer coatings was developed. The compliance modulus and phase lag of coating surface motion vs. the current pressure depend on viscoelastic properties of materials, ratio of wavelength to layer thickness l/H, and ratio of wave velocity to propagation velocity of shear vibrations in the base layer V/C_t,2⁰ Dynamic compliance of the two-layer coating consisting of a thick base layer and thin durable outer layer was calculated. The elasticity modulus of the outer layer ranged up to eight values of elastic modulus of the inner layer; the density of the outer layer either remained equal to the density of the inner layer or increased proportionally to the elastic modulus. Depending on  V/C_t,2⁰ two scenarios of compliant coating interaction with the turbulent flow were distinguished: resonant and broadband ones. It is shown that the vibration properties of two-layer coatings can be significantly better than the properties of the monolayer coatings. This makes it possible either to increase the coating strength or to work efficiently at lower velocities.

This paper describes a numerical solution of the bow shock shape ahead of some blunt and sharp axisymmetric noses containing sphere, blunt cone, and sharp cone at steady transonic flow in the Mach number range of 1.01 to 1.2. For validating the results, one sphere and three blunt cones are modeled, and their shock standoff distance is compared with other experimental and numerical studies. The flow over other noses with similar geometric parameters is then solved and compared with each other. In this study, the Reynolds-averaged Navier–Stokes equations are solved using the Spalart–Allmaras turbulence model. The purpose of this study is to determine the shock standoff distance for some blunt and sharp noses at low supersonic free flight speed. The shock standoff distance is determined from the Mach number curve on the symmetry line. The present numerical simulations reach down to M_∞=1.01 a range where it is almost very difficult to set in xperimental
studies. The shock wave locations were found to agree well with previous numerical and experimental studies. Our results are closer to the experimental results compared to other numerical studies. In addition, the results for shock standoff distances over paraboloids in these speed ranges have not been previously published as far as we know.

Intensification of mixing between the gaseous working body ejected through a jet nozzle with ambient medium is an important scientific and technical problem. Effective mixing can increase the total efficiency of power and propulsion apparatuses. The promising approach, although poorly studied, is generation of acoustic self-oscillation inside the jet nozzle: this impact might enhance the decay of a supersonic jet and improve the mixing parameters. The paper presents peculiar properties of acoustic self-excitation in jet nozzle. The paper presents results of experimental study performed for a model injector with a set of plates placed into the flow channel, enabling the excitation of acoustic self-oscillations. The study reveals the regularity of under-expanded supersonic jet decay in submerged space for different flow modes. Experimental data support the efficiency of using the jet nozzle with acoustic self-oscillation in application to the systems of gas fuel supply. Experimental results can be used for designing new power apparatuses for aviation and space industry and for process plants.

The influence of co/counter dual-twisted tapes (CoT/CT) on heat transfer rate in a circular tube has been investigated experimentally. In the experiment, the dual-twisted tapes are placed at the entry of the test tube in two arrangements: (1) each of dual twisted tape was twisted in the same direction that can produce co-swirl flow at the entry and (2) each of dual twisted tape was twisted in the opposite direction that can produce counter-swirl flow. Dual tapes were twisted in three different twist ratios (y/w = 3, 4, and 5) for generating different swirl intensities at the entry of the test section while the single twisted tape (ST) was also the test for comparison. The aim at using the dual twisted tapes is to create co/counter-rotating swirl flows having a significant influence on the flow turbulence intensity at the entry section leading to higher heat transfer enhancement. Average Nusselt numbers of CoT/CT are determined and also compared with those obtained from other similar cases, i.e., ST. The experimental results on the heat transfer rates indicated that the tubes with the dual twisted tapes (CoT/CT) are higher than those with the single tape at the entry section (x/D = 0 to 10). The heat transfer rates at longer distance became lower due to high interaction of each swirl. In addition, the mean Nusselt number and friction factor for the swirl generator created by the CT is nearly similar to CoT results.

The solution was obtained for a problem of gas hydrate growth in water with dissolved gas. The rate of hydrate formation depends on gas diffusion to the contact with gas hydrate. Three versions of problem configuration were considered: planar, radial, and spherical symmetry. For these cases, the values of the self-similarity coordinate were obtained: this parameter controls the growth of gas hydrate in water with gas dissolved and the level of top temperature in the hydrate zone. Analysis was performed for temperature fields related to heat release during hydrate formation.

Methods for calculating the geometric characteristics of the vapor phase in explosive wall boiling-up processes on a metal wall are analyzed. A monotonic growth of superheat in the liquid above the equilibrium evaporation temperature is specified. We show that the choice of the model for bubble interaction has a profound influence on the geometric characteristics which define the value of the heat flux. Computer simulation was employed to obtain the dependence of dry area on time in two interaction models. We have found that, for a model with instantaneous bubble coalescence, the dry area can be evaluated by the Kolmogorov formula using a correction factor for the most probable triple interaction. An approximation of the distribution length of wetting line over the lifetime of wetting-line segments is obtained. The possibility of using the obtained data for calculation of rapid condensation is analyzed.

Numerical simulation of transient melting regimes inside an enclosure in the presence of a local heat source has been carried out. Mathematical model formulated in terms of dimensionless variables such as stream function, vorticity, and temperature has been numerically solved by finite difference method. Effects of the Rayleigh number 4∙10⁵ ≤ Ra ≤ 5∙10⁷, Stefan number 2.21 ≤ Ste ≤ 5.53, and dimensionless time on velocity and temperature fields as well as on the local Nusselt number along the heat source surface have been analyzed in detail. The transient effects of the considered process at high values of the Rayleigh number have been identified.

In this study, the rate of conduction-radiation heat transfer between two thick concen-tric spheres is analytically investigated because of the ever-increasing importance of radiation shield applications. The heat transfer rate, the percentage of reduction in heat transfer, temperature and emissivity of surfaces are calculated when one and two thick radiation shields are placed between two thick spheres. The calculations show that the use of a radiation shield with a lower emissivity is better than two radiation shields with a higher emissivity to reduce the heat transfer rate. In addition, optimal combinations of radiation shields with different materials are proposed.

The oxidation of zirconium by supercritical CO₂ (20.2 and 14.1 MPa, and 823 K) results in the formation of a layer of the monoclinic ZrO₂ and amorphous carbon. In the constant electric field (E = 293 kV/m) when a sample of irconium is the anode, the formation of amorphous carbon leads to a growth of leakage current and a twelve-fold increase in the rate of zirconium oxidation.

The efficiency of thermoelectric conversion of heat from gas combustion was evaluated in a small-scale system consisting of two channels with opposing gas flows and thermocouples located in the separating wall. Combustion occurred in the chamber fed with fresh mixture heated by combustion products through heat-conducting walls of the channel. In the channel walls, there were thermoelectric converters. It has been shown that in this system, the maximum conversion efficiency of heat from gas combustion may be close to the maximum efficiency of thermoelectric conversion calculated by the maximum acceptable working temperature of the hot side of the converter. This conclusion is valid in the case when the adiabatic combustion temperature of the gas mixture is below the maximum allowable operating temperature of the hot side of the thermoelectric converter. The considered system is promising for the burning of low-calorific gas mixtures and does not require additional energy for cooling the cold side of the thermoelectric con-verter.

The effect of two-parameter k-ε and k-ω SST turbulence models and Reynolds stress model RSM on the description of processes at pulverized coal combustion in a fur-nace with a swirl burner is calculated in the present work. The mathematical model, which included the description of carrier phase motion based on the RANS approach, calculation of radiation transport through the P1 method, motion of particles based on the Lagrangian approach, combustion in the gas phase based on the hybrid model, and coal particle burning in the diffusion-kinetic approximation, was chosen for calculations. The calculated data were compared with experimental results on combustion of pulverized coal flame in the presence of flow swirl at the fire test bench with capacity of 2.4 MW. Comparative analysis showed that k-ε and k-ω SST turbulence models and Reynolds stress model have a little effect on distribution of axial and tangential velocities, temperature, and concentration of gases in the fur-nace.

The problem of heat and mass transfer has been solved numerically under the conditions of coal-water fuel particle ignition. The concurrent processes of evaporation, filtration of steam, thermal decomposition of the organic part of coal, thermal and chemical interaction of steam and coke carbon, and oxidation of products of their reaction and volatiles by the external oxidizer have been taken into account. The scales of influence of individual thermophysical and thermochemical properties of coals on the characteristics and conditions of ignition of coal-water slurry have been determined. 

Thermodynamic calculations of the plasma gasification process of carbonaceous wastes in air and steam ambient were carried out. A maximum yield of synthesis gas in such processes is predicted to be achieved at a temperature of 1600 K. On a specially developed plasma facility, plasma gasification experiments were performed for carbonaceous wastes. From the organic mass of carbonaceous waste and from its mineral mass, respectively, a high-calorific syngas and a neutral slag consisting predominantly of ferric carbide, calcium monosilicate, silica and iron, were obtained. A comparison between the experiment and the calculations has shown a good consistency between the data.

The aerodynamic structure of flow in a lab model of a perspective design of vortex furnace was studied. The chamber has a horizontal rotation axis, tangential inlet for fuel-air jets and vertical orientation of secondary injection nozzles. The Stereo PIV method was used for visualization of 3D velocity field for selected cross sections of the vortex combustion chamber. The experimental data along with “total pressure minimum” criterion were used for reconstruction of the vortex core of the flow. Results fit the available data from LDA and simulation.

Thermocapillary breakdown of a liquid film flowing due to gravity over a vertical plate with a heater of 150×150 mm is studied in a wide range of liquid properties (in particular, dynamic viscosity at the initial temperature varies from 0.91×10^-3 to 16.9×10^-3 Pa×s) and film Reynolds number (Re = 0.15-53.5). It is found that liquid viscosity has a significant effect on the threshold heat flux corresponding to film breakdown. To take into account the effect of liquid properties, the breakdown criterion traditionally used in literature was modified. This allowed successful generalization of all data obtained.