Study of the Temperature Fields in Oil and Gas Strata with Water Injection Based on the Perturbation Method

The problem of the thermal action on oil and gas strata by injection of a heating medium using expansion in a small parameter is reduced to an infinite sequence of boundaryvalue problems that are solved by the method of integral transforms. It is shown that, with an appropriate selection of the small parameter, the zerothorder approximation corresponds to a spaceaveraged (across the stratum thickness) solution of the main problem and leads to a concentratedcapacity scheme that is constructed assuming that the stratum temperature is independent of the vertical coordinate. The first approximation permitted marked refinement of calculations according to the concentratedcapacity scheme and an evaluation of its error. Spacetime temperature distributions are presented that have been calculated using the analytical solutions obtained.     

Mathematical Model of Vacuum‐Oscillating Drying of Lumber

A mathematical model of heat and mass transfer in vacuumoscillating drying of lumber in which the drying process is made up of alternating stages of warming up and vacuum treatment has been developed. At the stage of warming up, it has been proposed to use a superheated steam to intensify heat and masstransfer processes and to relax stresses occurring at the stage of vacuum treatment.     

Heat Exchange with Horizontal Cylinders in a Centrifugal‐Bubbling Bed

The authors present results of an analysis of experimental data on heat exchange on horizontal cylinders in rotating gasliquid flow. The hydrodynamic parameters of a thin film in a centrifugalbubbling bed have been determined based on the mathematical modeling of a film flow in the case of a highvelocity gasliquid flow about it. Results of a generalization of the data on heat exchange are given, and the hydrodynamic stability criteria for the film flow on the cylinder surface are evaluated.     

Modern Problems of Intensification of Heat Exchange in Channels

The current achievements in the field of intensification of heat exchange in tube heatexchange apparatus are considered. Requirements for highefficiency heattransfer surfaces have been formulated. Problems of intensification of heat exchange in bundles of finned tubes and in heatexchange apparatus under conditions of condensation and boiling of heattransfer agents and under scaling conditions have been investigated. Highefficiency designs of heatexchange apparatus are presented.     

A Model of Prediction of Forest‐Fire Hazard

A rather simple and physically substantiated deterministicprobabilistic expert system of prediction of forestfire hazard, which can be used in practice, is suggested. Results of the calculation by the verified model of drying of forest combustibles, which allows for partial pressure of water vapor, are compared with results obtained by different models and experimental data.     

Numerical Calculation of the Flow Regimes of a Fluid Partially Filling a Horizontal Rotating Heat‐Exchange Cylinder

Consideration is given to a numerical determination of a twodimensional unsteady viscous flow with the free surface in a stationarily rotating horizontal cylinder in which heatexchange processes are carried out. The markerandcell method in a polar coordinate system is used. The features of modeling of the walllayer regime and the circulating flow regime that occur in rapid and slow rotation of the cylinder, respectively, are discussed. Based on the given results of numerical calculations, the influence of the Reynolds number on the character of flow is analyzed.     

Investigation of the Process of Hardening of Diglycidyl Ether Bisphenol a by Phosphate Binders

The interaction between diglycidyl ether bisphenol A and conventional and waterdeficient phosphate binders has been investigated. The data of chemical analysis, IR spectroscopy, and differentialthermal analysis point to the formation of a spatially crosslinked epoxy polymer under the influence of the phosphate binders. It has been shown that conventional binders can be used as hightemperature hardeners of epoxy oligomers. When waterdeficient binders are used, the formation of a threedimensional polymer structure is observed at room temperature.     

Investigation of Parameters of the Ion Beam Formed in Crossed Electric and Magnetic Fields

The results of experimental investigations of the characteristics of the positive ion beam formed in an ionplasma system with discharge generation in crossed electric and magnetic fields are presented. The conditions for the discharge formation and the specific features of the developed configuration of the discharge unit are described. It is shown that such discharge systems are capable of forming broad lowenergy ion beams and can be used successfully in various fields of thinfilm technology.     

Study of Bulk and Nanoscale Materials by Tight‐Binding and Path Probability Methods

The generalized tightbinding molecular dynamics (TBMD) method is used to study the atomistic and mechanical properties of the nanoscale materials and the calculated properties are compared with those of the corresponding bulk materials. We report that the thermodynamic and mechanical properties of the nanoscale materials are quite different from those of the corresponding bulk materials. For instance, it has been found that the excess energies of dislocations in the small crystallites are very small and often take negative values due to the atomistic image effects. The edge dislocation in the carbon nanotubes, whose core is characterized by a pentagonheptagon pair is found to act as a center of the stress concentration and contribute to the peculiar nanoplasticity in the quasionedimensional (1D) cylindrical structures. Using the path probability method (PPM) in the statistical physics, we also study the growth and microstructure of strained SiGe deposited films on Si(001) substrate, taking into account the composition gradient and influence of the strain filed at the heterojunction.     

Heat and Mass Transfer in a Two‐Component Developed Turbulent Gas‐Vapor‐Droplet Flow

A calculation model is developed and a numerical study is made of the heat and mass transfer characteristics in a turbulent gas–vapor–droplet flow moving in a round tube. The model takes into account the evaporation of droplets, the diffusion of vapor into air, and the acceleration of a carrier flow. Distributions of the parameters of the twophase flow are obtained with respect to the tube radius for different initial concentrations of the gas phase. Heat and masstransfer calculations are compared to the experimental and numerical works. On the whole, the evaporation of the droplets in the vaporgas flow leads to the intensification of heat transfer as compared to a onecomponent vapordroplet flow and singlephase flow of vapor.     

Method of Protection and Diagnostics of the Combustion Chamber Wall on Exposure to a High‐Intensity Heat Flux

In the present work, consideration is given to the method of thermal protection of the walls of highpower installations (plasmatrons and gasphase nuclear reactors), made of porous refractory materials, with the use of gasdust protection. The algorithm for determining the mechanical, thermal, and thermophysical characteristics of the porous wall of a combustion chamber from the measured increase in the pressure on the exterior surface of the wall is given.     

High‐Temperature Radiative‐Convective Heat Exchange on the Surface of Glass‐Reinforced Plastics

The results of experimental investigations of heat exchange on the surface of a thermalprotective material — glassreinforced plastic — in the flows of hightemperature gases have been presented. It has been established that the influence of injection on the value of the heat flux does not exceed 10% in the range of variation of gas temperatures 300–2000 K and Reynolds numbers 350–9800.     

Analytical Solution of the Nonhomogeneous Kinetic Equation in the Problem of Isothermal Slip of a Rarefied Gas Along a Solid Spherical Surface

An analytical method of solution of a halfspace boundaryvalue problem for the nonhomogeneous kinetic Boltzmann equation with a collision operator in the form of an ellipsoidalstatistic model in the problem of isothermal slip of a rarefiedgas flow along a solid spherical surface is presented. Within the framework of the considered model, a correction to the coefficient of isothermal slip that is due to the wall curvature is obtained. Comparison with literature data is made.     

Role of the Structural‐Rheological State of Poly(Meth)Acrylate Solutions in Their Soaking into Capillary‐Porous Bodies

We have investigated the influence of the structuralrheological state of solutions of poly(meth)acryl copolymers on the rate of their capillary rise and the uniformity of the polymer distribution in the bulk of porous bodies — models of monuments of art made of ceramics, terracotta, loessial and lime plaster, and concrete. It has been found that in the region of concentrations corresponding to the transition of poly(meth)acrylate solutions from the viscousNewtonian to the structuralviscous rheological state there is a sharp decrease in the rate of capillary rise of solutions into clay, chalk, and cementsand specimens. A worsening of the uniformity of the polymer distribution over the height of the porous specimens, a decrease in their surface wetting with copolymer solutions, and a decrease in the value of the polymer adsorption on the filler surface are also observed.     

Analysis of Crystallization of a Supercooled Melt by the Integral‐Balance Method

Using the integralbalance method, the Stefan problem is solved for simply shaped crystals (a prism, a cylinder, and a sphere) grown in a supercooled melt. It is shown that the rate of crystal growth increases with the surfacetovolume ratio (in passage from a prism to a cylinder and a sphere). For all the three shapes of crystals studied the dependence of the speed of motion of the crystallization front on the supercooling is nonlinear and is characterized by a progressive increase.     

Computational Modeling of the Optical Pumping of Solid‐State Lasers and the Heating of the Active Element with Allowance for Water Cooling

Twodimensional nonstationary models of optical pumping of a solidstate laser in the presence of a reflector and heating of a cylindrical or plane active element with water cooling have been described. The results of calculations of the spacetime dependence of the pumping rate and the temperature in the active element have been given for different versions of a neodymium laser with a crystalline active medium in laserdiode pumping.     

Calculation of a Temperature Error by the Conjugate Equation

A temperature error depending on the error of initial information can be calculated by the conjugate problem. On estimation of the error at one time and coordinatelocal point the expenditures of the computation time and computer memory are double the expenditures for calculation of the heatconduction equation. The conjugatetemperature field obtained in this case allows calculation of the effect of the error of any parameter of the problem (initial conditions, boundary conditions, coefficients). In the linear case, the conjugatetemperature field depends on the position of the point under estimation; in the nonlinear case, it additionally depends on the temperature field. The approach considered can be applied to calculation of the error of a wide class of temperature functionals.     

Comparative Analysis of Simple Models of Drying of the Layer of Forest Combustibles, Including the Data of Experiments and Natural Observations

A comparative analysis of different simple models of drying of forest combustibles is considered. Results of the comparison of numerical calculations with experimental data and the data of natural observations are presented and discussed. A conclusion is drawn on the possibility of using simple mathematical models of drying the layer of forest combustibles in a new system of prediction of forestfire hazard.     

Energy‐Environmental Analysis of Combustion of Fuel Gases in Heating Furnaces of Metallurgical and Engineering Plants

Results of an energyenvironmental analysis of the expediency of purifying artificial fuel gases are given. Experimental investigations have been carried out in industrial furnaces of modern structure where various kinds of high and lowcalorific gaseous fuels are used.     

Influence of the Linearly Distributed Concentration of Carriers on the Operating Regimes of a Thermoelectric Arm

A numerical solution of the boundaryvalue problem on calculation of the temperature field in a onedimensional adiabatically insulated inhomogeneous thermoelectric arm has been obtained. The concentration gradient of nondegenerate carriers has been optimized, which enables one to substantially increase the thermo electric Qfactor of the arm. The calculations have been carried out for two operating regimes — the regime of maximum temperature difference and that of maximum refrigerating capacity. The possible limits of optimization of the concentration gradient of charge carriers have been established.