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Showing papers in "Journal of Engineering Physics in 2020"


Journal ArticleDOI
TL;DR: In this article, the dynamics of motion, interaction, and reflection of isolated temperature waves (solitons) in limited regions under the action of isolation temperature pulses of rectangular shape and the mechanism of refl ection of temperature solitons from the opposite boundary are investigated.
Abstract: Based on the new analytical solution of the problem of wave heat transfer, the dynamics of motion, interaction, and reflection of isolated temperature waves (solitons) in limited regions under the action of isolated temperature pulses of rectangular shape and the mechanism of refl ection of temperature solitons from the opposite boundary are investigated. In accord with this mechanism, fi rst the entire energy of a soliton is absorbed and then a reversetravelling temperature wave originates with the same space carrier as in the direct wave. During interaction of subsequent solitons with the refl ected ones, their energies are fi rst added up and then are separated into opposite directions (as a result of dissipation), preserving the kinematic characteristics. Since the time of action of isolated waves is proportional to several relaxation times and the depth of heating is equal to the limited number of nanometers, such investigations are of great interest also for the case in relativistic mechanics where high-power radiations interact with the surfaces of solid bodies.

24 citations


Journal ArticleDOI
TL;DR: In this article, a mathematical model of a shot from a smoothbore ballistic installation for a gun start of a group of supercavitating strikers has been developed, and a comprehensive parametric investigation has been conducted to determine conditions for loading the ballistic installation to achieve the required muzzle velocity.
Abstract: A mathematical model of a shot from a smoothbore ballistic installation for a gun start of a group of supercavitating strikers has been developed. To verify the mathematical model, experimental investigations into high-velocity launching of a group of bodies on a hydroballistic testing facility have been conducted. A comprehensive parametric investigation has been conducted to determine conditions for loading the ballistic installation to achieve the required muzzle velocity, ensuring a supercavitating regime of motion for a group of strikers in water.

11 citations


Journal ArticleDOI
TL;DR: An analytical representation of a turbulence spectrum in the inertial interval is given based on stochastic equations for the continual laws of continuous medium and the laws of the equivalence of measures between random and deterministic motions as mentioned in this paper.
Abstract: An analytical representation of a turbulence spectrum in the inertial interval is given based on stochastic equations for the continual laws of continuous medium and the laws of the equivalence of measures between random and deterministic motions in the theory of stochastic hydrodynamics. The analytical solution of these equations is presented in the form of spectral function E(k) ~ kn corresponding to the classical dependence E(k) ~ k–5/3 obtained earlier by A. N. Kolmogorov in the statistical theory on the basis of dimensional considerations. The presented solution confirms the possibility of determining partial solutions for the spectral function depending on the wave number on the base of single implications of the theory of stochastic hydrodynamics within the framework of which the solutions in the fi eld of wave numbers of turbulence generation were obtained.

11 citations


Journal ArticleDOI
TL;DR: Experimental studies of several types of nanomaterials (nanosilica, nanocarbon) and comparison of the results of their applications in cement concrete have been carried out as discussed by the authors.
Abstract: Experimental studies of several types of nanomaterials (nanosilica, nanocarbon) and comparison of the results of their applications in cement concrete have been carried out It has been established that the characteristics of cement concrete modified by these nanomaterials depend on the content of the latter in concrete The best results were obtained with an additive in which the said nanomaterials were used simultaneously

11 citations


Journal ArticleDOI
TL;DR: In this article, the effects of variable viscosity and thermal conductivity on an unsteady free convective MHD flow of a micropolar fluid past a vertical cone with variable heat flux, viscous dissipation, and Joule dissipation are carried out.
Abstract: A numerical investigation of the effects of variable viscosity and thermal conductivity on an unsteady free convective MHD flow of a micropolar fluid past a vertical cone with variable heat flux, viscous dissipation, and Joule dissipation is carried out. The fluid viscosity and thermal conductivity are modeled by inverse linear functions of temperature. The governing partial differential equations are reduced to nondimensional ones, which are discretized using an efficient and unconditionally stable implicit finite difference method of the Crank–Nicolson type and solved for prescribed boundary conditions by an iterative scheme based on the Gauss–Seidel method. Numerical results are presented for the velocity, temperature, and microrotation rate profiles. The values of the skin friction and Nusselt number for various combinations of parameters are given.

10 citations


Journal ArticleDOI
TL;DR: In this article, a non-stationary non-destructive rapid method of determining the thermal diffusivity of materials and finished articles has been suggested and tested experimentally without cutting out samples from them and preparation of the latter.
Abstract: A new nonstationary nondestructive rapid method of determining the thermal diffusivity of materials and finished articles has been suggested and tested experimentally without cutting out samples from them and preparation of the latter. The method is based on using an infrared imager to video record the infrared radiation of the surface originating as a result of its local stepwise heating by, say, a focused laser beam. Subsequent computer processing of the patterns of the nonstationary thermal field by the developed models and algorithms makes it possible to determine the thermal diffusivity of a material or an article in the case of one-sided access to them.

10 citations


Journal ArticleDOI
TL;DR: In this paper, similar solutions for the propagation of a spherical shock wave generated by a moving piston in a nonideal gas under the influence of a gravitational field and azimuthal magnetic field with monochromatic radiation are obtained.
Abstract: Similarity solutions for the propagation of a spherical shock wave generated by a moving piston in a nonideal gas under the influence of a gravitational field and azimuthal magnetic field with monochromatic radiation are obtained. The gravitational field is due to a central mass at the origin, i.e., the Roche model is valid. The gravitational effect of the gas itself is neglected in comparison with the attraction of the central mass at the origin. We considered that the radiation flux moves through an electrically conducting nonideal gas with constant intensity and energy is absorbed only behind the shock which moves in the direction opposite to the radiation flux. The results are discussed and compared with ones for a perfect gas, as well as for the cases of the influence of the gravitational field and of the absence of this field. The effect of the variations of the Alfven–Mach number, gravitational parameter, adiabatic exponent, and of the parameter of gas nonidealness are discussed in details.

7 citations


Journal ArticleDOI
TL;DR: In this article, the problem of the production of oil from a well, operating in the regimes of constant differential pressure or constant flow rate in an oil stratum, was solved by the use of theoretical models of filtration liquid flows in fractures of finite and infinite lengths.
Abstract: With the use of theoretical models of filtration liquid flows in fractures of finite and infinite lengths, formed in an oil stratum, the problem on the production of oil from a well, operating in the regimes of constant differential pressure or constant flow rate in this stratum, was solved. On the basis of approximate solution of the problem on the flow of oil from a stratum into a fracture formed in it by the method of successive changing stationary states, fairly simple analytical formulas have been obtained. A comparison of the results of numerical calculations of the practically important parameters of an oil stratum and a hydraulic fracture in it by the approximate formulas constructed and the corresponding exact formulas, which are much more complex than the approximate formulas, has shown that these results are almost identical. In particular, the errors in determining the evolution of the pressure field in a well and its flow rate by the approximate formulas did not exceed several percent. On the basis of numerical analysis of the approximate solutions obtained, the influence of the porosity and permeability of the stratum, the length of a fracture in it, and the rheological properties of the liquid saturating the stratum on the evolution of the pressure in the fracture, the flow rate of a well operating in the regime of constant differential pressure in the stratum, and the changes in the pressures in the fracture and in the well at a constant well flow rate was investigated.

7 citations


Journal ArticleDOI
TL;DR: In this article, an analysis of the dependences of the gas-flow velocity and of the local heat-transfer coefficient in such a system on time has been made, and the criterion of assessment of the efficiency of these systems, use was made of the level of turbulence of gas flow in them and the averaged coefficient of its heat transfer.
Abstract: Original methods for improving gas–air systems of turbocharged engines have been proposed. An analysis of the dependences of the gas-flow velocity and of the local heat-transfer coefficient in such a system on time has been made. As the criterion of assessment of the efficiency of these systems, use was made of the level of turbulence of gas flow in them and of the averaged coefficient of its heat transfer. Gasdynamic and heat-transfer characteristics of various modifications of the indicated systems have been considered.

6 citations


Journal ArticleDOI
TL;DR: In this article, a method is proposed for determining the order of separating a continuous mixture in such a cascade, minimizing the total heat losses in it, in the case where the temperatures in the dephlegmator and boiler of its columns are close to the boiling temperatures of the interfacial mixture fractions.
Abstract: The problem on estimation of the maximum production rate of a cascade of rectification columns, in which a continuous mixture is separated into fractions at their boiling points, and of the corresponding amount of heat expended in the rectification process is considered. A method is proposed for determining the order of separating a continuous mixture in such a cascade, minimizing the total heat losses in it, in the case where the temperatures in the dephlegmator and boiler of its columns are close to the boiling temperatures of the interfacial mixture fractions.

6 citations


Journal ArticleDOI
TL;DR: In this paper, a three-dimensional numerical model of nonstationary processes of transfer of momentum and heat on interaction of the building with the wind under the conditions of diurnal variations of the solar radiation intensity and air temperature is presented.
Abstract: The results of computational investigations of the aerodynamics of a building located in the urban area with a high density of buildings and of its heat exchange with the environment are presented. A three-dimensional numerical model of nonstationary processes of transfer of momentum and heat on interaction of the building with the wind under the conditions of diurnal variations of the solar radiation intensity and air temperature has been constructed. The model allows one to estimate the basic parameters of the heat exchange of the building with the environment under different seasonal conditions.

Journal ArticleDOI
TL;DR: In this paper, the authors presented results of experimental investigations into the process of collisions of water droplets in a gas medium with variation of the basic parameters in wide ranges corresponding to advanced gas-vapor-droplet technologies.
Abstract: The authors have presented results of experimental investigations into the process of collisions of water droplets in a gas medium with variation of the basic parameters in wide ranges corresponding to advanced gas-vapor-droplet technologies: sizes (radii) 0.1–1 mm, velocities of travel 0–10 m/s, angles of interaction (attack) 0–90o, relative volume concentration 0.1–10–3–8.5·10–3 m3 of water/m3 of the gas, velocity of motion of the flow 0–10 m/s, and temperature 20–1000oC; directions of flows: opposing, codirectional, and lateral. In processing the experimental results, the emphasis was on the influence of the relative volume concentrations of the droplets on the characteristics of their interaction. The relative probabilities of four typical regimes of interaction of the droplets have been calculated: recoil, coagulation, spread, and breakup (reduction in size). Parametric ranges have been shown for droplets for which the concentration growth of the latter in an aerosol leads to an increase in the probability of coagulation, recoil, and size reduction. Also, the authors have presented ranges of variation of the concentration of droplets in a gas medium, in which the probabilities of all the investigated interaction schemes are high. The experimental results have been processed with the existing approaches to generalization by calculating the angular factor of interaction and the Weber number.

Journal ArticleDOI
TL;DR: In this article, the influence of surface tension on two-phase drainage flows in a porous medium is investigated. André et al. made a study of the influence that surface tension has on the efficiency of displacement of the wetting fluid in the transition crossover zone.
Abstract: A study is made of the influence of surface tension on two-phase drainage flows in a porous medium Computational filtration experiments are conducted in a three-dimensional digital microtomographic model of sandstone To simulate two-phase flows, use is made of lattice Boltzmann equations; interfacial phenomena and wetting effects are described using the color-gradient-based method Calculations are carried out at the same rate of injection of a nonwetting fluid and at a ratio of the viscosities of nonwetting and wetting phases of 1:10 Results are obtained according to which growth in the interfacial tension contributes to the rise in the efficiency of displacement of the wetting fluid, which is recorded at the moment the injected phase breaks through, and to the decrease in the efficiency after its breakthrough It is established that distinctive features of flows with capillary fingering that arise at high surface tensions are the stepwise character of travel of the leading front and the growth of displacement channels in directions different from the hydrodynamic pressure difference It is shown that interfacial tension is a parameter whose variation enables us to change the type of two-phase flow Increase in the interfacial tension contributes to the transition of the flow with viscous fingering to a flow with capillary fingering The efficiency of displacement of the wetting fluid in the transition crossover zone is the lowest

Journal ArticleDOI
TL;DR: In this article, the aerodynamic characteristics of a rotating cylinder in the form of a truncated cone with a smooth surface and a rough surface have been investigated and the results have shown that the presence of the rough surface of the rotating cylinder leads to an increase of 25-30% in the lift conditions under which the Magnus effect contributes to the maximum increase in the maximum lift.
Abstract: Results of experimental investigations into the aerodynamic characteristics of a rotating cylinder in the form of a truncated cone with a smooth surface and a rough surface have been given It has been established that the variability of the cross section of the rotating cylinder in an air flow in the range of variation in the parameter of conicity 025–035 ensures a decrease in the drag coefficient with the values of the lift coefficient being preserved The results have shown that the presence of the rough surface of the rotating cylinder leads to an increase of 25–30% in the lift Conditions under which the Magnus effect contributes to the maximum increase in the lift and accordingly the increase in the efficiency of rotation of the cylinder in the form of a truncated cone have been determined experimentally

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the results of investigations of nucleate and fi lm regimes of boiling of nanofluids, and they showed that the increase in critical heat flux during the boiling of a nanoparticle layer on a heated surface contributes to the change in the microcharacteristics of the process of boiling and to the decrease in the wetting angle of the surface.
Abstract: The authors have analyzed the results of investigations of nucleate and fi lm regimes of boiling of nanofluids. In the nucleate regime of boiling of nanofluids, the increase in the critical heat flux compared to a pure fluid is observed; here, there can be both an increase and a decrease in the heat-transfer coefficient. The increase in the critical heat flux during the boiling of a nanofluid is linked to the formation of a deposited nanoparticle layer on a heated surface, which contributes to the change in the microcharacteristics of the process of boiling and to the decrease in the wetting angle of the surface. Results of theoretical investigation of the fi lm boiling of a nanofluid on a vertical heated surface have been presented. It has been shown that the greatest infl uence on the processes of heat and mass transfer in a vapor film is exerted by the superheating of the wall, the relation of the temperature and Brownian diffusions, and the concentration of nanoparticles in the fluid.

Journal ArticleDOI
TL;DR: In this article, the authors have modeled the one-stage synthesis of titania and silica composite nanoparticles in the working zone of a plasmachemical reactor by the chloride method based on separate oxidation of titanium and silicon tetrachlorides with pre-mixing of the reagents by bubbling.
Abstract: The authors have modeled the one-stage synthesis of titania and silica composite nanoparticles in the working zone of a plasmachemical reactor by the chloride method based on separate oxidation of titanium and silicon tetrachlorides with pre-mixing of the reagents by bubbling. Within the framework of the developed synthesis model, the authors have obtained data on the size of the nuclei of the composite particles, the shell thickness, and the ratio of the number of shell-coated and uncoated particles.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the overpressure and flame generated in the explosion of a gas in different regions of a room outside a vent in it using computational fluid dynamics, and they showed that the smaller the distance from the vent, the larger the oscillations of the indoor overpressure.
Abstract: The overpressure and flame generated in the explosion of a gas in different regions of a room outside a vent in it were investigated using computational fluid dynamics. The calculation data obtained were compared with the corresponding results of earlier large-scale experiments on this subject, and they show that the smaller the distance from the vent, the larger the oscillations of the indoor overpressure and that the outside region of the vent substantially influences the indoor explosion flow field. It was established that, as the outside-region length increases, the peak indoor overpressure approaches the experimental one, but the amplitude of the overpressure oscillations caused by the Helmholtz and Taylor effects increases substantially in this case. The numerical simulation of the explosion hazard of a ventilated gas in a room seems reasonable in the case where the outside region of a vent is not shorter than the room.

Journal ArticleDOI
TL;DR: The results of an experimental investigation into the parameters of combustion of peat and wood using thermography have been presented in this paper, where the mechanism of propagation of smoldering over the peat surface has been identified.
Abstract: The results of an experimental investigation into the parameters of combustion of peat and wood using thermography have been presented. The mechanism of propagation of smoldering over the peat surface has been identified. The temperature field on the surface of peat during its combustion under the influence of a local heat source has been obtained, and the velocity of propagation of the smoldering front has been estimated. Using the IR-diagnostics method, temperature distributions have been obtained over the surface of wood specimens exposed to heat action under conditions of a ground fire with and without fire-retardant treatment.

Journal ArticleDOI
TL;DR: In this article, a physical and mathematical model of the movement of a liquid droplet in a high-temperature air flow has been formulated with regard for the main factors of this movement.
Abstract: A physical and mathematical model of the movement of a liquid droplet in a high-temperature air flow has been formulated with regard for the main factors of this movement: the inertia of the droplet, its viscous friction, the surface tension of the liquid in it, the air drag, the gravity, lift, and Magnus forces acting on the droplet, its turbophoresis and thermophoresis, the convective heat flows inside the droplet, the turbulence and compressibility of the carrying medium, the concentration of the dispersed phase in it, the nonstationarity of the movement of the droplet, its phase transformations, the collisions of the droplet with the neighboring liquid droplets in the gas flow, the partial fragmentation of the droplet, and its breakdown. Numerical and experimental investigations of the influence of the indicated factors on the velocity of movement, the heating, and the intensity of evaporation of a liquid droplet in a high-temperature gas medium have been performed. The results of these investigations were generalized for determining the possible applications of the model developed.

Journal ArticleDOI
TL;DR: In this article, the authors considered the influence of the hydrodynamics and phase state of the flows in a double-flow heat exchange cell on the entropy production in it and obtained formulas for calculating the entropy in it as a function of the heattransfer coefficient, the heat load, the temperatures, and the water equivalents of flows in the cell.
Abstract: Consideration has been given to the influence of the hydrodynamics and phase state of the flows in a double-flow heat-exchange cell on the entropy production in it. For the case of the Newtonian kinetics of heat transfer in such a cell, the authors have obtained formulas for calculating the entropy production in it as a function of the heattransfer coefficient, the heat load, the temperatures, and the water equivalents of the flows in the cell.

Journal ArticleDOI
TL;DR: Using the integral Laplace transformation and generalized boundary conditions, the authors in this article obtained the analytical solution to a one-dimensional nonstationary heat-conduction problem for a half-space with a multilayer coating on piecewise uniform change in the ambient temperature.
Abstract: Using the integral Laplace transformation and generalized boundary conditions, the authors have obtained the analytical solution to a one-dimensional nonstationary heat-conduction problem for a half-space with a multilayer coating on piecewise uniform change in the ambient temperature. A study has been made and regularities have been established of thermal processes occurring in the body and the coating in thermal cycling.

Journal ArticleDOI
TL;DR: In this article, the hydrodynamics of a steady-state nonisothermal flow of a viscoelastic polymer medium in a plane channel and heat transfer in it under boundary conditions of the first kind have been investigated.
Abstract: The hydrodynamics of a steady-state nonisothermal flow of a viscoelastic polymer medium in a plane channel and heat transfer in it under boundary conditions of the first kind have been investigated. Fluid flow with a low Reynolds number and a high Peclet number was investigated, which made it possible to neglect the gravity and inertial forces, as well as the longitudinal thermal conductivity of the medium. From the rheological viewpoint, the polymer melt represents a viscoelastic fluid; therefore the Phan-Thien–Tanner fluid model was used as a rheological model of the fluid, with viscosity depending on temperature and pressure. A high-viscosity medium was considered; therefore a dissipation term was included into the equation of the energy of its flow. With the use of the indicated rheological model the velocity profile of fluid flow was obtained in an explicit form from the equation of fluid motion. It has been established that the dependence of the fluid viscosity on temperature and pressure exerts a noticeable influence on the distribution of the Nusselt number and of bulk temperature of the fluid along the channel length. It is shown that account for the temperature dependence of fluid viscosity leads to a decrease in the role of energy dissipation of its flow in the process of flow heating and that, conversely, the dependence of the fluid viscosity on pressure considerably enhances the dissipation effect. The problem has been solved numerically by the method of finite differences.

Journal ArticleDOI
TL;DR: In this article, the influence of external friction forces on the density distribution of the material in the bulk of its sample was investigated and the advantages of the indicated compaction method over the one-side high-temperature compaction of powder materials, used most frequently in power metallurgy and in self-propagating high temperature synthesis technologies, were substantiated.
Abstract: On the basis of theoretical analysis of the rheodynamics of a powder material in the process of its indirect compaction with active action of an external friction force, the influence of this friction force on the density distribution of the material in the bulk of its sample was investigated. The advantages of the indicated compaction method over the one-side high-temperature compaction of powder materials, used most frequently in power metallurgy and in self-propagating high-temperature synthesis technologies, were substantiated.

Journal ArticleDOI
TL;DR: Investigations have been conducted into the high-velocity motion of a group of supercavitating strikers on a hydroballistic testing facility, and a calculation procedure has been developed for modeling possible deviations of the strikers′ motion in water in a group start.
Abstract: The investigation is devoted to an experimental and theoretical research into the high-velocity motion of a group of supercavitating kinetic strikers in water. An experimental launching technique has been developed, and investigations have been conducted into the high-velocity motion of a group of supercavitating strikers on a hydroballistic testing facility, and a calculation procedure has been developed for modeling possible deviations of the strikers′ motion in water in a group start. Experimental data have been obtained on the motion of one and two supercavitating strikers on the initial portion of the path at velocities of the order of 1200 m/s, which serve as initial conditions for identifying the strikers’ deviation from the target at a distance of up to 100 m.

Journal ArticleDOI
TL;DR: In this paper, the ignition of typical forest combustible materials (birch leaves) at temperatures characteristic of a crown forest fire was investigated, and the dependence of the delay time of ignition of a birch-leaf sheet on the temperature of the surrounding medium was determined.
Abstract: The ignition of typical forest combustible materials (birch leaves) at temperatures characteristic of a crown forest fire was investigated. The dependence of the delay time of ignition of a birch-leaf sheet on the temperature of the surrounding medium was determined, and the mechanism of ignition of leaves in a high-temperature medium was revealed. A mathematical model of classification of forest combustible materials on the basis of experimental data on their properties has been developed.

Journal ArticleDOI
TL;DR: In this article, the heat transfer in the single-phase flow of a liquid in an asymmetrically heated horizontal minichannel was investigated, and the temperature distributions obtained for the liquid flow and the heater surface were used to determine the heat flow through the liquid-heater interface.
Abstract: The heat transfer in the single-phase flow of a liquid in an asymmetrically heated horizontal minichannel was investigated. Thermograms of the surface of a heater in the minichannel and the surface of its adiabatic part have been obtained with the use of an infrared camera, and they were used to construct temperature profi les for these surfaces. Stationary temperature distributions in the insulating foil, the heater surface, and the liquid fl ow in the minichannel have been obtained, respectively, with the use of the Laplace equation, the Poisson equation, and the energy equation involving the frictional heat losses. The solution of the system of these differential equations with special boundary conditions has culminated in the solution of three sequential inverse problems on the heat conduction in the indicated adjacent regions having different physical parameters. These problems were solved using the Trefftz method, and the temperature of the liquid flow in the minichannel was calculated by the Picard–Trefftz method. The temperature distributions obtained for the liquid flow and the heater surface were used to determine the heat transfer through the liquid–heater interface. The Trefftz and Picard–Trefftz methods yielded similar local heat transfer coeffi cients and temperature distributions.

Journal ArticleDOI
TL;DR: In this article, a mathematical model of multiphase nonisothermal filtration with chemical reactions and phase transitions in deformable porous media is developed, and the dependence of the porosity on porosity has been written in the form of a Kozeny-Carman equation, and a test problem of combustion in a low-permeability sample of a bituminous reservoir has been solved.
Abstract: The authors have developed a mathematical model of multiphase nonisothermal filtration with chemical reactions and phase transitions in deformable porous media. A modified Biot approach was used to describe filtration through a deformable porous medium. Equations for the stress–strain state have been formulated in terms of displacements, and the elastic rheology of a porous skeleton in nonisothermal form was used in the model. The dependence of the permeability on porosity has been written in the form of a Kozeny–Carman equation. A test problem of combustion in a low-permeability sample of a bituminous reservoir has been solved. Results of the work can be used to numerically substantiate experiments on the technology of interbedding combustion in low-permeability beds.

Journal ArticleDOI
TL;DR: In this paper, the authors have given new information on nonstationary gasdynamics and local heat transfer of pulsating flows in gas-air flow ducts of internal combustion engines, and also have proposed methods for improving the processes in intake and exhaust systems.
Abstract: It is well known that as of today, internal combustion engines are the most widespread energy sources among heat engines. Therefore, one relevant problem in the development of world energy is to improve operating processes, and also to modernize systems and elements of piston internal combustion engines with the aim of improving their technical and economic indices. In the present paper, the authors have given new information on nonstationary gasdynamics and local heat transfer of pulsating flows in gas–air flow ducts of internal combustion engines, and also have proposed methods for improving the processes in intake and exhaust systems. Experimental investigations were conducted on full-scale models of a single-cylinder internal combustion engine with supercharging and without it. Physical features of pulsations of gas flows in the engines′ gas–air flow ducts have been described. Calculated and experimental dependences of the change in the instantaneous velocity and the pressure of the gas flow in the gas–air flow ducts with time have been presented. Particular emphasis was placed on an analysis of the intensity of heat transfer in gas–air flow ducts of different configurations. It has been shown that lateral profiling of intake and exhaust pipelines exerts a positive influence on the technical and economic indices of piston engines without supercharging. A method to reduce pulsations of the pressure and velocity of gas flows (on the average, by a factor of 2) in the intake pipeline of a supercharged internal combustion engine has been proposed, which leads to an improvement of the reliability of the entire engine.

Journal ArticleDOI
TL;DR: In this paper, the working parameters of a spray drying installation with a combined supply of heat by convection and infrared radiation, the density of the heat flux in the infrared radiation device, and the intensity of mixing the gas phase were investigated.
Abstract: Results are presented of experimental investigations of the working parameters of a spray drying installation with a combined supply of heat by convection and infrared radiation, the density of the heat flux in the infrared radiation device, and the intensity of mixing the gas phase. The analysis of the obtained data shows that the supply of heat to the chamber by infrared radiation and the latter′s impact on the liquid′s spray pattern makes it possible to increase signifi cantly the moisture intensity of the chamber, to decrease the heat rate for evaporation of moisture, and to raise the installation′s efficiency.

Journal ArticleDOI
TL;DR: In this paper, a verified TERRA universal thermodynamic-calculation program was used for plasma recycling of agricultural waste, and no detrimental impurities were found in the products of plasma recycling.
Abstract: Thermodynamic calculations and experiments on plasma gasification of wood waste have been conducted. On the basis of a verified TERRA universal thermodynamic-calculation program, the authors have conducted an experiment on plasma recycling of agricultural waste. No detrimental impurities were found in the products of plasma recycling.