Том 52, № 3-4 (2016)
- Год: 2016
- Статей: 24
- URL: https://journals.rcsi.science/0009-2355/issue/view/14591
Research, Design, Calculations, and Operating Experience
Modeling of Bubble-induced Mixing of Organic Substrate in Biogas Generating Bioreactor
Аннотация
A mathematical model of bubble-induced mixing of organic substrate in a biogas generating bioreactor is developed. The model describes motion of a two-phase medium consisting of liquid phase–biomass and disperse phase–bubbling gas under turbulent operating conditions. The model is based on equations in both general dimensionless and criterial form, which allows its use for designing and calculating bubble reactors of various capacities.
Highly Efficient Methods of Machining Titanium for Oil-Gas Drilling Equipment
Аннотация
A method is proposed for combined machining of difficultly machinable materials with precooling of blanks. It is demonstrated with reference to titanium and its alloys that high surface quality and assigned performance properties of the components can be ensured with retention of prolonged cutting-tool life by controlling heat fluxes during high-speed machining with precooling. For making tools, the most preferable are tool materials with a high heat conductivity coefficient.
Article
Mixing Foaming Liquids in Centrifugal Action Machines
Аннотация
The possibility of mixing foaming liquids in a centrifugal field is investigated. A theoretical analysis of the formation of foam showed that under certain design and operational parameters of the cylindrical continuous-flow hydrocyclone the process of mixing foaming media can take place without foaming.
Development of Gas-Liquid Ejection Apparatus Construction Designs
Аннотация
Three designs of a gas-liquid ejection apparatus were developed: with a long ejector, a gas-liquid jet and a short ejector, and a combined one with a multi-tiered ejector. The effectiveness of the gas-liquid apparatuses was determined by the sulfite method. From the results of experimental studies it was found that the gas-liquid ejection apparatus with a multi-tiered ejector is considerably more effective than the others.
Analysis of Dynamic Load Capacity of the Top Drive of Drilling Rigs
Аннотация
Problems related to the occurrence of undesirable oscillations in the course of drilling deep oil and gas producing wells with the use of a top drive are presented. An example of a mathematical model is presented in order to demonstrate the quantitative characteristics of pulsations in the tool. The results of the study consist of recommendations for use in determining the design load on the motor of a top drive and in processing experimental data on the drilling process.
Effect of Solution Flow Pattern on Mass Transfer in Baromembrane Separation of Industrial Solutions and Effluents
Аннотация
The results of experimental research on hydrodynamics of solution flow in membrane channel are reported. Response curves correlating flow pattern with solution flow rate, pressure, and type of membrane module are obtained. A theoretical analysis of the research results is made with a description of the response curves using criterial equations that correlate empirical coefficients with solution flow rate in the channel, pressure, and type of membrane elements.
Adaptive Control System of the Electric Discharge Machining Process
Аннотация
The article presents the scientific rationale for the approach to the development of an adaptive management system for the electric discharge machining process based on artificial intelligence principles to achieve the required surface quality of the workpiece. A three-layer neural network for controlling the process of electric discharge machining and a block diagram of the research bench to study the efficiency of electric discharge machining with the use of the developed adaptive control system are described.
Verification of the Adequacy of an Algorithm for Estimating the Polycomposition of Gaseous Media Applied to a Multichannel Measurement System
Аннотация
A technique of verifying the adequacy of an algorithm for estimating the polycomposition of gaseous media in terms of the adequacy of a corresponding mathematical model of a multichannel system is developed. The mathematical model is based on a previously proposed iterational process (algorithm) for estimating the parameters of a model that takes into account the totality of data in all the channels. A technique for more precise verification of the adequacy of the mathematical model, by means of which a result in the form of the confidence limits of the parameters may be obtained, is developed with the use of a dispersion approach.
Increased Efficiency of Solar-Powered Absorption Thermotransformers
Аннотация
The physicochemical properties of activated carbons (AC) were investigated in order to determine their basic characteristics that define the absorption capacity of activated carbons with different absorbates (coolants). The absorption capacities of the working pairs AC–ammonia, AC–methylamine, and AC–ethylamine were investigated. Specific parametric coefficients for the Dubinin–Radushkevich structural equation were obtained. The experimental dependence of the daily cycle of solar-powered thermotransformers working with the pair AC–ammonia was presented and proved the positive effect of the work. The thermodynamic efficiencies of solar-powered thermotransformers with the working pairs were determined from the exergy coefficients and suggested areas for efficient application of solar-powered thermotransformers.
Investigation of the Effect of Microwave-Radiation Energy Flux on the Structure and Properties of Polymeric Insulating Materials
Аннотация
Mobile units for microwave processing of polymeric coatings directly on a pipe are designed. Ultrahigh-frequency (UHF) electromagnetic radiation has several advantages. It intensifies energy exchange in the material by converting radiant energy into kinetic energy of molecular vibrations and ensures uniform treatment of the substance in the irradiated volume. The energy flux is highly stable due to a lack of inertia upon varying its power.
Modeling of the Initial Adjustment Parameters of Petroleum Recovery Control Systems. Part 1. Degrees of Detail and Formulation of Models of Vectors of Variables with Disturbances
Аннотация
Features in the process of modeling the vectors of the input and output variables of petroleum recovery process control systems with different degrees of detail of their structures are considered. Methods of monitoring discharges of liquids at perforated depth intervals of water injection and petroleum producing wells of oil and gas deposits as the basic condition for implementing a real-time regime in these systems are proposed. Conditions for increasing the precision with which the parameters of the variables are monitored based on the hardware components employed in measurements of complex borehole media are considered.
Aerodynamics of a Cyclone Heat Exchanger
Аннотация
The results of an experimental and analytical study of the effect of gas flow rate (Reynolds number) on the pressure distribution, the tension of surface friction, and the characteristics of the boundary layer on the heat-transfer pipe surface of a cyclone heat exchanger offset from the aerodynamic axis of a highly turbulent swirling flow are provided and analyzed. It was found that the decrease of the Reynolds number below the value that defines the boundary of the cyclonic flow self-similarity changes the flow conditions around the pipe surface, the position of the critical points, the dimensions of the characteristic zones, and the flow regime of the boundary layer in its frontal part.
Development and Calculation of a Liquid Cooling System for a Piston Compressor Using Pressure Fluctuations During Gas Discharge
Аннотация
In this work, a new liquid cooling system for a piston compressor based on pressure fluctuations of discharged gas is described. The developed method of calculation based on the fundamental laws of conservation of motion, mass, and energy recorded for gas and coolant is implemented in the form of a package of applied programs for the calculation of the cooling system of a single-stage piston compressor.
Analysis of the Influence of Efficiency of Cooling of Gas in the Course of its Compression in a Volumetric Action Compressor
Аннотация
The influence of the ratio of the gain in technical work for gas compression to the amount of heat removed is analyzed for a constant and a variable mass of compressed gas. The analysis was carried out in the polytropic approximation and on the basis of a mathematical model with lumped parameters, and led to the identification of the areas of effective cooling of gas in the course of compression.
Calculation of Liquid Flow Through Pump-Compressor Slot Seal Made in the Form of Hydrodiode
Аннотация
The results of study of a piston hybrid machine that combines the function of a positive displacement pumpcum-compressor unit are reported. A distinctive feature of the studied machine is the presence between the piston and the cylinder wall of a slot seal made in the form of a hydrodiode. A numerical model of the motion of an incompressible viscous liquid in the channel of the hydrodiode made in 3D axisymmetric formulation is proposed. The turbulence effects are determined using SST (shear-stress transport) model. It is shown that the rate of liquid flow through the slot seal depends on the direction of motion. The physical nature of this phenomenon is analyzed.
The Relationship Between the Mass Flow Rates of a Liquid and the Discharge Pressures in the Pumping Cavity and in the Compressor Cavity of a Hybrid Energy-Converting Piston Machine
Аннотация
A technique of calculating the relationships between the discharge pressures in the pumping cavity and the compressor cavity of a hybrid energy-converting piston machine is proposed. Through the use of the results presented here, a relationship is found between the discharge pressure of the pumping cavity and that of the compressor cavity that assures equality between the mass flow rates of the liquid traveling out of the pumping and compressor cavities and, correspondingly, normal operation of a hybrid energy-converting piston machine.
Analysis and Optimization of Basic Geometric Parameters of Annular Slot Seal Made in the Form of Hydrodiode
Аннотация
This article is the second stage of the research on annular slot hydrodiode. Computational experiments were conducted to establish the correlation between the response functions of the hydrodiode and a number of geometric and hydraulic factors. The results are presented in the form of regression equations, which are used to optimize the geometry of the hydrodiode flow section with a view to minimizing the ratio of the rates of liquid flow through the hydrodiode in forward and reverse directions. The physical phenomena accompanying the hydrodiode operation are analyzed in detail.
Development and Investigation of a Piston Seal in the Form of a Smooth Stepped Groove For a Volumetric Hybrid Energy-Converting Piston Machine
Аннотация
The construction of the piston groove seal of a volumetric hybrid energy-converting piston machine is proposed and investigated. A technique of assessing the overall performance of the proposed groove seal is developed and the influence of the basic construction and regime parameters on the overall performance of the seal is estimated.
Industrial Ecology
Analysis of Operation of Electrostatic Precipitators at High Concentrations of Fine Dispersed Phase
Аннотация
Analysis of operation of electrostatic precipitators at high concentrations of the fine dispersed phase is given here. Changes in the parameters of the electrostatic precipitator in the presence of the dispersed phase are considered. Theoretical analysis of the process of corona discharge locking is given. Calculation results of electric field voltage distribution in the presence of a charged dispersed phase and the distribution of aerosol concentration over the cross section of the electrode gap are given. The expediency of using discharge electrodes with a low corona discharge ignition voltage is demonstrated.
Materials Science and Corrosion Protection
Assessment of the Impact of Various Seawater Components on the Corrosion Resistance of Carbon Steels
Аннотация
The resistance of steels with different carbon contents to sulfide stress corrosion cracking arising as a result of the joint effect of chlorides and sulfides contained in seawater is discussed. It is shown that corrosion cracking tests for samples under uniaxial tension at a constant strain rate can be used for accelerated testing. Parameters recommended in different regulations for assessment of steel resistance to stress corrosion cracking are compared. It is shown that the specific work of steel fracturing is an indicator reflecting most comprehensively the change in steel strength and plastic characteristics.
Fabrication Technology
Bearing Surface Area of Plate Macrorelief and Ways of Increasing It in the Course of Grinding Parts Made of Corrosion-Resistant Steel by Means of Aerobor Grinding Wheels
Аннотация
Monitoring of the operation of grinding of the end faces of parts used in the petrochemical industrial by means of digital photography and topograms of the end faces with the use of a comparatively simple method is proposed. A new numerical quality indicator that describes the relief of macro-irregularities is introduced for this purpose. The technique has been approved for grinding of corrosion-resistant steels by Aerobor wheels. Reasons for the occurrence of a pseudo-regular relief on a surface are established. A relationship between the kinematics of grinding and the variation in the bearing surface area is demonstrated by means of statistical analysis. Recommended fields of effective application of the results of the study are given.
Compressors, Pumps, and Pipeline Fittings
Analysis of the Motion Dynamics of Liquid in a Hybrid Energy-Converting Piston Machine with Gas Plenum in the Intake
Аннотация
A new hybrid energy-converting piston machine with gas plenum in the suction is proposed. A computation technique based on the laws of conservation of energy, mass, and motion and the equation of state, written for a gas and a cooling liquid, is developed. The computation technique is implemented in the form of computer programs for use in calculating the working processes of a piston machine.