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IMPORTANT RESULTS OF SCIENTIFIC RESEARCH

MECHANICS OF DEFORMABLE RIGID BODY, SEISMODYNAMICS AND STRUCTURAL STRENGTH OF BUILDINGS AND STRUCTURES

In 1943-1954, under the leadership of academicians M.T.Urazbaev and Kh.A. Rakhmatulin the basic relations of the theory of elasticity and plasticity, theoretical and applied mechanics, theoretical grounds of mechanics of a weighty deformable thread, wave propagation in media, the theory of vibrations and methods for calculating the dynamic strength of rods, plates and shells were developed.

Under the leadership of academician M.T. Urazbaev the effects of the Chatkal (1946) and Ashgabat (1948) earthquakes were analyzed and it was stated that seismic effects on stone buildings are several times greater than the loads calculated by the TU-58-48 standards. This circumstance led to the need for a substantial revision of the accepted methods for determining seismic effects, and a correction factor for seismic loads was proposed. The aftermath of earthquakes are widely used in the development of recommendations for seismic zoning of the territory of Central Asia and the use of local material in seismic resistant construction and in the preparation and refinement of the most important regulatory document - TU-58-48.

In 1954-1966 under the leadership of academicians V.Kabulov and T.Sh.Shirinkulov, research was conducted in the field of the theory of oscillations of elastic and elastoplastic rods, plates and shells of constant and variable cross section in linear and nonlinear statement, strength of structural elements, patterns of soil strain taking into account nonlinear creep, algorithmization issues in solids.

Under the leadership of academician M.T. Urazbaev and prof. V.T. Rasskazovsky the effect of impulsive loads on flexible and rigid structures was investigated according to a scheme with discrete and distributed mass. Methods for determining and evaluating seismic loads, design models of buildings of various design solutions, methods for calculating plate type dams for seismic effects were proposed, which made it possible to specify the requirements for seismic construction and design of buildings and structures.

The devastating Tashkent earthquake of April 26, 1966 gave a new impetus to the development of fundamental theory and applied research of seismic resistance of buildings and structures. Under the leadership of academician M.T. Urazbaev from 1966 to 1970, an analysis of seismic effects on the structure in the epicentral zone was conducted, the intensity of the earthquake and the boundaries of seismic zones were determined by the macroseismic effect. The aspects concerning the transferring of the main part of the territory of Uzbekistan to a nine-point zone, adapting existing model projects for mass construction to the conditions of a nine-point zone, and adding to the seismic magnitude scale were resolved. Regional graphs of dynamic coefficient for the nine-point zone were constructed, the spectra of seismic accelerations were investigated, and dynamic characteristics of the aftershocks of the earthquake were studied. Practical recommendations for the restoration of damaged buildings and design of new ones were developed. Together with other organizations, Building Code (SNiP) II-A.12-69 was drawn up, which took into account the results of studies on seismic resistance of structures and earthquake aftermath. Organization of the engineering seismometric service for the accumulation of factual material on the behavior of buildings and structures during earthquakes has begun. Laboratory and field studies of structures used in building restoration were conducted. Carrying capacity was estimated by experimental and theoretical methods and dynamic characteristics of buildings of the “structure” type were determined, as well as the main buildings of hydro-power plants, high-rise buildings of a frame-like structure. Separate stages of these studies are reflected in the monograph written by V.T.Rasskazovsky, T.R.Rashidov, K.S.Abdurashidov “Consequences of the Tashkent earthquake” (Tashkent: Fan, 1967).

In the late 1960s, scientists and specialists were faced with the question of design and construction of the Tashkent Metro in the conditions of high seismicity of a region and complex soil conditions. In 1974, the Institute, together with the “Tashmetroproekt” Institute, as the results of engineering-geological surveys, theoretical and experimental studies, solved such important problems as the choice of a route for subway lines, the depth of structures embedding during construction by open and closed excavation, the distance between strain joints depending on their geometric dimensions and soil conditions.

For the first time in the practice of metro construction, seismic-resistant structures of a round tunnel lining of prefabricated reinforced concrete elements and rectangular whole-section linings of open and closed excavation, underground stations of column type and single-vaulted metro stations consisting of large blocks were developed and implemented. Basic provisions and methods for calculating seismic stability of tunnels of shallow and deep embedding, developed under the guidance of Academician T.R.Rashidov and Prof. A.A.Ishanhodzhaev have found wide application in design and construction of the Tashkent and Sofia metro, as well as in the BAM tunnels.

These two circumstances in 1970-1982 significantly expanded the scope and intensity of development of both fundamental and applied research through extensive use of the achievements in mechanics and computing equipment in vibrations theory and strength of structural elements, in problems of soil dynamics and seismic resistance of buildings and structures. New directions developed in the theory of consolidation, taking into account linear and nonlinear creep of the soil skeleton, bending of beams, round plates and frames on an inhomogeneous solid foundation, oscillations of plates and shells, taking into account their rheological properties and interaction with the medium, unsteady oscillations of elastic and viscoelastic media were investigated; two-dimensional soil dynamics problems were solved. Nonlinear oscillations of deformable bodies were investigated depending on physical and geometric parameters, wave propagation in various media, and problems of wave diffraction on an obstacle were solved.

A method for determining the response of structures to seismic effects using weighting functions, physical methods for determining seismic effects, methods for the stability of earth structures were developed. Models of non-stationary multiplicative seismic process, inter-correlation functions and spectral densities of components of seismic accelerations were constructed. Seismic resistance of buildings of various design were investigated by experimental and theoretical methods taking into account spatial work and the interaction of their elements under dynamic effects. The regularities of strain in structural elements were revealed and the guidelines for the calculation of buildings on seismic effects were developed.

The problems of dam-water interaction as a single mechanical system during seismic effects were investigated. Design schemes were selected and refined and methods and programs were developed for the dynamic calculation of concrete dams (arch-type, gravity ones and others) taking into account the spatial nature of the structures, physical and mechanical properties of the foundation, the structure material and water medium. In the studies of Professors R.Kh.Mukhutdinova and M.Mirsaidov a method for calculating seismic dynamics of hydrotechnical and power structures was developed; stress-strain states of earth dams and strength properties of a inhomogeneous massif in the vicinity of underground hydrotechnical structures were investigated.

Methods and recommendations for the calculation of concrete gravitational and massive buttress dams were created, taking into account the non-stationary nature of seismic effect. Wave problems on seismic stability of structures were solved, the dynamics of plane and spatial systems were studied with regard to internal dissipation and wave entrainment of energy. Stress-strain states of earth dams were studied with regard to seismic belts, design values of dynamic characteristics and seismic accelerations of earth dams were determined. Studies of soil-underground structure interaction refer to significant theoretical investigations.

The problems of seismodynamics of underground structures were first developed under the leadership of Academician T. R.Rashidov in the late 1950s. A deep analysis of strong earthquakes aftermath was carried out and the main types of damage were established; the influence of the depths of embedding, soil conditions, geometrical dimensions, type of joints and construction quality on seismic resistance of underground pipelines for various purposes was revealed. As a result, a dynamic theory of seismic stability of underground pipelines was created, which for the first time took into account the relative displacements of the pipe-soil system during seismic wave propagation.

Under the guidance of Prof. G.Kh.Khozhmetov based on experimental studies in laboratory and field conditions for the first time the nature of the interaction of the underground structure with surrounding soil was established, a rheological model of the pipeline interaction, which has elastic-viscoplastic properties was worked out. Under the guidance of Corresponding member of the USSR Academy of Sciences A.A.Ilyushin and academician of the Republic of Uzbekistan T.R. Rashidov while studying the propagation of a stationary wave along the axis of underground pipeline the existence of two different wave propagation modes, conventionally called “pre-” and “supersonic” ones was revealed.

This effect significantly changed the idea of the stress state of underground structure and allowed us to give answers to many questions about the causes of damage and destruction of underground structures during strong earthquakes. A number of problems of seismic dynamics of underground pipelines were solved, taking into account the viscoelastic and elastoplastic properties of interaction, pipe material, joints in the nodes of pipeline systems, non-central and non-orthogonal joining of pipes in complex nodes, etc.

Later, the seismodynamic theory of underground structures was developed under the guidance of Academician Ya.N.Mubarakov in the study of the stress-strain state of underground spatial structures such as shells, plates and rod systems. Methods were developed for the dynamic calculation of underground cylindrical and spherical structures of closed and open profile, the oscillations of stage tunnels of rectangular and circular outline, underground stations of column and single-arched types under seismic effects were investigated. Full-scale experimental studies were carried out on the constructed section of the Tashkent metro, and recommendations were developed on the protection of structures against vibrations arising from the passage of subway trains.

A number of problems concerning oscillations of underground spatial structures were solved, taking into account design features, viscoelastic and elastic-plastic interaction with soil under seismic waves. The nature of the interaction of underground structure with soil by the seismic-explosion method in field conditions was studied. Seismic loads and parameters of interaction of underground structures with soil in three mutually perpendicular directions were determined. The scope of seimodynamic theory and wave dynamics in the study of the stress-strain state of underground structures was determined.

In 1983-1991, the aspects of wave nature of seismic effect, wave propagation in viscoelastic and viscoplastic medium, wave diffraction on the obstacles of various shapes were further developed. Prof. K.S. Sultanov has studied the interaction models under rigid contact, the occurrence of friction and free slip of an underground structure in soil, taking into account the loading conditions and properties of the medium. In the field of the dynamics of elastic and hydroelastic systems, the interactions of the soil base with structures equipped with a seismic isolation system, viscoelastic vibration dampers with distributed parameters for the protection of structures were investigated.

In 1992-2002, deterministic, probabilistic, and wave methods were developed and seismic resistance of the systems of underground structures was studied with regard to the viscoelastoplastic properties of interaction with soil under elastic and inelastic waves. The problems of wave propagation in a viscoelastic rod with external friction, cylindrical elastoplastic waves in structure-soil interaction, non-stationary problems of underground pipeline-soil interaction under dynamic effect, the seismodynamics of a complex node with diffraction forces were solved. Nonlinear nature of interaction of the systems of underground pipelines with soil and the influence of the diameter of underground pipes on the patterns of their interaction with soil were studied, and the dynamic coefficients for the underground structures were determined. In 1997 the results of research were included into the normative documents on earthquake-resistant construction, published by the State Committee on Architecture and Construction of Uzbekistan

The problems of wave propagation in a viscoelastic half-space, including a deformable barrier, were solved in a cylindrical body with various types of external friction. Nonstationary diffraction of plane elastic waves on obstacles of various configurations, subsonic flow around a cylindrical structure interacting with surrounding medium, unsteady interaction of extended underground structures with soil were studied. The interaction of plane waves with parallel tunnels, the propagation of waves originated from subway trains motion taking into account elastic-viscous-plastic properties of soil were investigated. Seimodynamic methods for calculating underground cylindrical tunnel structures of shallow and deep embedding were developed. The optimal distances between parallel tunnels, the permissible distances from the tunnel line to the buildings, the stiffness coefficient of the junctions between prefabricated elements of the circular tunnel lining were determined.

The laws of strain in “soil – foundation – building” system under nonstationary plane elastic compression wave were investigated. Methods were developed for assessing the vulnerability of buildings and structures, possible damage and losses during strong earthquakes in large cities (using as examples the cities: Tashkent, Samarkand, Namangan and Khiva)

The stress-strain state of the dam was studied under basic loads and special combinations of loads taking into account the elastic and elastoplastic properties of soil; and zones were found where compressive stresses could cause rupture cracks and continuity of impervious elements and transition zones. Recommendations were developed for ensuring the seismic stability of earth dams taking into account real data on their states.

Contribution to the development of years of research in the direction of the mechanics of deformable solid body, strength and seismic dynamics of buildings and structures was made by leading researchers of the Institute: Sh.R.Rizaev, Yu.R.Leiderman, N.I.Shukhgalter, Kh.S.Kariyev, A.I.Martem'yanov, F.T.Usmanov, V.E.Popov, L.I.Babich, Kh.Kasymov, B.M.Mardonov, M.A.Akhmedov, I.Kh.Aliev, A.K. Bakhtiyarov, V.G.Fasakhov, T.K.Abdullaev, T.M.Mavlyanov, K.S.Sultanov, M.Mirsaidov, R.N.Musheev, D.F.Rumi, A.Matkarimov, V.A.Omelyanenko, S.Jurabekov, R.Sh.Yamin, H.S.Sagdiev, K.J.Salyamova, Z.R.Teshaboev, U.T.Zakirov, B.S.Kuvanov, Sh.S.Yuldashev, M.K.Usarov, A.Khodzhimetov, I.I.Safarov, S.A.Abdukadirov, B.E.Khusanov, A.T.Buriev, P.Zh.Matkarimov, M.K.Usarov, R.A.Abirov, R.Sh.Indiaminov, E.V.Rozhkova and others.

THEORY OF MECHANISMS AND MACHINES OF THE COTTON COMPLEX, AGRICULTURAL, LIGHT AND TRANSPORT ENGINEERING

The beginning of the development of modern science of the theory of mechanisms and machines in Uzbekistan is associated with the names of the founders of scientific schools - academicians M.T.Urazbaev and Kh.A.Rakhmatulin. In 1943-1953 studies were carried out on the drying of raw cotton and determining its specific weight. The temperature field, heat transfer and evaporation were studied, the coefficients of evaporation and heat transfer for layer-by-layer drying of cotton were determined.

Since the 1950s, research was conducted on the development of processes and the creation of apparatuses for cotton harvesting machines in two directions: pulling raw cotton from bolls by forcing air flow and cleaning with spindle machines. The theory of a pneumatic cotton harvester operating on the principle of forcing air was developed. The parameters of the pneumo-forcing apparatus were determined and the pneumatic cotton-picking machine SKhNP-1 was tested under field conditions. The basic principles of the spindle machine operation were developed, their original designs and installations to the vertical spindle cotton harvesting machine ANTKh-1,2 were created.

For the development of research on the theory and practice of machines for various purposes in 1961, under the direct supervision of Academician Kh.Kh.Usmankhodjaev fundamental research on the structure, kinematics and dynamics of mechanisms, machines was conducted with extensive use of computer technology. Methods for modeling electromechanical systems were developed, covering a large class of machines with their features and links in the units of mechanisms. Mathematical and electronic models of machine units were proposed, the problems of motion of mechanisms and machine units were studied taking into account the characteristics of the engine, friction in the elements of kinematic pairs, elasticity and variability of masses. The following devices were created: “Universal epy-hypercyclograph” for studying the trajectory of points on the satellite surface; to determine the coefficients of friction, sliding, rolling and spinning between the elements of different kinematic pairs.

Analysis of the design and principle of operation of spindle harvesting machines, cotton ginning machines made it possible to create a fundamentally new design of the working body - a composite spindle in the form of a bearing rod and a helical cylinder tooth spring located on its surface. A model of a generalized dynamic kinematic pair (GDKP) of a new type is proposed, which made it possible to generalize the well-known studies on creating composite self-cleaning spindles of harvesting machines. These results in the field of the theory of cotton harvesting units led to the creation of a new direction - the study of the completeness stability of cotton picking and the determination of machine productivity over time. A new winding machine was invented for the cylindrical tooth spring of the gripping element of the composite spindle. On its basis and modernization of the design with the method of hot winding of spring, PO Tashselmash in the cooperation with the specialists of the Institute and NPO “Technolog” has introduced a line for the production of gripping elements.

Research has established a relationship between the absolute velocities of the satellite points and the gear ratio in the planetary mechanisms, and a formula has been obtained for determining the gear ratio in non-circular planetary mechanisms, which generalizes the well-known Willis formula. A new mechanism of spindle drive for cotton pickers was proposed, based on the coupling of cone clutches with the provision of satellite reverse. A friction-spring drive of the spindles of a vertical-spindle apparatus was created, its main parameters were obtained, and a calculation method was developed.

The scientists of the Institute, together with the subdivisions of the VPO “Soyuzmash-cotton growing”, developed a number of machines that made it possible to mechanize the harvesting of this most labor-consuming agricultural crop. In collaboration with the “Tashselmash” plant, experimental two-row hinged cotton harvesting machines were developed, manufactured and tested, carrying out triple time processing of cotton bushes - ANTKh-1.8. At state tests, they showed the highest yield of raw cotton in the main bunker. The results obtained were applied during the modernization of serial cotton-picking machines. Important applied investigation was carried out to create new designs of cotton harvesting machines; oscillations of drums, spindles and pullers of vertical spindle machines were investigated, resonant frequencies of working shafts of cotton harvesting machines and mechanisms were identified that ensure the spindle controllability and operation continuity.

By the decision of the Government of the Republic in 1986 on the basis of the Institute, under the leadership of Academician A.D. Glushchenko, the Interdisciplinary Scientific and Technical Center (ISTC) was established to create highly efficient cotton harvesting equipment, by joint efforts of the country's scientists. The analysis of various technological schemes of vertical spindle harvesting machines allowed developing a harvesting machine for multiple processing of cotton bushes (MPCB), semi-hinged cotton harvesting machine of the MKh-1.8 line, etc. The pneumatic and mechanical pickups, the new direct-motion cotton harvester were developed. Large-scale studies were carried out to determine the influence of the working bodies and the degree of bolls opening on the quality of raw cotton of machine harvesting. Dynamic phenomena were studied during the extraction of cotton from opened bolls with spindles and their effect on damage to cotton fiber. Techniques for assessing the technological process in cotton harvesting machines, predicting the completeness of picking, assessing the quality of cotton harvesting machines on the indices of raw cotton and cotton fiber were developed. The result of ISTC activities was cotton harvesting machines of the MKh-1.8, KhMM-1.8, KhNP-1.8M, KhS-25 types, created and introduced into production in 1994. Machines MKh-2.4 with MPCB devices were manufactured at PO “Tashselmash” and exported.

Developments of the Institute allowed to solve important problems of the cotton-industrial complex. The theory of the drive of the working body according to a given law of motion of the driven link, was developed and used to create a new drive mechanism for sprayers such as OBKh-14, OBKh-28, etc. With theoretical-experimental methods the oscillation of the mechanism of mote knife of the roller gin, the force of fibers pulling from cotton seeds were studied, as well as vibration mechanisms for the drive the fender organs of roller gins. A high-performance multi-roller gin was developed. Machine units with a multi-mass branched system were studied.

To solve the problem of mechanization and automation of production processes of the domestic leather-footwear and fur industry, the Institute’s studies, since 1982, have been aimed at developing new types of machines and equipment with scientifically substantiated parameters. According to the results of scientific-technical studies, a whole class of transmission mechanisms were developed, protected by patents of the Republic of Uzbekistan and applied in various types of roller technological machines.

Since 1987, the Institute, under the leadership of Academician O.V.Lebedev, began the development of the scientific grounds for the design and operational reliability of hydraulic drives for machines. In order to improve the hydraulic systems of machines, a hydraulic fluid with improved performance properties was investigated, the lubricating properties of working fluids and the use of low-viscosity oils in tractor hydraulic systems were evaluated. Dynamic characteristics of the electro-hydraulic drive with various changes in input effect, as well as the features of the dynamics of hydraulic system of the flexible manipulator, were investigated.

Research on the modeling and optimization of the technological process in the cleaning devices of horizontal spindle machines was conducted. Recommendations on the efficient use of horizontal-spindle cotton harvesting machines of Case-2022 type in farms were submitted to the Ministry of Agriculture and Water Resources of the Republic of Uzbekistan.

A generalized theory of the accumulation of the dynamic damageability of high-grade cotton varieties by working bodies of machines at its harvesting and primary processing was created. Rational modes of operation of these machines were established while minimizing mechanical damage to the fiber. The theory of contact interactions of the working bodies of machines for the processing of fiber material was developed in the example of cotton and leather. Generalized models, algorithms were developed and numerical studies were carried out to assess the effect of oscillations of the working bodies on fiber damage, and technical solutions were substantiated to reduce such damage and increase fiber yield and seed quality.

In the field of applied research of mechanisms and machines of the cotton complex, the methods for designing spindle cotton pickers were developed and a universal tractor-mounted cotton harvester was created for farms with row-spacing of 60 and 90 cm with replaceable harvesting units of various types. A rational, resource-saving cotton-harvesting machine hinged to the tractor and a technological chart of high-performance energy- and resource-saving machine systems for the primary processing of cotton in various conditions, taking into account time and quality indices of cotton harvesting, were created. A method for calculating the dynamic strength of the working unit of the deep-ripper was developed, its rational design was transferred to JSC BMKB-Agromash. The basic properties of domestic and foreign tractors with mechanical transmission were studied and the dependencies between the resistances of the tractor motion and transmission ratios were determined. Recommendations for improving the design of the hydraulic system of a wheeled tractor of TTZ-80 type and other modifications were developed.

The modeling of dynamics of drives with cyclic mechanisms for machines in cotton-industrial complex, creating new and improving existing systems of technological equipment for the raw cotton processing, creating a pulsation-flow pneumomechanical fiber cleaner, studying the dynamics of a fiber condenser of machine unit were conducted and recommendations were given to improve the efficiency of condenser operation. Dynamic and mathematical models of a machine unit of saw cylinder of a cotton gin with seed-removing device in the raw cotton chamber were developed. The modernized saw gin of 5DP-156M type was introduced into technological process in the Bektemir, Karasu, Yangiyul, Pskent, Alimkent plants.

The methods for calculating and creating devices for “semi-finished product-transporting conveyor - transition section – compression rolls” system were developed. Theoretical and experimental studies were carried out to determine the effect of the transfer mechanism of roller machines on the properties of material being processed and new transmission mechanisms of roller machines. A mathematical model to study the stress-strain state of a fiber sheet material was created and a pattern was established for changing the properties of material being processed in the contact zone of working rolls of roller machines. Coefficients of straightening leather semi-finished product were experimentally determined. The effect of kinematic relation of the working rolls on the properties of the processed semi-finished product. The dynamics of a roller pair was investigated determining the center of mass of an element of a leather semi-finished product between two rolls. The influence of the drive of compression rolls on the durability of their coatings was studied.

Scientific basis for resource-saving technology and a class of high-performance, competitive devices of oriented supply of sheet material to the contact area of the roller pair of technological machines (for example, in leather industry) were created. New technology and design of the roller machine of vertical type with working mechanisms, such as: the mechanism of material feeding into the processing zone along the vertical plane; pressure between compression rollers and gear-lever transmission drive mechanisms of a new generation were developed. A device has been created for transporting, straightening and oriented feeding of leather semi-finished product to the processing zone of the roller pair, ensuring smooth transition from the transporting device to the processing zone of the roller pair, improving the quality and yield of the useful area of the leather semi-finished product in the machining processes.

Innovative developments are being carried out to automate the technological process at a cotton-ginning plant (using the example of a plant in the Fergana region). By order of Uzcharmpoyafzali, on the basis of the developments of the Institute, a total modernization of the pressing machine is being carried out; the modernization of the hydraulic distributor of the TTZ-80 tractor has begun.

In the development of years of research in the field of mechanics of mechanisms and machines significant contribution was made by leading researchers of the Institute: M.I.Ismailov, L.M.Rozenblyum, A.A.Karimov, G.S.Kuzibaev, R.Kh.Malikov, K.M.Inogamov, I.Kh.Fayziev, T.Yu.Amanov, K.A.Karimov, S.B.Erofeev, Kh.T.Turanov, K.K.Ilyasov, A.I.Usmanov, Sh.Z.Bakhtiarov, A.Idrisov, V.G.Berezhnoy, R.D.Matchanov, E.Slivinsky, S.U.Rakhmatkariev, R.I.Karimov, A.Zh.Zhuraev, A.A.Rizaev, G.A.Bakhadirov, G.A.Khromova, M.T.Tashbaltaev, R.R.Hudaykuliyev, A.T.Yuldashev, A.A.Shermukhamedov, G.K.Annakulova, D.M.Muhammadiev, A.T.Abdukarimov, I.K. Khuzhayev, Z.M.Malikov, O.S.Norkuziev, N.B.Dzhuraeva and others.

MECHANICS OF FLUID, GAS, MULTIPHASE AND MULTI-COMPONENT MEDIA

Research in the field of mechanics of fluid and gas in 1943-1957 has been connected with the name of the Corresponding Member of the Academy of Sciences of Uzbekistan I.S.Arzhanykh, who has studied the synthesis of hydrodynamics and analytical mechanics, the vortex principle of analytical dynamics, the integral equations of steady motions of a viscous incompressible fluid and plane vortex motions of an ideal fluid.

Since 1947, research has been carried out under the leadership of Academician Kh.A.Rakhmatulin on the aerodynamics of permeable bodies and the theory of parachute. A number of problems of the flow of thin bodies in the two-velocity and two-temperature models were considered with regard to the reflection of solid particles on the body walls, and near-wall gas flow. The aerodynamic processes of the pneumatic cotton-picker were studied and a pneumatic separator was created to ensure the elimination of seeds damage during raw cotton transportation.

In the 1960s, under the leadership of Corresponding Member of the Academy of Sciences of Uzbekistan Zh.F.Fayzullaev a new direction has been developed – hydro-gas-dynamics of multiphase media based on the Kh.A. Rakhmatulin model on interpenetrating motion of media and quasi-homogeneous model of mixtures.

Under the guidance of Prof. Zh.A.Akilov research was conducted on the study of the relaxation time and the length of the initial section of phase. Hydromechanical models for the motion of mixtures and methods for determining the phase interaction coefficient were proposed.

Since the 1970s, the theory of the boundary layer has developed, having close links with the most important tasks of technology. Extensive research was carried out on the mathematical theory of the boundary layer for stationary and non-stationary flows of incompressible and compressible fluids. The motion of fluids and mixtures at magnetic processing was studied, and a new effect of magnetic processing on increasing evaporation from a wet surface was revealed.

Under the guidance of prof. K.Navruzov biomechanical studies of blood motion in blood vessels were conducted. Various problems of fluid flow were considered with account of wall elasticity, the effect of stenosis on blood flow. Hydrodynamic calculations of blood flow in prostheses used in surgery were performed.

Hydrodynamic principles of single and two-phase media flow in a pipe with porous and perforated walls were developed in relation to subsurface irrigation. Under the guidance of Professors A.I.Umarov and A.A.Shakirov, the effect of a small addition of water-soluble polymers on flow parameters of fluids and mixtures was studied. It was established that 0.001% of polymers added to water accelerate the precipitation of solid particles by 3-4 times, reduce the pipe resistance by 30%, increase the flow rate through the pores by 45%. Calculation methods were developed to ensure the rational use of irrigation water; problems of water transfer were solved, taking into account transpiration and evaporation. The problems of the two-phase media flow in open streams with variable flow rates were solved, and the channel zones subjected to erosion were established.

Under the guidance of M.I.Ismailov, wind resistance of various soil types was determined depending on the structure, moisture-content, surface erosion, as well as the degree of turbulence of the incident flow in the presence of pressure gradients along the flow. Analytical expressions were established for determining the threshold velocities, the intensity of blowing-off and entrainment in soils treated with different concentrations of anti-erosion preparations.

Research in the theory of turbulent jets of reacting gases was conducted. Under the guidance of Professors F.Aliyev and Z.Sh.Jumaev, heat and mass transfer was studied at the flow of reacting gases in flat and round turbulent jets in the process of diffusion combustion in the presence of a chemical equilibrium flow, and in chemical reaction. Mathematical models and algorithms were developed to solve a number of practically important problems on prediction of ground and pressure water level fluctuations, and the optimal calculation of gas fields.

In 1983-1991, non-stationary flow of two-phase media in a circular permeable pipe, the mechanics of porous media saturated with a two-phase mixture were investigated. More than ten models of elastic-viscous-inert-deformable continuous media with different relaxation and retardation times were developed. By solving one- and two-dimensional problems of hydrodynamics of viscous-inert-deformable medium flow, the regularities of the distribution of the main hydrodynamic parameters of the flow were established.

Further development of research (1992-2002) is reflected in studies by A.I.Umarov, A.A.Shakirov, I.N.Khusanov and Z.M.Malikov; in solving problems of fluid, multiphase, multicomponent mixtures flow in pipes, boundary layers, porous media, pneumatic and hydraulic transport and heat and mass transfer, with account of rheology. The processes of heat and mass transfer between phases and components are studied taking into account force and energy interactions during mixtures flow in pipes. The regularities of velocities distribution, pressures of flow and concentrations of the medium along the flow and over the pipe section are established, and effective methods of hydrotransport and combustion are proposed.

In 2002-2012, fundamental theory of multiphase and multicomponent media at mixture flow in pipes, open streams, transportation of oil and gases has been developed. The problems of viscoplastic fluid runoff (the Shvedov-Bingam model) and viscous-inert fluid (the Khusanov model) along an inclined plane were solved. The propagation of a pressure pulse at compressible fluid flow at different rheological properties in a deformable pipe was investigated. The calculated formula for the velocity of propagation of water hammer pressure depending on the concentration of air in the mixture was obtained.

Methods to determine the causes of casing crushing have been developed by applied studies; and technology that prevents possible complications and accidents during the drilling and operation of wells has been worked out. By mathematical modeling, calculation and experiment the crushing of the casing was established in the area of the salt layer at a distance of 2700-3000 m from the mouth, proved in practice. Studies have revealed the causes and conditions of pipe columns crushing during drilling and operation of wells. A method was developed for preventing the well pipe columns crushing in salt deposits.

A hydromechanical converter was developed for the structure of a gas-liquid flow, which increases the oil flow rate and the flush stage of well operation. The forced cyclic hydrodynamic processes, carried out by the devices in gas and oil flow moving in the pump-compressor pipe (PCP) of wells without using additional external energy, increase the oil debit by 10-20%, reduce the gas factor by 30% and make it possible to economically expend the reservoir pressure, prolonging the flush stage of well operation for 1-2 years. A hydrodynamic method was developed for implementing an energy-saving mixture flow structure at horizontal drilling of wells, and an experimental installation was created for studying the transportation of drilling chips in horizontal sections of wells.

Mathematical modeling of the dynamics of dust-air flow in curvilinear channels was built and a fundamentally new centrifugal dust catcher to clean industrial exhaust gases was developed.

The development of many years of research in the field of mechanics of fluid, gas, multiphase and multicomponent media was greatly contributed by leading researchers of the Institute: K.Sh.Latipov, E.A.Bagranov, O.Norkabulov, S.Dzhurabekov, S.Abidov, A.Azizov, A.Abdurakhimov, U.Mambetov, T.Akhrarov, B.Toshev, F.Buranov, Sh.Akhmedov, Z.Seydametova, Sh.Alimukhamedov, H.Mirkhamidova, U.Nurmatov, G.N.Soy, A.A.Rizaev, A.T.Yuldoshev and others.


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