Cylindrical Construction Research Articles

Application of structural steels in above-ground cylindrical tanks construction after normalized rolling

Application of structural steels in above-ground cylindrical tanks construction after normalized rolling

Comparative Analysis of Raft, Pile & Piled Raft Foundation using Designing Software

Raft foundations are essentially a slab that extends the entire length of the building, sustaining and dispersing its mass to the earth. A pile foundation is a collection of columns that are erected or inserted into the ground to distribute weight to the subsoil underneath. A pile is a long, cylindrical construction made made of a sturdy substance such as concrete. Building loads are transferred to hard strata, rocks, or high-bearing-capacity soil using piles. Pinned raft foundations are a combination of a pile and a raft slab. They’re frequently used for large structures and when the soil is insufficient to avoid excessive settling. As a result of this, the soil is less strained. Pile foundations are necessary in areas where buildings are large and heavy, yet the soil beneath them is weak. In areas where settlement. Deep foundations with pile rafts can help move strata Adding piles to a raft increases the effective size of the foundation and can help it sustain horizontal loads.On a G+20 residential structure, the research of raft, pile, and stacked raft foundations was conducted using structural software safe 16. For a zone factor II earthquake, a building’s seismic study is completed. The pile raft foundation has less upward soil carrying load and less settling than the raft foundation, according to a study of the G+20 structure for pile, raft, and piled raft foundations.

Numerical study on enhanced heat transfer and flow characteristics of supercritical hydrogen rocket engine's chamber wall using cylindrical ribs structure

One of the most critical issues in supersonic flight is the thermal protection of the rocket engine combustion chamber. The ribs' construction can improve heat transfer and coolant flow characteristics significantly. Ansys fluent was used to investigate the supercritical hydrogen fuel flow and heat transfer characteristics. Ribs spacing of 10 mm, 5 mm, and 2.5 mm were compared to determine the optimal spacing required to achieve maximum cooling influence and lower pressure drop to safeguard the overheated structure and lower the temperature of the walls. Compared to the smooth channel, the thermal performance factor and pressure drop of the 5 mm spacing increased by 32.5% and 16.64%, respectively, while the maximum temperature reduced by 12.07%. Therefore, the cylindrical rib construction with a 5 mm spacing is perfect for improving heat transfer, has acceptable pressure drops, and reduces thermal stratification inside the channel.

The influence of temperature changes on the integrity of tanks for storage of petroleum products and toxic substances

The round plate elements are widely used in engineering and power plants, as well as in the oil, chemical and construction industries. When the temperature changes due to technogenic and natural factors, they are deformed and there are temperature stresses, which are often the cause of their destruction. The magnitude of deformations and stresses depends on the magnitude and temperature gradient, as well as the physical and mechanical characteristics of the metal and the conditions of fixing the structural elements. It is shown that the greatest temperature stresses occur on the side surface of a cylindrical construction. The non-stationary temperature field in the round lamellar elements of engineering constructions, which changes with time, is investigated. Modeling the process of heating the round plates, the boundary conditions of the second kind are taken into account. Using the Laplace transformation, we obtained analytical expressions to study the temperature field and temperature deformations. The stress-strain state of round lamellar constructions with clamped edges due to a non-stationary temperature field is determined.This article proposes the methodology of research of a non-stationary stress-strain state in a cylindrical plate at heating on a side surface. The obtained results allow estimating the stress state at each point of the construction depending on the radius and physical and mechanical characteristics of the material from which the construction is made. The researches have shown that the temperature stresses that occur in plate constructions vary depending on the radius and time. The analysis of graphical researches shows that the destruction of the tank can occur by achieving a critical value of tangential stresses. The sharpest change of the tangential and radial stresses occurs at the initial moment of temperature action.

Finite-element modelling of electrodynamic processes as a method of determining the optimal number of turns on a winding of a machine press electromagnetic motor

This article presents the optimization problem solution employing the methods of finite-element modelling of electrodynamic processes for choosing the number of winding turns in an electromagnetic motor driving a machine press. The subject of the investigation is a new methodology for identifying optimization solutions to a differential equation describing the finite-element model of the electromagnetic motor and analyzing its calculated dynamic characteristics. The object of the investigation is a cylindrical construction of an electromagnetic motor with two working gaps and a combined composite armature. The basis of the finite-element model is a computational scheme and a software package created at the Department of Applied Mathematics at Novosibirsk State Technical University. It is illustrated that the applied computing apparatus and the software package allow performing an accurate search for the optimal number of turns on a winding of an electromagnetic motor at the design stage with due consideration for the required geometric parameters and the magnetic properties of the structural materials employed for obtaining the maximum final velocity of the armature in motion.

Thermal-Hydraulic Studies on the Shell-and-Tube Heat Exchanger with Minijets

In this paper a patented design of a heat exchanger with minijets, with a cylindrical construction is presented. It is followed by the results of its systematic experimental investigations in the single-phase convection heat transfer mode. Based on these results, validation of selected correlations (coming from the literature) describing the Nusselt number was carried out. An assessment of the heat exchange intensification level in the described heat exchanger was done through the comparison with a shell-and-tube exchanger of a classical design. The thermal-hydraulic characteristics of both units were the subjects of comparison. They were constructed for the identical thermal conditions, i.e., volumetric flow rates of the working media and the media temperatures at the inlets to the heat exchanger. The experimental studies of both heat exchangers were conducted on the same test facility. An increase in the heat transfer coefficients values for the minijets heat exchanger was observed in comparison with the reference one, whereas the generated minijets caused greater hydraulic resistance. Experimentally confirmed intensification of heat transfer on the air side, makes the proposed minijets heat exchanger application more attractive, for the waste heat utilization systems from gas sources.

Determination of electromagnetic parameters for improvement of efficiency of special electric drives

The research of electromagnetic parameters for improvement of efficiency of special electric drives is presented in article. The analysis of the received results was carried out. An object of a research were special electric drives with asynchronous motors of cylindrical construction. The studied special electric actuators possess improved mass-dimensional and power indicators due to constructional features and the used control systems. For different industries application of electric actuators with the seized characteristics is a relevant task. For modeling and design of special electric drives it is necessary to create new approaches for determination of electromagnetic parameters or to make significant correction of the existing approaches. On the basis of the offered mathematical model of the electromagnetic system presented in the form of set of electromagnets parameters of the studied electric drives were determined electromagnetic. The analysis of the conducted research shows that the received solution will allow to improve efficiency of the special electric drives used in difficult technological processes of different industries.

USING THE SEMIBENDING THEORIES IN SOLVING THIN WALLED CYLINDRICAL SHELL CONSTRUCTIONS.

The semibending theories of thin walled cylindrical shell construction neglect the increment in curvature of the shell in the axial direction. The basic differential equations of the shells using the semibending theories are derived for three different cases and are named as simpli-fied semibending, semibending theory with incompressible middle surface and semibending theory with compressible middle surface. The differen-ces between these theories depend on the values of the circumferential normal strain and the shear strain. The derived differential equations are solved and applied to the prnblems of influence lines of stresses and deformations for different loading conditions on a long shells.

Seismic Analysis Report for Air Intake Silencer

All internal combustion engines produce noise, the intensity and magnitude of the noise will vary greatly depending upon engine type naturally aspirated or turbocharged, horse power developed, means of scavenging, type of fuel used, number of cycles whether 2 cycle or 4 cycle engine etc. Among the pre-dominant source that makes up the engine noise are the engine intake and exhaust. The silencer plays a very crucial role in these devices for noise controlling which causes vibration in these devices. In this paper we are study about qualification of the intake air silencer for the Emergency Diesel Generator (EDG) of the Shin-Ulchin 1 & 2 (henceforth referred to as SUN12) nuclear power plant. The silencer is of double cylindrical shell construction with absorber material (mineral wool + glass cloth) filling the insulating regions in-between in order to dampen the noise transmission. The finite element method has been relied on in order to evaluate the seismic qualification of the equipment involved. For this purpose, the Finite Element Codes embedded in ANSYS Release 12.1 have been employed.

ПРИМЕНЕНИЕ МЕТОДА ПАРНЫХ СРАВНЕНИЙ ПРИ ПРОЕКТИРОВАНИИ КОМПОЗИТНЫХ КОРПУСОВ КОСМИЧЕСКИХ ТЕЛЕСКОПОВ

The problem of designing precision large-sized composite framework constructions is considered in the article. The prospects of using composite materials in large-sized supporting constructions of space telescopes are noted. The design task of creating a cylindrical construction of the telescope body of the optoelectronic complex is formulated at the verbal level and in standard form in terms of non-linear mathematical programming. The decomposition of the problem into a number of structural and parametric subtasks is proposed. The ways of solving the difficultly formalized problems of choosing structural solutions are discussed using the example of a composite framework construction of a space telescope. The choice of the concept of the framework telescope power scheme and the directive technology for its manufacture is considered in detail. To make a choice of design options and manufacturing techniques for designing the case, the method of pairwise comparisons from the system analysis was applied, taking into account the heterogeneous requirements for the product. New technical solutions are given: a shell with an external set of reinforcing ribs and the technology of its molding using elastic forming elements, confirmed by patents. Examples of framework structures from composite materials designed and manufactured using the presented methods are shown. The effectiveness of the applied methods in the design of composite framework in conditions of product requirements validity is confirmed by the parameters of the manufactured products.

Numerical Modeling of Local Penetration of Chloride-Containing Medium into Construction Elements Made of Reinforced Concrete

The task of modeling the kinetics of chloride-containing medium penetration into construction elements out of reinforced concrete that have partially damaged anti-corrosion protective coatings is being discussed. As a result, chlorides penetrate the construction element via local surface areas which leads to irregularities between chloride dispersion volumes. The kinetics of chloride penetration is described by the equation of diffusion to solve which the CONDUCT software complex by professor S. Patankar was used. The methodology used to solve the diffusional equation is described. The results of the evaluation of concentration field in the axial section of a cylindrical construction element, which was centrally reinforced, are given. The chloride diffusion was symmetrical to the axis, the medium was applied through the central ring area equal to one third of the side surface area while the rest of the surface was isolated. It was shown that the methodology of evaluation and its algorithm allow one to evaluate the concentration field of chlorides in reinforced concrete structural elements under local or asymmetrical action of the chloride - containing medium. The example given illustrates that after a certain time interval critical the concentration of chlorides develops even in protected areas which are located far from the initial damaged area. This means that the corrosion destruction of reinforced elements develops not only in the immediate damage area, but also further away from it.

Design Approach To High Voltage High Power Steam-Turbine Driven Alternator

The paper deals with the design methodology of high voltage high power alternators driven by steam turbines. These alternators run at a high speed of 3000 rpm in most part of the world (at 3600 rpm in USA) and are of cylindrical pole construction. The design procedure suggested in the text-books of design does not well-suit for large alternators of modern time. Modern high power alternators are designed with a low value of SCR to reduce the size, inertia and cost of the rotor. The diameter is limited by the consideration of centrifugal stresses. The no.of stator slots are determined by the no. of turns. The ventilating circuit has to be designed for hydrogen as coolant and in addition with water flowing through hollow conductors, if required. The data for the design variables and the design constraints are quite different from those for small power ratings. The materials to be chosen must be of very high quality. The computer programme has been chalked out and the case-study has been conducted keeping all these points in view.

On Cylindrical Graph Construction and its Applications

In this article we introduce the cylindrical construction, as an edge-replacement procedure admitting twists on both ends of the hyperedges, generalizing the concepts of lifts and Pultr templates at the same time. We prove a tensor-hom duality for this construction and we show that not only a large number of well-known graph constructions are cylindrical but also the construction and its dual give rise to some new graph constructions, applications and results. To show the applicability of the main duality we introduce generalized Grötzsch, generalized Petersen-like and Coxeter-like graphs and we prove some coloring properties of these graphs.

Constrained space deformation techniques for design optimization

We present a novel shape deformation method for its use in design optimization tasks. Our space deformation technique based on moving least squares approximation improves upon existing approaches in crucial aspects: It offers the same level of modeling flexibility as surface-based deformations, but it is independent of the underlying geometry representation and therefore highly robust against defects in the input data. It overcomes the scalability limitations of existing space deformation techniques based on globally supported radial basis functions while providing the same high level of deformation quality. Finally, unlike existing space deformation approaches, our technique directly incorporates geometric constraints–such as preservation of critical feature lines, circular couplings, planar or cylindrical construction parts–into the deformation, thereby fostering the exploration of more favorable and producible shape variations during the design optimization process.

Comparable Parameters of Small Power Linear Induction Drives

Parameters of some small power linear induction drives are investigated and compared in this article. These drives have beencreated and introduced into production in small and medium quantities by specialists of Automatics department in Vilnius GediminasTechnical University, have flat or cylindrical construction, designed for short time working mode. The investigated parameters are:phase current density of inductor, relative active power, power coefficient, asymmetry of phase currents, indices of transitionalprocesses. These results can be used in a new short time working linear induction drive design. Ill. 8, bibl. 7 (in Lithuanian; Summariesin Lithuanian, English and Russian).

Evaluation of mechanical abuse techniques in lithium ion batteries

Mechanical tests are a commonly used method for evaluating the safety performance of batteries. The mechanical blunt rod testing method, as well as sharp nail penetration, was performed on commercially available cells. Evaluation was carried out on different cell constructions as well as varying test conditions. Results obtained at ambient conditions were found to differ little from traditional sharp nail penetration testing. When tested at elevated temperatures it was observed that the results became heavily dependent upon the internal construction of the cell. Computed Tomography (CT) imaging confirmed this, showing differences in behavior depending on whether or not a solid core was used in the cylindrical cell construction. Pouch cells were tested as well, showing that a full penetration of the cell was necessary to initiate a failure event within the cell.

CFD analysis of mixing intensity in jet stirred reactors

Abstract The homogeneous stirred reactor designed for kinetic studies of the combustion of hydrocarbons with intensive internal recirculation in high temperature combustion chamber is described. The originality of our reactor lies in its construction which allows to intensively mix fuel and flue gases, measure gas temperature as well as obtain samples which can be used to investigate diffusion flames. The cylindrical construction enables to use the reactor in laboratory cylindrical electrically heated ovens. The CFD analysis of the reactors, the mixing parameters (turbulent Peclet number and mixing level) and the volume average temperature in the reactors were elaborated on the basis of the typical dimensions of classical reactors to kinetics research as well as the own reactor design. The results of the analysis allow to reveal advantages of our construction.

Comfort Evaluation in an Urban Boulevard by Means of Evaporative Wind Towers

To increase the comfort level of urban public areas during the summer period, several passive strategies can be implemented. In areas characterized by hot and dry summers, the most common techniques are based in solar shading, natural ventilation and evaporative processes. The case study analized in this work is a cylindrical construction called “Air Tree” that was built in a boulevard in Madrid. It is composed by sixteen evaporative wind towers that combine the three passive strategies. The main objective is to evaluate the thermal influence of this construction in the perception of heat and cold. This value has been quantified by the outdoor TS comfort index at 1m high in the pedestrian area. To that effect, temperature, humidity and radiation values recorded during the summer of 2008 have been used. Air velocities in the interest area have been obtained indirectly by CFD simulations, previously validated with experimental data. The results from this study show that the application of these techniques enhances the social and environmental quality of urban spaces.

Absolute magnetic helicity and the cylindrical magnetic field

The different magnetic helicities conserved under conditions of perfect electrical conductivity are expressions of the fundamental property that every evolving fluid surface conserves its net magnetic flux. This basic hydromagnetic point unifies the well known Eulerian helicities with the Lagrangian helicity defined by the conserved fluxes frozen into a prescribed set of disjoint toroidal tubes of fluid flowing as a permanent partition of the entire fluid [B. C. Low, Astrophys. J. 649, 1064 (2006)]. This unifying theory is constructed from first principles, beginning with an analysis of the Eulerian and Lagrangian descriptions of fluids, separating the ideas of fluid and magnetic-flux tubes and removing the complication of the magnetic vector potential’s free gauge from the concept of helicity. The analysis prepares for the construction of a conserved Eulerian helicity, without that gauge complication, to describe a 3D anchored flux in an upright cylindrical domain, this helicity called absolute to distinguish it from the well known relative helicity. In a version of the Chandrasekhar-Kendall representation, the evolving field at any instant is a unique superposition of a writhed, untwisted axial flux with a circulating flux of field lines all closed and unlinked within the cylindrical domain. The absolute helicity is then a flux-weighted sum of the writhe of that axial flux and its mutual linkage with the circulating flux. The absolute helicity is also conserved if the frozen-in field and its domain are continuously deformed by changing the separation between the rigid cylinder-ends with no change of cylinder radius. This hitherto intractable cylindrical construction closes a crucial conceptual gap for the fundamentals to be complete at last. The concluding discussion shows the impact of this development on our understanding of helicity, covering (i) the helicities of wholly contained and anchored fields; (ii) the Eulerian and Lagrangian descriptions of field evolution; (iii) twist as a topological property of solenoidal fields versus the linkage properties of open and closed discrete curves treated by Gauss, Caligarneau, Berger, and Prior; and (iv) the change of absolute helicity by resistive diffusion. These are important hydromagnetic properties of twisted magnetic fields in the million-degree hot, highly conducting corona of the Sun.

Optimization of repulsive passive magnetic bearings

Passive magnetic bearings are an attractive alternative to conventional ball bearings in applications where wear and tear must be minimal and cost or construction restrictions ban the use of active magnetic bearings. They also find applications as miniaturized high-speed bearings where no other low-friction solutions are available. We show that, for a given cylindrical construction volume, an optimized repulsive bearing design with respect to a maximal radial stiffness can be found. This optimal configuration is independent of the aspect ratio of the bearing, but is determined by the width of the air gap between rotor and stator. Our method can determine the optimal configuration for any bearing geometry. We develop a design for a miniaturized high-speed bearing as an example.