scholarly journals A STUDY ON SUDDEN EXPANSION HYDRODYNAMIC PHENOMENA OCCURRING IN CYLINDRICAL PIPES

2021 ◽  
Vol 6 (4) ◽  
pp. 63-71
Author(s):  
Arestak Sarukhanyan ◽  
◽  
Garnik Vermishyan ◽  
Keyword(s):  
Cross Section ◽  
Sudden Expansion ◽  
Expansion Factor ◽  
Transitional Area ◽  
Boundary Layer Equations ◽  
Hydrodynamic Parameters ◽  
Parabolic Law ◽  
Computer Aided ◽  
Hydrodynamic Processes ◽  
Relevant Section

Introduction: This paper studies the frequency with which hydrodynamic parameters change in the sudden expansion section of axisymmetric pressure flow, based on the boundary layer equations. Methods: The suggested method reveals the regularity of changes in the hydrodynamic parameters of the flow in the transitional area, making it possible to obtain a velocity profile in any cross-section under common initial and boundary conditions. Based on the general solutions, we studied the hydrodynamic processes occurring in the transitional area of the effective sudden cross-section expansion within the axisymmetric pressure movement, in the following cases: a) when the velocity is constant at any point of the inlet face; b) when the velocity is distributed along the inlet face according to the parabolic law. Our calculations were carried out for different values of the expansion factor. Results: Based on the results of the computer-aided experimental study, we obtained velocity diagrams along the length of the transitional area with constant and parabolic velocity distributions for fluid inflowing into the expanded section. We also determined the patterns of pressure distribution along the length of the relevant section.

scholarly journals The Study of Hydrodynamic Processes Occurring on Transition of Sudden Expanding of Hydraulic Section of Plane – Parallel Full Pipe Flow

TEM Journal ◽  
2020 ◽  
pp. 1494-1501
Author(s):  
Arestak Sarukhanyan ◽  
Arevshad Vartanyan ◽  
Garnik Vermishyan ◽  
Vache Tokmajyan
Keyword(s):  
Pipe Flow ◽  
Inlet Section ◽  
Transition Section ◽  
Hydrodynamic Parameters ◽  
Plane Parallel ◽  
Parabolic Law ◽  
Parabolic Distribution ◽  
Fluid Velocities ◽  
Calculation Results ◽  
Hydrodynamic Processes

The study regarding the regularity of changes in the hydrodynamic processes in the area of a sudden expanding in hydraulic section of the planeparallel full pipe flow of the liquid is carried out on the basis of the equations on the boundary layer. A method has been developed for determining the changes in the hydrodynamic parameters of the flow in the transition section which makes it possible to obtain the profile of the distribution of fluid velocities in any cross section of the channel based on the results of deformation of the areas of velocity under common initial and boundary conditions. The hydrodynamic processes occurring on transition of sudden expanding on hydraulic section of plane-parallel full pipe flow are studied in cases when: a) the velocity at any point of the inlet section of the channel is constant; b) the velocity at the inlet section is distributed according to the parabolic law. The calculation results for various values of the coefficient of expansion are given: Based on the results of computer simulation, the course of deformation of the velocity diagram along the length of the transition section was obtained for a constant and parabolic distribution of the velocities of the fluid flowing into the expanded section of the channel. The regularities of pressure distribution along the length of the studied section were also determined.

Computational and theoretical research of the injector block function

2020 ◽  
pp. 123-126
Author(s):  
В.В. Кожемякин ◽  
Р.А. Иванов ◽  
Е.С. Игнатьева
Keyword(s):  
Hydraulic Resistance ◽  
Cross Section ◽  
Flow Rate ◽  
Pressure Dependence ◽  
Theoretical Study ◽  
Water Jet ◽  
Theoretical Research ◽  
Sudden Expansion ◽  
Operating Modes ◽  
Coefficient Of Hydraulic Resistance

Работа посвящена расчетно-теоретическому исследованию работы блока инжекторов. Рассмотрен пароводяной струйный аппарат, который применяется в качестве средства циркуляции теплоносителя первого контура. Подвод дополнительного потока осуществляется на цилиндрическом участке с внезапным расширением сечения через перемычку. Для достижения поставленной цели разработана программа для ЭМВ, в которой смоделирована зависимость давления от нагрузки в контуре, а также проведено расчетно-теоретическое исследование влияние гидравлического сопротивления на расход перемычки. В данной работе рассмотрены только рабочие режимы, т.е. все инжекторы работают как насосы. В ходе работы было установлено, что при нагрузке в 30% увеличиваются коэффициенты инжекции пароводяного струйного аппарата, но характер работы перемычек не меняется. Так же было установлено, что расход через перемычку меняется не пропорционально коэффициенту гидравлического сопротивления перемычки. The paper is devoted to the computational and theoretical study of the injector block operation. A steam-water jet apparatus is considered, which is used as a means of circulating the primary circle coolant. The additional flow is supplied on the cylindrical section with a sudden expansion of the cross-section through the bridge. To achieve this goal, a computer program was developed that modeled the pressure dependence on the load in the circuit, and also a theoretical study of the influence of hydraulic resistance on the flow of the jumper was conducted. In this paper, only operating modes are considered, i.e. all the injectors function as pumps. In the process of the research, it was found that at a load of 30%, the injection coefficients of the steam-water jet apparatus increase, but the nature of the work of the jumpers does not change. It was also found out that the flow rate through the jumper does not change in proportion to the coefficient of hydraulic resistance of the jumper.

Regularities of changes in microhardness in the volume of EDT-69N binder cured at different temperatures

2020 ◽  
Vol 4 ◽  
pp. 65-71
Author(s):  
E.A. Veshkin ◽  
◽  
V.I. Postnov ◽  
V.V. Semenychev ◽  
E.V. Krasheninnikova ◽  
...  
Keyword(s):  
Cross Section ◽  
High Sensitivity ◽  
Sample Volume ◽  
Curing Temperature ◽  
Molding Temperature ◽  
Parabolic Law ◽  
Dimensionless Coefficient ◽  
Straight Line ◽  
Different Temperatures ◽  
The Difference

The change in the microhardness over the thickness of samples made of EDT-69N binder cured in vacuum and at atmospheric pressure at temperatures from 130 to 170°C was investigated. It was found that the change in microhardness along the thickness of the samples occurs according to the parabolic law, with the maximum values being achieved in the middle of the sample cross-section along the thickness. With an increase in the molding temperature, the microhardness in the middle section of the sample increases from 222 MPa at a molding temperature of 130°C to 410 MPa during molding at 170°C. At the critical molding temperature (170°C), the microhardness in all zones of the specimen cross section (subsurface, semi-average, and core) levels off, while the parabolic dependence degenerates into a straight line. It is shown that the method of scratching (sclerometry) demonstrated a sufficiently high sensitivity to the state of samples cured at different temperatures. With an increase in the molding temperature, the width of the sclerometric grooves decreases. At a critical molding temperature of 170°C, the groove width is stabilized and becomes constant throughout the sample thickness. To characterize the difference in the values of the microhardness of the cured binder in the sample volume, it is proposed to use a dimensionless “coefficient of volume anisotropy,” which can take a positive, negative or zero value. With an increase in the curing temperature of the binder and, accordingly, with an increase in the microhardness of the sample, the coefficient of volume anisotropy decreases, and when the samples are molded at the critical temperature, it turns to zero, which indicates the absence of anisotropy.

scholarly journals Challenges Faced While Designing Body in White

2021 ◽  
Vol 9 (9) ◽  
pp. 49-56
Author(s):  
Aditya Dhobale
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cross Section ◽  
Cross Sections ◽  
Element Analysis ◽  
Computer Aided ◽  
Safety Parameters ◽  
Body In White ◽  
White Sheet ◽  
Metal Design

Abstract: Construction of Body in White (BiW) revolves around plenty of challenges. Ranging from BiW fixtures to curbing weight of Body in White sheet metal design. This paper discusses about all the design aspects in BiW manufacturing in automobile and confronting challenges that occurs. At present, lots of existing theories are being applied and efforts to improve the same are being made. This paper provides a path on how components can be developed and make necessary improvements. CAE (Computer Aided Engineering) tools have been used for FEA (Finite Element Analysis) and also an example of stress analysis of automotive chassis is given. An outcome depending on behaviour of loads acting on frame is drawn. The importance of hollow tubes, tubes of different- cross sections to counter weight and ease the designing of BiW frame have been proposed. This paper also provides insight on safety parameters with current construction of tubular frame chassis. Other solutions such as hybrid tubes, foam padding and plastic trim have been pointed out in this paper. Keywords: CAE, FEA, manufacturing, loads, tubes, cycle-time, cross-section.

Modeling and analysis of traverse mechanism with eccentric gear and conjugated two-lobed non-circular gear

2016 ◽  
Vol 87 (17) ◽  
pp. 2106-2116
Author(s):  
Ying Wang ◽  
Jianneng Chen ◽  
Honglian Tao ◽  
Dehua Tao ◽  
Jian Li ◽  
...  
Keyword(s):  
Cross Section ◽  
Kinematic Model ◽  
Calculation Model ◽  
Mechanical Parameters ◽  
Analysis Program ◽  
Performance Requirement ◽  
Modeling And Analysis ◽  
Gear Drive ◽  
Computer Aided Analysis ◽  
Computer Aided

The most important performance requirement of a traverse mechanism is that the thickness of the silk package formed by the traverse mechanism is uniform or has little variation in the centre. To realize this requirement and overcome the structural shortcomings of traditional traverse mechanisms, a new kind of traverse mechanism is proposed in this paper. The proposed mechanism is characterized by a non-circular gear drive formed by an eccentric gear and a conjugated two-lobed non-circular gear. Its kinematic model is deduced, together with a calculation model for the formed shape of the silk package cross-section. Both of these models contain the influence caused by the shift motion. Based on these two models, a computer-aided analysis program for the traverse mechanism, using MATLAB, is developed and the influences of the mechanical parameters on the formed shape of the silk package are analyzed. Furthermore, the mechanical parameters based on the new traverse mechanism give a better performance when compared with the traditional mechanism.

scholarly journals Transfer relations: useful basis for computer-aided engineering of circular arch structures

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jiao-Long Zhang ◽  
Xian Liu ◽  
Yong Yuan ◽  
Herbert A. Mang ◽  
Bernhard L.A. Pichler
Keyword(s):  
Cross Section ◽  
Bending Moment ◽  
Arbitrary Cross Section ◽  
Computer Aided Engineering ◽  
Arch Bridge ◽  
Content Type ◽  
Circular Arch ◽  
Computer Aided ◽  
Arch Structures

Purpose Transfer relations represent analytical solutions of the linear theory of circular arches, relating each one of the kinematic and static variables at an arbitrary cross-section to the kinematic and static variables at the initial cross-section. The purpose of this paper is to demonstrate the significance of the transfer relations for structural analysis by means of three examples taken from civil engineering. Design/methodology/approach The first example refers to an arch bridge, the second one to the vault of a metro station and the third one to a real-scale test of a segmental tunnel ring. Findings The main conclusions drawn from these three examples are as follows: increasing the number of hangers/columns of the investigated arch bridge entails a reduction of the maximum bending moment of the arch, allowing it to approach, as much as possible, the desired thrust-line behavior; compared to the conventional in situ cast method, a combined precast and in situ cast method results in a decrease of the maximum bending moment of an element of the vault of the studied underground station by 46%; and the local behavior of the joints governs both the structural convergences and the bearing capacity of the tested segmental tunnel ring. Originality/value The three examples underline that the transfer relations significantly facilitate computer-aided engineering of circular arch structures, including arch bridges, vaults of metro stations and segmental tunnel rings.

scholarly journals Local Deplanation Of Double Reinforced Beam Cross Section Under Bending

2015 ◽  
Vol 45 (4) ◽  
pp. 31-40 ◽  
Author(s):  
Anguel Baltov ◽  
Ana Yanakieva
Keyword(s):  
Cross Section ◽  
Recycled Concrete ◽  
Thin Layers ◽  
Zero Energy ◽  
Transitional Area ◽  
Composite Layers ◽  
External Moment ◽  
The Cross ◽  
Bending Of Beams ◽  
Reinforcing Layer

Abstract Bending of beams, double reinforced by means of thin composite layers, is considered in the study. Approximate numerical solution is proposed, considering transitional boundary areas, where smooth quadratic transition of the elasticity modulus and deformations take place. Deplanation of the cross section is also accounted for in the areas. Their thickness is found equalizing the total stiffness of the cross section and the layer stiffness. Deplanation of the cross section of the transitional area is determined via the longitudinal deformation in the reinforcing layer, accounting for the equilibrium between the internal and the external moment, generated by the longitudinal stresses in the cross section. A numerical example is given as an illustration demonstrating model’s plausibility. The model allows the design and the calculation of recycled concrete beams double reinforced by means of thin layers. The approach is in agreement with modern design of nearly zero energy buildings (NZEB).

Limitations of the Boundary-Layer Equations for Predicting Laminar Symmetric Sudden Expansion Flows

1986 ◽  
Vol 108 (2) ◽  
pp. 208-213 ◽  
Author(s):  
J. P. Lewis ◽  
R. H. Pletcher
Keyword(s):  
Boundary Layer ◽  
Initial Conditions ◽  
Boundary Layer Equation ◽  
Reynolds Numbers ◽  
Equation Model ◽  
Sudden Expansion ◽  
Boundary Layer Equations ◽  
Flow Parameters ◽  
Numerical Predictions ◽  
Global Iteration

A finite-difference solution scheme is used to study the limitations and capabilities of the boundary-layer equation model for flow through abrupt, symmetric expansions. Solutions of the boundary-layer equations are compared with previous numerical predictions and experimental measurements. Some flow parameters are not well predicted for Reynolds numbers below 200. Global iteration over the flow field to include upstream effects does not significantly influence the predictions. Axisymmetric and two-dimensional flows are investigated. The effect of initial conditions is discussed

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