Статті в журналах: "Cylindrical pipe"

1

JG, Abuga. "Mathematical Modelling and Simulation of Aluminium Filling in Conical Pipe and Cylindrical Pipe under High Pressure." Physical Science & Biophysics Journal 6, no. 2 (July 5, 2022): 1–7. http://dx.doi.org/10.23880/psbj-16000215.

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The desired technology for manufacturing light-weight components from metal alloys mostly aluminum and magnesium alloy is Die casting. High pressure die casting requires the liquid metal to be forced at high speed and pressure through a metal pipe. In our study, we seek to study Aluminum filling under high pressure in two different pipes, cylindrical and conical pipes. Two cases are considered for the cylindrical pipe, when the pipe vertical and when the pipe in inclined at an angle of 450 with the horizontal. The governing equations are obtained and the results are compared. The governing equations are obtained and modeling is done using ANSYS FLUENT. The results show that inclining the cylindrical pipe causes a shift in the oscillations and the inclined pipe has slightly lower amplitude of oscillation implying a greater loss of energy due to the inclination. The inclined cylindrical pipe has higher damping compared to the vertical cylindrical pipe. It is also evident that the conical pipe has higher oscillations than the cylindrical pipe implying a greater loss of energy for the conical cylindrical.

2

Adachi, T., S. Ujihashi, and H. Matsumoto. "Impulsive Responses of a Circular Cylindrical Shell Subjected to Waterhammer Waves." Journal of Pressure Vessel Technology 113, no. 4 (November 1, 1991): 517–23. http://dx.doi.org/10.1115/1.2928789.

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The impulsive responses of semi-finite and finite pipes filled with fluid are analyzed in order to clarify the validity of Joukowsky’s theory and the fluid-pipe coupling effect. In the analysis, Flu¨gge’s dynamic bending shell theory and the potential theory of compressible perfect fluid are used. The analytical solutions in Laplace transformed domain are obtained. The inversion of the solutions is performed numerically using the algorithm of FFT. When a pipe is fairly long, it is shown that the result of Joukowsky’s theory which has no pipe inertia effect approximately agrees with that of the coupled theory. When a pipe is short, Joukowsky’s theory shows rough approximation of the responses. The response of the uncoupled theory with the inertia of a pipe is different from that of the coupled theory for both long and short pipes.

3

Afandiyev, Emin Musa, and Mahammadali Nuraddin Nuriyev. "ANALYSIS OF THE CONDITION OF A PIPE FIXED IN A CLAMPING DEVICE." EUREKA: Physics and Engineering, no. 1 (January 29, 2021): 78–85. http://dx.doi.org/10.21303/2461-4262.2021.001587.

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Due to the fact that clamping devices are widely used in various industries, the requirements for the operation of such devices are constantly increasing. This is due to an increase in the general requirements for processing accuracy, as well as an increase in the forces acting on the clamped part. The reliability of these devices when working with thin-walled cylindrical parts is of great importance. Thin-walled cylinders used in mechanical engineering are subject to significant loads. With prolonged exposure to loads from clamping forces, as well as from axial tensile forces, plastic deformations of cylindrical parts occur. In the oil and gas industry, when clamping drill and casing pipes in some areas in the capture zone, stresses exceed the yield strength. Multiple clamping of the pipe will reduce the pipe wall in the gripping area, which causes premature pipe failure. Therefore, increasing the holding capacity of clamping mechanisms is relevant. Analysis of broken drill pipes, which have been operating in wedge grips for a long time, showed that in most cases the pipes undergo plastic deformation caused by damage to the pipe surface by the teeth of the ram. To clarify the actual conditions of loading the pipe and the possibilities of increasing the capacity of the clamping devices, studies of the contact pressures in the clamping zone were carried out. A new pipe clamping chuck is also presented, which provides a sufficiently high reliability of fastening of cylindrical parts.

4

Idrus, Fairosidi, Nazri Mohamad, Ramlan Zailani, Wisnoe Wirachman, and Mohd Zulkifly Abdullah. "Experimental Model to Optimize the Design of Cylindrical Heat Pipes for Solar Collector Application." Applied Mechanics and Materials 393 (September 2013): 735–40. http://dx.doi.org/10.4028/www.scientific.net/amm.393.735.

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A heat pipe is a heat-transfer device that use the principles of thermal conductivity and phase change to transfer heat between two ends at almost constant temperature. The thermal peformance of cylindrical heat pipes depends on design parameters such as dimensions of the heat pipe, material, wick structure and the working fluid. An experimental strategy was designed to study the effect of these parameters on the thermal performance of cylindrical heat pipes. The experimental design was conceived by employing the Taguchi method. The final aim of the experiments is to come up with design parameters that will yield optimum thermal performance. This paper presents an efficient design of experiment and the associated experimental setup and procedures to be carried out in order to optimize the design of cylindrical heat pipes.

5

Fukuda, Izumi, Yasunori Harada, and Yuichi Tanaka. "Effect of Temperature on Plastic Buckling Strength of Shot Peened Pipe of Magnesium Alloys." Materials Science Forum 654-656 (June 2010): 747–50. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.747.

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This paper deals with the effect of temperature on plastic buckling strength of cylindrical pipe of some magnesium alloys subjected to shot peening process. Workpieces are three cylindrical pipes of AZ31, AZ61 and AZ80 magnesium alloys. The shape of pipe is 30mm in height, 16mm and 14mm in outer and inner diameters. The shot peening treatment was given on the surface of cylindrical pipe using an air-type peening machine. Plastic buckling strength test was performed under axial compression in a case of both ends with fixed condition, at several temperatures between 293K and 573K and at a crosshead speed of 1 mm/min using an Instron-type testing machine. From the experimental result, buckling stresses for all kinds of AZ31, AZ61 and AZ80 alloy pipe were strengthened after the shot peening treatment, but a few of differences for the increasing ratio. The buckling stress of the shot-peened pipe was kept higher than that of as received one up to the test temperature of 473K, however it tended to be around equal at 573K.

6

Doi, Taiga, Takashi Futatsugi, Michio Murase, Kosuke Hayashi, Shigeo Hosokawa, and Akio Tomiyama. "Countercurrent Flow Limitation at the Junction between the Surge Line and the Pressurizer of a PWR." Science and Technology of Nuclear Installations 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/754724.

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An experimental study on countercurrent flow limitation (CCFL) in vertical pipes is carried out. Effects of upper tank geometry and water levels in the upper and lower tanks on CCFL characteristics are investigated for air-water two-phase flows at room temperature and atmospheric pressure. The following conclusions are obtained: (1) CCFL characteristics for different pipe diameters are well correlated using the Kutateladze number if the tank geometry and the water levels are the same; (2) CCFL occurs at the junction between the pipe and the upper tank both for the rectangular and cylindrical tanks, and CCFL with the cylindrical tank occurs not only at the junction but also inside the pipe at high gas flow rates and small pipe diameters; (3) the flow rate of water entering into the vertical pipe at the junction to the rectangular upper tank is lower than that to the cylindrical tank because of the presence of low frequency first-mode sloshing in the rectangular tank; (4) increases in the water level in the upper tank and in the air volume in the lower tank increase water penetration into the pipe, and therefore, they mitigate the flow limitation.

7

Zinurov, V. E., A. V. Dmitriev, M. A. Ruzanova, and O. S. Dmitrieva. "Classification of bulk material from the gas flow in a device with coaxially arranged pipes." E3S Web of Conferences 193 (2020): 01056. http://dx.doi.org/10.1051/e3sconf/202019301056.

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The paper deals with the problem of classification of bulk material, based on silica gel, larger than 30 µm, from dusty gas flow. In order to solve this problem, the design of a classifier with coaxially arranged pipes is proposed. According to the conducted studies, it is more efficient to use a classifier with an inner conical pipe to solve the problems of separating the particles from the gas flows of various sizes, since a greater value is achieved for the centrifugal, inertial, gravitational and other forces acting on the dusty flow, that contribute to knocking the particles out of its structure, than in a classifier with a cylindrical inner pipe. On average, the efficiency of a classifier with a conical inner pipe is by 35.3% higher than that of a classifier with a cylindrical inner pipe. Classification of particles of bulk material, based on silica gel, larger than 30 µm from the dusty gas flows is solved most effectively by using a classifier with a conical inner pipe and hd parameter of 50 mm and a classifier with a cylindrical inner pipe and hd parameter of –10 mm.

8

JG, Abuga. "Analysis of Aluminium Filling in Cylindrical Pipe under High Pressure by Experiment and Mathematical Modelling." Physical Science & Biophysics Journal 7, no. 1 (January 5, 2023): 1–9. http://dx.doi.org/10.23880/psbj-16000236.

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The preferred method for producing lightweight metal components, mainly from aluminum and magnesium alloys, is through high pressure die casting. This process involves rapidly and forcibly injecting liquid metal into a metal mold under high pressure. Our study aims to compare results obtained from the numerical modelling of the filling of aluminum under high pressure with the experimental results. Two different cylindrical pipes are used. The results indicate for imposed values of KE = 14 and KW = 60 for pipe 1(Dentry/Drp=40/40) and pipe 2 (Dentry/Drp=16/40) respectively, the mathematical model with the same initial conditions gives some results which are close to the experimental data. The results also indicate that pipe 2 is damped faster than pipe and this is due to the singular pressure loss at the entry.

9

Kim, Jae-Hee, Jae-Cheol Lee, and You-Rack Choi. "PiROB: Vision-based pipe-climbing robot for spray-pipe inspection in nuclear plants." International Journal of Advanced Robotic Systems 15, no. 6 (November 1, 2018): 172988141881797. http://dx.doi.org/10.1177/1729881418817974.

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Among many pipes in a nuclear power plant, the spray pipes in the reactor building are one of the most important pipes in view of their function and safety aspects. However, it is very difficult to manually reach and inspect the pipes for defects or damage, because these pipes are installed in very high places. To carry out this kind of inspection more easily, we developed a mobile robot to climb up and down and to cross over such pipes. A mobile robot should be small and light enough that it can be practically and safely operated in a nuclear power plant. Our robot is able to overcome obstacles such as valves, pipe flanges, and T-shaped branches, and it also meets the requirements of fail-safe, autonomous grasping, and self-power without the cables to the remote control station. The robot has a five-degree-of-freedom manipulator and two grippers and moves along the cylindrical pipes bypassing the obstacles. The robot should be able to grasp the next pipe autonomously, because the robot works in places high off the ground where the remote operator cannot see the next pipe for the robot to grasp. This article proposes a vision-based scheme for grasping a cylindrical pipe semi-autonomously and describes its solution along with the forward kinematics and inverse kinematics of the mobile robot. The configuration of the pipe-climbing robot, including its hardware and software, is described, and the robot control with visual grasping is explained. The robot can be used practically for spray-pipe inspection as well as many potential other applications, such as inspection of the roof frame of a stadium consisting of pipes.

10

Li, Bing, Yu Lan Wei, Dan Zhang, and Qing Huang. "Influence of Lumped Mass on the Natural Frequency of Cylindrical Pipe." Advanced Materials Research 532-533 (June 2012): 403–7. http://dx.doi.org/10.4028/www.scientific.net/amr.532-533.403.

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The lumped mass on the cylindrical pipe affects the natural frequency of the cylindrical pipe. The first-three order natural frequencies and vibration modes of the cylindrical pipe with different lumped masses are analyzed by the bending vibration theory and finite element analysis, respectively. The results with different lumped masses are obtained by experiments. As shown in the results, the natural frequencies of the cylindrical pipe with lumped mass are lower than those without lumped mass. The greater the lumped mass is, the smaller the natural frequencies of the pipe are.

11

Doubrovsky, Michael, Liudmyla Kusik, and Vladyslava Dubravina. "Pipe pile with internal diaphragm as effective bearing element of deep-water structures." Herald of the Odessa National Maritime University, no. 72 (March 24, 2024): 16–29. http://dx.doi.org/10.47049/2226-1893-2024-16-29.

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One of the ways to reduce piling expenses is decreasing volume of piling works. It can be provided by shortening either the piles length or the number of pipes. These results may be achieved if each short-cut pile is improved and bears the same loading as a pile of normal length or if each pile of normal length is improved and bears larger axial force in comparison with its initially designed capacity. Presented study clarified possibilities to regulate the pipe pile’s bearing capacity using an internal rigid diaphragm (closure) placed inside the pile’s shaft. It increases the bearing capacity of the tubular pile due to additional soil reaction under the closure. Pressing the pipe pile’s model into sand box was assumed as the most gentle and precise method to study considered driving process. Besides results of such approach may be good adapted to predict pipe behavior in case of Press-in method of the pile installation. Some conclusions were made clarifying the diaphragm’s positive contribution to pile bearing capacity, the effect of the closure’s location along the pipe shaft, and the influence of the diaphragm’s design (flat, conical, and cylindrical closures). Numerical analysis of the gained experimental data gave the possibility to apply approximating functions with good correlation indexes

12

Li, Bing, Yu Lan Wei, Qi Bo Yan, and Yue Zhan Wang. "Vibration Characteristics of a Containing Liquid Cylindrical Pipe with Lumped Mass." Applied Mechanics and Materials 184-185 (June 2012): 641–44. http://dx.doi.org/10.4028/www.scientific.net/amm.184-185.641.

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The liquid within a cylindrical pipe affects the vibration characteristics of the pipe. Furthermore, these vibration characteristics are affected by lumped mass on the pipe. The natural frequencies and the vibration modes of the cylindrical pipe with different lumped masses can be obtained by finite element analysis. The natural frequencies of the containing liquid cylindrical pipe are obtained by experiments. The experimental results show that the natural frequencies of the containing liquid pipe are affected by the lumped mass. The greater the lumped mass is, the smaller the natural frequencies of the pipe are.

13

Maleki, I., and O. Rahmani. "A closed-form solution for the bending analysis of composite sandwich pipe with compliance core based on high-order sandwich theory." Journal of Sandwich Structures & Materials 22, no. 6 (July 25, 2018): 1786–811. http://dx.doi.org/10.1177/1099636218789622.

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In this paper, bending of cylindrical sandwich pipes based on the high-order theory of sandwich structures with flexible core is investigated. The cylindrical sandwich pipe is composed of a flexible core and two composite face sheets. Behavior of the cylindrical sandwich pipe is described by a high-order sandwich shell theory, which explains nonlinear distortions of cross-sectional plane of the flexible core as well as changes in its height. The theory based on variational principles and using an extremely thorough systematic closed-form approach is formulated. In this model, no assumption has been considered for displacement distribution of core components. In this study, stress and displacement of the flexible core are obtained through a three-dimensional elasticity solution and the face sheets are modeled using classical shell theory. Also, a comparison is made in order to verify high-order solution results between a closed-form solution, which is expanded for simply supported boundary conditions and results that are obtained from the commercial finite element method. Finally, influences of physical and geometrical parameters on behavior of the cylindrical sandwich pipe are investigated.

14

Suminar, Dian Ratna, and Nurcahyo Nurcahyo. "Karakteristik Hydrocyclone untuk Pemisahan Minyak dan Air." Jurnal Teknik Kimia dan Lingkungan 4, no. 2 (October 27, 2020): 133. http://dx.doi.org/10.33795/jtkl.v4i2.160.

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Eksplorasi minyak bumi dari sumur-sumur yang sudah tua menghasilkan minyak dengan kandungan air tinggi. Hydrocyclone suatu alat yang berfungsi untuk pemisahan cair-cair berdasarkan perbedaan berat jenis setiap komponen. Pemisahan ini terjadi dikarenanakan adanya gaya sentrifugal dan gaya gravitasi yang dihasilkan dari bentuk hydrocyclone yang seperti kerucut. Perancangan dan pembuatan hydrocyclone menghasilkan alat dengan spesifikasi sebagai berikut : diameter pipa masukan : 25,4 mm, diameter cylindrical section : 120 mm, tinggi cylindrical section : 120 mm, tinggi cone section : 600 mm, diameter pipa overflow : 25,4 mm, diameter pipa underflow : 25,4 mm. Laju alir optimum untuk pemisahan air-minyak tanah pada hydrocyclone adalah 91,8 liter/menit dengan kadar minyak tanah di overflow sebesar 11,4% dan kadar minyak tanah di underflow sebesar 3%.Petroleum exploration from old wells produces oil with a very high water content. Hydrocyclone is a device that functions for liquid-liquid separation based on differences in specific gravity of each component. This separation occurs due to the presence of centrifugal forces and gravitational forces resulting from cone-like forms of hydrocyclone. The design and manufacture of hydrocyclone produces tools with the following specifications: input pipe diameter: 25.4 mm, cylindrical section diameter: 120 mm, high cylindrical section: 120 mm, cone section height: 600 mm, overflow pipe diameter: 25.4 mm, underflow pipe diameter: 25.4 mm. The optimum flow rate for the separation of water-kerosene on hydrocyclone is 91.8 liters / minute with the level of kerosene in overflow of 11.4% and the level of kerosene in underflow of 3%.

15

Cao, Y., and A. Faghri. "Transient Multidimensional Analysis of Nonconventional Heat Pipes With Uniform and Nonuniform Heat Distributions." Journal of Heat Transfer 113, no. 4 (November 1, 1991): 995–1002. http://dx.doi.org/10.1115/1.2911233.

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A numerical analysis of transient heat pipe performance including nonconventional heat pipes with nonuniform heat distributions is presented. A body-fitted grid system was applied to a three-dimensional wall and wick model, which was coupled with a transient compressible quasi-one-dimensional vapor flow model. The numerical results were first compared with experimental data from cylindrical heat pipes with good agreement. Numerical calculations were then made for a leading edge heat pipe with localized high heat fluxes. Performance characteristics different from conventional heat pipes are illustrated and some operating limits concerning heat pipe design are discussed.

16

Celik, Metin, Geert Paulussen, Dennis van Erp, Wiebren de Jong, and Bendiks Boe. "Transient Modelling of Rotating and Stationary Cylindrical Heat Pipes: An Engineering Model." Energies 11, no. 12 (December 10, 2018): 3458. http://dx.doi.org/10.3390/en11123458.

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Rotating wickless and stationary capillary cylindrical heat pipes are widely used heat transfer devices. Transient behavior of such heat pipes has been investigated numerically with computational fluid dynamics and lumped parameter models. In this paper, the advantages of both methods are combined into a novel engineering model that is low in computational cost but still accurate and rich in the details it provides. The model describes the interior dynamics of the heat pipe with a 2D representation of a cylindrical heat pipe. Liquid and vapor volumes are coarsely meshed in the axial direction. The cells are allowed to change in size in the radial direction during simulation. This allows for tracking the liquid/vapor interface without having to implement fine meshing. The model includes the equations for mass, momentum and energy and is applicable to both rotating and stationary heat pipes. The predictions of the model are validated with other experimental, numerical, and analytical works having an average deviation of less than 4%. The effects of various parameters on the system are explored. The presented model is suitable for the simulation of heat pipe systems in which both the level of detail and the computational cost are crucial factors.

17

SUGIMATA, Etsuro, Hisai UEDA, Wataru KURIYAMA, Wataru OKUMURA, Mitsugu KIMIZU, Mitsuhiko TAKA, Daisuke MORI, and Kiyoshi UZAWA. "Formability of Braided CFRTP Cylindrical Pipe in Pipe Bending." Journal of Textile Engineering 63, no. 2 (2017): 49–54. http://dx.doi.org/10.4188/jte.63.49.

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18

Gabibov, Yu S., and Kh B. Salaeya. "Investigation of individual problems of calculation of drainage pipes in complex geotechnical conditions." Construction and Geotechnics 14, no. 1 (December 15, 2023): 59–73. http://dx.doi.org/10.15593/2224-9826/2023.1.05.

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The article notes that changes in the loads acting on the drainage pipe (pipeline) in accordance with the relative ability of the drainage pipe and the ground filling to deform are essential. To determine the magnitude of the loads on the drainage pipeline laid in the trench, the formula proposed by A. Marston most accurately corresponds to the results of experiments and is convenient for engineering practice. The perforation of the walls of the drainage pipe affects their strength not only when the pipes are crushed, but also for the conditions of transportation and installation of pipes. The contact interaction of the cross-section of the drainage pipe with the soil base is investigated, in this case, the interaction of cylindrical (having a semicircular contact) or reloid (having a contact of the circle sector) shells lying on an elastic soil base is considered. A differential equation is considered to describe the deformation of an elastic shell, which includes the stiffness parameter, linear differential operators, components of displacement of the neutral axis of the drainage pipe, external load and dimensionless coordinates. For the elastic base models of E.Winkler and V.Z.Vlasov, a general solution of the differential equation describing the deformation of the drainage pipe is proposed. The solution of this equation and the external load is presented in the form of double or single trigonometric series, depending on the task (two-dimensional or one-dimensional). A horizontally lying cylindrical (or reloid) shell (drainage pipe) supported on a ground base is considered. The contact pressure is determined by summing the Fourier coefficients. This solution additionally takes into account the distribution capacity of the ground base of the drainage pipe.

19

AHRARY, ALIREZA, LI TIAN, SEI-ICHIRO KAMATA, and MASUMI ISHIKAWA. "NAVIGATION OF AN AUTONOMOUS SEWER INSPECTION ROBOT BASED ON STEREO CAMERA IMAGES AND LASER SCANNER DATA." International Journal on Artificial Intelligence Tools 16, no. 04 (August 2007): 611–25. http://dx.doi.org/10.1142/s0218213007003461.

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Sewer environment is composed of cylindrical pipes, in which only a few landmarks such as manholes, inlets and pipe joints are available for localization. This paper presents a method for navigation of an autonomous sewer inspection robot in a sewer pipe system based on detection of landmarks. In this method, location of an autonomous sewer inspection robot in the sewer pipe system is estimated from stereo camera images. The laser scanner data are also used to ensure accurate localization of the landmarks and reduce the error in distance estimation by image processing. The method is implemented and evaluated in a sewer pipe test field using a prototype robot, demonstrating its effectiveness.

20

Tovsteleva, A. I. "Technical and economic advantages of using elongating mandrel made of forged blank when rolling on a continuous mill with a controlled‑movable mandrel." Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), no. 4 (December 20, 2021): 55–58. http://dx.doi.org/10.21122/1683-6065-2021-4-55-58.

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In the article, the current problem of reducing the cost of pipe‑rolling products, which is especially acute in the world market of metal products high competition conditions is considered. A significant share in the cost of pipe products stands at the cost of rolling tools. Reducing the cost of buying a deforming tool allows you to make considerable savings in the seamless pipes’ production. The article presents: analysis of the economic efficiency of manufacturing long cylindrical mandrels from a semi‑finished product – forged billet at OJSC «BSW – management company of «BMC» holding»; development of the technological process for the production of long mandrels depending on the required size; the results on the manufacture of long cylindrical mandrels from forged billet at OJSC «BSW – management company of «BMC» holding», as well as their industrial tests in the conditions of the pipe rolling shop. A positive result of using long mandrels of the PQF mill made of forged blanks was obtained.

21

Lipnitskyi, L. V., R. S. Melnyk, Yu E. Nikolaenko, V. Yu Kravets, and D. V. Pekur. "Impact of changing the shape of gravity heat pipe with threaded evaporator on its heat transfer characteristics." Technology and design in electronic equipment, no. 1-2 (2023): 27–33. http://dx.doi.org/10.15222/tkea2023.1-2.27.

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The modern development of electronics is associated with the problem of reducing the mass and size of the equipment while increasing its power. This leads to an increase in the temperature of both individual elements and the device as a whole, which contributes to a decrease in equipment reliability. This makes the development of inexpensive yet efficient cooling systems an urgent task. One of the ways to solve this problem is to use heat pipes of a new simplified design in cooling systems. This article compares the thermal characteristics of a cylindrical copper gravity heat pipe with a threaded evaporator before and after flattening. The working fluid used in the experiment was R141b. Experimental studies were conducted at two tilt angles relative to the horizontal under the conditions of forced convection cooling of the condensation zone. The influence of the change in the shape of the body from cylindrical to flat on the temperature in the heating zone of the heat pipe, thermal resistance, and heat transfer coefficients in the evaporation and condensation zones was shown in the range of heat power from 5 to 70 W. The choice of the heat pipe is justified based on the maximum thermal loads of electronic components and the orientation of the cooling system in space. Changing the shape of heat pipe from cylindrical to flat leads to a decrease in the maximum thermal power transmitted, but a flat heat pipe shape is more technologically feasible for use in cooling systems of electronic equipment.

22

Mishra, Dipti Prasad, and Subhash Chandra Paramanik. "Computation of Air Entrainment into a Mixing Pipe: An Experimental and Numerical Analysis." Journal of Mechanical Engineering 16, no. 2 (August 1, 2019): 11–28. http://dx.doi.org/10.24191/jmeche.v16i2.15323.

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Computations of entrainment of air into a pipe were performed by placing an air jet at the bottom of the pipe. An experiment was performed with cylindrical mixing pipe having different diameter, length and jet location. A flow meter was used to measure the flow through the nozzle and velocity at the mixing pipe exit was measured by anemometer. CFD analyses were performed using Ansys-Fluent 16 to match the experimental results for exit velocity and amount of air sucked into the pipe. Further numerical investigations were performed for a mixing pipe with hot jet to estimate the amount of air entrained as a function pipe diameter, pipe length, nozzle protrusion and pipe shape. It was found from the numerical simulations there exists an optimum pipe length and nozzle protrusion for highest entrainment of air. Also a particular frustum shaped pipe could suck highest air compared to cylindrical shaped pipe.

23

Hayashi, Takahiro, Koichiro Kawashima, Zongqi Sun, and Joseph L. Rose. "Guided Wave Propagation Mechanics Across a Pipe Elbow." Journal of Pressure Vessel Technology 127, no. 3 (January 24, 2005): 322–27. http://dx.doi.org/10.1115/1.1990210.

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Wave propagation across a pipe elbow region is complex. Subsequent reflected and transmitted waves are largely deformed due to mode conversions at the elbow. This prevents us to date from applying guided waves to the nondestructive evaluation of meandering pipeworks. Since theoretical development of guided wave propagation in a pipe is difficult, numerical modeling techniques are useful. We have introduced a semianalytical finite element method, a special modeling technique for guided wave propagation, because ordinary finite element methods require extremely long computational times and memory for such a long-range guided wave calculation. In this study, the semianalytical finite element method for curved pipes is developed. A curved cylindrical coordinate system is used for the curved pipe region, where a curved center axis of the pipe elbow region is an axis (z′ axis) of the coordinate system, instead of the straight axis (z axis) of the cylindrical coordinate system. Guided waves in the z′ direction are described as a superposition of orthogonal functions. The calculation region is divided only in the thickness and circumferential directions. Using this calculation technique, echoes from the back wall beyond up to four elbows are discussed.

24

DUGUET, Y., A. P. WILLIS, and R. R. KERSWELL. "Slug genesis in cylindrical pipe flow." Journal of Fluid Mechanics 663 (October 5, 2010): 180–208. http://dx.doi.org/10.1017/s0022112010003435.

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Transition to uniform turbulence in cylindrical pipe flow occurs experimentally via the spatial expansion of isolated coherent structures called ‘slugs’, triggered by localized finite-amplitude disturbances. We study this process numerically by examining the preferred route in phase space through which a critical disturbance initiates a ‘slug’. This entails first identifying the relative attractor – ‘edge state’ – on the laminar–turbulent boundary in a long pipe and then studying the dynamics along its low-dimensional unstable manifold, leading to the turbulent state. Even though the fully turbulent state delocalizes at Re ≈ 2300, the edge state is found to be localized over the range Re = 2000–6000, and progressively reduces in both energy and spatial extent as Re is increased. A key process in the genesis of a slug is found to be vortex shedding via a Kelvin–Helmholtz mechanism from wall-attached shear layers quickly formed at the edge state's upstream boundary. Whether these shedded vortices travel on average faster or slower downstream than the developing turbulence determines whether a puff or a slug (respectively) is formed. This observation suggests that slugs are out-of-equilibrium puffs which therefore do not co-exist with stable puffs.

25

Wei, Yu Lan, Bing Li, Li Gao, and Ying Jun Dai. "Vibration Response of a Thin-Walled Cylindrical Pipe with Liquid." Applied Mechanics and Materials 189 (July 2012): 345–49. http://dx.doi.org/10.4028/www.scientific.net/amm.189.345.

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Vibration characteristics of the thin-walled cylindrical pipe are affected by the liquid within the pipe. The natural frequencies and vibration modes of the pipe without liquid are analyzed by the theory of beam bending vibration and finite element model, which is based on the Timoshenko beam model. The first three natural frequencies and vibration modes of the pipe with or without liquid are acquired by experiments. As shown in the experiment results, the natural frequencies of the containing liquid pipe are lower than the natural frequencies of the pipe without liquid.

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. Sahu, S. R., and D. P. Mishra*. "Effect of Pipe Configurations on Air Entrainment into a Louvered Cylindrical Pipe: A Comparison between Open and Close Entrance of a Pipe." International Journal of Engineering Research 4, no. 4 (April 1, 2015): 173–77. http://dx.doi.org/10.17950/ijer/v4s4/402.

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Towfighi, S., T. Kundu, and M. Ehsani. "Elastic Wave Propagation in Circumferential Direction in Anisotropic Cylindrical Curved Plates." Journal of Applied Mechanics 69, no. 3 (May 1, 2002): 283–91. http://dx.doi.org/10.1115/1.1464872.

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Ultrasonic nondestructive inspection of large-diameter pipes is important for health monitoring of ailing infrastructure. Longitudinal stress-corrosion cracks are detected more efficiently by inducing circumferential waves; hence, the study of elastic wave propagation in the circumferential direction in a pipe wall is essential. The current state of knowledge lacks a complete solution of this problem. Only when the pipe material is isotropic a solution of the wave propagation problem in the circumferential direction exists. Ultrasonic inspections of reinforced concrete pipes and pipes retrofitted by fiber composites necessitate the development of a new theoretical solution for elastic wave propagation in anisotropic curved plates in the circumferential direction. Mathematical modeling of the problem to obtain dispersion curves for curved anisotropic plates leads to coupled differential equations. Unlike isotropic materials for which the Stokes-Helmholtz decomposition technique simplifies the problem, in anisotropic case no such general decomposition technique works. These coupled differential equations are solved in this paper. Dispersion curves for anisotropic curved plates of different curvatures have been computed and presented. Some numerical results computed by the new technique have been compared with those available in the literature.

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Suciu, Barenten. "Evaluation of the Damping Produced by the Motion of a Permanent Magnet inside of a Conductive Pipe." European Journal of Engineering and Technology Research 9, no. 1 (January 17, 2024): 16–22. http://dx.doi.org/10.24018/ejeng.2024.9.1.3126.

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In this study, a method to evaluate the electro-magnetic damping effect produced by the movement of a permanent magnet inside of a conductive pipe, is proposed. Neither the residual flux density of the magnet, nor the electric conductivity of the pipe is required, but instead, only the magnet height, the pipe length, and the falling time of the magnet inside the tube, are necessary to compute the damping coefficient. Accordingly, cylindrical neodymium magnets of close residual flux densities, but various diameters and heights, are tested against copper pipes of various thicknesses. Using the falling time measured for each magnet-pipe combination, the corresponding damping coefficient is computed, and the influence of various geometrical parameters on the damping coefficient is clarified. Clearance between the magnet and pipe is identified as essential to describe this damping phenomenon.

29

Ristic, Slavica, Jelena Ilic, Djordje Cantrak, Ognjen Ristic, and Novica Jankovic. "Estimation of laser-Doppler anemometry measuring volume displacement in cylindrical pipe flow." Thermal Science 16, no. 4 (2012): 1027–42. http://dx.doi.org/10.2298/tsci1204027r.

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Laser-Doppler anemometry application in measurements of the 3-D swirl turbulent flow velocity in the cylindrical pipe, behind the axial fan, have been analysed. This paper presents a brief overview of uncertainty sources in the laser-Doppler anemometry measurements. Special attention is paid to estimation of laser-Doppler anemometry measuring volume positioning in cylindrical pipe flow due to optical aberrations, caused by the pipe wall curvature. The hypothesis, that in the central part of the pipe (r/R < 0.6) exists a small, or negligible pipe wall influence on laser- -Doppler anemometry measuring position, is investigate. The required corrections, for measurements of axial, tangential, and radial velocity components such: shift of measuring volume and its orientation are analyzed and determined for used test rig and for some other pipe geometries.

30

Bai, Xiao Lan, and Yu Zhang. "Engineering Rules-Based Orthogonal and Variable-Steps Pipe Routing Algorithm for Aero-Engines." Advanced Materials Research 442 (January 2012): 104–8. http://dx.doi.org/10.4028/www.scientific.net/amr.442.104.

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Pipe routing is to design the routes for pipes in 3D space, meeting various constraints and engineering rules. This paper proposes the engineering rules-based orthogonal and variable-steps pipe routing algorithm. Firstly, the cylindrical coordinate system was adopted to describe the layout space and obstacles. In view of two endpoints of the pipe and obstacles in between, the local searching space was built. Then, the searching algorithm was given according to engineering rules, which was involved with the orthogonal searching directions and their order, the searching variable-steps. Moreover, the specific flow of this algorithm was described. The algorithm requires less memory space and has a fast search speed. The case study shows it is feasible and effective.

31

Xiang, Jianhua, Xi-bo Chen, Jiale Huang, Chunliang Zhang, Chao Zhou, and Haoxing Zheng. "Thermal Performances Investigation of Anti-Gravity Heat Pipe with Tapering Phase-Change Chamber." Energies 13, no. 19 (September 24, 2020): 5036. http://dx.doi.org/10.3390/en13195036.

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The objective of this study was to fabricate anti-gravity heat pipes with a tapering column phase-change chamber and changeable cross-sectional wick structure. The thermal performances of the anti-gravity heat pipes were experimentally investigated. Results show that the thermal resistances of the different heat pipes are less than 0.03 °C/W, except for the sharp conical chamber heat pipe under anti-gravity heating conditions (0.121 °C/W). Start-up times of different types of heat pipes are similar and the temperatures are steady within 3 to 5 min. The heat transfer ability of a conical chamber is always better than that of a cylindrical one. The performance of the sharp conical chamber heat pipe is the best under gravity assistance heating conditions. Contrarily, the blunt conical chamber heat pipe has the best heat transfer ability under anti-gravity heating conditions. Moreover, the heat transfer capability of the blunt conical chamber heat pipe is unaffected by the relative position of the heat and cold sources, which is suitable for constant temperature cooling applications with frequent switching of the heat and cold sources.

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Shevchenko, Nataliya, Vladyslav Kaliuzhnyi, and Viktoriia Andriievska. "NUMERICAL SIMULATION OF PROCESS FLUID FLOW IN THE PIPES OF A COILED TUBING INSTALLATION." Bulletin of the National Technical University "KhPI". Series: Hydraulic machines and hydraulic units, no. 1 (October 10, 2023): 60–65. http://dx.doi.org/10.20998/2411-3441.2023.1.10.

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Today, one of the modern trends is the use of coiled tubing technologies and improvement of the composition of washing agents (liquids). The features of coiled tubing technological sections are considered – spiral pipe laying, the ratio of the main dimensions of flexible pipes, drum and guide sector. The presence of a pipe conveyor gives special responsibility for ensuring the movement of a string of flexible pipes within a given load range. The length of the pipes reaches 5000 m. The radial dimensions of the well are 150 mm. The stages of determining the main parameters of a pumping unit for supplying process fluid to a well are listed. When carrying out technological operations, the pump must overcome the hydrodynamic losses of direct and reverse fluid supply into the well. It is necessary to take into account the possibility of misalignment of cylindrical pipes. To carry out technological operations to intensify oil production, multicomponent process fluids are used. The presence of chemical and polymer additives in liquids has a significant impact on the properties of aqueous and hydrocarbon systems and forms gels of varying density, viscosity and rheology. It is known that even a small content of polymer additives in the solution (6–30 g/l) leads to non-Newtonian behavior of the washing fluid in the well pipes. The work uses experimental data obtained by Region LLC of Ukraine. For numerical modeling of the hydrodynamic characteristics of a process fluid, linear and nonlinear models of a viscous fluid are used. In all cases, steady flow was considered. Due to the fact that the work uses the academic version of the ANSYS CFD package with limited capabilities in terms of the number of cells, the computational areas were selected using simplified schemes. The following schemes are considered: spiral – guide – straight pipe, only the spiral part of winding the pipe on a drum, an annular space between cylindrical pipes with possible eccentricity. The results of numerous studies are used to predict hydraulic resistance coefficients in pipes and the characteristics of pumping equipment for supplying process fluid to a well. The results can also be used for verification strength calculations of flexible pipe columns for hazardous sections.

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B. I., Obi, Okorie S. I., and Nlemigwe J. C. "Semi-Analytical Solution of Natural Convection Flow of Non-Newtonian Fluid With Temperature-Dependent Viscosity In Pipe." International Journal for Research in Applied Science and Engineering Technology 11, no. 9 (September 30, 2023): 782–86. http://dx.doi.org/10.22214/ijraset.2023.55618.

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Abstract: This paper presents semi-analytical solution of natural convection flow of non-newtonian fluid with temperaturedependent viscosity in pipe. The governing equations were solved using perturbation technique. The results obtained were analyzed for various thermo-solutal parameters involved in the dimensionless equations. Results within the constant viscosity show that increase in these parameters increases the velocity of the fluid flow as well as the temperature of the cylindrical pipe. It is observed that increase in the Reynold’s viscosity indices increases the temperature of the cylindrical pipe greatly.

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Idrus, Fairosidi, Nazri Mohamad, Ramlan Zailani, Wirachman Wisnoe, and Mohd Zulkifly Abdullah. "Thermal Performance of a Cylindrical Heat Pipe for Different Heat Inputs and Inclination Angles." Applied Mechanics and Materials 661 (October 2014): 148–53. http://dx.doi.org/10.4028/www.scientific.net/amm.661.148.

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An experimental study on thermal performance of a copper heat pipe operated with sintered powder wick has been performed. A miniature cylindrical heat pipe with small outer diameter, Ø10 mm and 300 mm in length, has been chosen in the study. An attempt is also made to design, fabricate and assemble a heat pipe test rig to be used for the experiment. The performance of the heat pipe is investigated at various heat inputs and inclination angles (orientations). The aim of this study is to evaluate and compare the thermal performance of the heat pipe based on temperature differential between the evaporator and condenser sections, thermal resistance and thermal conductivity. The results show that the orientation and heat input have significant effects on the thermal performance of the cylindrical heat pipe. The Ø10 mm heat pipe operates with good thermal performance at the heat input of 70 W - 80 W and at the inclination angle of 30° - 60°.

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Hambric, Stephen. "Practical Tutorial on cylindrical structure vibro-acoustics Part 1 - Vibrations." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 7 (February 1, 2023): 140–49. http://dx.doi.org/10.3397/in_2022_0026.

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The mathematics which describe the vibroacoustic behavior of cylindrical structures are imposing to say the least. Part 1 of this practical tutorial demystifies cylindrical shell vibration theory by using measured data from actual shells and pipes to explain key concepts. For any shell, you can estimate frequency ranges where shells behave like simple beams and flat plates, greatly simplifying calculations of modes of vibration and mobilities. The key is first calculating the ring frequency - the frequency where membrane waves can propagate fully around the shell circumference. Simple infinite structure theory may then be used to compute mean mobilities for beam, shell, and flat plate behavior. Modes of vibration for a cylinder depend on both longitudinal and circumferential harmonics, or a helical wavenumber. Cremer's simple approximate resonance frequency formula is used to show examples for a large diameter short shell and a small diameter long shell (a pipe). Finally, the measured modal densities of an elbowed pipe are compared to estimates from an empirical expression for modal density of a shell. In all cases in this tutorial, measurements and simple estimates agree well, showing that cylindrical shell vibrations may be estimated without difficult math or complex computer models.

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Alves dos Santos Júnior, Valdecir, Severino Rodrigues de Farias Neto, Antonio Gilson Barbosa de Lima, Igor Fernandes Gomes, Israel Buriti Galvão, Célia Maria Rufino Franco, and João Evangelista Franco do Carmo. "Heavy Oil Laminar Flow in Corrugated Ducts: A Numerical Study Using the Galerkin-Based Integral Method." Energies 13, no. 6 (March 15, 2020): 1363. http://dx.doi.org/10.3390/en13061363.

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Fluid flow in pipes plays an important role in different areas of academia and industry. Due to the importance of this kind of flow, several studies have involved circular cylindrical pipes. This paper aims to study fully developed internal laminar flow through a corrugated cylindrical duct, using the Galerkin-based integral method. As an application, we present a study using heavy oil with a relative density of 0.9648 (14.6 °API) and temperature-dependent viscosities ranging from 1715 to 13000 cP. Results for different fluid dynamics parameters, such as the Fanning friction factor, Reynolds number, shear stress, and pressure gradient, are presented and analyzed based on the corrugation number established for each section and aspect ratio of the pipe.

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Litvintceva, A. A., N. I. Volkov, N. I. Vorogushina, V. A. Moskovskikh, and V. V. Cheverda. "The effect of operating parameters on the heat transfer in the heat pipe." Journal of Physics: Conference Series 2119, no. 1 (December 1, 2021): 012088. http://dx.doi.org/10.1088/1742-6596/2119/1/012088.

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Abstract Heat pipes are a good solution for temperature stabilization, for example, of microelectronics, because these kinds of systems are without any moving parts. Experimental research of the effect of operating parameters on the heat transfer in a cylindrical heat pipe has been conducted. The effect of the working fluid properties and the porous layer thickness on the heat flux and temperature difference in the heat pipe has been investigated. The temperature field of the heat pipe has been investigated using the IR-camera and K-type thermocouples. The data obtained by IR-camera and K-type thermocouples have been compared. It is demonstrated the power transferred from the evaporator to the condenser is a linear function of the temperature difference between them.

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Li, Bo, Meng-Xiong Tang, He-Song Hu, Chun-Lin Liu, Zao Ling, Ding-Li Su, Zhen-Kun Hou, and Ying-Ping Xiao. "Theoretical Analysis of Drilling Unloading and Pile-Side Soil Pressure Recovery of Nonsqueezing Pipe Piles Installed in K0-Consolidated Soils." Buildings 14, no. 6 (June 5, 2024): 1670. http://dx.doi.org/10.3390/buildings14061670.

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Drilling with prestressed concrete (DPC) pipe pile is a nonsqueezing pile sinking technology, employing drilling, simultaneous pile sinking, a pipe pile protection wall, and pile side grouting. The unloading induced by drilling, the pipe pile supporting effect, and the dissipation of the negative excess pore-water pressure after pile sinking, all of which have significant effects on the recovery of soil pressure on the pile side, are the main concerns of this study, which aim to establish a method to reasonably evaluate the timing selection of pile side grouting. The theoretical solutions for characterizing the unloading and dissipation of the negative excess pore-water pressure are presented based on the cylindrical cavity contraction model and the separated variable method. By inverse-analyzing the measured initial pore pressure change data from borehole unloading, initial soil pressures on the pile side of each soil layer are determined using the presented theoretical solutions. Then, the presented theoretical solutions were verified through a comparative analysis with the corresponding measured results. Moreover, by introducing time-dependent coefficients αt1 and αt2 to characterize the pore pressure dissipation and rheology effects, the effects of the negative excess pore-water pressure dissipation on the pile-side soil pressure recovery are discussed in detail.

39

Guerra, Edmundo, Rodrigo Munguía, Yolanda Bolea, and Antoni Grau. "Detection and Positioning of Pipes and Columns with Autonomous Multicopter Drones." Mathematical Problems in Engineering 2018 (June 21, 2018): 1–13. http://dx.doi.org/10.1155/2018/2758021.

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A multimodal sensory array to accurately position aerial multicopter drones with respect to pipes has been studied, and a solution exploiting both LiDAR and vision sensors has been proposed. Several challenges, including detection of pipes and other cylindrical elements in sensor space and validation of the elements detected, have been studied. A probabilistic parametric method has been applied to segment and position cylinders with LIDAR, while several vision-based techniques have been tested to find the contours of the pipe, combined with conic estimation cylinder pose recovery. Multiple solutions have been studied and analyzed, evaluating their results. This allowed proposing an approach that combines both LiDAR and vision to produce robust and accurate pipe detection. This combined solution is validated with real experimental data.

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Wendoloski, J. C., F. R. Fricke, and R. C. McPhedran. "Boundary Conditions Of A Flanged Cylindrical Pipe." Journal of Sound and Vibration 162, no. 1 (March 1993): 89–96. http://dx.doi.org/10.1006/jsvi.1993.1104.

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Na, Won-Bae, and Tribikram Kundu. "EMAT-Based Inspection of Concrete-Filled Steel Pipes for Internal Voids and Inclusions." Journal of Pressure Vessel Technology 124, no. 3 (July 26, 2002): 265–72. http://dx.doi.org/10.1115/1.1491271.

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Concrete-filled steel pipes have been used as piles for supporting civil and marine structures. These piles provide good bending resistance, and can be easily spliced for long depth installation. However, these piles are usually exposed in hostile environments such as seawater and deicing materials. Thus, the outside corrosion of the steel pipe can reduce the wall thickness and the corrosion-induced delamination of internal concrete can increase internal volume or pressure. In addition, the void that can possibly exist in the pipe reduces the bending resistance. To avoid structural failure due to this type of deterioration, appropriate inspection and repair techniques are to be developed. The acoustic method is attractive for this inspection since it is relatively simple and versatile. Especially, guided wave techniques have strong potentials for this inspection because of long-distance inspection capability. There are different transducer-coupling mechanisms available for the guided wave inspection techniques. Electro-magnetic acoustic transducers (EMATs) give relatively consistent results in comparison to piezoelectric transducers since they do not need any couplant. EMATs are used for transmitting and receiving cylindrical guided waves through concrete-filled steel pipes. It is shown that EMAT-generated cylindrical guided wave techniques have good potential for the interface inspection of concrete-filled steel pipes.

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Burkitbayev, Arman, Delika M. Weragoda, Francesco Ciampa, Kin Hing Lo, and Guohong Tian. "A Numerical and Experimental Investigation on a Gravity-Assisted Heat-Pipe-Based Battery Thermal Management System for a Cylindrical Battery." Batteries 9, no. 9 (September 5, 2023): 456. http://dx.doi.org/10.3390/batteries9090456.

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A thermal management system for lithium-ion batteries is an essential requirement for electric vehicle operation due to the large amount of heat generated by these cylindrical batteries during fast charging/discharging. Previously, researchers have focused mostly on pouch and prismatic cells with heat pipes arranged in the horizontal direction. The current study introduces a novel vertically-oriented heat-pipe-based hybrid cooling battery thermal management system (BTMS) that numerically evaluates the thermal performance of the cylindrical batteries and the flow pattern within the cooling channel at C rates as high as 8C. The model was experimentally validated using five round heat pipes in a vertical orientation utilizing the effect of gravity to assist condensate flow through the heat pipe. The heat pipes were arranged in a staggered pattern to improve the overall heat transfer performance by means of forced convective cooling. This design allowed for maximizing the heat transfer process despite the lack of contact between the cylindrical-shaped batteries and round-shaped heat pipes. During this study, the temperatures of the evaporator end and the condenser end of the heat pipes and battery surfaces were monitored, and the thermal performances of the system were determined at varying inlet cooling liquid temperatures (15, 20, 25 °C) and high rates of 4C and 8C. Representatively, the proposed hybrid BTMS could maintain a maximum battery surface temperature of around 64 °C and a temperature difference between cells under 2.5 °C when the inlet velocity was 0.33 L/min and the cooling liquid temperature was 25 °C. The high temperatures reached the fourth and fifth heat pipes because they are part of the backflow design and are affected by backflow temperature. Nevertheless, the current design shows that the proposed system can maintain battery surface temperatures well within 5 °C.

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Trubayev, Oleksandr, and Andrew Larin. "On the modeling of boundary conditions for determining the critical speeds of rotation of rotors." Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines, no. 2 (December 31, 2022): 56–60. http://dx.doi.org/10.20998/2078-9130.2022.2.270867.

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The article is devoted to the definition of boundary conditions that allow achieving adequate results when calculating the critical speeds of rotation of rotors based on finite element models. Experimental determination of the frequencies of free vibrations of a laboratory rotor on ball bearings was carried out using a vibration measuring complex developed by the authors. Numerical studies of the free vibrations of a laboratory rotor and a cylindrical pipe with a wall thickness to length ratio of 1/10 were performed on the basis of a three-dimensional finite element model under various boundary conditions. Movable and fixed cylindrical hinges corresponding to floating bearings are used as supports in the calculation scheme of the laboratory rotor. Due to the fact that the dimensions of the bearings along the length of the shaft are small compared to the total length, it is assumed in the calculation model that the shaft is hinged along the edges at separate points of one circle on each bearing. Shaft mounting options at two, four and eight points are considered. The options for fastening a cylindrical pipe in the extreme sections at two points, a quarter of a circle and a full circle are considered. Comparison of experimental and numerical results, solutions obtained analytically and on the basis of the finite element method is carried out. An analysis of the modes of natural vibrations showed that with various options for fixing a cylindrical pipe, vibration modes arise associated with the deformation of the pipe as a shell. For example, when fixing a pipe along a quarter of a circle, among the forms №1-№10, only the second corresponds to the deformation of the pipe as a beam. The results of the study of free vibrations of a laboratory rotor show that the best option for boundary conditions, which makes it possible to approach the results of the experiment, is fastening on each bearing at two points located on the neutral line of the cross section when the rotor is bent. Numerical studies of the eigen frequencies of a cylindrical pipe show that it is with this type of boundary conditions that one can obtain results that are closest to the analytical solution.

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Imène Saad, Samah Maalej, and Mohamed Chaker Zaghdoudi. "Investigation of the Thermal Performance of a Nanofluid-filled Grooved Cylindrical Heat Pipe for Electronics Cooling." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 99, no. 2 (November 11, 2022): 135–54. http://dx.doi.org/10.37934/arfmts.99.2.135154.

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Thermal management of electric and electronic components is a critical issue and needs to consider enhanced cooling systems such as heat pipes. This study deals with the theoretical modeling of a nanofluid-filled copper cylindrical heat pipe for electronics cooling applications. The heat pipe includes helicoidal and trapezoidal capillary grooves. The model can predict the capillary limit as well as the heat transfer in the different sections of the heat pipe. The thermal resistances of the evaporation and condensation sections are calculated based on correlations for heat transfer, which are determined from experiments. Two working nanofluids are considered: water/CuO and water/Al2O3. The thermal performances are predicted for different concentrations and heat sink temperatures, and the heat pipe is positioned horizontally. For both nanofluids, the results indicate that augmenting the concentration of the nanoparticles leads to a capillary limit increase reaching up to 14 % and 25 % for water/Al2O3 and water/CuO, respectively, and an overall thermal resistance decrease reaching up to 51 % and 68 % for water/Al2O3 and water/CuO. Moreover, decreases up to 24 %, and up to 18 % in the evaporator wall temperatures are obtained for water/CuO and water/Al2O3 nanofluids, respectively. The nanofluid water/CuO gives the best thermal performance whatever the nanoparticle concentration and heat sink temperature.

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Bannikov, Alexander I., Vasilisa I. Alekseychuk, Olga A. Makarova, and Nikolay A. Dyatlov. "The Quality of a Surface Received by Processing the End of a Large Diameter Pipe with the Use of a Single-Row Cylindrical Brush." Materials Science Forum 973 (November 2019): 75–79. http://dx.doi.org/10.4028/www.scientific.net/msf.973.75.

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In this article we study the received quality of a welded large-diameter pipe after the processing by a single-row cylindrical brush. The speed of the brush influences the roughness of the pipe surface.

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FORBES, LAWRENCE K., and MICHAEL A. BRIDESON. "ON MODELLING THE TRANSITION TO TURBULENCE IN PIPE FLOW." ANZIAM Journal 59, no. 1 (July 2017): 1–34. http://dx.doi.org/10.1017/s1446181117000256.

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As a possible model for fluid turbulence, a Reiner–Rivlin-type equation is used to study Poiseuille–Couette flow of a viscous fluid in a rotating cylindrical pipe. The equations of motion are derived in cylindrical coordinates, and small-amplitude perturbations are considered in full generality, involving all three velocity components. A new matrix-based numerical technique is proposed for the linearized problem, from which the stability is determined using a generalized eigenvalue approach. New results are obtained in this cylindrical geometry, which confirm and generalize the predictions of previous recent studies. A possible mechanism for the transition to turbulent flow is discussed.

47

Chidsey, Thomas, David Eby, and Douglas Sprinkel. "A Breccia Pipe in the Deseret Limestone, South Flank of the Uinta Mountains, Northern Utah." Geosites 1 (March 11, 2020): 1–10. http://dx.doi.org/10.31711/geosites.v1i1.55.

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A breccia pipe is a cylindrical- or irregular-shaped mass of brecciated rock. A breccia consists of broken, angular fragments of rock cemented together by a fine-grained matrix. Hydrothermal breccia pipes form when hydrothermal solutions force their way towards the surface through zones of weakness or fracture zones and naturally break up the rocks in the process, i.e., hydrofracturing; breccia pipes can also form by collapse. Hydrothermal breccia pipes can contain ore deposits and, as will be discussed later, are associated with some large oil and gas accumulations in southeastern Utah.

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Tsarenko, S. N., A. V. Kostenko, E. L. Ignatkina, and E. A. Ponamareva. "Simulating Interaction of Liquid Steel with Gate Wall at Harmonic Motion." IOP Conference Series: Earth and Environmental Science 988, no. 5 (February 1, 2022): 052013. http://dx.doi.org/10.1088/1755-1315/988/5/052013.

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Abstract The problem of determining the forces of interaction of a viscous fluid with the cylindrical pipe wall is considered. It is assumed that near the pipe wall, the fluid motion is completely determined by viscous forces. The pipe moves along the streamline. The annular fluid element motion law is a special case of the Navier–Stokes equation in a cylindrical coordinate system. The equation is solved by the Fourier method in Bessel functions. Considering the orthogonality of the eigenfunctions, an equation for the squared norm is found. As an example, the case is considered when the pipe is subjected to vibration. Equations have been obtained for the velocities and viscous friction forces in the laminar sublayer. It has been found that when the pipe moves harmonically, the velocities and shear stresses at the pipe wall do not reach their maximum synchronously. The distribution of velocities and stresses in the section of the steel-pouring ladle gate channel has been considered for three vibration modes. The solution provided can be, in particular, used to determine the fluid–pipe wall interaction forces when the pipe is technologically affected by vibration, impulse, etc., as well as study moving joints such as piston, plunger, etc.

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Kita, Jaroslaw, Annica Brandenburg, and Ralf Moos. "Application of Cylindrical Pipe-Type LTCC Substrates as a Platform for Multi-Array Gas Sensors." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, CICMT (September 1, 2013): 000288–92. http://dx.doi.org/10.4071/cicmt-tha46.

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Thick-film technology-based gas sensors have been known for many years. On a ceramic substrate, a thick-film heater, electrodes, and a gas sensitive layer are deposited. Due to the ease of layer deposition, such structures are usually manufactured as planar ones. However, recently-suggested cylindrical pipe-type substrates made in LTCC technology offer unique inherent advantages for gas sensor technology, like a uniform temperature profile along the gas sensitive layer or a reduction of the distortion of the gas flow in the pipe. As shown in our previous study, cylindrical LTCC substrates with inner electrodes and integrated heaters may be very promising in the field of high-temperature gas sensors. In this paper, we continue our work on cylindrically shaped LTCC sensor substrates, with special focus on the construction of a platform with multiple heater/electrodes couples for multi-array gas sensors. For such multi-sensor structures, decoupling of the heat sources is the most important platform feature. Therefore, a cylindrical substrate with integrated heaters was FEM-modeled and optimized in the first stage. Subsequently, tubes with three integrated heaters were prepared. In this paper, it is discussed how reduced thermal masses can be obtained by thinner tube walls or by the integration of laser-patterned cavities and how different integrated heat sources can be decoupled.

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Ramachandran, Raghavan, Kalliappan Ganesan, and Lazarus Asirvatham. "The role of hybrid nanofluids in improving the thermal characteristics of screen mesh cylindrical heat pipes." Thermal Science 20, no. 6 (2016): 2027–35. http://dx.doi.org/10.2298/tsci150710006r.

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Experiments were conducted to study the thermal performance of meshed wick heat pipe by varying the working fluid and heat input. In this work four screen mesh wicked heat pipes were fabricated and tested. All the heat pipes were tested for heat input from 50W to 250W each with an increment of 50W in each step. The heat input range selected in this study is commonly encountered in most of the electronic application devices. The thermal resistance of all the heat pipes charged with different working fluids such as DI water, Al2O3/DI water nanofluid of volume concentration 0.1 % and hybrid nanofluid volume concentration 0.1%( with two different combinations of (Al2O3 50%- CuO 50%)/DI water and (Al2O3 25%- CuO 75%)/DI water)was determined. The maximum percentage reduction was found to be 58.87% for the hybrid nanofluid of (Al2O3 25%- CuO 75%)/DI water compared to base fluid. An important observation from the study is that, use of hybrid nanofluid can raise the operating range of the heat pipe beyond 250W which makes hybrid nanofluid as a potential substitute for the conventional working fluid.

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