Cylinder Body Research Articles

Serviceability restoration of operating fastening elements of the high pressure cylinder body of HPP steam turbines

Serviceability restoration of operating fastening elements of the high pressure cylinder body of HPP steam turbines

Effect of thread depth and implant shape on stress distribution in anterior and posterior regions of mandible bone: A finite element analysis

The ability of modern implant dentistry to achieve goals such as normal contour, function, comfort, esthetics, and health to totally or partially edentulous patients guaranteed it to be more effective and reliable method for the rehabilitation process of many challenging clinical situations. In regard to this, the current study evaluates the effect of changing implant shape design parameters on interface stress distribution within the mandible bone. A numerical procedure based on finite element (FE) method was adopted to investigate the influence of using different body design and thread depth of the inserted implant on the final stress situation. For the purpose of evaluation, a three-dimensional realistic FE models of mandible bone and inserted implant were constructed and analyzed using a pack of engineering software (Solidworks, and ANSYS). Six different commercial implant models (cylindrical and tapered) with three different V-shaped thread depths (0.25 mm, 0.35 mm, and 0.45 mm) were designed to be used in this study. The suggested implants used in this study were threaded in two different locations of mandible bone; the anterior region (Type I model) and posterior region (Type II model). A vertical static load of 250 N was directly applied to the center of the suprastructure of the implant for each model. For both models, evaluations were achieved to figure out the stress distribution patterns and maximum equivalent von Mises. The results obtained after implementation of FE dental-implant models show that the highest stresses were located at the crestal cortical bone around the implant neck. In addition, the simulation study revealed that taper body implant had a higher peak value of von Mises stress than that of cylinder body implants in all types of bones. Moreover, a thread depth of 0.25 mm showed highest peak of maximum von Mises stresses for Type I and Type II models. The simulation results indicate that all models have the same von Mises stress distribution pattern and higher peak von Mises stresses of the cortical bone were seen in tapered implant body in contrast to the cylindrical body.

Liquefied Petroleum Gas (LPG) Bottling Process and Required Safety During Bottling: A Case Study

Energy security is very important in the current world. Liquefied Petroleum Gas (LPG) is one of the significant energy sources. LPG can be produced from natural gas processing as well as crude oil refining. Now LPG is available in different sizes of cylinder. The bottling system of LPG in the cylinder is the main discussion topic of this paper. Safety requirement during bottling work is also explained in this research article. LPG cylinder can be filled in both automatically and manually. The automatic filling system is more secure and effective. A visible check of the cylinder is needed before refilling. Washing and drying are also conducted before filling if necessary. To avoid gas leakage from cylinder valve “O” ring must be checked before gas filling, if it is missing in valve must put it. After putting the cylinder body weight, modern machine carousel runs to fill the LP gas in the cylinder. The automatic carousel machine can fill several cylinders at a time. Cylinder checked by automatic weight checking scale to be ensured filling the stipulated value. After this to check the valve leak of LPG filled cylinder for security and safety. If all the process is positive, it is needed to put a safety cap on the cylinder valve and attach the thermo-sleeve for more safety. Then the filled cylinders are kept in the storage for distribution. The Personal Protection Equipment’s (PPEs) is must to wear during filling the cylinder.

Experiment on Noise Source Identification Based on Acoustic Array

In order to effectively control the noise source, the experiments on sound source identification were conducted on the generator side, intake side, and exhaust side of the test bench of the 2VQS EFI Volkwagen engine under different working conditions using the acoustic array. And applying the beamforming algorithm, the main noise sources at frequency range of 1000∼2000Hz were located at the three test surfaces. The result show that: In front of generator side, the source was mainly located at the generator, the crankshaft pulley and the intake manifold and the strongest sound pressure was focused on the generator; In front of intake side, the source was mainly located at the generator, the cylinder body, and the transmission case, and the strongest sound pressure was focused on the cylinder body; In front of exhaust side, the source was mainly located at the cylinder body, the three-way catalytic converter and the transmission case, and the strongest sound pressure was focused on the generator pulley and gear system. The strongest sound pressure of the three test surfaces increase with the rotational speed of engine, was nearly equal to 2500r/min, and changed smoothly more than 2500r/min.It provided a way for controlling engine noise.

Calculation of seismic performance of nuclear containment vessel structure under design base earthquake

To study dynamic response of the nuclear containment vessel structure under the action of design basis earthquake and evaluate the seismic performance of structure, the elastic time history analysis of nuclear containment vessel structure is performed to determine the most unfavorable displacement and stress distribution. A 3D nuclear containment vessel structure was modelled in FE package tool ABAQUS to perform time analysis. The maximum displacement in X direction occurred at the top of the structure dome under the excitation of three different seismic records; the time at which the top response acceleration peak of the structure does not coincide with the time of the base input seismic wave peak, and it is mainly related to the relation between the period of natural vibration and the period of seismic waves; Under the different seismic waves’ excitation of 0.2 g peak acceleration, the tensile stress around the equipment hole and near connection between the bottom plate and the cylinder body is large, while the maximum tensile stress appears around the hole of the device. In the design of nuclear containment vessel structure, the displacement of the top should be controlled and the reinforcement ratio around equipment hole should be increased.

Bond Graph Simulation of Error Propagation in Position Estimation of a Hydraulic Cylinder Using Low Cost Accelerometers

The indirect calculation from acceleration of transversal displacement of the piston inside the body of a double effect linear hydraulic cylinder during its operating cycle is assessed. Currently an extensive effort exists in the improvement of the mechanical and electronic design of the highly sophisticated MEMS accelerometers. Nevertheless, the predictable presence of measurement errors in the current commercial accelerometers is the main origin of velocity and displacement measurement deviations during integration of the acceleration. A bond graph numerical simulation model of the electromechanical system has been developed in order to forecast the effect of several measurement errors in the use of low cost two axes accelerometers. The level of influence is assessed using quality indicators and visual signal evaluation, for both simulations and experimental results. The obtained displacements results are highly influenced by the diverse dynamic characteristics of each measuring axis. The small measuring errors of a simulated extremely high performance sensor generate only moderate effects in longitudinal displacement but deep deviations in the reconstruction of piston transversal movements. The bias error has been identified as the source of the higher deviations of displacement results; although, its consequences can be easily corrected.

CFD simulation of an industrial hydrocyclone based on multiphase particle in cell (MPPIC) method

Due to the high efficiency of the hydrocyclone for the removal of particles and the ease of installation and operation and reasonable prices, simulation and modelling of hydrocyclones seem to be necessary. In this research, a CFD simulation was conducted to investigate the hydrocyclone performance with spiral inlet at Sarcheshmeh copper complex using the OpenFOAM software. Continuity and momentum equations were solved with the inclusion of buoyancy and drag forces by finite volume method. To simulate the turbulent flow, the large eddy simulation model (LES) was used. Multiphase Particle in Cell (MPPIC) method was applied to predict the behaviour of solid particles. There was a good agreement between the simulation results and the experimental data. The effect of operating parameters such as particle density, inlet mass flow rate of solid particles and inlet feed velocity, as well as the effect of design parameters like diameter and height of the vortex finder, the length of the cylinder and conical section and the type of inlet on the hydrocyclone performance were investigated. The results showed with increasing the feed velocity from 2.66 to 3.4 m/s and the height of the vortex finder from 0.15 to 0.45 m, the efficiency of the hydrocyclone increased by an average of 7.7% and 6.8% respectively. With increasing the length of the cylinder body of the hydrocyclone from 0.4 to 1 m, and the length of the conical section from 1 to 1.7 m, the particle separation efficiency increased by an average of 3.4% and 10.3% respectively. Hydrocyclone with tangential inlet had an average of 6.6% less efficiency than one from Sarcheshmeh copper complex. With decreasing the inlet mass flow rate of solid particles from 55.12 to 40.74 kg/s and the diameter of the vortex finder from 0.2 to 0.13 m, the separation efficiency increased by an average of 7.9% and 4.5% respectively.

Thermo-mechanical analysis of stress and deformation of engine cylinder block assembly as the attempt to explain an uncontrolled ignition of air-fuel mixture

The paper analyzes the possible cause of self-ignition of air-fuel mixture in spark-ignition internal combustion engine loaded with maximum power during tests on the engine dynamometer stand. It leads to incorrect engine operation and may also occur during the flight of an aircraft or helicopter. In order to explain the cause of incorrect engine operation, a non-linear analysis using the finite element method was applied. A discreet model of a simplified engine cylinder assembly system comprising a cylinder body and the liner was determined. The numerical analysis includes both the mechanical force resulting from loading the cylinder liner clamp in the body as well as the pressure of the working medium pressure and the load on the non-uniform temperature field taken from engine test-bed measurements. The results of nonlinear static analysis of stresses and strains for the cylinder body-liner connection have shown that in the area of TDC where outer piston ring turns back, high stresses and plastic deformation of the cylinder liner occurr, causing a lack of contact between these elements. This disrupts the heat transfer from the cylinder liner to the cylinder body and creates the possibility of uncontrolled ignition of the fuel-air mixture.

Analysis of the surface roughness for novel magnetorheological finishing of a typical blind hole workpiece

In modern high-performance machinery, parts which are highly finished and dimensionally accurate play a vital role. Surface finish enhances characteristics like wear, corrosion, pitting, and oxidation resistance of the surfaces. A novel magnetorheological polishing process using permanent magnets is developed to finish the internal cylindrical and bottom surfaces of the blind hole cylindrical workpiece. The process is capable of finishing the internal cylindrical and flat bottom surfaces of tubular and nontubular-shaped blind hole workpiece. Finishing of blind hole surfaces finds extensive application in dies and automotive components such as automobile actuators, cylinder body, valve seats, etc. In this study, two different tools for finishing the internal and flat bottom surfaces of blind hole cylindrical workpiece have been developed. The causal factor for material removal in the form of microchips is abrasive wear. The present study focuses on the calculation of forces acting on abrasive particles and mathematical modeling and simulation of the surface roughness. The performance of both newly developed tools for finishing the cylindrical blind hole mild steel workpiece is evaluated. After 275 finishing cycles, the Ra values improved by 55.2% in the internal cylindrical ferromagnetic workpiece and by 53.33% after 75,000 cycles on the flat surface of ferromagnetic blind hole workpiece. The theoretical and experimental values of the surface roughness are found to be consistent. The experimental surface roughness values of blind hole internal cylindrical surfaces are within 6.26% of the theoretical values, whereas in finishing the blind hole bottom surface it is found within 7.9% of the theoretical values.

Numerical investigation of body and hole effects on the cavitating flow behind a disk cavitator at extremely low cavitation numbers

Supercavitation has been recently proposed as an effective method for drag reduction of underwater vehicles. For this purpose, a cavitator is used to generate a large continuous bubble to cover the vehicle. Extremely low cavitation numbers are required in these applications to provide a sufficiently voluminous cavity. In this study, the effects of body presence inside the cavity of a disk-shaped cavitator are studied numerically. An element based finite volume approach is used for solving Reynolds-averaged Navier-Stokes equations. In order to validate the numerical scheme, turbulence and cavitation models, the cavitating flow over a hemispherical nosed cylinder body and also behind a disk-shaped cavitator has been simulated and the numerical results are validated against existing analytical and experimental data. Next, the effects of body presence inside the cavity of the disk-cavitator on the cavity characteristics are investigated. Results show that the cavity length is slightly smaller when it closes on the body, in comparison with the freely-closing cavity. Furthermore, the effects of adding a concentric hole with various diameters to the disk-cavitator on the cavity features are examined. The degree of drag reduction and changes of the cavity dimensions are determined at various cavitation numbers.

Manyetize Olmuş Jeolojik Yapıların Model Parametrelerinin Belirlenebilmesi için Gelişmiş Lokal Dalga Sayısı Tekniğinin Toplam Alan Manyetik Anomalilere Uygulanması

In this study, enhanced local wave number (ELWN) technique is presented to compute some model parameters of isolated and magnetized geological structures such as horizontal position (exact origin), depth and source geometry using the total field magnetic anomalies (TMAs). The technique uses analytical signal amplitude (ASA) and first- and second-degree horizontal and vertical derivatives of observed TMAs, and then simply computes the model parameters without requiring a priori knowledge about the nature of the causative magnetized body. Additionally, inclination and declination angles of both magnetization and ambient field have no effects on the results. In the ELWN technique source geometry, viz., structural index (contact/fault, dyke, horizontal cylinder and sphere) is determined using the depth and exact origin computed previously. Hypothetic simulations performed using TMAs due to some simple shaped geological models have showed the ability of the technique. Moreover, an actual magnetic data taken over the Kesikköprü iron deposit (Central Turkey), one of the largest iron reserve in Turkey,has been also analysed. A depth of 21.39 m has been computed for the magnetized geological source which includes the mafic rocks rich in magnetic properties, and the iron ore body. The structural indices obtained have indicated a dike-like or an intermediate form between a dike and a horizontal cylinder body for the magnetized source. These findings are compatible with those of a recently published study. Hence, the use of ELWN technique is proposed for rapid and reliable model parameter estimations from TMAs as an alternative or supportive experiment to the inverse modelling studies.

Effect of Dome Curvature on Failure Mode of Type4 Composite Pressure Vessel

In this work, a series of burst tests and structural analyses have been carried out to demonstrate that, in terms of failure mode, Type 4 composite cylinder is saferwith a dome designed according to the isotensoid dome theory.In the test series, three sample vessels were used: (1) designed as guided by the isotensoid dome theory (called iso-dome cylinder); (2) with dome longer compared to uniform-stress design (called prolate cylinder); and (3) with dome wider than uniform-stress design (called oblate cylinder). Structural analyses have been performed using ABAQUS finite element code based on the periodic symmetry to circumferential direction. As a result, the maximum stresses are induced around the bodies of all three cylinders. However, the analyses, with the assumption of possible defect demonstrate that the maximum stresses are induced around the dome knuckles for the prolate and the oblate cylinders. The results of the ambient hydraulic burst tests for the three cylinders, conducted in compliance with KGS AC411-2015, show that the burst initiates from the cylinder body of the iso-dome cylinder and from the dome knuckles of the prolate and the oblate cylinders. Finally, it is recommended that, to comply with DOT CFFC 2007, the dome shape should be designed and fabricated as guided by the isotensoid dome theory.

Vortex Oscillations Around a Hemisphere-Cylinder Body with a High Fineness Ratio

Vortex unsteadiness around a hemisphere cylinder at angles of attack of 10–80 deg was studied using large-eddy simulation and dynamic mode decomposition. The cylinder body has a fineness ratio of 24.5 (length-to-diameter ratio). The results revealed that oscillations of leeward vortices exist over a forebody at the whole range of angles of attack in addition to vortex shedding at an afterbody. The vortex oscillations consist of antisymmetric modes (alternate oscillation) and symmetric modes (in-phase oscillation). The alternate vortex oscillations correspond to the most energetic modes and are responsible for fluctuating sectional side forces at the forebody that are greater than the ones from vortex shedding at the afterbody. The Strouhal numbers of both alternate vortex oscillations and shedding at angles of attack of 10–40 deg are similar with , whereas at angles of attack of 50–80 deg, the Strouhal numbers are apparently divided into two regimes: the vortex oscillations with at the forebody, and the vortex shedding with at the afterbody. The vortex shedding regions progressively move forward with increasing angles of attack, and accordingly the regions of vortex oscillations contract and eventually only exist near the nose at sufficiently high angles of attack. The computed frequencies are in good agreement with the measured values of hot-wire probes in previous experiments.

Fault Diagnosis Research on Impact System of Hydraulic Rock Drill Based on Internal Mechanism Testing Method

In the production and manufacturing process of hydraulic rock drill, there are small impact energy and low impact frequency, and a fault diagnosis method based on the internal mechanism testing and testing of the hydraulic rock drill is proposed. This method is used to test the change law of hydraulic oil in the rock drill, by retaining the test holes on the cylinder body and other important components of the hydraulic rock drill. At the same time, the mathematical method is used to deal with the test curve, and the influence of pressure pulsation characteristics of the front and rear chambers of the impact piston and the left and right valve chambers of the reversing valve on the impact performance of the rock drill is analyzed. Based on Newton’s law, the model of the impact piston and reversing valve is established. According to the velocity and other parameters of the impact piston, the size of the impact piston switch point is calculated. The coupling between the movement of the impact piston and the movement of the reversing valve is analyzed according to the model established. Comparing the results of the experimental data, the correctness of the fault diagnosis analysis method and model is verified. The effect of the fault rock drill and the improved model is compared, and the theoretical basis is provided for the fault diagnosis of the rock drill and the design of a new type of rock drill.

Buckling of axially compressed composite cylinders with geometric imperfections

Cylindrical shell structures buckle at service loads which are much lower than their associated theoretical buckling loads. The main source of this discrepancy is the presence of various imperfections which are created on the cylinder body during different processes as manufacturing, handling, assembling and machining. Many cylindrical shell structures are still designed against buckling based on the experimental data introduced by NASA SP-8007 as conservative lower bound curves. This study employed the numerical based Linear Buckling mode shape Imperfection (LBMI) method and modified it using a stochastic method to assess the effect of geometrical imperfections in more details on the buckling of cylindrical shells with and without the cutout. The comparison of results with those obtained from the numerical Simcple Perturbation Load Imperfection (SPLI) method for cylinders with and without cutout revealed a good correlation. The effect of two parameters of size and number of cutouts on the buckling load was investigated using the linear buckling and Modified LBMI methods. Results confirmed that in cylinders with a small cutout inserting geometrical imperfection using either SPLI or modified LBMI methods significantly reduced the value of the predicted buckling load. However, in cylinders with larger cutouts, the effect of the cutout is dominant, thus considering geometrical imperfection had a minor effect on the buckling loads predicted by both SPLI and modified LBMI methods. Furthermore, the modified LBMI method was employed to evaluate the combination effect of cutout numbers and size on the buckling load. It is shown that in small cutouts, an increasing in the cutout size up to a certain value resulted in a remarkable reduction of the buckling load, and beyond that limit, the buckling loads were constant against D/R ratios. In addition, the cutout number shows a more significant effect on decreasing the buckling load at small D/R ratios than large D/R ratios.

ВДОСКОНАЛЕННЯ МЕТОДУ ВИПРОБУВАННЯ ТА ТЕХНІЧНОГО ДІАГНОСТУВАННЯ ГІДРОДЕМПФЕРІВ НА ВИПРОБУВАЛЬНОМУ СТЕНДІ ИГК-90.1

The article examines ways to improve the test method and technical diagnostics of hydraulic dampers of traction rolling stock on the test stand of ИГK-90.1 which are operated in the production divisions of PJSC «Ukrainian Railways». A brief review of modern test benches is given and the type of the test stand ИГK-90.1 is selected for its further modernization. The calculations of the energy capacity of hydraulic dampers, which formed the basis for software and modernization of the design of the test stand ИГK-90.1, are given. At the indicated type of test stand, the authors carried out experimental studies of the hydrodynamic type НЦ1100, graphical dependences were obtained for the force and resistance parameter, as well as the energy capacity from the piston displacement speed. In addition, a graph of the temperature change along the outer vertical surface of the cylinder body during the test is obtained. On a concrete example test of hydraulic damper of type НЦ1100, the expediency of introducing a new defining technical parameter (energy-capacity) for the evaluation of the operability and functionality of hydraulic diodes for their main purpose has been proved. The authors obtained an analytical expression for the transformation balance of the energy loading of the hydraulic damper to the work on the piston movement and the thermal energy of heating the working fluid in the cylinder. On the basis of this, the software of the ИГK-90.1 computer bench has been improved, which made it possible to obtain graphical dependencies of the hydro damper’s energy intensity on the piston moving speed. In the long run, it is planned to further upgrade the software to the PC booth to conduct resource tests of hydraulic damps to form a database, which will be the basis for the thermal diagnosis of the technical state of the hydraulic damp. The prospect of applying a new technical parameter in practice and using the obtained research results in the development and implementation of an automated remote thermal control system for hydraulic diodes during their operation on railway transport is indicated.

Influence of non-uniform mean flow on acoustic scattering from complex geometries

An immersed boundary computational model is presented to study the influence of non-uniform mean flow on acoustic scattering from complex geometries. It is firstly demonstrated from two benchmark problems that an absorbing treatment for the interior of solid domain in the developed immersed boundary method is not necessary. Then, simulations for acoustic scattering both from a circular cylinder and multiple bodies with different mean flow models are performed. It is found that the existence of a core wake region in a background mean flow model plays a significant role in accurately predicting acoustic directivity. When a sound source is in the core wake region, the background mean flow model has an obvious influence on the predicted acoustic directivity whether for a simple circular cylinder or multiple bodies; when the sound source is away from the core wake region, consistent results for different background mean flow models in most directions are obtained. However, about a maximum 8 dB discrepancy in the “front arm” direction of a circular cylinder and about a maximum 4.8 dB discrepancy in the downstream direction for the multi-element airfoil are caused respectively for the parallel and viscous mean flow models.

Key issues in theoretical and functional pneumatic design

This paper studies the energy release of the pneumatic engine in different thermodynamic processes, the isothermal process is the highest power output process, while adiabatic process is the lowest energy output process, and the energy release of the pneumatic engine is a multi-state thermodynamic process between them. Therefore heat exchanging should be increased between the pneumatic engine and the outer space, the gas expansion process in the cylinder should be as close as possible to the isothermal process. Heat exchange should be increased between the cylinder and the external spaces. Secondly, the fin structure is studied to increase the heat exchanging between the cylinder body and the outside space. The upper part has fin structures and the lower cylinder has no fin structure, this structure improved the working efficiency of pneumatic engine. Finally the cam and the hydraulic bottle of pneumatic engines are designed. Simulation and theoretical calculation are used to the analysis of the whole structure, which lay the foundation for the manufacturing and design of the pneumatic engines.

Performance Simulation of High Capacity Hydrostatic Buffer with Silicone Gum

재사용이 가능한 철도차량용 버퍼는 가스-유압식 완충기가 널리 사용되어 오고 있으나, 최근 몇 년 동안에 실리콘 검을 사용한 정수압 완충기에 대한 요구가 점차 커지고 있다. 실리콘 검은 스프링과 유사한 압축 특성을 가지고 있으며, 고점도 층류 유동에 따른 감쇠 특성도 가지고 있다. 높은 예하중을 갖는 완충기에 적합한 실리콘 검 완충기는 단순한 디자인과 간편한 유지보수 등의 이점이 있다. 실리콘 검 완충기의 동적 특성을 해석하기 위해, 본 논문에서는 연속 방정식, 피스톤과 실린더 바디 사이의 환형 틈새에서 전단 박하특성을 갖는 비뉴톤 유체의 압력과 유량 관계식, 하드 패킹에서의 마찰력을 포함하는 운동 방정식을 적용한 수학 모델을 제시하였다. 또한 정수압 검 완충기의 동적 완충력을 해석하고 TÜ V 충돌 시험 결과와 해석 결과를 비교하였다.

Finite water depth effect on wave-body problems solved by Rankine source method

Finite water depth effect for wave-body problems are studied by continuous Rankine source method and non- desingularized technique. Free surface and seabed surface profiles are represented by continuous panels rather than a discretization by isolated points. These panels are positioned exactly on the fluid boundary surfaces and therefore no desingularization technique is required. Space increment method is applied for both free surface source and seabed source arrangements to reduce computational cost and improve numerical efficiency. Fourth order Runge-Kutta iteration scheme is adopted on the free surface updating at every time step. The finite water depth effect is studied quantitatively for a series of cylinders with different B/T ratios. The accuracy and efficiency of the proposed model are validated by comparison with published numerical results and experimental data. Numerical results show that hydrodynamic coefficients vary for cylinder bodies with different ratios of B/T. For certain set of B/T ratios the effect of finite water depth increases quickly with the increase of motion frequency and becomes stable when frequency is relatively large. It also shows that water depths have larger hydrodynamic effects on cylinder with larger breadth to draft ratios. Both the heave added mass and damping coefficients increase across the frequency range with the water depths decrease for forced heave motion. The water depths have smaller effects on sway motion response than on heave motion response.