Cylinder Body Research Articles

Study on the Influence Mechanism of Spoiler on Flow and Combustion Process in Rotary Engine Cylinder

Abstract The spoiler is vital for optimizing rotary engines, yet its impact on the flow and combustion process within the cylinder remains ambiguous, thereby impeding the optimization efforts for rotary engines. This article, by analyzing the motion of the rotary, discovers a form of high-speed local gas flow within the cylinder due to local pressure differences resulting from interactions among the combustion chamber, cylinder body, and spoiler structure. This phenomenon is named “pressure differential flow” to differentiate it from the forced flow induced by the spoiler. Using mathematical models and three-dimensional simulations, we analyze the intensity of pressure differential flow at various spoiler heights and its regulatory effects on the flow and combustion characteristics within the cylinder. The results indicate that the flow caused by the spoiler in the cylinder is primarily divided into forced flow and pressure differential flow, with the intensity of the latter increasing as the spoiler height increases. When the spoiler height is greater than 75% of the maximum height, the pressure difference flow becomes more apparent, with both forced flow and pressure difference flow coexisting in the cylinder; when the spoiler height is less than 75% of the maximum height, the pressure difference flow is less noticeable, and the forced flow caused by the spoiler dominates. Pressure differential flow can reduce ignition delay and increase the maximum cylinder pressure, but it can also delay ignition timing and reduce combustion stability.

Mechanism of vortex oscillation around a hemisphere–cylinder body

Previous studies have shown that low-frequency vortex oscillations occur around a hemisphere–cylinder body at different angles of attack, but the underlying mechanism is still unclear. In this study, we examine the origin of the vortex oscillation using numerical simulations and global linear stability analysis. The vortex oscillation is reproduced using numerical simulations, and the oscillatory modes are computed through dynamic mode decomposition (DMD). We obtain the base flow through a selective frequency damping method, which exhibits a pair of steady leeward vortices over the body. The four unstable modes are computed using a modified Arnoldi iteration. The antisymmetric mode with a Strouhal number of 0.105 is discovered to be responsible for the alternate oscillation of the vortex pair, and the mode with a Strouhal number of 0.220 corresponds to the in-phase vortex oscillation. Their frequencies have good agreement with the modes of DMD. The other two unstable modes with higher frequencies, one antisymmetric and one symmetric, are harmonic frequencies of the above two modes. The study conclusively verifies that the vortex oscillation over a hemisphere–cylinder body originates from a global flow instability.

Comparison of composite cylinder damage under different working conditions

Abstract The finite element model of the carbon fiber all-wound aluminum cylinder was created to analyze the damage caused by high pressure, and the progression of damage as pressure increased was examined. The damage initially occurs in the transitional area between the cylinder end and cylinder body before progressing to the winding layer of the cylinder. The failure characteristics of the circumferential wound layer contrast with those of the spiral wound layer.

Study of high power steam turbine forced oscilla-tions near operating frequency

Problem. Forced oscillations of the turbine unit-foundation-base system near the operating frequency are considered. Goal. The purpose of the work is to study forced vibrations of the turbine unit-foundation-base system near the operating frequency range to assess the vibration state of the system and determine the causes of increased vibrations. The object of the study is the turbine unit-foundation-base system. The system consists of a single reinforced concrete foundation on which a steam turbine and generator are installed. The subject of the study is the amplitude-frequency dependences of forced oscillations of the turbine unit-foundation-base system. Methodology. The study was carried out using vibration methods and the finite element method. Also worth noting is the use of original methods developed directly by the author for constructing models of complex mechanical engineering systems. Results. As a result of the research, three-dimensional finite element models of low-pressure cylinder housings, the foundation and the entire turbine unit-foundation-base system were built. The conducted research allows us to draw a conclusion regarding the reasons for the increased level of vibration near the operating frequency and directions for their prevention. Originality. Regarding the methods for constructing a model of the turbine unit-foundation-base system, it should be noted that they are unique. The features of the applied modeling method make it possible to take into account the variable interaction between the low-pressure cylinder bodies and the foundation. Fixpoints are also taken into account. Previous studies of the turbine unit-foundation-base system did not allow us to determine the causes of increased vibrations of the shaft line supports. Practical significance. The results of the work relate to direct practical application. As a result of the work, conclusions were drawn about the ways to increase the vibration reliability of the turbine unit-foundation-base system and further directions for research.

Effect of groove angle on the residual stress and deformation of nuclear waste container cylinder body welded by plasma arc welding

AbstractAs an important barrier for high‐level radioactive waste transportation and deep burial disposal, the welding quality of nuclear waste container is particularly important. At present, nuclear waste container is usually manufactured by plasma arc welding. Therefore, in order to manufacture nuclear waste container parts with high quality, based on the finite element simulation software simufact welding, this paper uses a combination of numerical simulation and experimental verification to simulate the temperature field, stress field and deformation of the longitudinal weld of 316L nuclear waste container cylinder body by selecting different welding groove angles. The test results show that the groove angle of the V‐groove increases, the residual stress distribution and size increase, and the deformation increases. The stress value of the I‐shaped groove is between the V‐shaped groove angle of 30° and 45°, but the deformation is the smallest. In practical engineering applications, residual stress and deformation need to be considered comprehensive. Reasonable groove angle plays an important role in controlling residual stress and deformation after welding.

Utilizing numerical simulation to determine the reasonable parameters for the design of hydraulic rock-splitting head

The hydraulic rock splitter with a wedge-type splitting head has various advantages, such as simple operation, high work efficiency, safety, shortened work time, and minimal environmental impact. The splitting head driven by a hydraulic cylinder, is the focus of this research, as it directly influences work efficiency. This paper introduces the general structure of the rock splitter machine and the hydraulic cylinder-driven splitting head, along with the method for selecting suitable parameters. To evaluate and select suitable variables, this study establishes procedures and calculation methods for two sets of problems: determining the parameters for the wedge and the parameters for the hydraulic cylinder. The numerical test results provide a design dataset applicable to real-world scenarios, including the wedge angle, cylinder stroke, cylinder diameter, pressure, minimum cylinder wall thickness, and piston rod diameter, corresponding to the respective rock-splitting forces. These parameters meet the set objectives of cylinder pushing force and minimize the cross-sectional area of the cylinder body, contributing to weight reduction and operational convenience.

Condition Monitoring of Pneumatic Drive Systems Based on the AI Method Feed-Forward Backpropagation Neural Network.

Machine condition monitoring is used in a variety of industries as a very efficient strategy for equipment maintenance. This paper presents a study on monitoring a pneumatic system using a feed-forward backpropagation neural network as a classifier and compares the results obtained with different sensor signals and associated extracted features as input for classification. The vibrations of the body of a pneumatic cylinder are acquired using both common industrial sensors and low-cost sensors integrated into an Arduino board. Pressure sensors for both chambers and a position sensor are also used. Power spectral density (PSD) is used to extract features from the acceleration signals, as well as statistical indices. Statistical indices are considered for pressure and position sensors. The results, which are based on experimental data obtained on a test bench, show that a feed-forward neural network makes it possible to identify the operating states with a good degree of reliability. Even with low-cost instrumentation, it is possible to realize reliable condition monitoring based on vibrations. This last result is particularly important as it can help to further increase the uptake of this maintenance approach in the industrial environment.

The Effect of the Layout of a Rigid Splitter Plate on the Flow-Induced Vibration of a Downstream Cylinder Subjected to Wake Flow

In this study, the effect of additional positions of rigid splitter plates on the response characteristics of tandem cylinders at a Reynolds number of 150 and a fixed distance ratio of 5.0 was numerically investigated via the computational fluid dynamics (CFD) method. Four layouts for the cylinder–plate body, including a downstream cylinder (DC), a downstream cylinder–plate body with a wake side plate (DCP), a downstream plate–cylinder body with an incoming flow side plate (DPC), and a downstream plate–cylinder–plate body with a double-sided plate (DPCP), are considered. The results show that the splitter plate attached to the incoming flow side or the wake side can suppress the vibration of the downstream cylinder in a specific reduced velocity range (4.0 < Ur ≤ 10.0). Compared with the DC, the maximum response amplitude of the DPC and DCP in the lock-in region is reduced by 30.8% and 47.4%, and the lock-in bandwidth is also significantly narrower. The layer separation point of the upstream cylinder moves downstream upon adding splitter plates to both the incoming flow and wake sides, and the resulting splitter shear layer of the DPCP is completely parallel to the free flow, while the maximum response amplitude is reduced by 93.6%, which realizes the best effect of stream-induced vibration suppression.

On the Thermoelastic Influence of Fluid-Gas Phase Transition Pressure on the Closed Structural Storage Container

The current paper presents a finite element method (FEM) axisymmetric solution based on commercial software for an isotropic closed-ended container filled with fluid, located in the triple point phase (liquefied gas) while being converted into gas through a phase transition to critical point phase by a simultaneously rapid change of pressure and temperature to their critical values. The whole chemical process will be simulated through thermo-elastic analysis that is controlled by temperature-displacement dynamic coupling and subjected to step function boundary conditions alongside liquefied triple point initial conditions. In the process, the maximum principal stresses will be determined and illustrated as dependent on the container thickness. In the process, investigation will be carried out for prominent parameters, like, container hollow geometry type (spherical, ellipsoidal, and cylindrical) and raw material of the container. Commercial software solution calibration against existing literature solutions has been performed. Also, the solution accuracy was examined by element size mesh analysis to be coherent. In conclusion, the best materials to use were Molybdenum TZM and Tungsten while the preferred shape is the ellipsoidal shape. However, a typical vessel that is still durable with sufficient thermal strength for gas storage purposes is a cylinder body container with spherical ended cups made from Aluminum 6061 T6.

The analysis of the destabilizing motion of a hyperbolic cooling tower during demolition blasting

The destabilizing motion characteristics of the hyperbolic cooling tower in demolition blasting are thoroughly investigated through the establishment of a numerical simulation calculation model, leading to the following conclusions regarding its destabilizing motion. The tensile-compression elastic-plastic model, which possesses the characteristics of parameter modification function and independence from unit size, can more effectively capture the mechanical properties of concrete materials and find better application in the simulation and calculation research of reinforced concrete structures. The self-oscillation frequency check and collapse morphological analysis are employed to validate the accuracy of the simulation calculation model for hyperbolic cooling towers, as well as to assess the rationality of parameters in the tensile-compression elastic-plastic model. The collapse of a cooling tower induces flexural deformation in the lateral wall, tensile disturbance in the upper and middle sections of the cylinder, and compressive disturbance in the vertical cross-section. The cylinder body has incurred damage as a result of the tower wall’s front end striking the ground at the directional window position on the front side of the throat, leading to a significant extrusion deformation issue. The buckling deformation in the central and lower sections of the rear wall propagated towards the back side of the tower wall upon reaching the ground, ultimately resulting in an “inverted V-shaped” damage along the buckling deformation line. The research findings hold significant relevance for future endeavors.

Von Kármán vortex streets around invisible bluff bodies

Satellite images captured during the past decade identify clearly von Kármán vortex streets in the atmosphere above certain islands in the Atlantic and Pacific Oceans. The vortex streets are visible due to the cloud formations since the latter behave as unintended tracers of the fluid motion driven by winds. Experimental as well as numerical simulation results of von Kármán vortex shedding for flow around a cylinder or other bluff body identify the latter in a certain range of Reynolds numbers. The satellite images, however, show these von Kármán vortex structures at elevations well above the ground level inviting the appealing question of where is the cylinder or the bluff body? This short paper identifies the answer to this question as the creation of Taylor–Proudman columns above the islands that are invisible until a tracer makes them detectable at a certain height above the island. The latter also provides the clarification that the flow is geostrophic at the leading order and consequently two-dimensional (i.e., variations occur in the horizontal directions with no leading order changes in the vertical direction). In addition, this paper shows that a small Rossby number is not a necessary requirement for the creation of Taylor–Proudman columns. The latter can emerge also if a certain modified Beltrami condition is satisfied even when Rossby number is not small.

Fire safety parametric analysis of vehicle mounted hydrogen tanks based on a coupled heat transfer and thermomechanics model

Evaluating the fire safety of hydrogen storage cylinders is crucial before hydrogen can be widely used in fuel cell vehicle applications. This research presents a comprehensive 3D hydrogen cylinder fire safety model that couples ANSYS FLUENT to ANSYS-mechanical and simulates a vehicle-mounted hydrogen cylinder when subjected to fire. By considering a volumetric heat source that is beneath the hydrogen cylinder and by factoring the effects of complex heat transfer (convection, radiation, etc.), fluid dynamics, and the mounting space's solid wall, the temperature distributions across the hydrogen cylinder wall are calculated with greater accuracy than existing models that over-simplify the fire source model. Moreover, the temperature distributions are input to ANSYS Mechanical to calculate the induced mechanical stress. Then, a series of parametric analyses are conducted to evaluate their influence on maximum temperature and mechanical stress. Results reveal that thermal radiation is the dominant heat transfer mechanism from the fire source to the cylinder body. Decreasing the cylinder body's thermal conductivity can reduce maximum mechanical stress by 7%.Meanwhile, increasing the cylinder body thickness introduced more thermal strain to increase the maximum mechanical stress, which is not conducive to improving fire safety.

Experimental Study of Identifying Emission Sources of Acoustic Signals on the Cylinder Body of a Two-Stroke Marine Diesel Engine

In this paper, an experimental method was utilized to investigate acoustic emission (AE) characteristics and to identify emission sources of the nonlinear AE signal on the cylinder body of a large low-speed two-stroke marine diesel engine in real-working conditions on the sea in misfiring and normal firing modes. Measurements focused on the AE signal acquired in a transverse direction in low-frequency (20–80 kHz), medium-frequency (100–400 kHz) and high-frequency (400–900 kHz) ranges. The collected signals were analyzed on the crank angle and crank angle-frequency domains. The results showed that all potential sources of the nonlinear AE signal could be mapped in the low-frequency range. However, only the AE signal caused by the combustion process at around the top dead center could be well-observed in the medium-to-high-frequency range. The findings also revealed that in normal firing conditions, the AE energy radiated by friction in the down-stroke period was smaller than in the up-stroke process due to gas-sealing forces. Moreover, the AE energy in the misfiring condition was higher than in the normal firing state. These outcomes considerably contributed understandings to characteristics of friction and wear around the mid-stroke area of the cylinder on a two-stroke marine diesel engine.

A NEW FORCE MEASUREMENT MECHANISM IN WIND TUNNEL: CFD AND EXPERIMENTAL VALIDATION ON A CYLINDER

Wind tunnel tests are experiments carried out in private and state-supported institutions, which are of great importance for studies in aerodynamics. Wind tunnels are essential in the defense industry, the automotive industry, and even the construction industry. In this study, a force sensor holder (FSH), in the open subsonic wind tunnel test room is designed, and it is made to measure angled structures, angled prototypes, and especially for wings. The critical angles of wings and the angles of attack are necessary, especially regarding aerodynamic performance. This force sensor holder can be adjusted at 0-90 degree angles and used experimentally. After holder manufacturing, experiments and CFD analysis are carried out at a 0 degree angle on the cylinder body. This study conducts a Computational Fluid Dynamics (CFD) analysis using Realizable k-ε, and SST k-ɷ turbulence models. In this study, the accuracy of the CFD analysis of the drag coefficient on a cylinder is evaluated through a comparison with both experimental and literature data. The results revealed that the CFD analysis has a deviation of 5,11% (using the Realizable k- model) and 5,22% (using the SST k- ɷ model) from the literature data. On the other hand, the experimental results show a discrepancy of 3,77% compared to the literature data. These findings demonstrate the effectiveness of the CFD analysis in predicting drag coefficients and highlight the importance of validating such simulations with experimental data.

Comparative evaluation based on FEA of thermal analysis of IC engine cylinder using different materials

Because it seals the working ends of the cylinder and houses a combustion chamber, as well as a spark plug and valves, the cylinder head is an important component of an IC engine. The heat created in the combustion chamber is very dynamic, allowing just a few microseconds to transmit the heat, which if not dispersed will cause the piston to squeeze due to overheating. As a result, excellent waste heat distribution through the cylinder body is critical to the IC engine's smooth operation. As the geometry of cylinder is problematical and the temperature within the combustion chamber is still indefinite, heat transmission through the cylinder body comprises of conduction through fins and convective heat transfer owing to surrounding air movement. Traditional heat transfer evaluation methods are quite difficult. The primary goal of this study is to examine and analyse the heat transmission of cylinder bodies constructed of various materials, including Aluminium alloy, magnesium alloy, cast iron, and stainless steel. The vehicle's speed was limited to 40 km/h, and the fin thickness was limited to 3 mm for all materials. SolidWorks is used to model the cylinder engine block with rectangular fins as well as its thermal analysis. According to thermal study results, heat dissipation is optimum in the Aluminium alloy 6061, whereas stainless steel has the least dissipation.

Improving technology for manufacturing casting case of truck clutch release cylinder

The object of research: Manufacturing technology of body castings for trucks using the example of a clutch release cylinder body made of gray cast iron with flake graphite EN-GJL-200.
 Investigated problem: Finding ways to reduce the weight and size characteristics of cast parts.
 The main scientific results: A mathematical model has been developed that has made it possible to determine the optimal compositions of alloying Cr/Ni – Cu/Ti complexes that ensure an increase in the grade of cast iron by increasing the tensile strength at elevated carbon contents. This makes it possible in the future to reduce the thickness of the walls of the castings, achieving a reduction in their weight and size characteristics
 The area of practical use of the results of the study: Automotive industry in terms of technology for manufacturing cast parts for trucks
 Innovative technological product: Improved technology for manufacturing the clutch release cylinder body due to optimization of melt technology and out-of-furnace processing allows for targeted selection of melt processing modes, ensuring an increase in the strength characteristics of cast iron for cast body parts, thereby moving from the EN-GJL-200 cast iron grade to the EN grade -GJL-250 and EN-GJL-300.
 The scope of the innovative technological product: Foundries of engineering enterprises, in particular those producing trucks, in which iron castings are produced

Effect of Compressed Natural Gas (CNG) on corrosion behaviour of brass valve of CNG cylinder

In this case study, failure root cause analysis of the Compressed Natural Gas (CNG) cylinder brass valve was investigated. Detailed metallurgical analysis of the cracked CNG valve was performed. Higher content of sulphur and carbon while depletion of zinc observed by Scanning Electron Microscope (SEM) - Energy Dispersive Spectroscopy (EDS) analysis at crack location and on black corrosion product. Microstructure analysis of the cross section near to fracture surface indicated dendritic structure of alpha and beta phase and depletion of zinc from beta phase at the inner diameter (ID) of valve and near to crack region by SEM-EDS analysis. The overall observation indicates that the failure of brass valve body of CNG cylinder was due to the dezincification. As per the IS 15958 standard, the CNG valves, which have failed, may be due to more than specified limit of the corrosive components (S and CO2) in the CNG. This resulted into diffusion of sulphur and carbon dioxide in beta phase at internal surface of valve. Adsorbed sulphur and CO2 from the CNG lead to the preferential dezincification from beta phase throughout the inner diameter (ID) of the valve. Electrochemical reaction during dezincification lead to weak spongy copper layer, which subsequently initiated and propagated crack to the outer diameter (OD) and resulted into leakage and failure.

Effects of the inlet particle spatial distribution on the performance of a gas-solid cyclone separator

The present study was aimed at the inlet particle spatial distribution of a gas-solid separator with high solid loading and investigated its effects on cyclone performance and the inner flow pattern. The flow fields of a cyclone with different rectangular particle flow areas on the inlet surface were numerically simulated using a four-way coupling method. The simulated results indicate that reducing the inlet particle flow area and lowing the inlet particle position can effectively reduce the scattered particles inside the cyclone separator and enhance the separation performance. Vertically gathering the particles to the centerline can also weaken the particle back-mixing. The particles near the roof account for the swirling particle ceiling phenomenon. The inlet particle spatial distribution affects the pressure drop mainly by affecting the gas tangential velocity in the cylinder body. Moreover, compared to the horizontal particle distribution on the inlet surface, the vertical particle distribution has greater effects on cyclone performance.

Study of natural oscillations of a high-power steam turbine near the operating frequency

Annotation. Problem. The natural frequencies and features of the natural forms of the turboset-foundation-base system near the operating frequency are considered. Goal. The aim of the work is to study the natural frequencies and modes of natural oscillations of the turboset-foundation-base system near the operating frequency range to assess the vibrational state of the system and determine the causes of increased vibrations. The object of the study is the system of turboset-foundation-base. The system consists of a single reinforced concrete foundation on which a steam turbine and a generator are installed. The subject of the study is the natural frequencies and forms of natural oscillations of the turboset-foundation-base system. Methodology. The study was carried out by oscillation methods and the finite element method. The use of original methods developed directly by the author for constructing models of complex machine-building systems should also be mentioned. Results. As a result of the research, three-dimensional finite element models of low-pressure cylinder bodies, the foundation and the entire turboset-foundation-base system were built. The conducted study allows us to draw a conclusion regarding the causes of an increased level of vibration near the operating frequency and directions for their prevention. Originality. Regarding the methods of constructing a model of the turboset-foundation-base system, their uniqueness should be noted. The features of the applied modeling method make it possible to take into account the variable interaction between low-pressure cylinder bodies and the foundation. Fixpoints are also taken into account. Previous studies of the turboset-foundation-base system did not allow us to determine the nature of the oscillation modes near the operating frequency. Practical value. The results of the work relate to direct practical application. As a result of the work, conclusions were made about ways to increase the vibration reliability of the turbine unit-foundation-base system and further research directions.

Deformable nose design for the non-penetrating projectile

This paper deals with the design of a deformable nose for the non-penetrating projectile in order to prevent its body deformation. Numerical, analytical and experimental studies have been carried out to analyze the effect of different nose shapes on the projectile deformation when it hits the brick wall. The projectile consists of an aluminum nose, a thin-walled steel cylinder body, and an end connector. This non-penetrating projectile can be used to carry a cargo that must reach its destination safely, for example in firefighting applications. To pursue this goal, the criterion utilized for the best design in this paper is stress and strain analysis. The geometric shape of the noses includes three types: type (a), type (b), and type (c). The first type of nose was flat shape. This nose was detached from the projectile by impact and did not prevent the projectile deformation. The second type of nose was a combination of flat and conical shapes. The projectile was also deformed by this nose. The third type of nose was a combination of flat, conical, and spherical shapes. Due to the maximum absorption of the impact energy, this type of nose prevented the deformation of the cargo and projectile.