Conical Surface Research Articles

Flow analysis of a control ball valve in a common rail fuel injector

The electronic control common rail fuel injection system is one of the key technologies being used in modern diesel engines to improve the engine performance. A numerical simulation was conducted to study the characteristics of the fuel flow around the ball valve in the common rail fuel injector. The lift of the control ball valve and static pressure of the flow field around the control ball valve were measured respectively. The simulation was performed with the measurements as boundary conditions such that the flow characteristics can be correlated with the valve lift and the pressure upstream of the ball valve. Simulation results showed that during the valve opening and closing, a high pressure area appeared below the ball valve, while cavitation appeared in the area around the control ball valve. Specifically, the cavitation mainly appeared around the sealing circle, and its upstream area and the conical surface from the entrance to a certain distance downstream. The flow throttling happened at the outlet orifice under the steady-state condition when the valve was at the maximum opening position. The cavitation around the control ball valve was more serious under higher rail pressure conditions. The formation and development of the cavitation was found to be depending on the lift position of the ball valve and pressure of the flow around the ball valve during the valve opening and valve closing. Higher value of void fraction appeared in the flow when the lift of the ball valve was at a larger opening position. It was found that cavitation around the ball valve will affect the consistency and stability of the fuel flow. And cavitation erosion found at the valve seat from a simplified durability test appeared to be close to the place where cavitation appeared from simulation. Therefore, it is suggested that simulation work can be used to examine if cavitation occurs in the flow path of the control ball valve inside the injector in design phase and make necessary changes on the design to prevent the cavitation and the resulting damages to the control ball valve in the injector.

Влияние формы тороидальной задней поверхности на углы режущего клина и механические напряжения вдоль режущей кромки сверла

Introduction. Drilling holes with standard tolerance varying from IT8 to IT12 is widely used in industrial production. However, at present time, there are neither comprehensive studies, nor scientifically justified recommendations for the rational choice of the geometry of the cutting part of drills with a toroidal flank surface. Therefore, the computer-aided design (CAD) of new drill designs with a toroidal flank surface and finite element modeling (FEM) of the stressed state of its cutting part are important tasks. The purpose of the work is reducing both the range of change in the rake angle and the wedge angle of the cutting wedge along the cutting edge from the periphery to the center and the equivalent stresses in the cutting wedge. In this paper we investigate changes in the rake and wedge angles of the cutting wedge depending on the radius of the generatrix line of the toroidal flank surface as well as changes in equivalent stresses in the cutting wedge, which depend on changes in the radius of the generatrix line of the toroidal flank surface. The research methods include the fundamentals of the theory of cutting, CAD methods, and the FEM, which was applied in this work to new drill designs. Results and discussion. It is found that the range of changes in the rake angle and the wedge angle of the cutting wedge of the drill decreases compared to the standard design with decreasing radius of the generatrix line of the flank surface. A CAD system for drills with a toroidal flank surface is developed. As a result, the range of changes in the rake angle along the cutting edge decreased by 86 % for a drill with a minimum radius of the generatrix line of the toroidal surface compared to that with the conical flank surface, the range of the wedge angle of the cutting wedge decreased by 56 %, and the maximum equivalent stresses decreased by 2.13 times. It is also important to note that in this case, the wedge angle is close to constant for half of the drill tooth. These indicators exceed those for existing designs of the twist drills that indicate the key achievement of this paper.

Mathematical modeling of non-stationary deformation of cylindrical structures

The paper investigates the dynamic behavior of a hollow elastic cylinder of finite length, placed in a rigid cylindrical shell, under a sharp change in internal pressure. A numerical solution of a two-dimensional dynamic problem is obtained using the method of spatial characteristics. The stress-strain state of an elastic cylinder is described by a system of hyperbolic equations with two circular conical surfaces as characteristic surfaces. The outer cones correspond to longitudinal waves; the inner ones correspond to transverse waves. The calculations were carried out under various conditions at the ends and the outer (contact) surface of the cylinder and shell. An analysis of the results for a cylinder with load-free ends shows that the absence of gluing the outer surface of the cylinder with the shell leads to a significant increase in the velocities of the points of the cylinder. Under the action of internal pressure, the ends move apart, resulting in a significant increase in the radial velocities of the internal channel. Qualitative patterns of behavior of the structures under consideration, which are widely used in mechanical engineering, on impact-type impacts, can be used to improve and optimize them at the design stage.

Geometric frustration of hard-disk packings on cones.

Conical surfaces pose an interesting challenge to crystal growth: A crystal growing on a cone can wrap around and meet itself at different radii. We use a disk-packing algorithm to investigate how this closure constraint can geometrically frustrate the growth of single crystals on cones with small opening angles. By varying the crystal seed orientation and cone angle, we find that-except at special commensurate cone angles-crystals typically form a seam that runs along the axial direction of the cone, while near the tip, a disordered particle packing forms. We show that the onset of disorder results from a finite-size effect that depends strongly on the circumference and not on the seed orientation or cone angle. This finite-size effect occurs also on cylinders, and we present evidence that on both cylinders and cones, the defect density increases exponentially as circumference decreases. We introduce a simple model for particle attachment at the seam that explains the dependence on the circumference. Our findings suggest that the growth of single crystals can become frustrated even very far from the tip when the cone has a small opening angle. These results may provide insights into the observed geometry of conical crystals in biological and materials applications.

Cross-hatch textured cone enables Dual-Mode water transport and collection

Spontaneous droplet transport has broad application prospects in water collection, whereas droplet self-transport is still limited by slow transport velocity, short distance, and poor integrity. Here, a novel cross-hatch textured cone (CHTC) with gradient microchannels and circular grooves is proposed to realize ultrafast long-distance self-transport of multi-scale droplets, whose self-transport velocity is 1–4 orders of magnitude faster than natural or biomimetic structures with single curvature gradient. The CHTC triggers two modes of fluid transport: Droplet transport by Laplace pressure difference and capillary suction pressure-induced fluid transfer in microchannels on cone surfaces. The gradient microchannels connected by circular grooves ensure that the residual water layer and the water droplet detained on the CHTC can still be spontaneously transported to the base to eventually realize the entire droplet transport. A theoretical formula on the suction pressure is established to elucidate the driving force responsible for the self-transport of both detained water droplet and the residual water layer. The fog collection efficiency of the CHTC is about twice as high as the cone without microchannels. These findings will open the door to achieving ultrafast long-distance and lossless self-transport of droplets and will provide tremendous inspiration for the design of the water collection apparatus.

Visualization of the membrane surface and cytoskeleton of oligodendrocyte progenitor cell growth cones using a combination of scanning ion conductance and four times expansion microscopy.

Growth cones of oligodendrocyte progenitor cells (OPCs) are challenging to investigate with conventional light microscopy due to their small size. Especially substructures such as filopodia, lamellipodia and their underlying cytoskeleton are difficult to resolve with diffraction limited microscopy. Light microscopy techniques, which surpass the diffraction limit such as stimulated emission depletion microscopy, often require expensive setups and specially trained personnel rendering them inaccessible to smaller research groups. Lately, the invention of expansion microscopy (ExM) has enabled super-resolution imaging with any light microscope without the need for additional equipment. Apart from the necessary resolution, investigating OPC growth cones comes with another challenge: Imaging the topography of membranes, especially label- and contact-free, is only possible with very few microscopy techniques one of them being scanning ion conductance microscopy (SICM). We here present a new imaging workflow combining SICM and ExM, which enables the visualization of OPC growth cone nanostructures. We correlated SICM recordings and ExM images of OPC growth cones captured with a conventional widefield microscope. This enabled the visualization of the growth cones' membrane topography as well as their underlying actin and tubulin cytoskeleton.

A novel roundness error evaluation method for high-speed EMU train axles

This article proposes a novel roundness error evaluation method for high-speed electric multiple units (EMU) train axles to evaluate the roundness error of the minimum zone circle. This method utilizes the adaptive ability of Bayesian linear regression to the data to solve the initial center of the circle, avoiding the multiple search process, which not only improves the data utilization and simplifies the solving steps but also has a strong noise immunity. The method first establishes a Hough space model, maps the collected data points to the Hough space, and forms different conical surfaces; then, by Bayesian linear regression, the probability density function is set with the distance from the space point to the conical surface as a parameter, and through continuous iteration, the point with the highest probability value is the more accurate initial center of the circle. Finally, the final optimal center of the circle is obtained by the principle of minimum inclusion region. We conducted experimental studies on axles of different diameters and compared them with other methods. The results prove the practicality and effectiveness of the technique.

A theoretical investigation on heat transport feature of Sutterby nanofluid flow above a conical surface

ABSTRACT Theoretical analysis is performed to examine the heat convection in hydromagnetic Sutterby nanofluid flow across a cone in the attendance of Darcy-Forchheimer and modified temperature flux effects. The enhanced heat transmission was investigated using Maxwell and interfacial layer (nanolayer) approaches by considering ethylene glycol (EG) based spherical copper (Cu) nanoparticles. An exact model is developed and verified numerically using the bvp5c MATLAB scheme. Simultaneous outcomes are obtained for Maxwell and nanolayer approaches. Pertinent parameters influence on momentum and energy fields is examined via plots and tables. The nanolayer approach reported higher thermal conductivity than the Maxwell approach. Also, modified heat flux commendably improves the heat diffusion rate of Sutterby nanofluid without affecting the wall resistance.

Paint Film Formation Characteristics on Conical Surfaces for Electrostatic Air Spray Painting

When a curved target surface is coated in an electrostatic spray-painting process, the paint film pattern on curved targets will deform, and the thickness will change compared with the planar target due to the curvature characteristics of the target, the inhomogeneous electric field, and the flow field. Therefore, directly using the planar deposition distribution for painting the trajectory planning of curved surfaces causes large errors and low paint transfer efficiency. A study investigating the curved surface paint film thickness distribution characteristics is presented in this research to understand the relations among the target surface curvature, the electrostatic field, and the flow field distribution. Spray-painting process simulations were performed for conical surfaces of different curvatures. Moreover, the paint particle’ trajectories, electric potential, and film deposition distribution were computed using ANSYS Fluent. The paint transfer efficiencies of these targets were computed. The results show that when the generatrix curvature of the conical surface increases gradually, the electric field intensity near the wall increases, which enhances the deposition of charged droplets on the wall. Moreover, the airflow field velocity increases as the curvature increases, which leads to a large diffusions of the spray flow field, so the paint thickness decreases, and the transfer efficiency is low.

Explicit potential function and fast algorithm for computing potentials in [formula omitted] conic surface resistor network

Resistor network research is of great importance, yet many resistor networks and their large-scale fast computations have not received sufficient attention. This paper proposes a new resistor network with idiosyncratic shape, i.e., a α×β conic surface (CS) resistor network that resembles the upper part of a three-dimensional Dirac function. Utilizing the Recursion Transform (RT-V) method of Tan, a recursive matrix equation model is constructed based on Kirchhoff’s law and nodal voltages, which contains the modified tridiagonal Toeplitz matrix. By using the orthogonal matrix transformation, the eigenvalues and eigenvectors of the modified tridiagonal Toeplitz are obtained. The discrete sine transform of the fourth type (DST−IV) is utilized to solve node voltages, while the explicit potential function is represented by the Chebyshev polynomials of the second kind. In addition, explicit potential functions for some special cases are provided, and the potential distribution is illustrated using dynamic three-dimensional graph. To achieve a rapid calculation of the potential, a fast algorithm based on the multiplication of DST-IV with a vector is proposed. In the end, analysis of computational efficiency for the explicit potential function and the fast algorithm are shown.

Cause for concern? Significant cement coverage in retrieved metaphyseal cones after revision total knee arthroplasty

BackgroundMetaphyseal cones are used to manage bone loss in revision total knee arthroplasty with increasing popularity. Post-operative radiographs and explant procedures suggest that cement may extrude around the cone implant into the cone-bone interface and prevent biologic in- or on-growth. The purpose of this study was to perform a retrieval analysis to describe the pattern of direct cementation onto the porous surface area of metaphyseal cones. MethodsEighteen tibial and femoral cones were identified in an institutional implant retrieval registry. Anterior, posterior, medial and lateral quadrants were digitally mapped for direct cementation, bone ongrowth and fibrous ongrowth were calculated as a percentage of the porous surface area. Plain radiographs from prior to cone explant were analyzed for the presence of cement in all four quadrants and compared with results of the retrieval analysis. ResultsMean bone ongrowth was 25%, direct cementation was 24% (31% in tibial cones) and fibrous ongrowth was 29% of the porous surface area of the retrieved cones. There were no significant differences when comparing patterns of bone or fibrous ongrowth or cementation between anterior, posterior medial and lateral porous surfaces for tibia cones, femoral cones or all cones grouped together. Plain radiographs significantly underestimated the amount of cement covering the cone (p = 0.02). ConclusionIn this retrieval study, we found significant cement extrusion around the porous surface of metaphyseal cones in revision TKAs. Optimizing the cone-bone interface may reduce the risk of cement extrusion and theoretically reduce the risk of aseptic loosening.

Channel Competition and Control of Relaxation Pathways in S1 State of Acrolein: Role of Conical Intersection and Surface Crossing.

Channel competition and further photochemical control of relaxation pathways in excited molecules are of primary importance in photochemistry and related areas. Acrolein, as the simplest and most typical α,β-enone, is suitable to provide a model for understanding the photochemistry and photophysics of α,β-enones. Here, the ultrafast dynamics in acrolein following S1(nπ*) excitation has been studied by time-resolved photoelectron imaging (TRPEI) and mass spectroscopy. The competition between intersystem crossing (ISC) and internal conversion (IC) is investigated. The key factor influencing the decay pathways and the relative contributions are revealed to be the position of the excitation relative to the energy of the S1/S0 conical intersection (CI), which is obtained to be 3.65-3.76 eV experimentally. If the excitation is above the CI, IC is superior to ISC and most excited molecules go back to the ground. Otherwise, ISC will dominate the relaxation and lead the triplet products formation. These results show the potential of affecting the dynamics and governing the fate of excited molecules by adjusting the excitation conditions from the point of view of chemical control.

Investigation of polarization transformations performed with a refractive bi-conical axicon using the FDTD method

We investigate polarization transformations carried out with a refractive bi-conical axicon using the FDTD method. The approach is based on the transformation of a circularly polarized optical beam into an azimuthally polarized beam due to the use of a single refractive element with two conical surfaces. On the inner surface of the element, polarization conversion occurs due to the reflection and refraction of rays at the Brewster angle, while the outer surface operates as a converted beam collimator. The distributions of the components of the electric field vector and the polarization vector at different distances from the optical element are considered as criteria for a successful polarization transformation. By numerical simulation of the performance of a bi-conical axicon made of glass with a refractive index of n = 1.4958, the efficiency of the proposed approach for a circularly polarized Gaussian beam with a wavelength of λ = 1.5 µm is shown. The proposed element is shown to be immune to chromatic aberrations in a significant range of changes in the refractive index of the element material and incident wavelengths (1.5 ≤ n ≤ 1.7; 1 μm ≤ λ ≤ 1.5 μm).

Hierarchical Policy Learning With Demonstration Learning for Robotic Multiple Peg-in-Hole Assembly Tasks

The force-based control algorithm of robotic multiple peg-in-hole assembly is a challenge. Forthe difficulty of low adapt-ability of model-based control algorithms and low learning effi-ciency of model-free control algorithms, a goal-based hierarchical policy learning (HPL) algorithm that combines conventional con-trol algorithm and demonstration learning algorithm is proposed to learn the assembly skill. Firstly, the goal-based HPL algorithm adds goal as a new variable to the action value function. Multiple states reached in each episode are randomly selected as sub-goals to improve the distributionof positive rewards. Secondly, an initial policy that combines conventional control algorithm and demon-stration learning algorithm is designed. The combined coefficient of these two algorithms is learned by HPL algorithm. Finally, a conical surface is used to compute the forces and moments of sim-plified assembly simulation model. Our algorithm is well imple-mented in both simulation and real-world environments. The ex-perimental results verify the effectiveness of the proposed method.

Interaction of conical monolithic thin-walled reinforced concrete shells with the soil of the foundation

Conical monolithic thin-walled reinforced concrete blocks (shells) can be used as foundations for frame structures and buildings with load-bearing walls. As an analogue of columnar foundations, this type has the advantage of the speed of installation. It almost wholly excludes earthwork and formwork from the technological process, provided that the physical and mechanical properties of the soil base are improved. Shells are immersed in the supporting soil base with the help of dynamic or static loading. Additional soil base compaction occurs due to interaction with the conical outer surface of the shells. The work aims to develop the theoretical foundations for modelling, mathematical description and the possibility of optimizing the process of sinking monolithic thin-walled spatial reinforced concrete shells that model foundations for low-rise technological or residential facilities. Based on the analysis of the ”hammer-head-shell-soil” system, an elastic-viscous-plastic model with an attached soil mass was developed and presented, which is used as a basis for developing a system of nonlinear differential equations of the second order. The article provides recommendations on the impact of structural and technological factors on the failure rate and the contact stresses in the hammer-shell zone. The following factors have a significant influence on the failure of the shell: the height of the hammer lift, soil resistance, and the ratio of the masses of the hammer and the shell. The effect of shock-absorbing elements is insignificant. The greatest influence on the magnitude of the contact forces in the zone of the hammer-shell has: the height of the fall of the hammer and the stiffness of the resilient gasket.

Cables1 links Slit/Robo and Wnt/Frizzled signaling in commissural axon guidance.

During neural circuit formation, axons navigate from one intermediate target to the next, until they reach their final target. At intermediate targets, axons switch from being attracted to being repelled by changing the guidance receptors on the growth cone surface. For smooth navigation of the intermediate target and the continuation of their journey, the switch in receptor expression has to be orchestrated in a precisely timed manner. As an alternative to changes in expression, receptor function could be regulated by phosphorylation of receptors or components of signaling pathways. We identified Cables1 as a linker between floor-plate exit of commissural axons, regulated by Slit/Robo signaling, and the rostral turn of post-crossing axons, regulated by Wnt/Frizzled signaling. Cables1 localizes β-catenin, phosphorylated at tyrosine 489 by Abelson kinase, to the distal axon, which in turn is necessary for the correct navigation of post-crossing commissural axons in the developing chicken spinal cord.

Soret–Dufour mass transfer effects on radiative chemically dissipative MHD plain convective water nanofluid (Al2O3, Cu, Ag, & TiO2) flow across a temperature-controlled upright cone surface with heat blow/suction

In the current analysis, we delivered a computational approach to the 2D boundary layer heat and mass transfer flow of water-based nanofluids over a vertical cone saturated by porous media with heat generation/absorption, thermal radiation, chemical reactions, the Soret–Dufour number, viscous dissipation, and a magnetic field. The controlling partial differential equations are converted into devoid of dimensions form and numerically dealt with by Crank–Nicolson through an implicit finite difference approach. Specifically, the given parameters, such as volume fraction (ϕ), MHD-Magnetohydrodynamics (M), Soret/Dufour (Sr-Du), viscous dissipation (ϵ), chemical reaction (λ), thermal radiation (Rd), and heat blowing/suction (Δ), have an impact on boundary layer flow characteristics (velocity, temperature, concentration, drag coefficient, rate of heat transfer, and mass transfer rate) are thoroughly studied, and the outcomes are visually and tabulated to demonstrate the actual significance of the problem.

Bioconvective periodic MHD Eyring-Powell fluid flow around a rotating cone: Influence of multiple diffusions and oxytactic microorganisms

Investigating the effects of periodic magnetic field and triple diffusion on bioconvection flow through a rotating cone populated by oxytactic bacteria and an Eyring-Powell fluid is innovative and significant. The magneto-bioconvection flow of an Eyring-Powell multi-diffusive fluid across a spinning cone is investigated in this paper, considering the effect of oxytactic microorganisms. The non-similar technique is used in the mathematical analysis of the flow over a spinning cone. The flow under consideration contains two diffusive species: liquid hydrogen and liquid oxygen. In light of the periodic magnetic field, the surface gradients, notably skin friction, exhibit wavy effects in the boundary layer domain. The governing equations for the fluid flow in the current flow problem, accompanied by heat diffusion, species diffusion, rotation, bioconvection, and periodic magnetic, are highly coupled nonlinear PDEs dependent on the proper initial and boundary conditions. Mangler's transformations convert them into non-dimensional forms, and numerical non-similar solutions are produced using implicit finite difference approximation and quasi-linearisation. The enriching values of bioconvective Rayleigh number Rb decline the velocity F, as a result, lessen the friction between the surrounding fluid and the cone's surface. The improving Peclet number Pe and microbial density difference σ reduced the microorganism density profile and heightened the microorganism density number Re-1/2Nn.

Optimized Packing of 3D Objects Bounded by Spherical and Conical Surfaces

Introduction. Optimizing the packing of arbitrary geometric objects in additive manufacturing opens up new possibilities for increasing the efficiency of additive manufacturing of parts of a complex configuration due to the saving of energy, material and time resources. Additive manufacturing, a cornerstone in fields such as space engineering, medicine, mechanical engineering, and energy, has its efficiency hinging on the optimization of the 3D printing process. Given its widespread application, refining this process is of utmost importance. The purpose of the paper. The paper aims to develop an approach for packing assembled parts of complex geometry in the working area of a 3D printer, while adhering to the standards of 3D printing. Results. For the analytical description of the complex shaped industrial products, a, so called, “composed spherical cone” is used. This generates a family of such objects as spheres, cylinders, spherical cylinders, cones, truncated cones and spherical discs. Using the normalized quasi-phi-function of composed spherical cones, a mathematical model of the problem is presented in the form of a nonlinear programming problem. A solution strategy is developed, encompassing three primary stages: generation of feasible starting points, search of local minima and search of a better local minimum. Numerical examples of packing various industrial products in a 3D printer chamber is provided. 3D-parts are approximated by composed spherical cones with different metric parameters. Conclusions. The conducted numerical simulation confirms the effectiveness of the proposed optimization approach. This study emphasizes the importance of further research and innovation in the field of 3D printing and its optimization, and also demonstrates the potential of using mathematical models to solve practical problems in a production environment. Keywords: packing, assembled spherical cone, mathematical modeling, optimization, additive manufacturing.

On constant-ratio surfaces of rotation in Euclidean 4-space

The general rotational surfaces of [Formula: see text] were first studied by Moore. The Vranceanu surfaces are special examples of this kind of surfaces. These constant-ratio surfaces are surfaces for which the ratio of the norms of the tangent and normal components of the position vector fields is constant. However, spherical surfaces and conical surfaces are also trivial examples of constant-ratio surfaces. Thus, if the norms of the tangent or normal components of the position vector fields are constant, then the given surface is called [Formula: see text]-constant or [Formula: see text]-constant, respectively. In this paper, we considered three types of rotational surfaces lying in [Formula: see text]-dimensional Euclidean space [Formula: see text]. We have obtained the necessary and sufficient conditions for these surfaces to satisfy the [Formula: see text]-constant, [Formula: see text]-constant or constant-ratio conditions. With the help of these results, we characterized the meridian curves of the surfaces. Further, we also give some examples to support the results obtained.