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Journal articles on the topic 'Conical rotors'

Author: Grafiati

Published: 4 June 2021

Last updated: 15 February 2022

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Baroiu, Nicuşor, Viorel Păunoiu, Virgil Gabriel Teodor, Florin Susac, and Nicolae Oancea. "Geometrical analysis, for rapid prototyping, of the compressor’s helical conic rotor model." MATEC Web of Conferences 178 (2018): 02006. http://dx.doi.org/10.1051/matecconf/201817802006.

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The conical rotary compressor represents a solution for gases compression, for relatively small flow, in conditions of a superior energetic efficiency. Although the theoretical solution for the helical conical compressor was elaborated decades ago, a viable technology solution become possible at industrial level only after the development of machine tools with numerically controlled axes. In this paper is proposed a study, analytical and graphical, concerning the geometry of conical rotary compressor’s rotors, modelled by rapid prototyping technology. The propose modelling allow to elaborate various constructive forms for conical compressor’s rotors.

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Rane, Sham, Ahmed Kovačević, and Nikola Stošić. "Grid Generation for CFD Analysis and Design of a Variety of Twin Screw Machines." Designs 3, no. 2 (2019): 30. http://dx.doi.org/10.3390/designs3020030.

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A detailed study of the fluid flow and thermodynamic processes in positive displacement machines requires 3D CFD modeling in order to capture their real geometry, including leakage gaps. However, limitations in the conventional computational grids, used in commercial software packages, exclude their use for classical twin screw machines. The screw compressor rotor grid generator (SCORG) is a customized grid generation tool developed to overcome these limitations. This paper shows how it can be further extended to include non-conventional rotor designs, such as those with variable lead or profile variation and even internally geared machines with conical rotors. Other arrangements possible with this improvement include multiple gate rotors to increase volumetric displacement or dual lead, high wrap angle rotors for very high-pressure differences and vacuum applications. A case study of a water-injected twin screw compressor is included to demonstrate its use for both detailed flow analysis and design.

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Hufenbach, W., M. Gude, B. Zhou, and L. Kroll. "Stress and failure analysis of thick-walled conical composite rotors." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 218, no. 1 (2004): 1–8. http://dx.doi.org/10.1177/146442070421800101.

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Mohiuddin, M. A., and Y. A. Khulief. "Modal characteristics of rotors using a conical shaft finite element." Computer Methods in Applied Mechanics and Engineering 115, no. 1-2 (1994): 125–44. http://dx.doi.org/10.1016/0045-7825(94)90191-0.

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Biryuk, Andrey, Mikhail Drobotenko, Igor Ryadchikov, and Alexander Svidlov. "Optimal Gyrodine Rotor Shape in the Class of Conical Bodies." Mathematical Physics and Computer Simulation, no. 4 (February 2021): 69–81. http://dx.doi.org/10.15688/mpcm.jvolsu.2020.4.7.

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The problem is to find the optimal shape of the gyrodine rotor and its angular rotation speed that maximizes the angular momentum relative to the axis of rotation at a fixed radius, mass and material of the rotor, taking into account the final strength of the material. The gyrodine rotor is a body of revolution, the thickness of which depends only on the distance r to the axis of rotation, r ∈ [0,R], where R is the radius of the rotor. The rotor surface is defined by rotating the curves z = ±z(r) around the axis. When the rotor is spinning, it undergoes deformation due to centrifugal forces. Normal stress fields appear: radial and annular. Assuming the rotor to be thin, deformations can be described by the functions of the radial displacement of the rotor points u(r). Stress fields can be expressed in terms of this function. The functions u(r) and z(r) are related by the equation of the elastically deformed state. This equation is supplied with the boundary conditions for the absence of radial stresses at r = R and the condition for the absence of displacement on the axis of rotation u(0) = 0. Using the numerical solution of the equation, the problem is solved for the class of conical rotors z(r) = a + br with two parameters a and b. The numerical method is used due to the fact that even in this relatively simple case the problem cannot be solved analytically. Several integrable cases are used to analyze the calculation error in the numerical solution of the problem. The dependence of the problem on the Poisson ratio μ ∈ (−1.1) is investigated, with the remaining parameters fixed. The gain in the angular momentum relative to a rotor of constant thickness is compared. The optimal steel conical rotor (μ = 0.3) is 2.068 times thicker at the center than at the edge. Its advantage in the angular momentum over the rotor of constant thickness is 3.2 %.

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Suhina, Tomislav, Saeed Amirjalayer, Sander Woutersen, Daniel Bonn, and Albert M. Brouwer. "Ultrafast dynamics and solvent-dependent deactivation kinetics of BODIPY molecular rotors." Physical Chemistry Chemical Physics 19, no. 30 (2017): 19998–20007. http://dx.doi.org/10.1039/c7cp02037f.

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The fluorescent excited state of a molecular rotor based on the meso-substituted boron-dipyrromethane (BODIPY) core decays rapidly to the ground state via a conical intersection. The fluorescence is strongly increased in viscous solvents, but solvent polarity has only a small effect.

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Sanz-Andrés, Ángel, Santiago Pindado, and Félix Sorribes-Palmer. "Mathematical Analysis of the Effect of Rotor Geometry on Cup Anemometer Response." Scientific World Journal 2014 (2014): 1–23. http://dx.doi.org/10.1155/2014/537813.

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The calibration coefficients of two commercial anemometers equipped with different rotors were studied. The rotor cups had the same conical shape, while the size and distance to the rotation axis varied. The analysis was based on the 2-cup positions analytical model, derived using perturbation methods to include second-order effects such as pressure distribution along the rotating cups and friction. The comparison with the experimental data indicates a nonuniform distribution of aerodynamic forces on the rotating cups, with higher forces closer to the rotating axis. The 2-cup analytical model is proven to be accurate enough to study the effect of complex forces on cup anemometer performance.

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Mohiuddin, M. A., and Y. A. Khulief. "Modal characteristics of cracked rotors using a conical shaft finite element." Computer Methods in Applied Mechanics and Engineering 162, no. 1-4 (1998): 223–47. http://dx.doi.org/10.1016/s0045-7825(97)00345-9.

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Wohlbru¨ck, R. "Stability of a Rotor Whose Cavity Has an Arbitrary Meridian and Is Partially Filled With Fluid." Journal of Vibration and Acoustics 107, no. 4 (1985): 440–45. http://dx.doi.org/10.1115/1.3269285.

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The stability of an elastically supported rotor spinning with constant angular velocity is studied. The rotor has a cavity of arbitrary meridian and is partially filled with an ideal fluid. The motions of the system are governed by linearized equilibrium conditions for the rotor and field equations as well as boundary conditions for the fluid. Due to the arbitrary shape of the meridian, it is not possible to solve the boundary value problem in closed form. Therefore a variational expression is developed which satisfies the boundary conditions naturally. The variational problem is solved approximately by the finite element method. The results, incorporated in the equilibrium conditions for the rotor, lead to stability statements. For numerical and experimental investigations, two rotors, one with an elliptical and one with a conical cavity are used. The fill medium is water. There is a close correlation between numerical and experimental results.

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Стаценко, В. В., О. П. Бурмістенков та Т. Я. Біла. "ВПЛИВ КОНСТРУКЦІЙ ВІДЦЕНТРОВИХ ЗМІШУВАЧІВ НА ЇХ ЗГЛАДЖУВАЛЬНУ ЗДАТНІСТЬ". Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 142, № 1 (2020): 11–18. http://dx.doi.org/10.30857/1813-6796.2020.1.1.

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Studying the influence of continuous centrifugal mixers design features on their smoothing ability. The methods used are discrete elements, mathematical modeling and regression analysis. The paper considers five continuous centrifugal mixers designs with conical and parabolic rotors. The mixers design features are determined, allowing to change their smoothing ability. Mathematical models of the bulk materials particles movement inside each mixer have been developed based on the discrete element method. The considered mixers reaction to a step change of the key component amount is investigated. The transients parameters are calculated and the particles average residence time in the mixer is determined. It is established that the introduction of turbulizers in the mixers design increases the particles kinetic energy, which leads to a decrease in their residence time in the mixer. Moreover, the absence of a turbulizer leads to a decrease in the mixing intensity. It was also found that the most effective way to increase the mixer smoothing ability is the introduction of additional rotors. In terms of the technological and design parameters combination, the use of mixers with a conical rotor and a turbulizer is the most effective from the point of view for increasing the smoothing ability. On the discrete element method basis, the bulk materials particles movement models in continuous centrifugal mixers of five designs have been developed. The influence of the mixers design features on their smoothing ability and average mixing time is determined. The results obtained allow us to select the appropriate mixer design according to the specified requirements for smoothing ability.

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Baskharone, E. A., and S. J. Hensel. "Interrelated Rotordynamic Effects of Cylindrical and Conical Whirl of Annular Seal Rotors." Journal of Tribology 113, no. 3 (1991): 470–80. http://dx.doi.org/10.1115/1.2920648.

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A comprehensive approach for computing the dynamic coefficients of an annular seal is presented. The coefficients are partly those associated with a uniform lateral eccentricity mode of the rotor (known as the cylindrical whirl mode) and with an angular eccentricity (which gives rise to a conical whirl type). The rotor excitation effects in both cases are treated as interrelated by recognizing the fluid-exerted moments resulting from the lateral eccentricity and the net fluid force resulting from the angular eccentricity. In all cases, the rotor is assumed to undergo a whirling motion around the housing centerline. The computational procedure is a finite-element perturbation model in which the zeroth-order undisplaced-rotor flow solution in the clearance gap is obtained through a Petrov-Galerkin approach. Next, the rotor translational and angular eccentricities, considered to be infinitesimally small, are perceived to cause virtual distortions of varied magnitudes in the finite element assembly which occupies the clearance gap. Perturbations in the flow variables including, in particular, the rotor surface pressure, are then obtained by expanding the finite-element equations in terms of the rotor eccentricity components. The fluid-exerted forces and moments are in this case computed by integration over the rotor surface, and the full matrix of rotordynamic coefficients, in the end, obtained. The computational model is verified against a bulk-flow model for a sample case involving a straight annular seal. Choice of this sample model for validation was made on the basis that no other existing model has yet been expanded to account for the mutual interaction between the cylindrical and conical rotor whirl, which is under focus in this study.

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Yang, S.-C. "A mathematical model of a cc-type single-screw compressor." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 218, no. 4 (2004): 437–48. http://dx.doi.org/10.1177/095440620421800408.

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In this paper, a method is proposed for determining a basic profile of a cc-type single-screw compressor including the gate rotor and the screw rotor. The cc-type has a cylindrical screw and two cylindrical gate rotors. Based on this method, a mathematical model of the meshing principles of a cc-type screw rotor meshed with a gate rotor, that has either straight edge teeth or conical teeth, is presented. The inverse envelope concept is used to determine the cutting-edge curve of a gate rotor. Based on this concept, the required cutter for machining a cc-type screw rotor can be obtained by the envelope of a one-parameter family. The obtained screw rotor is an envelope to the family of the gate rotor's surfaces. The obtained envelope becomes the generating surface. The inverse envelope can be used to obtain the envelope to the family of generating surfaces. Then the profile of a gate rotor cutting-edge curve can be easily obtained. The surface analysis including contact lines is shown for the design and manufacture of a screw compressor. As an example, the cc-type single-screw compressor with a compressor ratio of 11:6 was determined with the aid of the proposed mathematical model. Using rapid prototyping (RP) and manufacturing technology, a cc-type single-screw rotor with a gate rotor was designed. The RP primitives provide an actual full-size physical model that can be analysed and used for further development. Results from these mathematical models should have applications in the design of cc-type single-screw compressors.

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Suhina, Tomislav, Saeed Amirjalayer, Benedetta Mennucci, et al. "Excited-State Decay Pathways of Molecular Rotors: Twisted Intermediate or Conical Intersection?" Journal of Physical Chemistry Letters 7, no. 21 (2016): 4285–90. http://dx.doi.org/10.1021/acs.jpclett.6b02277.

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Elhannani, Abdelhak, Kaddour Refassi, Abbes Elmeiche, and Mohamed Bouamama. "Vibration analysis of functionally graded tapered rotor shaft system." Mechanics and Mechanical Engineering 23, no. 1 (2019): 241–45. http://dx.doi.org/10.2478/mme-2019-0032.

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Abstract This investigation deals with the vibration analysis of a rotating tapered shaft in Functionally Graded Material (FGM). The dynamic system is modeled using the Timoshenko beam theory (FSDBT) with consideration of gyroscopic effect and rotary inertia. The equations of motion are expressed by the hierarchical finite element method based on bi-articulated boundary conditions. The material properties are continuously varied in the thickness direction of a hollow shaft according to the exponential law function (E-FGM). The presented model is validated by comparing the numerical results found with the available literature. Various analyses are carried out to determine the influence of taper angle and material distribution of the two extreme materials on the dynamic behavior of FGM conical rotors system.

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Li, Dantong, Zhilong He, Chuang Wang, et al. "Design methodology and performance analysis of conical rotors for dry screw vacuum pumps." Vacuum 185 (March 2021): 110025. http://dx.doi.org/10.1016/j.vacuum.2020.110025.

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SHENGBO, LI, А. YU KORNEEV, WANG SICONG, and E. V. MISHCHENKO. "THE ANALYSIS OF THE TRAJECTORIES OF MOTION RIGID ROTOR IN THE CONICAL LIQUID FRICTION BEARINGS." Fundamental and Applied Problems of Engineering and Technology 6 (2020): 114–20. http://dx.doi.org/10.33979/2073-7408-2020-344-6-114-120.

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The calculation procedure of the trajectories of motion of the rigid rotor in the conical liquid friction bearings is offered. The equations set of motion is written for two-bearing rotor in the conical liquid friction bearings.The results are illustrated by the plots of trajectories for the conical bearings with oil lubricant.

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Wang, Ke, Xing Wei Sun, and Xin Chen. "Research on NC Manufacturing Technique of Double Conical Screw." Key Engineering Materials 407-408 (February 2009): 279–82. http://dx.doi.org/10.4028/www.scientific.net/kem.407-408.279.

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Conical screw rotor is the key part of conical double-screw extruder, with complex geometrical features, such as variable outside and inside diameter, unequal groove depth, varied head and lead. The manufacturing process is complicated and difficult. The precision and efficiency of conventional machining method is lower, the mating character of machined screw rotor is bad and the exchangeability is hard. On the basis of studying the geometric character and contacting process of double conical screw, this paper presents a new NC manufacturing method to envelope milling screw rotor with several axes moving combined. The automatic programming system for screw rotor NC machining is developed. This research increases the machining level of conical double screw. It has conspicuous engineering meaning.

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Kamesh, Punithavathy, Michael J. Brennan, and Roy Holmes. "On the stabilising effect of gyroscopic moments in an automotive turbocharger." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 10 (2012): 2485–95. http://dx.doi.org/10.1177/0954406212438142.

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Automotive turbochargers, which operate at very high speeds, exceeding 180,000 r/min, exhibit two strong sub-harmonic modes of vibrations due to oil-whirl instability. These are a conical mode and an in-phase whirl mode. The gyroscopic effects can be very important in such a rotor system. This article presents a theoretical investigation into these effects on the conical whirl instability of a turbocharger induced by the angular (tilting) motion of a rigid rotor. A simplified linear model is used to analyse the rotor-bearing system by investigating the effects of the gyroscopic moment on the internal moments. A gyroscopic coefficient, defined by the geometry of the rotor, is shown to govern the stability of the conical whirl motion. A threshold value of ½ is determined for this coefficient to suppress the conical whirl. This value remains unaffected if the rotor is asymmetric and is supported by floating ring bearings, which is the case in a practical turbocharger.

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Mikiton, N. E., Yu V. Minaev, S. A. Revenko, G. F. Streletskii, and G. G. Averbakh. "Sluice feeder with conical rotor." Chemical and Petroleum Engineering 25, no. 2 (1989): 63–64. http://dx.doi.org/10.1007/bf01245843.

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Pan, Coda H. T., and Daejong Kim. "Stability Characteristics of a Rigid Rotor Supported by a Gas-Lubricated Spiral-Groove Conical Bearing." Journal of Tribology 129, no. 2 (2007): 375–83. http://dx.doi.org/10.1115/1.2647443.

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Five-degree-of-freedom (5-DOF) characterization of the stability of a gas-lubricated conical bearing of the spiral-groove design is presented for bearing numbers up to 500. Critical points in stability analysis are identified in impedance contour plots separately for axial, cylindrical, and conical modes. The stability thresholds with respect to each mode are graphed as functions of the bearing number. For axial and cylindrical modes, the threshold parameter is the rotor mass. For the conical mode, the threshold parameter is an equivalent mass that is dependent on both transverse and polar radii of gyration of the rotor. An application example illustrates a rational procedure to specify nominal bearing clearance and its allowable tolerance range.

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Li, Yan, Desheng Zhang, and Fuhai Duan. "Dynamic characteristics of opposed-conical gas-dynamic bearings." Industrial Lubrication and Tribology 72, no. 3 (2019): 415–25. http://dx.doi.org/10.1108/ilt-07-2019-0264.

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Purpose The purpose of this paper is to investigate dynamic characteristics of opposed-conical gas-dynamic bearings considering five degree-of-freedom motion, including translation and tilt. Design/methodology/approach The steady-state Reynolds equation and perturbed Reynolds equations are solved on the surface of conical bearings, and both stiffness and damping coefficients are calculated. A formula for quickly calculating critical mass is deduced to discriminate the stability of the rotor considering the five degree-of-freedom motion. Findings Results show that the stability of the rotor is mainly determined by translation rather than tilt. The formula of critical mass is validated by comparing the results with traditional Routh–Hurwitz criterion. Originality/value The formula proposed in this paper greatly simplifies the solution of critical mass, which facilitates the rotor stability design. It is applicable for opposed-conical bearings, opposed-hemispherical bearings and spherical bearings. The results provide theoretical guidance for the design of gas-dynamic bearings.

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Korneev, A. Yu. "Rigid-rotor dynamics of conical hydrodynamic bearings." Russian Engineering Research 34, no. 3 (2014): 131–35. http://dx.doi.org/10.3103/s1068798x14030083.

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Greenhill, L. M., W. B. Bickford, and H. D. Nelson. "A Conical Beam Finite Element for Rotor Dynamics Analysis." Journal of Vibration and Acoustics 107, no. 4 (1985): 421–30. http://dx.doi.org/10.1115/1.3269283.

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The development of finite element formulations for use in rotor dynamics analysis has been the subject of many recent publications. These works have included the effects of rotatory inertia, gyroscopic moments, axial load, internal damping, and shear deformation. However, for most closed-form solutions, the element geometry has been limited to a cylindrical cross-section. This paper extends these previous works by developing a closed-form expression including all of the above effects in a linearly tapered conical cross-section element. Results are also given comparing the formulation to previously published examples, to stepped cylinder representations of conical geometry, and to a general purpose finite element elasticity solution. The elimination of numerical integration in the generation of the element matrices, and the ability of the element to represent both conical and cylindrical geometries, make this formulation particularly suited for use in rotor dynamic analysis computer programs.

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Kanemori, Yuji, and Takuzo Iwatsubo. "Forces and Moments Due to Combined Motion of Conical and Cylindrical Whirls for a Long Seal." Journal of Tribology 116, no. 3 (1994): 489–98. http://dx.doi.org/10.1115/1.2928871.

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The mutual interaction effects of cylindrical and conical whirl on the dynamic fluid forces and moments, which act on a long annular seal, were studied experimentally. A whirling motion composed of cylindrical and conical whirls is actuated by intentionally giving the phase difference between the seal exit and inlet whirling movements. This whirling motion is believed to generate during actual pump running. The experiment was conducted by changing the phase difference, at various rotor speeds and with a pressure difference between the seal inlet and exit. The result of this study revealed that fluid forces and moments are greatly dependent on the phase difference of the whirl, namely the long seal has a significant coupling between displacements and rotations. Furthermore, dynamic fluid forces and moments were derived theoretically, assuming that total fluid force acting on the rotor could be determined by superposing fluid forces due to conical and cylindrical whirling movements. It was confirmed that the experimental results moderately agree with the theoretical values, if the rotor and seal are set in concentric alignment, the principle of superposition becomes applicable.

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Alazemi, Saud F. E. M. D., Irfan Hilmy, and Erry Y. T. Adesta. "Indentation Mechanism in Rotary Hammer Forging Process: Analytical and Numerical Approach." International Journal of Engineering Materials and Manufacture 3, no. 4 (2018): 190–99. http://dx.doi.org/10.26776/ijemm.03.04.2018.03.

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Rotary hammer forging process is getting popular since it has many advantages comparing to the conventional forging process. The mechanism of the movement in term of orbital motion of the conical upper die become concern of this research. This article present the three stages of the modelling of the rotary hammer forging. The first stage is the development of the orbital motion of the conical upper die. Three-dimensional CAD model of the conical upper die was developed to determine the orbital motion as a function of the four parameters: Nutation, Precession, Spin and Rocking-Die mechanism. A reasonably accurate design of the conical upper die and the workpiece had been developed based on motion because of interaction of conical upper die and upper part of workpiece geometries. The behaviour of orbital motion with any active combination of those four parameters was observed. The second stage was the development of the conical upper die with the specific feature in order to generate a product with an unsymmetrical shape of upper part of the product. The sequence and mechanism of the formation of the upper part of product were generated. The third stage was the analysis of the stress strain state during the formation of the upper part of the workpiece. An elastic-plastic, dynamic analysis of 3D rotary hammer forging mechanism with the concern at the workpiece and their interaction with a model of dies have been performed. Verification of the indentation mechanism of the rotary hammer forging had been done by validating the result with the existing experimental results.

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Tang, Jiqiang, Xiaofeng Zhao, Ying Wang, and Xu Cui. "Adaptive neural network control for rotor’s stable suspension of Vernier-gimballing magnetically suspended flywheel." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 233, no. 8 (2018): 1017–29. http://dx.doi.org/10.1177/0959651818813625.

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Vernier-gimballing magnetically suspended flywheel with conical hybrid magnetic bearing can produce gyro moment by tilting the rotational rotor around a certain radial direction. When rotor is tilted, the nonlinear variation of conical magnetic bearing’s displacement stiffness and the coupling interference can result in not only poor stability of suspension control system but also precision’s degradation of gyro moment. To solve these two problems, the forces acting on tilted rotor are analyzed, and furthermore, a nonlinear model considering variation of displacement stiffness is constructed accordingly, then a radial basis function neural network is utilized to estimate the nonlinear variation of displacement stiffness and disturbance, and the adaptive controller with nonlinear variation compensation is presented based on the Lyapunov stability theory. Compared with cross-feedback method in tilting control and proportional–integral–derivative method in translation control, simulation researches are done, and the results indicate that the presented control method does well in estimating nonlinear variation and has better performances on suspension control when rotor is tilted.

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Marian, Marius Gheorghe, Tudor Sajin, and Abdelkrim Azzouz. "Study of Micro Hydropower Plant Operating in Gravitational Vortex Flow Mode." Applied Mechanics and Materials 371 (August 2013): 601–5. http://dx.doi.org/10.4028/www.scientific.net/amm.371.601.

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This paper refers to experimental study of a new type of micro hydropower plant for energy conversion of low river water heads into mechanical work by imposing gravitational vortex flow in spiral form through a vertical conical channel. In this vortex, at different heights of the conical channel, are positioned rotor blades of the turbine with different values of specific speed. The characteristics of the gravitational vortex of water flow through the conical channel, the speed and the power characteristics of the micro hydropower plant were investigated and attempts to efficiency modeling were performed.

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Genta, G., and A. Gugliotta. "A conical element for finite element rotor dynamics." Journal of Sound and Vibration 120, no. 1 (1988): 175–82. http://dx.doi.org/10.1016/0022-460x(88)90342-2.

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Wu, Ningning, Hong Guo, Shuai Yang, and Shaolin Zhang. "Thermal effect on stability and minimum oil film thickness of a deep/shallow pockets conical bearing." Industrial Lubrication and Tribology 72, no. 10 (2020): 1251–57. http://dx.doi.org/10.1108/ilt-12-2019-0542.

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Purpose This paper aims to study the influence of thermal effect on the performance for a high-speed conical hybrid bearing including stability and minimum oil film thickness. Design/methodology/approach A thermal hydrodynamic (THD) model and dynamic model of single mass rigid rotor system were established by taking conical hybrid bearing with shallow and deep pockets as the research object, dynamic coefficient and stability parameters of bearing-rotor system were obtained by using finite element method (FEM) and finite difference method (FDM) to solve computational models of Reynolds equation, energy equation and viscosity-temperature equation. Minimum oil film thickness was obtained based on bearing force balance. Dynamic coefficient was compared with previous findings. Findings After considering thermal effect, the dimensionless critical mass decreases, a significant decrease in the instability speed, and the stability of the system decreases greatly; the minimum oil film thickness decreases because of thermal effect. Originality/value The thermal effect is combined with dynamic characteristics to analyze stability of the rotor system for a conical hybrid bearing. Influence of thermal effect on minimum oil film thickness is studied. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0542/

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Shyue-Cheng, Yang, and Tsang-Lang Liang. "STUDY OF A SINGLE SCREW COMPRESSOR WITH A CONICAL TEETH GATE ROTOR." Transactions of the Canadian Society for Mechanical Engineering 32, no. 3-4 (2008): 333–52. http://dx.doi.org/10.1139/tcsme-2008-0022.

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From a geometric viewpoint, a mathematical model of a single screw compressor with a conjugate pair of meshing conical teeth gate rotor is a conjugate problem. Coordinate transformation and envelope theory are applied to determine the sets of spatial points of the contacting surfaces that define the main rotor of a single screw compressor. Envelope theory and analytical procedure are used to derive mathematical models of a gate rotor and a main rotor. Stress analysis for the single screw compressor mechanism is performed. PowerMILL software package is used to simulate the manufacture of a main rotor. A numerical example with a compressor ratio of 11:6 is presented to demonstrate the application of the mathematical models developed in this paper.

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Fang, Jiancheng, Chune Wang, and Jiqiang Tang. "Modeling and analysis of a novel conical magnetic bearing for vernier-gimballing magnetically suspended flywheel." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 13 (2013): 2416–25. http://dx.doi.org/10.1177/0954406213517488.

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The vernier-gimballing magnetically suspended flywheel can generate control moment in radial directions by tilting the spinning rotor to rotate around the radial axes. In order to reduce the extra tilting torque caused by the uniform distribution of flux density and the magnetic coupling among different channels, a novel 3 degrees of freedom conical permanent-magnet-biased magnetic bearing is proposed in the paper. The axial and radial stators are both designed with the normal directions of the midst faces directing to the centroid of the rotor, so as to decrease the extra torque by shortening the length of torque arm. A novel structure of radial X and Y stator poles separated by nonmagnetic material is proposed, and the upper and lower conical stators are designed to be mirror structures with each other, so that the magnetic coupling can be reduced. The mathematical model of the proposed permanent-magnet-biased magnetic bearing is constructed by methods of equivalent magnetic circuit and finite element. Calculations and simulations are carried out on the suspension force, extra tilting torque, and force coupling. The results show that with the conical structure, the extra tilting torque can be decreased from 10.83 Nm to 0.11 Nm when the rotor tilts around X axis for 1°. The magnetic forces among X, Y, and Z directions are almost decoupled even when the rotor shifts in some direction. All the results prove that the novel permanent-magnet-biased magnetic bearing is suitable for application in vernier-gimballing magnetically suspended flywheel.

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SATOH, Munetake, Takashi FUJIMOTO, and Kei MIYANAMI. "Measurement of the dynamic physical properties of solid particles by a rotary shear tester with a conical rotor." Journal of the Society of Powder Technology, Japan 24, no. 7 (1987): 462–68. http://dx.doi.org/10.4164/sptj.24.462.

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Ovsyannikova, E. E., and A. M. Gus’kov. "Stabilization of a Rigid Rotor in Conical Magnetic Bearings." Journal of Machinery Manufacture and Reliability 49, no. 1 (2020): 8–15. http://dx.doi.org/10.3103/s1052618820010100.

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Wang, Chun'e, and Jiqiang Tang. "Design and Mathematical Analysis of a Novel Reluctance Force-Type Hybrid Magnetic Bearing for Flywheel with Gimballing Capability." Mathematical Problems in Engineering 2013 (2013): 1–17. http://dx.doi.org/10.1155/2013/836058.

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Magnetically suspended flywheel (MSFW) with gimballing capability fulfills requirements of precision and maneuvers for space applications. A novel reluctance force-type hybrid magnetic bearing (RFHMB) is presented based on analysis of demerits of Lorentz force-type magnetic bearing and common RFHMB. It features that radial and axial magnetic bearing units are integrated into a compact assembly with four separate biased permanent magnets and two conical stators; four radial poles with shoes and rotor made of iron-based amorphousness can reduce eddy loss. Equivalent magnetic circuits of permanent magnets and their control currents are presented. Simulation results indicate flux density fluctuates from 0.272 T to 0.41 T; rotor tilting does not affect the suspension force when rotor only tilts aroundX-axis orY-axis. When rotor drifts inX,Y, orZdirection and tilts aroundX-axis orY-axis simultaneously, force in corresponding directions slightly increases with tilting angle’s enlargement, but the maximum change does not exceed 14%. Additional tilting torque mainly determined by uniformity of flux density in conical air gaps is 0.05 Nm which is far smaller than 11 Nm in common RFHMB; magnetic suspension force is effectively decoupled amongX,Y, andZdirections; results prove that MSFW with gimballing capability theoretically meets maneuvering requirement of spacecraft.

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Srinivas, Abhinaya, LGanesh Jeevanandan, Lavanya Govindaraju, and Erulappan Muthu Ganapathi Subramanian. "Comparative Evaluation of The Efficacy Of Rotary file system (Kedo-S) Vs Hand K-Files In Root Canal Preparation Of Primary Teeth Using Cone Beam Computed Tomography (CBCT) - An In Vitro Study." Brazilian Dental Science 22, no. 2 (2019): 197–202. http://dx.doi.org/10.14295/bds.2019.v22i2.1705.

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Objective: To evaluate the efficacy of rotary Kedo-S and hand K-files in shaping ability in primary canines using cone beam computed tomography. Materials and Methods: Thirty extracted primary maxillary and mandibular canines were selected. Using cone beam computed tomography the teeth were scanned before instrumentation. In Group I, the teeth were prepared using stainless steel K file up to the size of 40. In the Group II teeth, U1 size Kedo-S rotary file was used in crown down technique. The instrumented teeth were scanned again with cone beam computed tomography and the images were compared. Results: The canal taper was more conical for rotary Kedo-S files as compared to K-files, which was statistically significant. Conclusion: Canal preparation with Rotary files resulted in more conical canals when compared to manual instrumentation in primary teeth that contributes to more uniform obturation.KeywordsCBCT; Hand K-files; Kedo-S file system; Primary teeth; Pulpectomy; Rotary instrumentation.

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Mitome, K. "Inclining Work-Arbor Taper Hobbing of Conical Gear Using Cylindrical Hob." Journal of Mechanisms, Transmissions, and Automation in Design 108, no. 1 (1986): 135–41. http://dx.doi.org/10.1115/1.3260776.

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The inclining work-arbor taper hobbing is considered one of the most practical methods to cut a conical gear. But an exact hobbing theory has not been made clear, and besides an ideal hobbing machine available inpractical use has not been developed so far. In this paper, an exact kinematic analysis of this taper hobbing is presented, and an imaginary generating rack is obtained. A gear generated by this rack is defined as an ideal gear. Practical hobbing of conical involute gears is discussed. A hobbing machine having an inclining rotary table is tested, and some test gears are cut and inspected. And it is confirmed that the ideal gear can be considered representative of the gear cut by this taper hobbing, and the hobbing machine with an inclining rotary table has a practical utility. Finally, grinding of the conical involute gear based on the principle of this taper hobbing is presented.

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Satoh, Munetake, Takashi Fujimoto, and Kei Miyanami. "Measurement of the Dynamic Physical Properties of Solid Particles by a Rotary Shear Tester with a Conical Rotor [Translated]†." KONA Powder and Particle Journal 6 (1988): 39–46. http://dx.doi.org/10.14356/kona.1988008.

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Khadem, Siamak E., and Reza Nezamoleslami. "Investigation of the Free Vibrations of Composite Anisogrid Lattice Conical Shells Formed by Geodesically Spiral and Circumferential Ribs." International Journal of Applied Mechanics 09, no. 04 (2017): 1750047. http://dx.doi.org/10.1142/s1758825117500478.

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This paper focuses on the dynamic behavior of composite anisogrid lattice conical shells. Lattice composite conical shell consists of composite helical and circumferential ribs and thin outer skin. The free vibration analysis of anisogrid composite lattice conical shell is presented. A smeared method is employed to calculate the variable coefficients of stiffness of conical shell and more close to the realistic applications. The lattice part of conical shell is modeled as a beam, so in addition to the axial loads, ribs endure shear loads and bending moments. The first-order shear deformation shell theory is used to account for the effects of transverse shear deformations and rotary inertia. The current results are verified with 3D finite element model of conical shell by ANSYS Software and those reported in the literature. Some special cases as influences of geometric parameters of lattice part of shell, effects of boundary conditions and circumferential wave number on natural frequencies of the shell are discussed. It was concluded that employment of the smear method could be recommended for determining the coefficients of stiffness of the composite lattice conical shells with outer skin. Also increasing the vertex angle of cone increases the natural frequencies of conical shell.

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Sorge, Francesco. "Damping of rotor conical whirl by asymmetric dry friction suspension." Journal of Sound and Vibration 321, no. 1-2 (2009): 79–103. http://dx.doi.org/10.1016/j.jsv.2008.09.009.

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Tanaka, M., and H. Kamiya. "Evaluation of flow properties of toner powder using conical rotor." Powder Technology 181, no. 1 (2008): 36–44. http://dx.doi.org/10.1016/j.powtec.2007.06.004.

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Tenhunen, A., T. Benedetti, T. P. Holopainen, and A. Arkkio. "Electromagnetic forces of the cage rotor in conical whirling motion." IEE Proceedings - Electric Power Applications 150, no. 5 (2003): 563. http://dx.doi.org/10.1049/ip-epa:20030365.

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Vasileiou, G., N. Rogkas, S. Tsolakis, V. Spitas, and P. Zalimidis. "Design of a new-concept conical positive displacement slurry pump for continuous de-clogging." MATEC Web of Conferences 287 (2019): 01017. http://dx.doi.org/10.1051/matecconf/201928701017.

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Slurry pumps are extensively used in the construction industry while positive displacement screw pumps are used in most mobile concrete pump applications. The aggregate size is known to significantly affect pump performance in terms of clogging. Large aggregates tend to be trapped against the stator-rotor interface, blocking the continuous and smooth operation of the screw pump. In order to avoid the development of excessive stress values able to damage the rotor-stator mechanism of the pump, the typical de-clogging mechanism deployed by most positive displacement screw slurry pumps includes reversing the rotation of the pump driving motor thus allowing the aggregates to be carried away with the mixture, so that the pump can soon resume its operation. This procedure causes frequent start-stops of the pump resulting in dis-continuation of the pumped mixture lasting a few seconds, that while being of little importance in most construction applications, can be of significance in applications requiring higher levels of accuracy and continuous mixture flow. In the context of this work, a novel concept of positive displacement screw slurry pump is presented, including a continuous de-clogging mechanism, without the need to reverse the rotation of the driving motor. This de-clogging operation is achieved through the modification of the geometry of both the rotor and stator introducing a conical form along the axial direction. This configuration of the rotor-stator, allows for small displacements along the axial direction, which in turn increases the size of the cavities facilitating the de-clogging of the pump. Variable pitch is also introduced to both the rotor and stator in order to ensure constant mass flow of the mixture throughout the length of the screw pump covering for the velocity increase as a result of the conical geometry. The axial movement of the rotor in relation to the fixed stator, is achieved through the elastic support of the rotor in the axial direction, that allows for small axial displacements, when stresses induced from trapped aggregates exceed the stiffness of the support. The proposed concept comprises a passive real-time de-clogging mechanism that greatly reduces pump idle time compared to the conventional mechanism described earlier, providing smoother operation and stable mass flow of the mixture.

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Song, Yun Guang, Zun Qiang Fan, Xiao Dong Sun, et al. "Experimental Research on the Levitation Support Way of Ultrasonic Thrust Bearing." Applied Mechanics and Materials 423-426 (September 2013): 1571–76. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1571.

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In this paper, two ways of levitation support of ultrasonic thrust bearing are disscussed. Based on the mechanism of the near-field ultrasonic levitation, the front cover of the piezoelectric transducer is designed as conical structure.The ultrasonic radiation pressure which distributes on the conical surface can be decomposed into the axial and radial supporting the levitation subject bidirectionally. Finnally contrast experiments are carried out, indicating that when the requirement of levitation mass being satisfied, the way of bidirectional support runs more stably compared with the pure way of the axial levitation support.It supposes that the way of bidirectional levitation support is more conducive to improve the rotating speed of the rotor.

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Fan, Qiuxia, Qianqian Zhang, Guirong Liu, et al. "An experimental study on wearing of conical picks interacting with rock." Transactions of the Canadian Society for Mechanical Engineering 43, no. 4 (2019): 544–50. http://dx.doi.org/10.1139/tcsme-2018-0225.

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Wearing of conical picks on a coal mining machine and roadheaders are investigated experimentally using a full-scale rotary cutting machine. This study considers three types of conical picks with different tip materials to examine the effects of wear resistance of conical picks and wear characteristics in response to cutting load. The influence of pick wear on the cutting load and pick tip temperature are analyzed, thereby providing an experimental-based guideline for reducing pick wear. The results indicate that the cemented carbide pick has the best wear resistance among the three kinds of picks studied, and the pick life can be significantly extended for picks with a wear-resistant coating surface. It is also found that pick wear has the greatest influence on the normal force. Thermal fatigue and overloading are two factors that cause pick wear failure. The results can also be used to design the conical pick with wear-resistant coating and to validate the numerical models.

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Jing, Y., Y. Lie, and X. Jing. "Coupled dynamics and control of a rotor-conical magnetic bearing system." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 220, no. 7 (2006): 581–86. http://dx.doi.org/10.1243/13506501j07503.

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OHTSUKA, Yoshiomi, Yasusuke JINNOUCHI, Takashi NAGATA, and Masanobu INOUE. "Conical Mode Instability of a Rotor Equipped with Flexible Cantilever Beams." Transactions of the Japan Society of Mechanical Engineers Series C 68, no. 665 (2002): 24–29. http://dx.doi.org/10.1299/kikaic.68.24.

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Wei, Shi Yang, Guang Zhen Cheng, Zhe Tong, Jia Hang Ma, Yan Chun Gu, and Qi Feng You. "Structure Optimization Design about the Wet Grinding Sanding Machine with Double Cooling System." Applied Mechanics and Materials 685 (October 2014): 208–11. http://dx.doi.org/10.4028/www.scientific.net/amm.685.208.

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This paper introduced a wet grinding sanding machine, it is used for fine material. The machine was consists of three parts by stirring grated agencies, cooling system, material handling systems. Rotor and its Rod pin using the whole cast structure, low cost, conical rod pin to improve bending strength. Annular space between the cylinder and the cylinder liner formed cylinder cooling water channel, it connected respectively inlet and return pipes. Hollow spindle, inner pipe, pipe joint and rotor cavity form rotor cooling water channel, dual cooling effect is good. Shell fixed to the cylinder, turn the handle nut, interaction between the thread and the external thread on the piston, forces the pistons to axial movement, used to adjust the working volume and pressure of sanding machine.

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Hou, Zhong Lin, Tan Zhao, Zhen Xu, et al. "The New Heat Source Model of AZ31B Magnesium Alloy Laser-TIG Hybrid Welding." Key Engineering Materials 815 (August 2019): 120–24. http://dx.doi.org/10.4028/www.scientific.net/kem.815.120.

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A new heat source model consisted of inverted conical heat source and rotary Gauss body heat source is established using the CAE software for the keyhole effect of laser-TIG hybrid welding. The inverted conical heat source is used for analyzing the wide upper part of weld pool due to the rapid heat up by the laser and arc. The rotary Gauss body heat source model is used for analyzing the long and narrow lower part of weld pool formed by the laser. The result showed that, compared with other single source mode, this new heat source model may get a better simulation of the weld pool morphology, especially the inflection point near the keyhole. It provides a new method to predict the morphology and size of the weld pool of magnesium alloy laser-TIG welding.

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Cheng, Wenjie, Zhikai Deng, Ling Xiao, Bin Zhong, and Wenbo Duan. "Rotor dynamic experimental investigation of an ultra-high-speed permanent magnet synchronous motor supported on a three-pad bidirectional gas foil bearing." Advances in Mechanical Engineering 11, no. 9 (2019): 168781401987536. http://dx.doi.org/10.1177/1687814019875368.

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With a 10-kW, 120,000-r/min, ultra-high-speed permanent magnet synchronous motor taken as a prototype, experimental research is conducted on the rotor dynamic behaviours of a three-pad bidirectional gas foil bearing high-speed motor rotor system. Load-carrying properties of the three-pad bidirectional gas foil bearing are analysed, and natural frequencies of conical and parallel whirling modes of the elastically supported rotor are calculated based on an appropriate simplification to the stiffness and damping coefficients of the gas foil bearings. The prototype passes through a 90,000-r/min coast-down experiment. Experiments show that there are violent subsynchronous whirling motions that are evoked by the gas foil bearing–rotor system itself. The cause of shaft orbit drift is analysed, and the corresponding solution is put forward. The theoretical analysis and experimental results can offer a useful reference to the bearing–rotor system design of ultra-high-speed permanent magnet motors and its subsequent dynamic analysis.

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Tang, Jiqiang, Biao Xiang, and Chun’e Wang. "Rotor׳s Suspension for Vernier-gimballing magnetically suspended flywheel with conical magnetic bearing." ISA Transactions 58 (September 2015): 509–19. http://dx.doi.org/10.1016/j.isatra.2015.05.011.

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