The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
C.y. Wang - One of the best experts on this subject based on the ideXlab platform.
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Off-centered stagnation flow towards a Rotating Disc
International Journal of Engineering Science, 2008Co-Authors: C.y. WangAbstract:Abstract Stagnation flow towards an off-centered Rotating Disc is studied. A three dimensional similarity transform reduces the Navier–Stokes equations to a set of nonlinear ordinary differential equations which are integrated numerically. It is found that the non-alignment complicates the flow field and surface shear, but does not affect the torque. Similarity equations for convective heat transfer with dissipation are also obtained.
J. Michael Owen - One of the best experts on this subject based on the ideXlab platform.
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Performance of Pre-Swirl Rotating-Disc Systems
Journal of Engineering for Gas Turbines and Power, 2000Co-Authors: Hasan Karabay, Robert Pilbrow, Michael T. Wilson, J. Michael OwenAbstract:This paper summarizes and extends recent theoretical, computational, and experimental research into the fluid mechanics, thermodynamics, and heat transfer characteristics of the so-called cover-plate pre-swirl system. Experiments were carried out in a purpose-built Rotating-Disc rig, and the Reynolds-averaged Navier-Stokes equations were solved using two-dimensional (axisymmetric) and three-dimensional computational codes, both of which incorporated low-Reynolds-number k-e turbulence models. The free-vortex flow, which occurs inside the Rotating cavity between the Disc and cover-plate, is controlled principally by the pre-swirl ratio, β p : this is the ratio of the tangential velocity of the air leaving the nozzles to that of the Rotating Disc. Computed values of the tangential velocity are in good agreement with measurements, and computed distributions of pressure are in close agreement with those predicted by a one-dimensional theoretical model. It is shown theoretically and computationally that there is a critical pre-swirl ratio, β p,crit , for which the frictional moment on the Rotating Discs is zero, and there is an optimal pre-swirl ratio, β p,opt , where the average Nusselt number is a minimum. Computations show that, for β p β p,opt , whether the temperature of the cooling air increases or decreases as β p increases depends on the flow conditions and on the temperature difference between the Disc and the air. Owing to the three-dimensional flow and heat transfer near the blade-cooling holes, and to unquantifiable uncertainties in the experimental measurements, there were significant differences between the computed and measured temperatures of the blade-cooling air. In the main, the three-dimensional computations produced smaller differences than the two-dimensional computations.
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Performance of Pre-Swirl Rotating-Disc Systems
Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration, 1999Co-Authors: Hasan Karabay, Robert Pilbrow, Michael T. Wilson, J. Michael OwenAbstract:This paper summarises and extends recent theoretical, computational and experimental research into the fluid mechanics, thermodynamics and heat transfer characteristics of the so-called cover-plate pre-swirl system. Experiments were carried out in a purpose-built Rotating-Disc rig, and the Reynolds-averaged Navier-Stokes equations were solved using 2D (axisymmetric) and 3D computational codes, both of which incorporated low-Reynolds-number k-e turbulence models. The free-vortex flow, which occurs inside the Rotating cavity between the Disc and cover-plate, is controlled principally by the pre-swirl ratio, βp: this is the ratio of the tangential velocity of the air leaving the nozzles to that of the Rotating Disc. Computed values of the tangential velocity are in good agreement with measurements, and computed distributions of pressure are in close agreement with those predicted by a one-dimensional theoretical model.It is shown theoretically and computationally that there is a critical pre-swirl ratio, βp,crit, for which the frictional moment on the Rotating Discs is zero, and there is an optimal pre-swirl ratio, βp,opt, where the average Nusselt number is a minimum. Computations show that, for βp βp,opt, whether the temperature of the cooling air increases or decreases as βp increases depends on the flow conditions and on the temperature difference between the Disc and the air. Owing to the three-dimensional flow and heat transfer near the blade-cooling holes, and to unquantifiable uncertainties in the experimental measurements, there were significant differences between the computed and measured temperatures of the blade-cooling air. In the main, the 3D computations produced smaller differences than the 2D computations.Copyright © 1999 by ASME
S.b. Singh - One of the best experts on this subject based on the ideXlab platform.
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Thickness Variation Parameter in a Thin Rotating Disc by Finite Deformation
FME Transactions, 2013Co-Authors: Thakur Pankaj, S.b. Singh, Kaur JatinderAbstract:Seth’s transition theory is applied to the problems of thickness variation parameter in a thin Rotating Disc by finite deformation. Neither the yield criterion nor the associated flow rule is assumed here. The results obtained here are applicable to compressible materials. If the additional condition of incompressibility is imposed, then the expression for stresses corresponds to those arising from Tresca yield condition. It has been observed that effect of thickness for incompressible material of the Rotating Disc required higher percentage increased in angular speed to become fully plastic as compared to Rotating Disc made of compressible materials. For flat Disc compressible materials required higher percentage increased in angular speed to become fully plastic as compared to Disc made of incompressible material. With effect of thickness circumferential stresses are maximum at the external surface for compressible materials as compared to incompressible materials whereas for flats Disc circumferential stresses are maximum at the internal surface for incompressible material as compared to compressible materials.
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Creep Modeling in a Composite Rotating Disc with Thickness Variation in Presence of Residual Stress
International Journal of Mathematics and Mathematical Sciences, 2012Co-Authors: Vandana Gupta, S.b. SinghAbstract:Steady-state creep response in a Rotating Disc made of Al-SiC (particle) composite having linearly varying thickness has been carried out using isotropic/anisotropic Hoffman yield criterion and results are compared with those using von Mises yield criterion/Hill's criterion ignoring difference in yield stresses. The steady-state creep behavior has been described by Sherby's creep law. The material parameters characterizing difference in yield stresses have been used from the available experimental results in literature. Stress and strain rate distributions developed due to rotation have been calculated. It is concluded that the stress and strain distributions got affected from the thermal residual stress in an isotropic/anisotropic Rotating Disc, although the effect of residual stress on creep behavior in an anisotropic Rotating Disc is observed to be lower than those observed in an isotropic Disc. Thus, the presence of residual stress in composite Rotating Disc with varying thickness needs attention for designing a Disc.
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Creep Analysis in Anisotropic Composite Rotating Disc with Hyperbolically Varying Thickness
Applied Mechanics and Materials, 2011Co-Authors: Vandana Gupta, S.b. SinghAbstract:Steady state creep in a anisotropic Rotating Disc made of Al-SiCp composite having hyperbolically varying thickness has been investigated using Hill’s yield criterion. The creep behavior is supposed to follow the Sherby’s law in present study. The stress and strain distributions are calculated for different combinations of anisotropic constants. The change in the radial stress is not significant while the tangential stress is changed with the change in the material constants. The tangential strain rates are highest at the inner radius of the Disc and then decreases towards the outer radius of the Disc. The radial strain rate which is compressive in nature becomes tensile in middle of the Disc for some specific values of anisotropic constants. The study reveals that the anisotropy has a significant effect on the creep behavior of Rotating Disc. Thus for the safe design of the Rotating Disc the effect of anisotropy should be taken care of.
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Creep Analysis of an Isotropic Functionally Graded Rotating Disc
2010Co-Authors: Minto Rattan, Neeraj Chamoli, S.b. SinghAbstract:Creep response for isotropic axisymmetric Rotating Disc made of a particle-reinforced FGM has been investigated in the present study. The result obtained for non linear variation of particle distribution along the radial distance of the Disc are compared with that of Discs containing the same amount of particle distributed uniformly or linearly along the radial distance. The Disc under investigation is made of AlSiC particulate composite. Creep behavior of the Disc is described by Sherby’s model. The material parameters of creep vary along the radial distance in the Disc due to varying composition, and this variation has been estimated by regression fit of the available experimental data. It is found that a functionally graded Rotating Disc with parabolic profile can be more efficient than those with uniform distribution or linear variations of particle.
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Effect of Anisotropy on the Creep of a Rotating Disc of Al-SiCp Composite
2010Co-Authors: Neeraj Chamoli, Minto Rattan, S.b. SinghAbstract:The steady state creep behaviour of an anisotropic Rotating Disc is investigated in the present study. The Disc under investigation is made of aluminium silicon carbide particulate composite. The creep behaviour is described by Sherby’s law. The stress and strain rate distributions are calculated for anisotropic Disc for different values of the anisotropic constants and compared with that of an isotropic Disc. The study revealed that anisotropy of the material has a significant effect on the creep behaviour of the Rotating Disc therefore while designing the Disc the effect of anisotropy should be taken care of.
Richard G. Compton - One of the best experts on this subject based on the ideXlab platform.
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Pulse voltammetry at the Rotating Disc electrode
Journal of Electroanalytical Chemistry, 2001Co-Authors: James L. Melville, Richard G. ComptonAbstract:A backwards-implicit-based finite difference simulation of differential pulse voltammetry (DPV) and square wave voltammetry (SWV) at a Rotating Disc electrode has been developed. Results show that under comparable physical conditions convection independence is reached at lower rotation frequencies when employing SWV than when using DPV. The relative extent of convection and diffusion control of mass transport as the rotation frequency changes is quantified and equations are presented that permit conditions to be identified corresponding to diffusion-only transport.
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Pulse voltammetry at the Rotating Disc electrode
Journal of Electroanalytical Chemistry, 2001Co-Authors: James L. Melville, Richard G. ComptonAbstract:A backwards-implicit-based finite difference simulation of differential pulse voltammetry (DPV) and square wave voltammetry (SWV) at a Rotating Disc electrode has been developed. Results show that under comparable physical conditions convection independence is reached at lower rotation frequencies when employing SWV than when using DPV. The relative extent of convection and diffusion control of mass transport as the rotation frequency changes is quantified and equations are presented that permit conditions to be identified corresponding to diffusion-only transport. © 2001 Elsevier Science B.V
José Coca - One of the best experts on this subject based on the ideXlab platform.
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Hydrodynamics of a Rotating Disc contactor
Separation and Purification Technology, 1997Co-Authors: María A. Morís, Fernando V. Díez, José CocaAbstract:Abstract The hydrodvnamic behavior of a Rotating Disc contactor (72 mm in diameter, operating height of 1.1 m, 22 mixing compartments) was studied using the two-phase system water—kerosene. Parameters such as the axial dispersion coefficient, the total hold-up, the hold-up profile and the characteristic velocity were measured at various flow rates and rotor speeds. A comparison of the experimental results and values predicted from several correlations is reported. Some modifications for the calculation of the total hold-up and the hold-up profiles are suggested.
