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Cuizhi Gao - One of the best experts on this subject based on the ideXlab platform.

  • Numerical analysis of Axial gas flow in cyclone separators with different vortex finder diameters and inlet dimensions
    Powder Technology, 2020
    Co-Authors: Qing Wei, Guogang Sun, Cuizhi Gao
    Abstract:

    Abstract The flow field of cyclone separators was simulated with different vortex finder diameters and inlet dimensions using the Reynolds Stress Model to determine the mechanism of stagnation of Axial Velocity. Two flow patterns of Axial Velocity in cyclone were observed with changing vortex finder diameter and inlet dimension. As vortex finder diameter and inlet dimension increased, stagnation worsened. If the pressure gradient at the centerline of cyclone separator is positive, stagnation of Axial Velocity appears in the separation space of cyclone. The variation of the dimensionless critical vortex finder diameter of stagnation with inlet dimension was attributed to the proportion distribution of energy loss in cyclone. Finally, response surface methodology and Muschelknautz method of modeling (MM) were applied and yielded parameters with significant effects on stagnation. The variance analysis confirmed a larger quantitative contribution from inlet dimension on stagnation compared to that of vortex finder diameter, which will be useful for the structural optimization of cyclone.

Thierry Magin - One of the best experts on this subject based on the ideXlab platform.

  • collisionless ion modeling in hall thrusters analytical Axial Velocity distribution function and heat flux closures
    Physics of Plasmas, 2020
    Co-Authors: Stefano Boccelli, Thomas Charoy, Alvarez A Laguna, Pascal Chabert, Anne Bourdon, Thierry Magin
    Abstract:

    The genesis of the ion Axial Velocity distribution function (VDF) is analyzed for collisionless Hall thruster discharges. An analytical form for the VDF is obtained from the Vlasov equation, by applying the Tonks–Langmuir theory in the thruster channel, under the simplifying assumptions of monoenergetic creation of ions and steady state. The equivalent set of 1D unsteady anisotropic moment equations is derived from the Vlasov equation, and simple phenomenological closures are formulated, assuming a polynomial shape for the ion VDF. The analytical results and the anisotropic moment equations are compared to collisionless particle-in-cell simulations, employing either a zero heat flux (Euler-like equations) or the polynomial-VDF closure for the heat flux. The analytical ion VDF and its moments are then compared to experimental measurements.

Qing Wei - One of the best experts on this subject based on the ideXlab platform.

  • Numerical analysis of Axial gas flow in cyclone separators with different vortex finder diameters and inlet dimensions
    Powder Technology, 2020
    Co-Authors: Qing Wei, Guogang Sun, Cuizhi Gao
    Abstract:

    Abstract The flow field of cyclone separators was simulated with different vortex finder diameters and inlet dimensions using the Reynolds Stress Model to determine the mechanism of stagnation of Axial Velocity. Two flow patterns of Axial Velocity in cyclone were observed with changing vortex finder diameter and inlet dimension. As vortex finder diameter and inlet dimension increased, stagnation worsened. If the pressure gradient at the centerline of cyclone separator is positive, stagnation of Axial Velocity appears in the separation space of cyclone. The variation of the dimensionless critical vortex finder diameter of stagnation with inlet dimension was attributed to the proportion distribution of energy loss in cyclone. Finally, response surface methodology and Muschelknautz method of modeling (MM) were applied and yielded parameters with significant effects on stagnation. The variance analysis confirmed a larger quantitative contribution from inlet dimension on stagnation compared to that of vortex finder diameter, which will be useful for the structural optimization of cyclone.

Stefano Boccelli - One of the best experts on this subject based on the ideXlab platform.

  • collisionless ion modeling in hall thrusters analytical Axial Velocity distribution function and heat flux closures
    Physics of Plasmas, 2020
    Co-Authors: Stefano Boccelli, Thomas Charoy, Alvarez A Laguna, Pascal Chabert, Anne Bourdon, Thierry Magin
    Abstract:

    The genesis of the ion Axial Velocity distribution function (VDF) is analyzed for collisionless Hall thruster discharges. An analytical form for the VDF is obtained from the Vlasov equation, by applying the Tonks–Langmuir theory in the thruster channel, under the simplifying assumptions of monoenergetic creation of ions and steady state. The equivalent set of 1D unsteady anisotropic moment equations is derived from the Vlasov equation, and simple phenomenological closures are formulated, assuming a polynomial shape for the ion VDF. The analytical results and the anisotropic moment equations are compared to collisionless particle-in-cell simulations, employing either a zero heat flux (Euler-like equations) or the polynomial-VDF closure for the heat flux. The analytical ion VDF and its moments are then compared to experimental measurements.

Tasawar Hayat - One of the best experts on this subject based on the ideXlab platform.

  • numerical study for soret and dufour effects on mixed convective peristalsis of oldroyd 8 constants fluid
    International Journal of Thermal Sciences, 2017
    Co-Authors: Tasawar Hayat, Shahid Farooq, A Alsaedi, Bashir Ahmad
    Abstract:

    Abstract This article examined Soret and Dufour effects on peristaltic transport of an Oldroyd 8-constants fluid in a curved channel. Aspects of mixed convection and radially applied magnetic field are considered. Convective conditions of heat and mass transfer at the channel walls are imposed. Governing problems for Velocity, temperature and concentration are reduced for long wavelength and low Reynolds number considerations. Resulting problems are analyzed numerically. Specifically the analysis Velocity, temperature, concentration and heat transfer coefficient are focused for the emerging parameters. It is noticed that Axial Velocity enhances for larger material parameter of fluid. Impact of mixed convection decays Axial Velocity. Furthermore temperature and concentration have opposite behavior for Soret and Dufour numbers.

  • combined effects of rotation and thermal radiation on peristaltic transport of jeffrey fluid
    International Journal of Biomathematics, 2015
    Co-Authors: Tasawar Hayat, M Rafiq, Bashir Ahmad
    Abstract:

    The objective of this communication is to examine the effect of rotation on the peristaltic motion of non-Newtonian fluid. Constitutive relationship of Jeffrey fluid is employed in the mathematical formulation and related analysis. The thermal radiation and Joule heating effects are also considered. An electrically conducting fluid in a channel with compliant boundaries is taken. Solution expressions are established through assumptions of large wavelength and low Reynolds number. Impact of Taylor and Hartman numbers on the Axial Velocity is similar in a qualitative sense. There is reverse effect of Taylor number on the secondary Velocity when compared with the Axial Velocity. Temperature and heat transfer coefficients are increasing functions of Taylor number.

  • peristaltic transport of copper water nanofluid saturating porous medium
    Physica E-low-dimensional Systems & Nanostructures, 2015
    Co-Authors: F M Abbasi, Tasawar Hayat, Bashir Ahmad
    Abstract:

    Abstract Prime goal of present study is to model the problem for peristaltic transport of copper–water nanofluid in an asymmetric channel. The fluid fills porous space. Analysis is carried out in the presence of mixed conviction, viscous dissipation and heat generation/absorption. Long wavelength and low Reynolds number approximations are utilized in problem formulation. Numerical computations are presented for the Axial Velocity, pressure gradient, streamlines, temperature and heat transfer rate at the boundary. Graphical analysis is carried out to examine the effects of sundry parameters on flow quantities of interest. Results revealed that the Axial Velocity of copper–water nanofluid decreases with an increase in the nanoparticle volume fraction. Copper nanoparticles prove effective coolant since they sufficiently reduce the fluid temperature and show increase in the heat transfer between the fluid and solid boundary. Moreover temperature of the fluid decreases by increasing the permeability of porous medium.

  • peristaltically induced motion of a mhd third grade fluid in a deformable tube
    Physica A-statistical Mechanics and Its Applications, 2006
    Co-Authors: Tasawar Hayat
    Abstract:

    We consider incompressible, magnetohydrodynamic (MHD) third grade fluid confined in a circular cylindrical tube. The tube surfaces are electrically non-conducting. Travelling sinusoidal wave is imposed on the tube which induces peristaltic motion in the fluid. The stream function, Axial Velocity and pressure gradient are determined analytically for small Deborah number (Γ). The analysis consists of a perturbation expansion in terms of the Deborah number up to O(Γ). Solutions for pressure rise and frictional force per wavelength are given through the use of numerical integration. The general solution of highly non-linear equation for the hydrodynamic third grade fluid is developed. The results are finally compared with the third grade hydrodynamic and Newtonian fluid cases. It is found that the Axial Velocity increases by increasing Deborah number but decreases for large values of Hartmann number.