Fast cell determination of the DSMC molecules in multi-stage turbo molecular pump design

Date

2011-06-01

Author

Sengil, N.
Edis, Fırat Oğuz

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

244
views

0
downloads

In this study, an existing 2D parallel DSMC solver is modified, to analyze the multi-stage turbomolecular pumps more efficiently. Generally, molecule movements are traced cell-by-cell in DSMC solvers both in structured and unstructured meshes in order to determine which cell the DSMC molecule is positioned in. These calculations require time consuming trigonometric operations. If a nonrectangular physical domain can be converted into a rectangular computational domain using curvilinear coordinates, then it would be possible to calculate the DSMC molecule cell information not only in a very short time, but also with simple arithmetic operations. In this study, it is shown that the curvilinear coordinate technique is quite faster compared to cell-by-cell tracing technique. After that, the present 2D parallel DSMC solver is renewed to use implicit molecule indexing to shorten the calculation time even further. Thirdly, dynamically changing representative molecular ratios are used to decrease the statistical errors. Following that, molecule transfer method between computational domains is revised to employ different time steps and blade spacings. Finally, calculations are shown to be in close agreement with the previously published experimental results.

Subject Keywords

General Engineering, General Computer Science

URI

https://hdl.handle.net/11511/64856

Journal

COMPUTERS & FLUIDS

DOI

https://doi.org/10.1016/j.compfluid.2011.01.045

Collections

Department of Aerospace Engineering, Article

Suggestions

OpenMETU
Core

A unifying grid approach for solving potential flows applicable to structured and unstructured grid configurations Cete, A. Ruhsen; Yuekselen, M. Adil; Kaynak, Uenver (Elsevier BV, 2008-01-01) In this study, an efficient numerical method is proposed for unifying the structured and unstructured grid approaches for solving the potential flows. The new method, named as the "alternating cell directions implicit - ACDI", solves for the structured and unstructured grid configurations equally well. The new method in effect applies a line implicit method similar to the Line Gauss Seidel scheme for complex unstructured grids including mixed type quadrilateral and triangle cells. To this end, designated al...
Mathematical modeling of horizontal two-phase flow through fully eccentric annuli Ömürlü, Çiğdem; Özbayoğlu, Evren; Department of Petroleum and Natural Gas Engineering (2006) The primary objective of this study is to understand the mechanism, the hydraulics and the characteristics, of the two-phase flow in horizontal annuli. While achieving this goal, both theoretical and experimental works have been conducted extensively. The METU-PETE-CTMFL (Middle East Technical University, Petroleum and Natural Gas Engineering Department, Cuttings Transport and Multiphase Flow Laboratory) multiphase flow loop consists of 4.84 m long eccentric horizontal acrylic pipes having 0.1143m inner dia...
A Cascadable Random Neural Network Chip with Reconfigurable Topology Badaroglu, Mustafa; Halıcı, Uğur; Aybay, Isik; Cerkez, Cuneyt (Oxford University Press (OUP), 2010-03-01) A digital integrated circuit (IC) is realized using the random neural network (RNN) model introduced by Gelenbe. The RNN IC employs both configurable routing and random signaling. In this paper we present the networking/routing aspects as well as the performance results of an RNN network implemented by the RNN IC. In the RNN model, each neuron accumulates arriving signals and can fire if its potential at a given instant of time is strictly positive. Firing occurs at random, the intervals between successive ...
A computational procedure for estimating residual stresses and secondary plastic flow limits in nonlinearly strain hardening rotating shafts Eraslan, Ahmet Nedim (Springer Science and Business Media LLC, 2005-03-01) A computational procedure to estimate the residual stress distributions and the limit angular speeds for avoiding secondary plastic deformation in nonlinearly strain hardening rotating elastic-plastic shafts is given. The model is based on von Mises yield condition, J(2) deformation theory and a Swift-type hardening law. The boundary value problem for the governing nonlinear differential equation is solved by a shooting method using Newton iterations with numerically approximated tangent. Solid as well as h...
MHD flow and heat transfer in a lid-driven porous enclosure Pekmen, B.; Tezer, Münevver (Elsevier BV, 2014-01-20) The mixed convection flow in a lid-driven square cavity filled with a porous medium under the effect of a magnetic field is studied numerically using the dual reciprocity boundary element method (DRBEM) with Houbolt time integration scheme. Induced magnetic field is also taken into consideration in terms of magnetic potential in solving magnetohydrodynamic (MHD) flow and temperature equations. Effects of the characteristic dimensionless parameters as Darcy (Da), Magnetic Reynolds (Rem), Grashof (Gr) and Har...

Citation Formats

N. Sengil and F. O. Edis, “Fast cell determination of the DSMC molecules in multi-stage turbo molecular pump design,” COMPUTERS & FLUIDS, pp. 202–206, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/64856.