Axisymmetric Flow Model with and without Swirl in a Piston-Cylinder Arrangement with Idealized Valve Operation

1980 ◽  
Author(s):  
J. I. Ramos ◽  
W. A. Sirignano
Keyword(s):  
Flow Model ◽  
Axisymmetric Flow ◽  
Piston Cylinder ◽  
Valve Operation

Study of Laminar, Unsteady Piston-Cylinder Flows

1993 ◽  
Vol 115 (4) ◽  
pp. 687-693 ◽  
Author(s):  
H. Stro¨ll ◽  
F. Durst ◽  
M. Peric´ ◽  
J. C. F. Pereira ◽  
G. Scheuerer
Keyword(s):  
Stokes Equations ◽  
Axisymmetric Flow ◽  
Simple Algorithm ◽  
Laser Doppler ◽  
Sudden Expansion ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Measuring Point ◽  
Curvature Effects ◽  
Piston Cylinder

The present paper concerns numerical investigation of a piston-driven, axisymmetric flow in a pipe assembly containing a sudden expansion. The piston closes the larger of the two pipes. The impulsively starting intake flow is the topic of this investigation. Results of numerical calculations and laser-Doppler measurements are presented to provide an insight into the features of the flow. The calculation procedure employed in this study is based on a finite-volume method with staggered grids and SIMPLE-algorithm for pressure-velocity coupling (Patankar and Spalding, 1972). The convection and diffusion fluxes in the Navier-Stokes equations are discretized with first order upwind and second order central differences, respectively. A fully implicit Euler scheme is used to discretize the temporal derivatives. The Navier-Stokes equations were suitably transformed to allow prediction of the flow within the inlet pipe (fixed grid) and cylinder region (moving grid) simultaneously (once-through procedure). Laser-Doppler measurements of both axial and radial velocity components were performed. Refractive index matching was used to eliminate the wall curvature effects. For each measuring point 20 cycles were measured, showing high repetition rates. Comparison of measured and predicted velocity profiles shows good agreement.

A Novel Thermal Model for the Piston/Cylinder Interface of Piston Machines

2009 ◽  
Author(s):  
Matteo Pelosi ◽  
Monika Ivantysynova
Keyword(s):  
Temperature Field ◽  
Energy Dissipation ◽  
Film Thickness ◽  
Elastic Deformation ◽  
Flow Model ◽  
Piston Cylinder ◽  
Gap Flow ◽  
First Time ◽  
Fully Coupled

The lubricating gaps of piston machines represent the main source of energy dissipation. The lubricating gap in these machines has to fulfill a sealing and bearing function. Therefore the prediction of the gap flow, the load carrying ability and the energy dissipation is necessary. The paper discusses a novel fully coupled model for the determination of piston/cylinder gap behavior considering the contribution of solid parts temperature induced strain. In particular, the non-isothermal gap flow model considers the squeeze film effect due to the micro-motion of the moveable parts and simultaneously the change of fluid film thickness due to the elastic deformation of the solid bodies caused by the fluid pressure field and the parts temperature field. The determination of the temperature field inside the parts, by means of detailed finite volume models, allows for the first time to accurately predict solid parts thermal expansion, which is directly affecting the gap film thickness. Therefore, the novelty of the developed fully coupled fluid-structure-thermal interaction model is the integration of a finite element solver for the determination of surface thermo-elastic deformation in a dynamic non-isothermal fluid flow model. This will allow for the first time to solve the thermo-elastohydrodynamic lubrication problem under changing load conditions, considering the impact of several different physical phenomena.

Nonuniform Flow in a Compressor Due to Asymmetric Tip Clearance

2000 ◽  
Vol 122 (4) ◽  
pp. 751-760 ◽  
Author(s):  
Seung Jin Song ◽  
Seung Ho Cho
Keyword(s):  
Analytical Study ◽  
Flow Model ◽  
Axisymmetric Flow ◽  
Tip Clearance ◽  
Linear Perturbation ◽  
Flow Variable ◽  
Nonuniform Flow ◽  
Downstream Flow ◽  
Perturbation Approximation ◽  
Flow Nonuniformity

This paper presents an analytical study of flow redistribution in a compressor stage due to asymmetric tip clearance distribution. The entire stage is modeled as an actuator disk and it is assumed that upstream and downstream flow fields are determined by the local tip clearance. The flow is assumed to be inviscid and incompressible. First, an axisymmetric flow model is used to connect upstream and downstream flows. Second, a linear perturbation approximation is used for nonaxisymmetric analysis in which each flow variable is assumed to consist of a mean (axisymmetric value) plus a small perturbation (asymmetric value). Thus, the perturbations in velocity and pressure induced by the tip clearance asymmetry are predicted. Furthermore, rotordynamic effects of such flow nonuniformity are examined as well. [S0889-504X(00)01404-5]

Magnetohydrodynamic Vortex Containment, Part 3: 1-D Axisymmetric Flow Model

2007 ◽  
Vol 23 (2) ◽  
pp. 404-413
Author(s):  
Raymond J. Sedwick ◽  
Daniel A. Zayas
Keyword(s):  
Flow Model ◽  
Axisymmetric Flow

Non-Uniform Flow in a Compressor due to Asymmetric Tip Clearance

2000 ◽  
Author(s):  
Seung Jin Song ◽  
Seung Ho Cho
Keyword(s):  
Analytical Study ◽  
Flow Model ◽  
Axisymmetric Flow ◽  
Tip Clearance ◽  
Linear Perturbation ◽  
Flow Variable ◽  
Compressor Stage ◽  
Actuator Disc ◽  
Downstream Flow ◽  
Perturbation Approximation

This paper presents an analytical study of flow redistribution in a compressor stage due to asymmetric tip clearance distribution. The entire stage is modeled as an actuator disc, and it is assumed that upstream and downstream flow fields are determined by the local tip clearance. The flow is assumed to be inviscid and incompressible. First, an axisymmetric flow model is used to connect upstream and downstream flows. Second, a linear perturbation approximation is used for non-axisymmetric analysis in which each flow variable is assumed to consist of a mean (axisymmetric value) plus a small perturbation (asymmetric value). Thus, the perturbations in velocity and pressure induced by the tip clearance asymmetry are predicted. Furthermore, rotordynamic effects of such flow non-uniformity are examined as well.

Effects of Flow and Geometry Boundary Conditions on Fluid Motion in a Motored IC Model Engine

1982 ◽  
Vol 196 (1) ◽  
pp. 1-10 ◽  
Author(s):  
C Arcoumanis ◽  
A F Bicen ◽  
N S Vlachos ◽  
J H Whitelaw
Keyword(s):  
Boundary Conditions ◽  
Cylinder Head ◽  
Laser Doppler Anemometry ◽  
Fluid Motion ◽  
Axisymmetric Flow ◽  
Ic Engine ◽  
Piston Cylinder ◽  
Wide Range ◽  
Inlet Geometry ◽  
Flow Configurations

Measurements of ensemble-averaged axial velocities and the r.m.s. of the corresponding fluctuations, obtained by laser-Doppler anemometry, are reported for axisymmetric flow in a non-compressing piston-cylinder assembly motored at 200 rev/min simulating an IC engine. The inlet geometry comprised an open valve, located centrally and flush with the cylinder head, with seat angles of 30° and 60° and incorporating 30° swirl vanes. Results are presented for bore-to-stroke ratios of 0.83 and 1.25 and swept-to-clearance volume ratios of 2,3 and 9. The results indicate strong similarities between the flow structures for different stroke and clearance; a system of vortices is formed with a large vortex occupying most of the flow space and with smaller vortices in the corners between the wall, piston and cylinder head. The influence of valve seat angle is more pronounced and results, for the 30° angle, in adherence of the incoming jet to the cylinder head with increase of the overall turbulence levels and creation of stronger and longer living vortices. Previous results obtained in related compressing and non-compressing flow configurations are reviewed and, together with the present results, enable the influence of a wide range of possible geometric and flow boundary conditions to be quantified.

scholarly journals Nozzle Shape Optimization for an MPD Thruster Using a Two-Dimensional Axisymmetric Flow Model

2011 ◽  
Vol 59 (687) ◽  
pp. 90-96 ◽  
Author(s):  
Masakatsu NAKANE ◽  
Masao NAGAO ◽  
Yoshio ISHIKAWA ◽  
Kenichi KUBOTA ◽  
Ikkou FUNAKI
Keyword(s):  
Shape Optimization ◽  
Flow Model ◽  
Axisymmetric Flow ◽  
Two Dimensional ◽  
Nozzle Shape
Sign in / Sign up

Export Citation Format

Share Document