| |

International Journal of Fluid Mechanics Research International Journal of Fluid Mechanics Research
 

Get Adobe Flash player

 

ISSN: 1064-2277 Print

  You can order a single issue or an individual article, as well as view the table of contents or article abstract by clicking on the volume number, then the issue number in the right sidebar.  

Institutional price: $1811.00

Online subscription
Add subscription to shopping cart
click 'Save as...' here to save XML metadata   Year 2007, Volume 34 / Issue 1

DOI: 10.1615/InterJFluidMechRes.v34.i1

Pages: 98

DOI: 10.1615/InterJFluidMechRes.v34.i1.40 Article price - $50.00 Add to shopping cart

Steady and Unsteady Analysis of the Effects of Radial Gap Size in a Centrifugal Compressor Stage


ABSTRACT

In this paper, a computational analysis of a high-speed centrifugal compressor stage is presented. The main emphasis is placed on steady and unsteady investigations on the effect of different radial gap size between the leading edge of the vaned diffuser and the impeller tip on the detailed aerodynamics and the stage peak efficiency. The simulations were carried out for the stage with a backswept impeller and downstream vaned diffusers with different size of the radial gap. The impeller consisted of 8 full blades and 8 splitters and the downstream diffusers consisted of 22 vanes, with their leading edge at a radius of 1.075 and 1.150 times the radius of the impeller tip respectively. The steady and unsteady CFD analysis was carried out using the Reynolds-averaged Navier - Stokes solver CFX-TASCflow. For the steady state simulations, an averaging approach is used at the interface between the impeller and the diffuser. For the unsteady simulation, the method of geometry scaling is used in order to deal with the problem of unequal pitch. In this case one passage of the impeller was modeled in combination with three diffuser passages. The size of the radial gap influences considerably the detailed aerodynamic interactions in the vaneless and semi-vaneless space, the levels of unsteadiness and the amount of mixing occurring in this region. An important conclusion is that as the gap increases, the stage peak efficiency increases. The flow physics contributing to this result are quite complex and are addressed in the paper. The analysis was focused on impeller, vaneless space and vaned diffuser channel and comparisons with available experimental data are carried out.


pages 52-65


<< Previous article   Next article >>

 
begell house, inc.
publishers
50 Cross Highway
Redding, CT 06896
Tel.: (203) 938 1300
Fax: (203) 938 1304