0
TECHNICAL PAPERS

# A Computational Study of Torque and Forces Due to Compressible Flow on a Butterfly Valve Disk in Mid-stroke Position

[+] Author and Article Information
Zachary Leutwyler1

Department of Mechanical Engineering, University of Houston, Houston, TX 77204-4006zleutwyler@houston.rr.com

Charles Dalton

Department of Mechanical Engineering, University of Houston, Houston, TX 77204-4006dalton@uh.edu

1

Currently with Kalsi Engineering Inc., Sugar Land, TX.

J. Fluids Eng 128(5), 1074-1082 (Feb 11, 2006) (9 pages) doi:10.1115/1.2236129 History: Received April 22, 2005; Revised February 11, 2006

## Abstract

The ability to accurately predict the aerodynamic torque and lift and drag forces on a 2-D model of a 0.18 aspect ratio biconvex circular-arc disk operating in a compressible flow using computational fluid dynamics (CFD) was investigated. Fluent 6.0 was the CFD package utilized to perform these calculations. Grid-convergence and time-convergence/stability were analyzed first, followed by a qualitative study of the Spalart-Allmaras, $k-ε$, and $k-ω$ turbulence models with their enhancement features and model variants. Fluent was used to predict the pressure profile on the disk surface for disk positions 30, 45, and 60 deg (where 0 deg is the fully closed position) and over a range of pressure ratios. The pressure ratios were selected to determine the capability of CFD to accurately predict the flow field and resulting torque in flows ranging from nearly incompressible to highly compressible. Fluent predictions for the pressure profiles on the disk were compared to test data so that the lift and drag forces and aerodynamic torque could be determined responsibly. Acceptable comparisons were noted.

<>

## Figures

Figure 1

Illustrates the biconvex circular-arc disk (BiCAD) with a 0.18 aspect ratio (ASR), which was modeled after the test disk of Morris (1). The coordinate x measures from the shaft center line along the disk chord.

Figure 2

Comparison of Fluent results with test data (1) for case 1 for disk angles of 30, 45, and 60 deg

Figure 3

Comparison of Fluent results with test data (1) for case 6 for disk angles of 30, 45, and 60 deg

Figure 4

Evolution of pressure field for the disk at 45 deg for cases 1, 3, 4, 5, and 6

Figure 5

Comparison of the dimensionless pressure profiles of the numerical results for the k-ε RNG, k-ε realizable, k-ω SST, and the Spalart-Allmaras turbulence models. The test data corresponds to a disk at 45 deg and a pressure ratio of 0.24 (1).

Figure 6

The computational grid, mesh 1, used to obtain results for the BiCAD at 45 deg

Figure 7

Time-averaged lift, drag, and aerodynamic torque coefficients for the disk at 45 deg as a function of the operating pressure ratio

Figure 8

The Mach number vector plot for case 4 clearly shows the vortex formations caused by the expanding supersonic flow

Figure 10

The Mach number vector plot for case 1 clearly shows the absence of vortex formations immediately downstream of the disk. The maximum Mach number is 0.85.

Figure 9

The pressure contours for case 4 downstream of the BiCAD due to the vortex formations and oblique shockwaves. The range of pressure values was set to capture the pressure field downstream of the disk and to omit the higher pressure upstream of the disk. The pressure contours range from 13.8kPa (2 psia) to 124kPa (18 psia). Low pressures are represented by dark lines and high pressures represented by lighter lines.

Figure 11

The pressure contours for case 1 downstream of the BiCAD. The pressure contours range from 86.5kPa (12.55 psia) to 87.5kPa (12.7 psia). The pressure field is nearly uniform in the local vicinity downstream of the disk due to the absence of vortex formations. Low pressures are represented by dark lines and high pressures represented by lighter lines.

Figure 12

Time-dependent coefficients for cases 1, 3, and 5 with the disk at 45 deg

## Errata

Some tools below are only available to our subscribers or users with an online account.

### Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections

• TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
• EMAIL: asmedigitalcollection@asme.org