0
TECHNICAL PAPERS

# Numerical Simulation and Experimental Measurement of Pressure Pulses Produced by a Pulp Screen Foil Rotor

[+] Author and Article Information
Mei Feng1

Pulp and Paper Centre and Department of Mechanical Engineering,  The University of British Columbia, 2385 East Mall, Vancouver BC, Canada, V6T 1Z4

Jaime Gonzalez, James A. Olson

Pulp and Paper Centre and Department of Mechanical Engineering,  The University of British Columbia, 2385 East Mall, Vancouver BC, Canada, V6T 1Z4

Carl Ollivier-Gooch

Department of Mechanical Engineering, The University of British Columbia, 2324 Main Mall, Vancouver BC, Canada, V6T 1C4

Robert W. Gooding

1

Now with Temec Engineering Group Ltd. Suite 375, 6450 Roberts St., Burnaby, BC, Canada, V5G 4E1

J. Fluids Eng 127(2), 347-357 (Oct 29, 2004) (11 pages) doi:10.1115/1.1881672 History: Received August 11, 2003; Revised October 29, 2004

## Abstract

Pressure screening is an efficient means of removing various contaminants that degrade the appearance and strength of paper. A critical component of a screen is the rotor, which induces a tangential velocity to the suspension and produces pressure pulses to keep the screen apertures clear. To understand the effect of key design and operating variables for a NACA foil rotor, a computational fluid dynamic (CFD) simulation was developed using FLUENT , and the results were compared to experimental measurements. Comparing the pressure pulses obtained through CFD to experimental measurements over a wide range of foil tip speeds, clearances, angles of attack, and foil cambers, general trends of the pressure pulses were similar, but the overall computed values were 40% smaller than the measured values. The pressure pulse peak was found to increase linearly with the square of tip speed for all the angles of attack studied. The maximum magnitudes of negative pressure pulse occurred for the NACA 0012 and 4312 foils at a $5deg$ angle of attack and for the NACA 8312 foil at $0deg$. The stall angle of attack was found to be $∼5deg$ for NACA 8312, $∼10deg$ for NACA 4312, and $∼15deg$ for NACA 0012. The positive pressure peak near the leading edge of the foil was eliminated for foils operating at a positive angle of attack. The magnitude of the negative pressure coefficient peak increased as clearance decreased. Increased camber increases both the magnitude and width of the negative pressure pulse.

<>

## Figures

Figure 1

Schematic diagram of cross-sectional screen

Figure 2

Schematic of foil showing angle of attack and clearance

Figure 3

Representative computational mesh

Figure 4

Calculation domain and boundary conditions

Figure 5

Computed skin friction coefficient distributions over an NACA 0012 airfoil

Figure 6

Numerical estimates of effect of rotating speed on pressure pulse (0deg angle of attack constant gap)

Figure 7

Numerical pressure coefficient versus position, x/Chord, (0deg angle of attack constant gap)

Figure 8

Experimental pressure coefficient versus position, x/Chord (0deg angle of attack)

Figure 9

Numerical pressure coefficient versus position, x/Chord (20deg angle of attack)

Figure 10

Experimental pressure coefficient versus position, x/Chord (20deg angle of attack)

Figure 11

Pressure contour and particle path lines. degree of attack (a)=0, (b)=5, (c)=10, (d)=15, and (e)=20

Figure 12

Numerical pressure coefficient versus position, x/Chord for five different angles of attack

Figure 13

Experimental pressure coefficient versus position, x/Chord for five different angles of attack

Figure 14

Numerical pressure coefficient versus position, x/Chord for four different clearances (0deg angle of attack)

Figure 15

Numerical pressure coefficient versus position, x/Chord for four different clearances (5deg angle of attack)

Figure 16

Numerical pressure coefficient versus position, x/Chord for four different clearances (20deg angle of attack)

Figure 17

Numerical and experimental suction pressure coefficient peak versus clearance for three different angles of attack

Figure 18

Numerical pressure coefficient versus position (x/Chord) for 0deg angle of attack

Figure 19

Experimental pressure coefficient versus position (x/Chord) for 0deg angle of attack

Figure 20

Pressure contour and particle path lines for NACA 4312: degree of angle of attack (a)=0, (b)=5, (c)=10, (d)=15, and (e)=20

Figure 21

Pressure contour and particle path lines for NACA 8312: degree of angle of attack (a)=0, (b)=5, (c)=10, (d)=15, and (e)=20

Figure 22

Numerical pressure coefficient versus position (x/Chord), NACA4312 (five angles of attack)

Figure 23

Experimental pressure coefficient versus position (x/Chord), NACA4312 (five angles of attack)

Figure 24

Numerical pressure coefficient versus position (x/Chord), NACA8312 (five angles of attack)

Figure 25

Numerical and experimental minimum pressure coefficient versus angle of attack (deg)

Figure 26

Numerical pressure pulse width versus angle of attack

Figure 27

Numerical normalized pressure pulse strength versus angle of attack

## Discussions

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