0
RESEARCH PAPERS

# Transport of Particulates in an Internal Cooling Ribbed Duct

[+] Author and Article Information
Anant Shah, Danesh K. Tafti

High Performance Computational Fluids, Thermal Sciences and Engineering Lab, Mechanical Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061

Earlier studies were done with a development time of 23.5 nondimensional time units. No difference was found in the measured particle statistics with the shorter development time.

This is a reasonably good approximation for erosion of ductile materials.

J. Turbomach 129(4), 816-825 (Aug 04, 2006) (10 pages) doi:10.1115/1.2720509 History: Received August 02, 2006; Revised August 04, 2006

## Abstract

A ribbed square duct ($P∕e=10$, $e∕Dh=0.10$) subjected to sand ingestion is studied using large-eddy simulations (LES). Particle sizes of $10μm$, $50μm$, and $100μm$ with nondimensional response times (normalized by friction velocity and hydraulic diameter) of 0.06875, 1.71875, and 6.875, respectively are considered. The calculations are performed for a nominal bulk Reynolds number of 20,000 under fully-developed conditions. Distributions of impingement density, impingement velocities and angles, together with fractional energy transfer are presented for each surface. It is found that about 40% of the total number of $10micron$ particles are concentrated in the vicinity (within 0.05 $Dh$) of the duct surfaces, compared to 25–30% of the 50 and $100micron$ particles. The $10micron$ particles are more sensitive to the primary and secondary flow velocities than the larger particles. While the $10micron$ particles exhibit high energy transfer to the surface near the rib side-wall junction and immediately upstream of the rib, the larger particles exhibit more uniform distributions. The largest fraction of incoming particulate energy is transferred to the front face of the rib and is between one to two orders of magnitude larger than the other surfaces. As particle size increases, substantial particle energy is also transferred to the back face of the rib by particles bouncing off the front face and carrying enough momentum to impinge on the back face of the preceding rib.

<>

## Figures

Figure 7

Impact angle on the side wall: (a) 10μm; (b) 50μm; (c) 100μm

Figure 8

Fractional energy transfer to side wall (ψ×106): (a) 10μm; (b) 50μm; (c) 100μm

Figure 9

Number of particles impinging on the ribbed wall in 1.3ms: (a) 10μm; (b) 50μm; (c) 100μm

Figure 10

Average impingement velocities at the ribbed wall: (a) 10μm; (b) 50μm; (c) 100μm

Figure 11

Average impingement angles at the bottom wall: (a) 10μm; (b) 50μm; (c) 100μm

Figure 6

Impact velocity on the side wall: (a) 10μm; (b) 50μm; (c) 100μm

Figure 5

Number of particles impinging on the side wall in 1.3ms: (a) 10μm; (b) 50μm; (c) 100μm

Figure 4

Time evolution of particle distribution near duct surfaces

Figure 3

(a) Mean streamline distribution in the z-symmetry plane. Reattachment occurs at 4.1e downstream of rib. The leading edge eddy extends between 0.8 and 0.9e upstream of rib. (b) Mean lateral or spanwise flow velocity (wb) in the vicinity of the smooth wall. Taken from (11).

Figure 2

Computational domain nondimensionalized by the hydraulic diameter (Dh)(11)

Figure 1

Comparison of mean streamwise velocity predicted by the current model with particle statistics by Wang and Squires (14). Particles compared: 70μm copper, 50μm glass, and 28μm Lycopodium.

Figure 14

Average impingement velocities on the front surface of the rib: (a) 10μm; (b) 50μm; (c) 100μm

Figure 13

Number of particles impinging the front surface of the rib in 1.3ms: (a) 10μm; (b) 50μm; (c) 100μm

Figure 12

Fractional energy transfer to the ribbed wall (ψ×106): (a) 10μm; (b) 50μm; (c) 100μm

Figure 17

Number of particles impinging on the back surface of the rib in 1.3ms: (a) 10μm; (b) 50μm; (c) 100μm

Figure 16

Fractional energy transfer to the front face of the rib (ψ×106): (a) 10microns; (b) 50microns; (c) 100microns

Figure 15

Average impingement angles on the front surface of the rib: (a) 10μm; (b) 50μm; (c) 100μm

Figure 20

Fractional energy transfer to back face of the rib (ψ×106): (a) 10microns; (b) 50microns; (c) 100microns

Figure 19

Average impingement angles on the back surface of the rib: (a) 10μm; (b) 50μm; (c) 100μm

Figure 18

Average impingement velocities on the back surface of the rib: (a) 10μm; (b) 50μm; (c) 100μm

## 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.

Topic Collections