0

Effects of Various Modeling Schemes on Mist Film Cooling Simulation

[+] Author and Article Information
Xianchang Li

Department of Mechanical Engineering, Lamar University, Beaumont, TX 77710xianchang.li@lamar.edu

Ting Wang

Energy Conversion & Conservation Center, University of New Orleans, New Orleans, LA 70148-2220twang@uno.edu

J. Heat Transfer 129(4), 472-482 (Jan 03, 2007) (11 pages) doi:10.1115/1.2709959 History: Received March 01, 2006; Revised January 03, 2007

Abstract

Numerical simulation is performed in this study to explore film-cooling enhancement by injecting mist into the cooling air with a focus on investigating the effect of various modeling schemes on simulation results. The effect of turbulence models, dispersed-phase modeling, inclusion of different forces (Saffman, thermophoresis, and Brownian), trajectory tracking, and mist injection scheme is studied. The effect of flow inlet boundary conditions (with/without air supply plenum), inlet turbulence intensity, and the near-wall grid density on simulation results is also included. Simulation of a two-dimensional (2D) slot film cooling with a fixed blowing angle and blowing ratio shows a 2% mist (by mass) injected into the cooling air can increase the cooling effectiveness about 45%. The renormalization group (RNG) $k-ε$ model, Reynolds stress model, and the standard $k-ε$ turbulence model with an enhanced wall treatment produce consistent and reasonable results while the turbulence dispersion has a significant effect on mist film cooling through the stochastic trajectory calculation. The thermophoretic force slightly increases the cooling effectiveness, but the effect of Brownian force and Saffman lift is imperceptible. The cooling performance deteriorates when the plenum is included in the calculation due to the altered velocity profile and turbulence intensity at the jet exit plane. The results of this paper can provide guidance for corresponding experiments and serve as the qualification reference for future more complicated studies with 3D cooling holes, different blowing ratios, various density ratios, and rotational effect.

<>

Figures

Figure 1

Computational domain

Figure 2

Meshes

Figure 3

Baseline cooling effectiveness and enhancement

Figure 4

y+ along the wall with different grid systems

Figure 5

Cooling effectiveness with different grid systems

Figure 6

Effect of turbulence models on single-phase film cooling performance

Figure 7

Flow field close to the jet exit predicted by different turbulence models

Figure 8

Effect of turbulence models on mist film cooling performance

Figure 9

Distribution of Reynolds stresses close to the jet exit predicted by the RSM model

Figure 10

Reynolds stresses predicted by the RSM model

Figure 11

Effect of the number of injection locations

Figure 12

Effect of number of stochastic tracking

Figure 13

Residual histories

Figure 14

Effect of inlet turbulence intensity

Figure 15

Effect of inlet plenum on film cooling performance

Figure 16

Velocity vector and droplet trajectories near the jet slot with inlet plenum for mist film cooling

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