Validation and Analysis of Numerical Results for a Varying Aspect Ratio Two-Pass Internal Cooling Channel

Abstract

Numerical results for an internal ribbed cooling channel including a 180 deg bend with a 2:1 inlet and a 1:1 aspect ratio outlet channel were validated against experimental results in terms of spatially resolved heat transfer distributions, pressure losses, and velocity distributions. The numerical domain consisted of one rib segment in the inlet channel and three ribs segments in the outlet channel to reduce the overall numerical effort and allow for an extensive parametric study. The results showed good agreement for both heat transfer magnitudes and spatial distributions, and the numerical results captured the predominate flow physics resulting from the 180 deg bend. The production of Dean vortices and acceleration of the flow in the bend produced strongly increased heat transfer on both the ribbed and unribbed walls in the outlet channel in addition to increases due to the ribs. Numerical simulations were performed for a wide range of divider wall-to-tip wall distances, which influenced the position of the highest heat transfer levels on the outlet walls and changed the shape of the heat transfer distribution on the tip wall. Analysis of section averages of heat transfer in the bend and outlet channel showed a strong influence of the tip wall distance, while no effect was seen upstream of the bend. A similarly large effect on pressure losses in the bend was observed with varying tip wall position. Trends in averaged heat transfer varied linearly with tip wall distance, while pressure losses followed a nonlinear trend, resulting in an optimum tip wall distance with respect to heat transfer efficiency.

Computational study of plasma actuator on film cooling performance for different shaped holes

“…It is clear to see that the Re k-ε model is among one of the three models that are relatively closer to the experimental data. This matches well with Shevchuk et al 23 and Hassan et al 24 Three types of wall-function methods are adopted in the near-wall region, and the Non-equilibrium wall function is suggested to be as the best one, as shown in Fig. 11.…”

Numerical investigation of a novel tube design for the geothermal borehole heat exchanger

“…The structured and hybrid grids provide the same accuracy in simulations [29] and because of the several rounded shapes constituent the GHE, the hybrid grid is more suitable and it was adopted. Grid-independency studies with three grids sized from a coarse mesh of 357,642 cells to a finer mesh of 398,454 cells lead to the final conclusion that the average grid size for providing the necessary near-wall grid resolution and grid-independency for the GHEs studied fell within the 369,833 cells.…”

Fabrication and heat transfer characteristics of C/SiC pyramidal core lattice sandwich panel

“…5, the model is consisted of two face sheets and pyramidal lattice core with 4 Â 4 unit cells along the two in-plane directions. Mesh sensitivity study is a necessary analysis to ensure that the numerical simulation results are grid-independent [22,23]. The geometrical model was meshed through the preprocessor of Abaqus.…”