Effect of Mesh Topologies on Wall Heat Transfer and Pressure Loss Prediction of a Blade Coolant Passage

Abstract

This paper studies the effect of mesh topologies such as hybrid and structured meshes on the evaluation of wall heat transfer coefficient (HTC) and pressure loss of a blade cooling passage. An experimental model is chosen; it has five-row of stream wise staggered elliptical pin-fin fitted inside a 10o wedge-shape duct and one-row of fillet circular pin-fin in the exit region. Simulations consider two types; i.e. warm test with isothermal wall condition and cold test with adiabatic wall condition respectively, in order to evaluate flow and thermal characteristics such as HTC and pressure loss. Further simulations are carried out by varying Re number, wall surfaces roughness, inlet turbulence intensity and turbulence models. It was found that for unstructured or structured mesh with proper near wall and middle passage grid resolutions, CFD predicted HTC and pressure loss are in good agreement with available experimental data. The wall surface roughness is found to have significant impact on HTC, simulations produce results in better agreement with experimental measurements. Simulation results also confirm that inlet turbulence intensity and turbulence model have insignificant effect of predicting the pin-fin wall and end wall heat transfer coefficient.

Pin-fin shape and orientation effects on wall heat transfer predictions of gas turbine blade

“…Unstructured meshes were applied for all configurations, resulting in 5.2-5.6 million elements. Actually, these meshes could be minimized by applying the structured mesh as used in the numerical study of wall heat transfer and 020008-2 pressure loss of streamwise staggered elliptical pin-fin [7]. The mesh characteristics of a full computational domain are summarized in Table 2.…”

“…A common practice to enhance heat transfer performance of a blade internal coolant passage is to insert small obstacles, i.e., pin-fins, ribs or other objectives in order to increase surface areas as well as to promote the near-wall turbulence intensity level. In the past, blade coolant passage performance has been studied experimentally and numerically for various configurations of staggered and/or in-line arrangements with cylindrical pin-fins [1] [3], elliptical pin-fins [4] [5], streamwise elliptical pin-fins [6] [7], spanwise elliptical pin-fin [8] [9], double in-line ribs array [10] [11]. Han and Rallabandi [12] reviewed the latest developments on the turbine blade cooling techniques.…”

DES study of blade trailing edge cutback cooling performance with various lip thicknesses

“…[15], Tarchi et al [39] and Effendy et al [40], who studied similar subjects through the staggered arrays of pin-fin cooling. For example, the peak heat transfer occurred in the last row of the pin-fin located in a wedge duct, and the increase of the heat transfer coefficient is stronger within a contraction channel than that in a parallel duct.…”

Enhancing Heat Dissipation in Microchannel Heat Sinks: A Comprehensive Study on Al2O3 Nanoparticle Concentration and Flow Rate Dependencies

“…However, the extensive usage of these devices can lead to elevated temperatures, resulting in a decline in their overall performance. A heat exchanger is imperative to ensure that electronic devices remain at optimal temperatures [1,2].…”