An experimental and numerical study of gas-solid aerosol heat transfer in a turbine blade internal cooling channel with V-shaped ribs

Abstract

Atmospheric particulate matter that is inevitably ingested in the internal cooling channels of a turbine blade forms a gas-solid, two-phase aerosol coolant, thereby altering the internal heat transfer and flow resistance characteristics. Experimental investigations into the heat transfer characteristics of aerosol coolants were conducted for various particle sizes (0.65–100

m) across a Reynolds number ( Re ) range of 15,000 to 55,000. In parallel, numerical simulations based on an Eulerian-Eulerian approach were performed to offer complementary physical information regarding the heat transfer and flow fields. The study demonstrated that the area-averaged Nusselt number (Nu) ratios decreased with increasing Re for all particle sizes. Conversely, the corresponding friction factor ratios increased, leading to a decline in comprehensive thermal performance evaluated using a performance evaluation criterion (PEC). Streamwise distributions showed that the regionally averaged Nu ratios for all aerosol coolants initially rose and then fell. Although the introduction of particles did not alter the wall heat transfer distribution from the airflow, it significantly influenced the heat transfer intensity in the most fore regions of the channel. At Re = 15,000, the 0.65

mu μ $ \mu $

m particles exhibited excellent flow-following capability, largely preserving the original flow field structures within the channel. In contrast, the 100

mu μ $ \mu $

m particles were dominated by their inertia, which not only dissipated turbulent kinetic energies but also disrupted the rib-induced vortex structures beneficial for heat transfer, resulting in lower heat transfer coefficients for the 100

mu μ $ \mu $

m aerosol compared to the 0.65

mu μ $ \mu $

m aerosol across all regions.