Numerical analysis of multiple influences on turbine vane endwall film cooling characteristics

While increasing the turbine inlet temperature is an effective approach to improve thermal efficiency, it introduces a significant challenge: the endwall of the inlet guide vane becomes more susceptible to damage from concentrated thermal stress. Therefore, optimized film cooling configurations and flow parameters are essential for achieving advanced endwall cooling performance. Employing numerical simulations, this research numerically investigates the effects of multiple influences on endwall cooling performance. The considered variables include: mass flow ratios (MFR_s = 0.5%-1.5%; MFR_f = 0.45%-0.75%), film hole diameters (d_f = 0.5–1 mm), hole expansion angles (β = 6°-14°), and density ratios (DR = 1.0–2.5). The parametric effects are quantified through the analysis of three key metrics: the adiabatic film-cooling effectiveness, the Nusselt number, and the net heat flux ratio. The simulation results indicate that increasing the mass flow ratio yields a significant enhancement in endwall film coverage and consistently maintains the net heat flux ratio below 0.5. Closely-spaced, small-diameter film holes effectively suppress film lift-off under high mass flow ratios. Furthermore, an increased momentum ratio is identified as the key factor for enhancing endwall film coverage. However, an excessively large expansion angle of fan-shaped hole diminishes coolant momentum, leading to a rapid deterioration of local cooling performance. While a higher density ratio enhances film adhesion under high mass flow ratio, a lower density ratio conversely promotes more uniform film coverage due to its greater flow momentum.