A novel concept for a rib turbulator for optimizing the cooling performance in a square channel

Abstract

In gas turbine operations, realizing the appropriate cooling of blades and vanes is crucial for ensuring long-term durability and high thermal efficiency. Internal convective cooling is widely used to direct coolant through a channel comprising rib turbulators to enhance the effectiveness of the cooling process. In this study, a numerical simulation is conducted to evaluate the effects of novel rib turbulator configurations under mist/steam two-phase conditions, specifically in relation to secondary flow and heat transfer characteristics. The morphologies of the secondary flow distribution and mist droplet trajectories induced by different rib turbulator configurations are carefully evaluated to elucidate the underlying mechanism of the heat transfer enhancement. Thus, the findings indicate that the configuration of the rib turbulator significantly affects the secondary flow distribution. In the novel concepts of discrete v-shaped rib turbulators with a single break and those with a double break, a notable increase in the longitudinal secondary flow was observed with a higher turbulence intensity. Moreover, such secondary flow compels mist droplets to accumulate and assemble at various locations within the channel. Subsequently, the heat transfer enhancement was localized in areas where the mist droplets accumulated in significant quantities. In terms of the optimization of the rib turbulator configuration, the adoption of a v-shape with a single break and discrete channel resulted in an enhancement of the Nusselt number by 45.07 % and the thermal performance factor by 88.57 %.