CCS and Power Systems
Advanced Energy Systems - Hydrogen Turbines
Improving Durability of Turbine Components Through Trenched Film Cooling and Contoured Endwalls
Performer: University of Texas at Austin
Project No: FE0005540
- Completed experimental simulation of a turbine vane with TBC. Measurements were made with a matched Biot number conducting model to obtain overall effectiveness with and without film cooling on the pressure side of the vane.
- Completed experiments where contaminant depositions on the leading edge and pressure side of a turbine vane with TBC were simulated using a unique molten wax spray technique. Results showed that the contaminant deposition acted as an insulating layer on the TBC surface, therefore decreasing the vane metal temperature.
- Results from the previous year showed that relatively thick TBC, with a thickness to hole diameter ratio of t/d = 1.0, caused a dramatic increase in overall cooling effectiveness. An important part of this year’s work was to evaluate a moderate thickness TBC with thickness t/d = 0.6, i.e. 40% thinner than the TBC of FY2012. Although the overall cooling effectiveness was lower with the moderate thickness TBC, the cooling due to TBC still has a dominating effect.
- Measurements of temperature, velocity, and total pressure loss were taken in the wake of the turbine vane for cases with and without deposition, as well as with and without film cooling. Deposition was simulated using our unique molten wax spray technique. Results showed film cooling has a negligible effect on the velocity deficit and pressure loss in the wake, while deposition has a significant effect.
- Experiments measuring overall effectiveness of a matched Biot number flat endwall model have been conducted for film cooling only, as well as internal impingement cooling plus film cooling.
- Experiments with impingement were completed at two impingement heights representing the range of heights that will occur with the contoured endwall and in an engine.
- A one-dimensional analysis used to calculate the overall effectiveness based on results from impingement alone and film alone had good agreement at low blowing ratios, and reasonable agreement at high blowing ratios.
- Additional thermocouples were installed on the backside of the endwall, which were used to derive values for internal heat transfer coefficient.
- Deposition was dynamically simulated on the flat endwall. Internal endwall temperatures were measured to be higher with deposition, indicating an increase in heat transfer coefficient due to roughness effects.