The durability of gas turbine engines is strongly dependent on the component temperatures. Melt points for common turbine blade materials are exceeded by the combustion temperature to the point where cooling methods must be employed. One such method, film cooling, is used extensively and utilizes cavities inside the airfoils so that cooler air from other gas turbine sections, typically compressor air, can be supplied to those cavities and then discharged through small openings, or film cooling holes. This air provides a thin, cool, insulating blanket along the external surface of the turbine blade.
Trenches especially help with lateral cooling because they increase cooling effectiveness between individual cooling holes as that cooling air is spread over the length of a row of shaped holes without increasing demand for the mass flow of air. Many proposed trench configurations have been tested in recent years, and the best performing configurations so far involve shaped holes in a trench. Investigators at the Air Force Research Lab have advanced film cooling with the state-of-the-art MTS configuration.
- The MTS hole configuration is easier to manufacture as it uses a smaller trench that is machined after the shaped holes making for a simple, two-step manufacturing process
- This process also allows for sharp edges to be readily “burned off,” both as part of the manufacturing process and inherently during operation of a gas turbine, providing smoother shapes that still permit mixing and may prevent local losses
- US patent 9,441,488 available for license
- Potential for collaboration with Air Force researchers