Minking Chyu, Mechanical Engineering Turbine blades in modern gas turbines are exposed to temperatures that exceed the blade s melting point. Furthermore, combustion temperatures are constantly being raised to increase turbine efficiency and meet tougher emissions standards. In order to maintain the integrity of the blades, active cooling is necessary. High speed air is blown around and through the blades to prevent melting. Within the blade, rough walls, ribs, or impingement jets are used to induce turbulence and increase the heat transfer properties of the flow.
Impingement jets are high pressure air jets that impact a surface, thereby cooling it.
Due to the highly complex nature of such flows, an analytical solution is not possible. Liquid crystal techniques are used to obtain the heat transfer characteristics while a relatively new laser-based technique can be used to obtain flow field data. A single laser beam is spread into a thin laser sheetwhich is used to obtain the velocities of a cross-section of a flow. This research focuses on the use of this method to study the flow field of impingement jets. Once this data is combined with heat transfer data using liquid crystal techniques, engineers will have a better understanding of the physical mechanisms behind turbine blade cooling with impingement jets.