An Experimental Investigation of the Effect of Dimples on Turbine Adiabatic Film Cooling

<p>This experiment explored the ability of a row of cylindrical dimples' vortex shedding to entrain the cooling film in the boundary layer for longer distances thus enhancing cooling on a turbine leading edge model. The experiment utilized a semi-cylindrical leading edge followed by an after body with straight surfaces. A foam leading edge drilled with cooling holes allowed for a determination of adiabatic film effectiveness using an Infrared Thermography (IR) technique to measure surface temperature distributions. Two test models were utilized one with a row of seven dimples placed upstream from the cooling-hole while the other model had a row of seven downstream. Five blowing ratios were tested: 0.5 0.75 1.0 1.25 and 1.5. It was observed that the dimples introduced disturbances in the boundary layer that encouraged vertical and lateral diffusion of the cooling film that caused reattachment of coolant jet liftoff. Dimples placed upstream of the cooling hole improved spanwise averaged adiabatic film cooling effectiveness by up to 60% for far downstream locations. Dimples placed downstream of the cooling hole enhanced ?? up to 30% for far downstream locations.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>