Executive Summary : | High performance gas turbine engines are expected have high thrust-to-weight ratio, power, efficiency and low specific fuel consumption, and incorporate modern technology to meet future ‘Net zero’ and ‘Carbon zero’ requirements. High turbine entry temperature is an imperative requirement for high performance gas turbine engines. This rise of temperature directly impacts the first stage nozzle guide vanes (NGVs) as they are subjected to the most extreme aero-thermal conditions due to direct impact of hot gases coming from combustion chamber. These vanes are the most critical to engine performance because they control the orientation of flow entering the rest of the turbine. To sustain these elevated temperatures for long operational durations, most advanced turbine cooling techniques have to be deployed. Film cooling is by far the most investigated turbine cooling technology, however it suffers from issues like formation of vortical structures, unidirectional and steady flow. Sweeping jet film cooling (SJFC) works on the concept of fluidic oscillator. It is a recent technology with improved cooling effectiveness and reduced coolant consumption. Rapid advancement of additive manufacturing technology helps to incorporate intricate structures such as sweeping jet in turbine blades. The targeted objective of the present proposal is to experimentally investigate the SJFC technique using an innovative approach of flat plate under the influence of imposed favorable pressure gradient comparable with the suction surface of High Pressure Turbine vane using wind tunnel. An attempt would be made to understand the effects of various freestream parameters such as freestream Reynolds number, Turbulence intensity, flow Incidence angles and blade solidity (number of blades) on the performance of SJFC. Along with these, the effect of the coolant stream parameters namely blowing ratio, density ratio, cooling hole geometry, and number of holes will also be investigated unheated plate. There is an extreme need for an innovative research methodology that enables aero-thermal characterization of SJFC. A state of the art experimental facility will be developed for this purpose. The objectives of the study include an aerodynamic characterization of flow over a flat plate with and without SJFC in an environment that simulates the actual HP turbine vane passage flow structures using Particle Image Velocimetry (PIV) and other measurement instruments. A heat-transfer oriented study will then be carried out to understand the effects of earlier stated parameters along with the thermal aspects to assess the thermal performance of SJFC using IR camera, thermocouples and other heat transfer measuring instruments. With the accomplishment of the goals of this research, a detailed understanding of revolutionary SJFC is expected to be achieved which will enhance the performance of future gas turbine engines by improving the turbine cooling technology. |