Flow visualization of longitudinal vortices induced by an inclined impinging jet in a crossflow—effective cooling of high temperature gas turbine blades

• Published in: Energy conversion and management Vol. 38; no. 10; pp. 1145 - 1153
• Main Authors: Nakabe, K., Inaoka, K., Ai, T., Suzuki, K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.07.1997; Elsevier
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Flow visualization; Heat transfer enhancement; Impinging jet; Longitudinal vortex; PTV; Vortex generator; Heat transfer enhancement; Impinging jet; Vortex generator; Flow visualization; PTV; Longitudinal vortex; Visualization; Nusselt number; Cooling; Gas turbines; Jet flow; Turbine blade; Crossflow; Velocity distribution; High temperature; Experimental study; Turbines
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/S0196-8904(96)00144-6

One of the most fundamental principles to improve the energy conversion efficiency is to raise the working temperature of a gas turbine. In order to realize high temperature gas turbines, development of effective cooling system of turbine blades is indispensable. The attention was paid to the utilization of longitudinal vortices to enhance the heat transfer from the inner surfaces of turbine blades. Effectiveness of longitudinal vortices in enhancing wall heat transfer were already confirmed for the case of a disturbed flat plate boundary layer with the insertion of a wing-type vortex generator (WVG) attached to a large-eddy-break-up (LEBU) plate. Pressure loss due to a form drag of the WVG, however, was not small. Then, longitudinal vortices generated by an inclined jet (VG jet) into crossflow have been examined to apply for effective cooling of gas turbine blades. Flow visualization and heat transfer experiments were conducted for a duct flow including longitudinal vortices without the insertion of any body in addition to a conventional impinging jet with crossflow. It was experimentally demonstrated that jet impingement is effective for heat transfer augmentation even in the case with crossflow, and that the longitudinal vortices have been confirmed to be generated by the insertion of the VG jet. The generated vortices are expected to effectively enhance the heat transfer from the inner surface of the blades of a gas turbine.