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Airfoil, Platform, and Cooling Passage Measurements on a Rotating Transonic High-Pressure Turbine

Nickol, Jeremy B
http://rave.ohiolink.edu/etdc/view?acc_num=osu1459857581

Abstract Details

2016, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
An experiment was performed at The Ohio State University Gas Turbine Laboratory for a film-cooled high-pressure turbine stage operating at design-corrected conditions, with variable rotor and aft purge cooling flow rates. Several distinct experimental programs are combined into one experiment and their results are presented. Pressure and temperature measurements in the internal cooling passages that feed the airfoil film cooling are used as boundary conditions in a model that calculates cooling flow rates and blowing ratio out of each individual film cooling hole. The cooling holes on the suction side choke at even the lowest levels of film cooling, ejecting more than twice the coolant as the holes on the pressure side. However, the blowing ratios are very close due to the freestream massflux on the suction side also being almost twice as great. The highest local blowing ratios actually occur close to the airfoil stagnation point as a result of the low freestream massflux conditions. The choking of suction side cooling holes also results in the majority of any additional coolant added to the blade flowing out through the leading edge and pressure side rows. A second focus of this dissertation is the heat transfer on the rotor airfoil, which features uncooled blades and blades with three different shapes of film cooling hole: cylindrical, diffusing fan shape, and a new advanced shape. Shaped cooling holes have previously shown immense promise on simpler geometries, but experimental results for a rotating turbine have not previously been published in the open literature. Significant improvement from the uncooled case is observed for all shapes of cooling holes, but the improvement from the round to more advanced shapes is seen to be relatively minor. The reduction in relative effectiveness is likely due to the engine-representative secondary flow field interfering with the cooling flow mechanics in the freestream, and may also be caused by shocks and other compressibility effects within the cooling holes which are not present in low speed experiments. Another major focus of this work is on the forward purge cavity and rotor and stator inner endwalls. Pressure and heat transfer measurements are taken at several locations, and compared as both forward and aft purge flow rates are varied. It is seen that increases in forward purge rates result in a flow blockage and greater pressure on the endwalls both up and downstream of the cavity. Thus, even in locations where the coolant does not directly cover the metal surface, it can have a significant impact on the local pressure loading and heat transfer rate. The heat transfer on the platform further downstream, however, is unchanged by variations in purge flow rates.
Randall Mathison (Advisor)
Michael Dunn (Committee Member)
Sandip Mazumder (Committee Member)
Jeffrey Bons (Committee Member)
207 p.
Aerospace Engineering; Engineering; Mechanical Engineering
gas turbine; heat transfer; aerodynamics; film cooling; shaped holes; purge; cavity; cooling; blowing; serpentine; rotating; transonic; high pressure turbine; platform; endwall

Recommended Citations

Citations

  • Nickol, J. B. (2016). Airfoil, Platform, and Cooling Passage Measurements on a Rotating Transonic High-Pressure Turbine [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1459857581

    APA Style (7th edition)

  • Nickol, Jeremy. Airfoil, Platform, and Cooling Passage Measurements on a Rotating Transonic High-Pressure Turbine. 2016. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1459857581.

    MLA Style (8th edition)

  • Nickol, Jeremy. "Airfoil, Platform, and Cooling Passage Measurements on a Rotating Transonic High-Pressure Turbine." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1459857581

    Chicago Manual of Style (17th edition)

osu1459857581
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© 2016, some rights reserved.Creative Commons License Airfoil, Platform, and Cooling Passage Measurements on a Rotating Transonic High-Pressure Turbine by Jeremy B Nickol is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.