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Zagnoli Thesis FINAL.pdf (10.63 MB)

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A Numerical Study of Deposition in a Full Turbine Stage Using Steady and Unsteady Methods

Zagnoli, Daniel Anthony
http://rave.ohiolink.edu/etdc/view?acc_num=osu1429796426

Abstract Details

2015, Master of Science, Ohio State University, Aero/Astro Engineering.
A computational study was performed to investigate deposition phenomena in a high-pressure turbine stage. Steady mixing-plane and unsteady sliding mesh calculations were utilized. Three-dimensional, steady and unsteady RANS calculations were performed in conjunction with published experiments completed on a similar turbine geometry which provided boundary conditions and pressure data to validate flow solutions. Particles were introduced into the flow domain and deposition was predicted using a Lagrangian particle tracking method with the critical viscosity model to predict deposition. For the steady method, in order to track particles from the mixing plane through the blade domain, particle positions were saved after passing through the vane domain and inserted into the blade domain using two different methods which were named averaged and preserved. Both methods yielded nearly identical results. For the unsteady simulation particles were tracked through a sliding mesh interface with particle position, velocity, and temperature preserved at exit of the vane domain and inlet of the blade domain. Deposition results for the steady mixing plane using both particle averaging techniques and unsteady sliding interface were compared for particles of different sizes. Large particles produce localized impact and deposit zones near the hub and tip for all methods. Steady methods deviated from unsteady methods at all particle diameters by neglecting unsteady vane wake motion causing different impact locations and subsequent multiple rebounds. At low Stokes numbers (2.8-11) the steady methods overpredicted impacts, by 30% and 25% respectively, because wake motion and particle drag dominated particle trajectories, pulling them away from pressure surface. At a high Stokes number (31) the steady method underpredicted impacts and deposits as wake motion caused a shift in initial impact locations. However, the larger particle inertia of these particles allowed subsequent impacts on adjacent suction surfaces causing a large increase in impact and capture efficiencies.
Jeffrey Bons, Dr. (Advisor)
Ali Ameri, Dr. (Committee Member)
Jen-Ping Chen, Dr. (Committee Member)
135 p.
Aerospace Engineering; Engineering; Fluid Dynamics; Mechanical Engineering
turbine; unsteady; deposition; particles; numerical; computational; CFD; erosion; rotating; sliding mesh; mixing plane;

Recommended Citations

Citations

  • Zagnoli, D. A. (2015). A Numerical Study of Deposition in a Full Turbine Stage Using Steady and Unsteady Methods [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429796426

    APA Style (7th edition)

  • Zagnoli, Daniel. A Numerical Study of Deposition in a Full Turbine Stage Using Steady and Unsteady Methods. 2015. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1429796426.

    MLA Style (8th edition)

  • Zagnoli, Daniel. "A Numerical Study of Deposition in a Full Turbine Stage Using Steady and Unsteady Methods." Master's thesis, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429796426

    Chicago Manual of Style (17th edition)

osu1429796426
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This open access ETD is published by The Ohio State University and OhioLINK.