The aim of this work is the application of desensitization techniques on the tip region of the turbine blade used in turbopumps applications. It is worth to study this region of the turbine because it has influence in turbomachines performances. Given the complexity of the tip geometries analyzed, structured meshes automatic generation is not feasible, therefore it is necessary to generate unstructured meshes that allow flow calculation through CFD techniques. Thus, as a first step, unstructured tetrahedral meshes (with prismatic layers close to the surfaces) with different Yplus values were generated, considering that the tip region is not yet desensitized. Subsequently, turbulent 3-D flow calculations were performed at design and off design conditions. The methodology used is to present in a didactic way, for graduate students, the advantages and disadvantages of the unstructured mesh in relation to the structured one, already used in previous research. Unstructured meshes were generated using ICEM software (ANSYS), while structured ones were generated using AxCent software (NREC). The machine under study is the first stage of the hydraulic axial turbine used in the Low Pressure Oxidizer Turbopump of the Space Shuttle Main Engine, considering 3.0% tip clearance configuration relative to blade height. All simulations were done using CFX program (ANSYS). The result shows the comparison between the two mesh types considering the difficulty and time generation, discretization quality, effect of Yplus parameter variation on flowfield, simulation time, and stage performance parameters calculation for different operating points.


Comparative Study Between Structured and Unstructured Meshes Applied in Turbopump\u2019s Hydraulic Turbine

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

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