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You searched for +publisher:"Texas A&M University" +contributor:("Schobeiri, M. T."). Showing records 1 – 2 of 2 total matches.

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Texas A&M University

1. Abdelfattah, Sherif Alykadry. Numerical and Experimental Analysis of Multi-Stage Axial Turbine Performance at Design and Off-Design Conditions.

Degree: 2013, Texas A&M University

Computational fluid dynamics or CFD isan importanttool thatis used at various stages in the design of highly complex turbomachinery such as compressorand turbine stages that are used in land and air based power generation units. The ability of CFD to predict the performance characteristics of a specific blade design is challenged by the need to use various turbulence models to simulate turbulent flows as well as transition models to simulate laminar to turbulent transition that can be observed in various turbomachinery designs. Moreover, CFD is based on numerically solving highly complex differential equations, which through the use of a grid to discretize the geometry introduces numerical errors. Allthese factors combine to challenge CFD?s role as a predictor of blade performance. It has been generallyfound that CFD in its current state of the art is best used to compare between various design points and not as a pure predictor of performances. In this study the capability of CFD, and turbulence modeling, in turbomachinery based geometry is assessed.Three different blade designs are tested, that include an advanced two-stage turbine blade design, a three stage 2D or cylindrical design and finally a three stage bowed stator and rotor design. Allcases were experimentally tested at the Texas A&Muniversity Turbomachinery Performance and Flow Research Laboratory (TPFL).In all cases CFD provided good insights into fundamental turbomachinery flow physics, showing the expected improvement from using 2D cylindrical blades to 3D bowed blade designs in abating the secondary flow effects which are dominant loss generators.However, comparing experimentally measured performance results to numerically predicted shows a clear deficiency, where the CFD overpredicts performance when compared to experimentallyobtained data, largely underestimating the various loss mechanisms. In a relative sense, CFD as a tool allows the user to calculate the impact a new feature or change can have on a baseline design. CFD will also provide insight into what are the dominant physics that explain why a change can provide an increase or decrease in performance. Additionally,as part of this study, one of the main factors that affect the performance of modern turbomachinery is transition from laminar to turbulent flow.Transition is an influential phenomena especially in high pressure turbines, and is sensitive to factors such asupstream incidentwake frequency and turbulence intensity.A model experimentally developed, is implemented into a CFD solver and compared to various test results showing greater capability in modeling the effects of reduced frequency on the transition point and transitional flow physics. This model is compared to industry standard models showing favorable prediction performance due to its abilityto account for upstream wake effects which most current model are unable to account for. Advisors/Committee Members: Schobeiri, M. T. (advisor), Han, Je-Chin (committee member), Lau, Sai C (committee member), Chen, Hamn-Ching (committee member).

Subjects/Keywords: Turbomachinery; CFD; Secondary Flows; Turbines

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Abdelfattah, S. A. (2013). Numerical and Experimental Analysis of Multi-Stage Axial Turbine Performance at Design and Off-Design Conditions. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151083

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Abdelfattah, Sherif Alykadry. “Numerical and Experimental Analysis of Multi-Stage Axial Turbine Performance at Design and Off-Design Conditions.” 2013. Thesis, Texas A&M University. Accessed November 22, 2019. http://hdl.handle.net/1969.1/151083.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Abdelfattah, Sherif Alykadry. “Numerical and Experimental Analysis of Multi-Stage Axial Turbine Performance at Design and Off-Design Conditions.” 2013. Web. 22 Nov 2019.

Vancouver:

Abdelfattah SA. Numerical and Experimental Analysis of Multi-Stage Axial Turbine Performance at Design and Off-Design Conditions. [Internet] [Thesis]. Texas A&M University; 2013. [cited 2019 Nov 22]. Available from: http://hdl.handle.net/1969.1/151083.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Abdelfattah SA. Numerical and Experimental Analysis of Multi-Stage Axial Turbine Performance at Design and Off-Design Conditions. [Thesis]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151083

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Sharma, Kapil. Inter-stage and Performance Tests of a Two-stage High-pressure Turbine.

Degree: 2011, Texas A&M University

The existing 3-stage research turbine at Turbomachinery Performance and Flow Research Laboratory (TPFL) facility, Texas A & M University (TAMU) was replaced with a newly designed and manufactured 2-stage turbine in accordance with the design requirements as per DooSan, DHI. This new design of turbine consisted of bowed stator and rotor blades to study the effect on reduction of secondary ow losses and thus improvement in turbine efficiency if any. The new design also incorporated labyrinth seals on both inner and outer shrouds. Extensive Inter-stage and Performance experiments were carried out on this new turbine. Inter-stage measurements were accomplished by traversing three 5-hole probes radially and circumferentially, using the existing probe traverse system in TPFL. Performance tests were conducted for varying pressure ratio, at fixed rotational speed and for varying rotational speed with fixed pressure ratio and the efficiency was plotted against u/c_0. Each condition was tested and measured two to three times to check for reproducibility of the data. The results from inter-stage experiments show that the rotor row loss coefficient is about four times higher than the stator row loss coefficient. This high rotor loss coefficient reduces the total to static efficiency. From the performance tests, the maximum total-to-static efficiency observed was 85.2 percent located at around u/c_0 = 0.75. This relatively low efficiency is in consonance with the inter-stage results (high rotor loss coefficient). Advisors/Committee Members: Schobeiri, M T. (advisor), Han, J C. (committee member), Hassan, Y A. (committee member).

Subjects/Keywords: 2-stage turbine; rotor blades; bowed stator

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sharma, K. (2011). Inter-stage and Performance Tests of a Two-stage High-pressure Turbine. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9090

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Sharma, Kapil. “Inter-stage and Performance Tests of a Two-stage High-pressure Turbine.” 2011. Thesis, Texas A&M University. Accessed November 22, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9090.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Sharma, Kapil. “Inter-stage and Performance Tests of a Two-stage High-pressure Turbine.” 2011. Web. 22 Nov 2019.

Vancouver:

Sharma K. Inter-stage and Performance Tests of a Two-stage High-pressure Turbine. [Internet] [Thesis]. Texas A&M University; 2011. [cited 2019 Nov 22]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9090.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sharma K. Inter-stage and Performance Tests of a Two-stage High-pressure Turbine. [Thesis]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9090

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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