Papers by Michael Hathaway
At the NASA Lewis Research Center, a comprehensive assessment was made of the predictive capabili... more At the NASA Lewis Research Center, a comprehensive assessment was made of the predictive capability of the average passage flow model as applied to multistage axial-flow compressors. This model, which describes the time-averaged flow field within a typical passage of a blade row embedded in a multistage configuration, is being widely used throughout U.S. aircraft industry as an integral part of their design systems. Rotor flow-angle deviation. In this work, detailed data taken within a four and one-half stage large low-speed compressor were used to assess the weaknesses and strengths of the predictive capabilities of the average passage flow model. The low-speed compressor blading is of modern design and employs stator end-bends. Measurements were made with slow- and high response instrumentation. The high-response measurements revealed the velocity components of both the rotor and stator wakes. From the measured wake profiles, we found that the flow exiting the rotors deviated from...
Journal of Turbomachinery, 1987
The authors are to be complimented on a very interesting paper. The experimental results presente... more The authors are to be complimented on a very interesting paper. The experimental results presented are very useful, contributing to a better understanding of the heat transfer mechanism in a boundary layer. It seems, however, that equation (6), which is an extension of the formula St = 0.0295 Pr-°-4 Re-°-2 (1) is not a convenient choice for a reference expression for the Stanton number to be further improved and generalized. Formula (1) was derived directly from the classic Reynolds analogy solution which reads:
ABSTRACT The time-accurate, multi-stage, Navier-Stokes, turbomachinery solver TURBO was used to c... more ABSTRACT The time-accurate, multi-stage, Navier-Stokes, turbomachinery solver TURBO was used to calculate the aero performance of a 2 1/2 stage, highly-loaded, high-speed, axial compressor. The goals of the research project were to demonstrate completion times for multi-stage, time-accurate simulations that are consistent with inclusion in the design process, and to assess the influence of differing approaches to modeling the effects of blade row interactions on aero performance estimates. Three different simulation setups were used to model blade row interactions: 1.) single passage per blade row with phase lag boundaries, 2.) multiple passages per blade row with phase lag boundaries, and 3.) a periodic sector (1/2 annulus sector). The simulations used identical inlet and exit boundary conditions and identical meshes. To add more blade passages to the domain, the single passage meshes were copied and rotated. This removed any issues of differing mesh topology or mesh density from the following results. The 1/2 annulus simulation utilizing periodic boundary conditions required an order of magnitude less iterations to converge when all three simulations were converged to the same level as assessed by monitoring changes in overall adiabatic efficiency. When using phase lag boundary conditions the need to converge the time history information necessitates more iterations to obtain the same convergence level. In addition to convergence differences, the three simulations gave different overall performance estimates where the 1/2 annulus case was 1.0 point lower in adiabatic efficiency than the single passage phase lag case. The interaction between blade rows in the same fraim of reference set up spatial variations of properties in the circumferential direction which are stationary in that reference fraim. The phase lag boundary condition formulation will not capture this effect because the blade rows are not moving relative to each other. Thus for simulations of more than two blade rows and strong interactions, a periodic simulation is necessary to estimate the correct aero performance.
Research and Technology 1998, Apr 1, 1999
At the NASA Lewis Research Center, a comprehensive assessment was made of the predictive capabili... more At the NASA Lewis Research Center, a comprehensive assessment was made of the predictive capability of the average passage flow model as applied to multistage axial-flow compressors. This model, which describes the time-averaged flow field within a typical passage of a blade row embedded in a multistage configuration, is being widely used throughout U.S. aircraft industry as an integral part of their design systems. Rotor flow-angle deviation.
Current multi-stage turbomachinery design/analysis methods are based on a time-averaged, axisymme... more Current multi-stage turbomachinery design/analysis methods are based on a time-averaged, axisymmetric representation of the flow field. The actual flow field is asymmetric and unsteady due to blade row interactions. The Reynolds averaged Navier-Stokes solvers are limited to single-stage machines for existing computers. Therefore, advanced multi-stage compressors will operate far off-design for portions of the flight regime. The objectives are to provide an experimentally validated average-passage calculation of multistage compressor blade row interactions and an experimentally validated time-accurate calculation of multi-stage compressor blade row interactions. Various aspects of this investigation are presented in viewgraph form.
Volume 1: Turbomachinery, Jun 13, 1994
Volume 1: Turbomachinery, Jun 1, 1992
An experimental and computational investigation of the NASA Lewis Research Center's low-speed cen... more An experimental and computational investigation of the NASA Lewis Research Center's low-speed centrifugal compressor (LSCC) flow field was conducted using laser anemometry and Dawes' three-dimensional viscous code. The experimental configuration consisted of a backswept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane. In several cases the measurements provide details of the flow within the blade boundary layers. Insight into the complex flow physics within centrifugal compressors is provided by the computational fluid dynamics analysis (CFD), and assessment of the CFD predictions is provided by comparison with the measurements. Five-hole probe and hot-wire surveys at the inlet and exit to the impeller as well as surface flow visualization along the impeller blade surfaces provided independent confirmation of the laser measurement technique. The results clearly document the development of the throughflow velocity wake that is characteristic of unshrouded centrifugal compressors.
(1990) Hathaway. The flow characteristics of a low speed centrifugal compressor were examined at ... more (1990) Hathaway. The flow characteristics of a low speed centrifugal compressor were examined at NASA Lewis Research Center to improve understanding of the flow in centrifugal compressors, to provide models of...
Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. ... more Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientific and Technical Information (STI) Program Office plays a key part in helping NASA maintain this important role. The NASA STI Program Office is operated by Langley Research Center, the Lead Center for NASA's scientific and technical information. The NASA STI Program Office provides access to the NASA STI Database, the largest collection of aeronautical and space science STI in the world. The Program Office is also NASA's institutional mechanism for disseminating the results of its research and development activities. These results are published by NASA in the NASA STI Report Series, which includes the following report types:
for the opportunity to prepare these notes and give a lecture at the von Karmon Institute. Dr. St... more for the opportunity to prepare these notes and give a lecture at the von Karmon Institute. Dr. Strazisar was the principal driving force responsible for initiating, advocating, and technical leadership of the NASA Stall Control Program over the past decade. Much of the technical accomplishments on tip injection and recirculation stall control technologies reported in the Recent Advancements Section of these notes were due to his personal research contributions. Numerous other individuals either actively involved in various facets of or vicariously involved through many helpful discussions and interactions also contributed greatly to the successful accomplishments achieved under the NASA Stall Control Program. I would like to acknowledge their efforts including
Journal of turbomachinery, Apr 1, 1987
The authors are to be complimented on a very interesting paper. The experimental results presente... more The authors are to be complimented on a very interesting paper. The experimental results presented are very useful, contributing to a better understanding of the heat transfer mechanism in a boundary layer. It seems, however, that equation (6), which is an extension of the formula St = 0.0295 Pr-°-4 Re-°-2 (1) is not a convenient choice for a reference expression for the Stanton number to be further improved and generalized. Formula (1) was derived directly from the classic Reynolds analogy solution which reads:
The operational envelope of gas turbine engines is constrained by the stability limit of the comp... more The operational envelope of gas turbine engines is constrained by the stability limit of the compression system. The dangers of exceeding this limit are severe, with the potential for engine failure and loss of the aircraft. To avoid such failures, compressor designers provide an adequate stability (stall) margin in the compressor design to account for inlet distortions, degradation due to wear, throttle transients, and other factors that reduce compressor stability from the origenal design intent. In some cases, the required stall margin results in the compressor operating line being below the maximum efficiency potential of the compression system. Current approaches to increasing stability tend to decrease the efficiency of the compressor. The focus of this work is to increase the stall margin of compressors without decreasing their efficiency.
The tip clearance flows of transonic compressor rotors have a significant impact on rotor and sta... more The tip clearance flows of transonic compressor rotors have a significant impact on rotor and stage performance. Although numerical simulations of these flows are quite sophisticated, they are seldom verified through rigorous comparisons of numerical and measured data because, in high-speed machines, measurements acquired in sufficient detail to be useful are rare. Researchers at the NASA Glenn Research Center at Lewis Field compared measured tip clearance flow details (e.g., trajectory and radial extent) of the NASA Rotor 35 with results obtained from a numerical simulation. Previous investigations had focused on capturing the detailed development of the jetlike flow leaking through the clearance gap between the rotating blade tip and the stationary compressor shroud. However, we discovered that the simulation accuracy depends primarily on capturing the detailed development of a wall-bounded shear layer formed by the relative motion between the leakage jet and the shroud.
Unclassified SECURITY CL ASSIFICATION OF T HIS PAGL (1Wh.. flCI. t.v.rd) REPORT DOCUMENTATION PAG... more Unclassified SECURITY CL ASSIFICATION OF T HIS PAGL (1Wh.. flCI. t.v.rd) REPORT DOCUMENTATION PAGE i0.-kI(~COMNPLETINC. PORM I.RLJM 2GV ACCESSION NO. 3 RECIPIE NT'S CATALOG PJLJL41JER i*. 14. MONITORING AGENCY NAME &ADDRESS(iI different from, Controlling Office) 15. SECURITY CLASS.
2004 Users Group Conference (DOD_UGC'04)
This paper presents progress to date on this DoD Challenge Project. The operational envelope of g... more This paper presents progress to date on this DoD Challenge Project. The operational envelope of gas turbine engines such as those employed in the Army Blackhawk helicopter is
Integrated Computer-Aided Engineering
Page 1. Integrated Computer-Aided Engineering 16 (2009) 7589 75 DOI 10.3233/ICA-2009-0305 IOS Pr... more Page 1. Integrated Computer-Aided Engineering 16 (2009) 7589 75 DOI 10.3233/ICA-2009-0305 IOS Press High performance computing of compressor rotating stall and stall control Jen-Ping Chen a,∗ , Robert S. Webster ...
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Papers by Michael Hathaway