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  • 1
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    Small Engine Technology. Task 4: Advanced Small Turboshaft Compressor (ASTC) Performance and Range Investigation (1997)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This contact had two main objectives involving both numerical and experimental investigations of a small highly loaded two-stage axial compressor designated Advanced Small Turboshaft Compressor (ASTC) winch had a design pressure ratio goal of 5:1 at a flowrate of 10.53 lbm/s. The first objective was to conduct 3-D Navier Stokes multistage analyses of the ASTC using several different flow modelling schemes. The second main objective was to complete a numerical/experimental investigation into stall range enhancement of the ASTC. This compressor was designed wider a cooperative Space Act Agreement and all testing was completed at NASA Lewis Research Center. For the multistage analyses, four different flow model schemes were used, namely: (1) steady-state ADPAC analysis, (2) unsteady ADPAC analysis, (3) steady-state APNASA analysis, and (4) steady state OCOM3D analysis. The results of all the predictions were compared to the experimental data. The steady-state ADPAC and APNASA codes predicted similar overall performance and produced good agreement with data, however the blade row performance and flowfield details were quite different. In general, it can be concluded that the APNASA average-passage code does a better job of predicting the performance and flowfield details of the highly loaded ASTC compressor.
    Keywords: Aircraft Propulsion and Power
    Type: NASA-CR-198503 , NAS 1.26:198503 , E-10333
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Investigation of Advanced Counterrotation Blade Configuration Concepts for High Speed Turboprop Systems. Task 2: Unsteady Ducted Propfan Analysis (1991)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The primary objective was the development of a time dependent 3-D Euler/Navier-Stokes aerodynamic analysis to predict unsteady compressible transonic flows about ducted and unducted propfan propulsion systems at angle of attack. The resulting computer codes are referred to as Advanced Ducted Propfan Analysis Codes (ADPAC). A computer program user's manual is presented for the ADPAC. Aerodynamic calculations were based on a four stage Runge-Kutta time marching finite volume solution technique with added numerical dissipation. A time accurate implicit residual smoothing operator was used for unsteady flow predictions. For unducted propfans, a single H-type grid was used to discretize each blade passage of the complete propeller. For ducted propfans, a coupled system of five grid blocks utilizing an embedded C grid about the cowl leading edge was used to discretize each blade passage. Grid systems were generated by a combined algebraic/elliptic algorithm developed specifically for ducted propfans. Numerical calculations were compared with experimental data for both ducted and unducted flows.
    Keywords: AERODYNAMICS
    Type: NASA-CR-187106 , NAS 1.26:187106
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Time-dependent aerodynamic analysis of ducted and unducted propfans at angle of attack (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A three-dimensional unsteady aerodynamic analysis is described for predicting the time-dependent flow about ducted and unducted propfans operating at angle of attack. Although the freestream is assumed to be uniform, the flow relative to the rotating blades varies with circumferential position, resulting in an inherent unsteadiness due to the nonaxial inflow. The time-dependent Euler equations are solved utilizing a Runge-Kutta time-stepping scheme. The analysis is based on a finite-volume discretization employing a multiple-block grid network. To permit the use of large calculation time steps, an implicit residual smoothing scheme previously tested for unsteady flow calculations in two dimensions is extended to three spatial dimensions. For unducted propfans, a single H-type grid block is used for each blade passage to determine the time-periodic flowfield. For ducted propfans (ultra-high bypass fans) a body-centered C-type grid is wrapped about the cowl to improve the accuracy of the analysis in the high gradient flow region near the cowl leading edge. Numerical results are compared with available data for both ducted and unducted propfans operating at angle of attack.
    Keywords: AERODYNAMICS
    Type: ASME PAPER 91-GT-190
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
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    Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems, task 1: Ducted propfan analysis (1990)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The time-dependent three-dimensional Euler equations of gas dynamics were solved numerically to study the steady compressible transonic flow about ducted propfan propulsion systems. Aerodynamic calculations were based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. An implicit residual smoothing operator was used to aid convergence. Two calculation grids were employed in this study. The first grid utilized an H-type mesh network with a branch cut opening to represent the axisymmetric cowl. The second grid utilized a multiple-block mesh system with a C-type grid about the cowl. The individual blocks were numerically coupled in the Euler solver. Grid systems were generated by a combined algebraic/elliptic algortihm developed specifically for ducted propfans. Numerical calculations were initially performed for unducted propfans to verify the accuracy of the three-dimensional Euler formulation. The Euler analyses were then applied for the calculation of ducted propfan flows, and predicted results were compared with experimental data for two cases. The three-dimensional Euler analyses displayed exceptional accuracy, although certain parameters were observed to be very sensitive to geometric deflections. Both solution schemes were found to be very robust and demonstrated nearly equal efficiency and accuracy, although it was observed that the multi-block C-grid formulation provided somewhat better resolution of the cowl leading edge region.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-185217 , NAS 1.26:185217 , EDR-14622
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 5: Unsteady counterrotation ducted propfan analysis (1993)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The primary objective of this study was the development of a time-marching three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict steady and unsteady compressible transonic flows about ducted and unducted propfan propulsion systems employing multiple blade rows. The computer codes resulting from this study are referred to as ADPAC-AOAR\CR (Advanced Ducted Propfan Analysis Codes-Angle of Attack Coupled Row). This document is the final report describing the theoretical basis and analytical results from the ADPAC-AOACR codes developed under task 5 of NASA Contract NAS3-25270, Unsteady Counterrotating Ducted Propfan Analysis. The ADPAC-AOACR Program is based on a flexible multiple blocked grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. For convenience, several standard mesh block structures are described for turbomachinery applications. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. Numerical calculations are compared with experimental data for several test cases to demonstrate the utility of this approach for predicting the aerodynamics of modern turbomachinery configurations employing multiple blade rows.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-187126 , NAS 1.26:187126
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 5: Unsteady counterrotation ducted propfan analysis. Computer program user's manual (1993)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The primary objective of this study was the development of a time-marching three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict steady and unsteady compressible transonic flows about ducted and unducted propfan propulsion systems employing multiple blade rows. The computer codes resulting from this study are referred to as ADPAC-AOACR (Advanced Ducted Propfan Analysis Codes-Angle of Attack Coupled Row). This report is intended to serve as a computer program user's manual for the ADPAC-AOACR codes developed under Task 5 of NASA Contract NAS3-25270, Unsteady Counterrotating Ducted Propfan Analysis. The ADPAC-AOACR program is based on a flexible multiple blocked grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. For convenience, several standard mesh block structures are described for turbomachinery applications. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. Numerical calculations are compared with experimental data for several test cases to demonstrate the utility of this approach for predicting the aerodynamics of modern turbomachinery configurations employing multiple blade rows.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-187125 , NAS 1.26:187125
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Investigation of Advanced Counterrotation Blade Configuration Concepts for High Speed Turboprop Systems. Task 8: Cooling Flow/heat Transfer Analysis User's Manual (1994)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The focus of this task was to validate the ADPAC code for heat transfer calculations. To accomplish this goal, the ADPAC code was modified to allow for a Cartesian coordinate system capability and to add boundary conditions to handle spanwise periodicity and transpiration boundaries. This user's manual describes how to use the ADPAC code as developed in Task 5, NAS3-25270, including the modifications made to date in Tasks 7 and 8, NAS3-25270.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-195360 , E-9025 , NAS 1.26:195360
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 8
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    Investigation of Advanced Counterrotation Blade Configuration Concepts for High Speed Turboprop Systems. Task 8: Cooling Flow/heat Transfer Analysis (1994)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The focus of this task was to validate the ADPAC code for heat transfer calculations. To accomplish this goal, the ADPAC code was modified to allow for a Cartesian coordinate system capability and to add boundary conditions to handle spanwise periodicity and transpiration boundaries. The primary validation case was the film cooled C3X vane. The cooling hole modeling included both a porous region and grid in each discrete hold. Predictions for these models as well as smooth wall compared well with the experimental data.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-195359 , E-9024 , NAS 1.26:195359
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 9
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    Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 2: Unsteady ducted propfan analysis computer program users manual (1991)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The primary objective of this study was the development of a time-dependent three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict unsteady compressible transonic flows about ducted and unducted propfan propulsion systems at angle of attack. The computer codes resulting from this study are referred to as Advanced Ducted Propfan Analysis Codes (ADPAC). This report is intended to serve as a computer program user's manual for the ADPAC developed under Task 2 of NASA Contract NAS3-25270, Unsteady Ducted Propfan Analysis. Aerodynamic calculations were based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. A time-accurate implicit residual smoothing operator was utilized for unsteady flow predictions. For unducted propfans, a single H-type grid was used to discretize each blade passage of the complete propeller. For ducted propfans, a coupled system of five grid blocks utilizing an embedded C-grid about the cowl leading edge was used to discretize each blade passage. Grid systems were generated by a combined algebraic/elliptic algorithm developed specifically for ducted propfans. Numerical calculations were compared with experimental data for both ducted and unducted propfan flows. The solution scheme demonstrated efficiency and accuracy comparable with other schemes of this class.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-187105 , NAS 1.26:187105
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 10
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    Energy Efficient Engine Low Pressure Subsystem Aerodynamic Analysis (1998)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The objective of this study was to demonstrate the capability to analyze the aerodynamic performance of the complete low pressure subsystem (LPS) of the Energy Efficient Engine (EEE). Detailed analyses were performed using three- dimensional Navier-Stokes numerical models employing advanced clustered processor computing platforms. The analysis evaluates the impact of steady aerodynamic interaction effects between the components of the LPS at design and off- design operating conditions. Mechanical coupling is provided by adjusting the rotational speed of common shaft-mounted components until a power balance is achieved. The Navier-Stokes modeling of the complete low pressure subsystem provides critical knowledge of component acro/mechanical interactions that previously were unknown to the designer until after hardware testing.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1998-208402 , E-11234 , NAS 1.15:208402 , AIAA Paper 98-3119 , Propulsion; Jul 13, 1998 - Jul 15, 1998; Cleveland, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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