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Daniel J. Dorney - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Tip Clearance on Hot Streak Migration in a High-Subsonic Single-Stage Turbine
    Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery, 2000
    Co-Authors: Daniel J. Dorney, Douglas L. Sondak
    Abstract:

    Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-Stage rotor blades in Turbines. This heating of the rotor blades can lead to thermal fatigue and degrade Turbine performance. The results of recent studies have shown that variations in the circumferential location, or clocking, of the first-Stage vane airfoils can be used to minimize the adverse effects of the hot streaks due to the hot fluid mixing with the cooler fluid contained in the vane wake. In addition, the effects of the hot streak/airfoil count ratio on the heating patterns of Turbine airfoils have been quantified. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a Single-Stage high-pressure Turbine geometry operating in high subsonic flow to study the effects of tip clearance on hot streak migration. Baseline simulations were initially performed without hot streaks to compare with the experimental data. Two simulations were then performed with a superimposed combustor hot streak; in the first the tip clearance was set at the experimental value, while in the second the rotor was allowed to scrape along the outer case (i.e., the limit as the tip clearance goes to zero). The predicted results for the baseline simulations show good agreement with the available experimental data. The simulations with the hot streak indicate that the tip clearance increases the radial spreading of the hot fluid, and increases the integrated rotor surface temperature compared to the case without tip clearance.Copyright © 2000 by ASME

  • Effects of Hot Streak Shape on Rotor Heating in a High-Subsonic Single-Stage Turbine
    Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery, 2000
    Co-Authors: Daniel J. Dorney, Karen Gundy-burlet
    Abstract:

    Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-Stage rotor blades in Turbines. This heating of the rotor blades can lead to thermal fatigue and degrade Turbine performance. The results of recent studies have shown that variations in the circumferential location (clocking) of the hot streak relative to the first-Stage vane airfoils can be used to minimize the adverse effects of the hot streak. The effects of the hot streak/airfoil count ratio on the heating patterns of Turbine airfoils have also been evaluated. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a Single-Stage high-pressure Turbine operating in high subsonic flow. In addition to a simulation of the baseline Turbine, simulations have been performed for circular and elliptical hot streaks of varying sizes in an effort to represent different combustor designs. The predicted results for the baseline simulation show good agreement with the available experimental data. The results of the hot streak simulations indicate: that a) elliptical hot streaks mix more rapidly than circular hot streaks, b) for small hot streak surface area the average rotor temperature is not a strong function of hot streak temperature ratio or shape, and c) hot streaks with larger surface area interact with the secondary flows at the rotor hub endwall, generating an additional high temperature region.© 2000 ASME

  • Effects of Tip Clearance on Hot Streak Migration in a High-Subsonic Single-Stage Turbine
    Journal of Turbomachinery, 2000
    Co-Authors: Daniel J. Dorney, Douglas L. Sondak
    Abstract:

    Experimental data have shown that combustor temperature nonuniformities can lead to the excessive heating of first-Stage rotor blades in Turbines. This heating of the rotor blades can lead to thermal fatigue and degrade Turbine performance. The results of recent studies have shown that variations in the circumferential location, or clocking, of the first-Stage vane airfoils can be used to minimize the adverse effects of the hot streaks due to the hot fluid mixing with the cooler fluid contained in the vane wake. In addition, the effects of the hot streak/airfoil count ratio on the heating patterns of Turbine airfoils have been quantified. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a Single-Stage high-pressure Turbine geometry operating in high subsonic flow to study the effects of tip clearance on hot streak migration. Baseline simulations were initially performed without hot streaks to compare with the experimental data. Two simulations were then performed with a superimposed combustor hot streak; in the first the tip clearance was set at the experimental value, while in the second the rotor was allowed to scrape along the outer case (i.e., the limit as the tip clearance goes to zero). The predicted results for the baseline simulations show good agreement with the available experimental data. The simulations with the hot streak indicate that the tip clearance increases the radial spreading of the hot fluid, and increases the integrated rotor surface temperature compared to the case without tip clearance.

  • Unsteady numerical simulations of radial temperature profile redistribution in a Single-Stage Turbine
    Journal of Turbomachinery, 1996
    Co-Authors: Daniel J. Dorney, John R. Schwab
    Abstract:

    Experimental data taken from gas Turbine combustors indicate that the flow exiting the combustor can contain both circumferential and radial temperature gradients. A significant amount of research recently has been devoted to studying Turbine flows with inlet temperature gradients, but no total pressure gradients. Less attention has been given to flows containing both temperature and total pressure gradients at the inlet. The significance of the total pressure gradients is that the secondary flows and the temperature redistribution process in the vane blade row can be significantly altered. Experimental data previously obtained in a Single-Stage Turbine with inlet total temperature and total pressure gradients indicated a redistribution of the warmer fluid to the pressure surface of the airfoils, and a severe underturning of the flow at the exit of the Stage. In a concurrent numerical simulation, a steady, inviscid, three-dimensional flow analysis was able to capture the redistribution process, but not the exit flow angle distribution. In the current research program, a series of unsteady two- and three-dimensional Navier-Stokes simulations have been performed to study the redistribution of the radial temperature profile in the Turbine Stage. The three-dimensional analysis predicts both the temperature redistribution and the flow underturning observed in the more » experiments. « less

  • Unsteady Numerical Simulations of Radial Temperature Profile Redistribution in a Single-Stage Turbine
    Volume 1: Turbomachinery, 1995
    Co-Authors: Daniel J. Dorney, John R. Schwab
    Abstract:

    Experimental data taken from gas Turbine combustors indicate that the flow exiting the combustor can contain both circumferential and radial temperature gradients. A significant amount of research recently has been devoted to studying Turbine flows with inlet temperature gradients, but no total pressure gradients. Less attention has been given to flows containing both temperature and total pressure gradients at the inlet. The significance of the total pressure gradients is that the secondary flows and the temperature redistribution process in the vane blade row can be significantly altered. Experimental data previously obtained in a Single-Stage Turbine with inlet total temperature and total pressure gradients indicated a redistribution of the warmer fluid to the pressure surface of the airfoils, and a severe underturning of the flow at the exit of the Stage. In a concurrent numerical simulation, a steady, inviscid, three-dimensional flow analysis was able to capture the redistribution process, but not the exit flow angle distribution. In the current research program, a series of unsteady two- and three-dimensional Navier-Stokes simulations have been performed to study the redistribution of the radial temperature profile in the Turbine Stage. The three-dimensional analysis predicts both the temperature redistribution and the flow underturning observed in the experiments.

Douglas L. Sondak - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Tip Clearance on Hot Streak Migration in a High-Subsonic Single-Stage Turbine
    Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery, 2000
    Co-Authors: Daniel J. Dorney, Douglas L. Sondak
    Abstract:

    Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-Stage rotor blades in Turbines. This heating of the rotor blades can lead to thermal fatigue and degrade Turbine performance. The results of recent studies have shown that variations in the circumferential location, or clocking, of the first-Stage vane airfoils can be used to minimize the adverse effects of the hot streaks due to the hot fluid mixing with the cooler fluid contained in the vane wake. In addition, the effects of the hot streak/airfoil count ratio on the heating patterns of Turbine airfoils have been quantified. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a Single-Stage high-pressure Turbine geometry operating in high subsonic flow to study the effects of tip clearance on hot streak migration. Baseline simulations were initially performed without hot streaks to compare with the experimental data. Two simulations were then performed with a superimposed combustor hot streak; in the first the tip clearance was set at the experimental value, while in the second the rotor was allowed to scrape along the outer case (i.e., the limit as the tip clearance goes to zero). The predicted results for the baseline simulations show good agreement with the available experimental data. The simulations with the hot streak indicate that the tip clearance increases the radial spreading of the hot fluid, and increases the integrated rotor surface temperature compared to the case without tip clearance.Copyright © 2000 by ASME

  • Effects of Tip Clearance on Hot Streak Migration in a High-Subsonic Single-Stage Turbine
    Journal of Turbomachinery, 2000
    Co-Authors: Daniel J. Dorney, Douglas L. Sondak
    Abstract:

    Experimental data have shown that combustor temperature nonuniformities can lead to the excessive heating of first-Stage rotor blades in Turbines. This heating of the rotor blades can lead to thermal fatigue and degrade Turbine performance. The results of recent studies have shown that variations in the circumferential location, or clocking, of the first-Stage vane airfoils can be used to minimize the adverse effects of the hot streaks due to the hot fluid mixing with the cooler fluid contained in the vane wake. In addition, the effects of the hot streak/airfoil count ratio on the heating patterns of Turbine airfoils have been quantified. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a Single-Stage high-pressure Turbine geometry operating in high subsonic flow to study the effects of tip clearance on hot streak migration. Baseline simulations were initially performed without hot streaks to compare with the experimental data. Two simulations were then performed with a superimposed combustor hot streak; in the first the tip clearance was set at the experimental value, while in the second the rotor was allowed to scrape along the outer case (i.e., the limit as the tip clearance goes to zero). The predicted results for the baseline simulations show good agreement with the available experimental data. The simulations with the hot streak indicate that the tip clearance increases the radial spreading of the hot fluid, and increases the integrated rotor surface temperature compared to the case without tip clearance.

  • AIAA 99-2384 Effects of Hot Streak/Airfoil Ratio in a High-Subsonic Single-Stage Turbine
    1999
    Co-Authors: Douglas L. Sondak
    Abstract:

    Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-Stage rotor blades in Turbines. This heating of the rotor blades can lead to thermal fatigue and degrade Turbine performance. The results of recent studies have shown that variations in the circumferential location, or clocking, of the first-Stage vane airfoils can be used to minimize the adverse effects of the hot streaks due to the hot fluid mixing with the cooler fluid contained in the vane wake. Less effort has been put into determining the effects of the hot streak/airfoil count ratio on the heating patterns of Turbine airfoils. In the present investigation, threedimensional unsteady Navier-Stokes simulations have been performed for a Single-Stage high-pressure Turbine geometry operating in high subsonic flow. Simulations were initially performed without hot streaks to compare with the experimental data. The ratio of the number of hot streaks to the number of vanes and rotors was then varied. The predicted results demonstrate a complex interaction between the hot streak *Associate Professor, Senior Member AIAA t Senior Analyst, Senior Member AIAA 1 Assistant Professor, Member AIAA Copyright 01999 by Daniel Dorney, Douglas Sondak and Paul Cizmas. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission. and the secondary flows in the rotor.

Michael B. Giles - One of the best experts on this subject based on the ideXlab platform.

John R. Schwab - One of the best experts on this subject based on the ideXlab platform.

  • Unsteady numerical simulations of radial temperature profile redistribution in a Single-Stage Turbine
    Journal of Turbomachinery, 1996
    Co-Authors: Daniel J. Dorney, John R. Schwab
    Abstract:

    Experimental data taken from gas Turbine combustors indicate that the flow exiting the combustor can contain both circumferential and radial temperature gradients. A significant amount of research recently has been devoted to studying Turbine flows with inlet temperature gradients, but no total pressure gradients. Less attention has been given to flows containing both temperature and total pressure gradients at the inlet. The significance of the total pressure gradients is that the secondary flows and the temperature redistribution process in the vane blade row can be significantly altered. Experimental data previously obtained in a Single-Stage Turbine with inlet total temperature and total pressure gradients indicated a redistribution of the warmer fluid to the pressure surface of the airfoils, and a severe underturning of the flow at the exit of the Stage. In a concurrent numerical simulation, a steady, inviscid, three-dimensional flow analysis was able to capture the redistribution process, but not the exit flow angle distribution. In the current research program, a series of unsteady two- and three-dimensional Navier-Stokes simulations have been performed to study the redistribution of the radial temperature profile in the Turbine Stage. The three-dimensional analysis predicts both the temperature redistribution and the flow underturning observed in the more » experiments. « less

  • Unsteady Numerical Simulations of Radial Temperature Profile Redistribution in a Single-Stage Turbine
    Volume 1: Turbomachinery, 1995
    Co-Authors: Daniel J. Dorney, John R. Schwab
    Abstract:

    Experimental data taken from gas Turbine combustors indicate that the flow exiting the combustor can contain both circumferential and radial temperature gradients. A significant amount of research recently has been devoted to studying Turbine flows with inlet temperature gradients, but no total pressure gradients. Less attention has been given to flows containing both temperature and total pressure gradients at the inlet. The significance of the total pressure gradients is that the secondary flows and the temperature redistribution process in the vane blade row can be significantly altered. Experimental data previously obtained in a Single-Stage Turbine with inlet total temperature and total pressure gradients indicated a redistribution of the warmer fluid to the pressure surface of the airfoils, and a severe underturning of the flow at the exit of the Stage. In a concurrent numerical simulation, a steady, inviscid, three-dimensional flow analysis was able to capture the redistribution process, but not the exit flow angle distribution. In the current research program, a series of unsteady two- and three-dimensional Navier-Stokes simulations have been performed to study the redistribution of the radial temperature profile in the Turbine Stage. The three-dimensional analysis predicts both the temperature redistribution and the flow underturning observed in the experiments.

Timo Siikonen - One of the best experts on this subject based on the ideXlab platform.

  • Numerical Simulation of Real-Gas Flow in a Supersonic Turbine Nozzle Ring
    Journal of Engineering for Gas Turbines and Power, 2002
    Co-Authors: J. Hoffren, T. Talonpoika, Jaakko Larjola, Timo Siikonen
    Abstract:

    In small Rankine cycle power plants, it is advantageous to use organic media as the working fluid. A low-cost Single-Stage Turbine design together with the high molecular weight of the fluid leads to high Mach numbers in the Turbine. Turbine efficiency can be improved significantly by using an iterative design procedure based on an accurate CFD simulation of the flow. For this purpose, an existing Navier-Stokes solver is tailored for real gas, because the expansion of an organic fluid cannot be described with ideal gas equations. The proposed simulation method is applied for the calculation of supersonic flow in a Turbine stator. The main contribution of the paper is to demonstrate how a typical ideal-gas CFD code can be adapted for real gases in a very general, fast, and robust manner.