UTSR Presentation Heat Transfer Developmentincreased jump cooling flow, or to improve the cycle...
Transcript of UTSR Presentation Heat Transfer Developmentincreased jump cooling flow, or to improve the cycle...
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UTSR Presentation
Heat Transfer Development
Robert LaFasoMentor: Yong Kim
Group Manager: Hee Koo MoonDepartment Manager: Dan Burnes
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Overview
Personal Background Projects at Solar Turbines
Hot Gas Ingress Model w/ Finesse T250E 2-D Steady State Thermal Model w/ ANSYS T250E Jump Cooling w/ ANSYS
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Hometown: Cheyenne, Wyoming School: University of Wyoming
Major: BS Energy Systems Engineering Minor: Mathematics Est. Grad. Date: Spring 2017
Extra Curricular Activities Student Government Tau Beta Pi Sigma Nu Fraternity
Personal Background
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Overview
Personal Background Projects at Solar
Hot Gas Ingress Model w/ Finesse T250E 2-D Steady State Thermal Model w/ ANSYS T250E Jump Cooling Change Study w/A ANSYS
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Hot Gas Ingress Model w/ Finesse
Goals Use Finesse to simulate ingress and generate reliable hot gas
ingress predictions Generate Taw and HTC to be applied to 2D thermal model Build a model that will allow for the minimization of disk purge
cooling flows About Finesse Finesse is software that solve 1-D Fluid Flow Networks with
portions designed specifically for turbomachinery secondary flow
It is an iterative solver that takes user input connectors and BC and solves to minimize mass imbalance and calculate mass flow rate
Uses Solar Turbine’s proprietary DCAT (Disk Cavity Analysis Tool) connector to simulate flow through rotating disk cavities.
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Hot Gas Ingress Model w/ Finesse
Ingress Overview Hot air from main flow path enters disk cavity between rotor
and stator. Bleed air is used to purge the disk cavity of the ingress gas Ingress is driven by pressure variation in the main air flow
path
Figure 1: Circumferential Pressure distribution that drives ingress [1] Figure 2: Schematic of Hot Gas Ingress [2]
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Hot Gas Ingress Model w/ Finesse
Ingress Modeling The ingress and egress paths are modeled as short orifices
connecting disk cavities creating flow loops. Flow loops are built of orifice connectors and DCAT
connectors. Previous research indicates that ingress tends to hug the
stator walls. This was the basis for the cell rotation direction.
Figure 3: Finesse Model and its Analogous Physical System
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Important Parameters Ingress is quantified by effectiveness Ingress area ratio describes the relationship
between the ingress and egress flows throughthe smallest gap between the flow discouragers
Discharge coefficients of the ingress and egress orifices are a function of these two parameters.
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1 1
Figure 4: Ingress and Egress area schematic
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Arizona State Disk Cavity Rig and Data Report by ASU published in 2015 reported
ingress levels and mass flow rate at 4 flow rates Manipulated until the effectiveness calculated
in Finesse matched data from published report Demonstrated an exponential relationship
between calculated and the given purge massflow rate
Hot Gas Ingress Model w/ Finesse
Figure 6: ASU Experimental Setup [1]
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rA = 0.5000e-1.5927x
R² = 0.9865
0.0
0.1
0.2
0.3
0.4
0.5
0.0000 0.5000 1.0000
Ingr
ess
Are
a R
atio
Non-Dimensional Purge Flow Rate Figure 5: rA and Purge flow Relationship
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Sensitivity Testing Looked into the effect different modeling methods had on the
results. Adjusted parameters included: Number of cells Rotational mass flow Orifice area for orifices that connect the cells Rotation speed Discharge coefficient for orifices that connect the cells
Hot Gas Ingress Model w/ Finesse
Figure 8:Ingress Level Sensitivity to Number of cells
Figure 9: 3 Cell Ingress model or Titan 130
Figure 7: 4 Cell Ingress Model ofTitan 130
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Hot Gas Ingress Model w/ Finesse
Sensitivity Testing Helped to define consistent settings that are robust and
accurate and addressed issues with: Rotation direction not conforming to experimental results where the
ingress flow path tends to hug the stator. Iterative solutions not converging quickly, monotonically, or at all Merging the ingress model with existing secondary flow Finesse
models resulting in crashes
Figure 10: Finesse Error Display Showing an Unstable Converging System. The error should
ideally decrease monotonically Figure 11: Ingress model flow network with the top
cell rotating in the incorrect direction.
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Hot Gas Ingress Model w/ Finesse
Modeling Comparison Compared the output data of the ingress model to the data for
current modeling techniques New method to compares favorably to experimental CO2 data
Percent error is ~15% New method caused discontinuities because of mixing at nodes By design, the new method produces a hotter stator-side wall and
a cooler rotor-side wall.
Figure 12:Table of Experimental CO2 Ingress Data and Ingress Data from the Finesse Ingress Model
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LocationLow Purge Flow High Purge Flow
Experimental Finesse Experimental FinesseDisk Cavity Midpoint 16.3% 16.6% 7.3% 7%
Disk Cavity Bottom 14% 11% 5.6% 3.2%
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Hot Gas Ingress Model w/ Finesse
Modeling Comparison Cont. (Data for T250E Stg 1)
Figure 13: Plots comparing the data produced by the current modeling method (Blue) of modeling disk cavities with the data produced by the new ingress modeling method (Red)
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Overview
Personal Background Projects at Solar
Hot Gas Ingress Model w/ Finesse T250E 2-D Steady State Thermal Model w/ ANSYS T250E Jump Cooling Change Study w/ ANSYS
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T250E 2-D Thermal Model w/ ANSYS
Goals Utilize an existing ANSYS 2-D Transient model built by Agilis
Engineering and apply the boundary HTC and adiabatic wall temperature boundary conditions generated by the Finesse network
Solve the ANSYS 2-D Transient Model for the full load steady state metal temperature in the disk cavities.
Updating the ANSYS Model The ANSYS model was not built to have the HTC and Taw defined
for each surface element Previous temperature boundary conditions were from fluid elements Previous model applied same temperature to rotor and stator walls Modified the model to accept a manually input Taw as the bulk
temperature for convective heat transfer calculations. Unique Taw and HTC for each finite element
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Results Application of the new ingress model derived boundary
conditions resulted in changes that match expected results. Strongest decrease of temperature occurred at the leading
edge platform tip of both the stage 1 rotor and stage 2 stator Temperature increases were stronger for elements at lower
radial positions.
T250E 2-D Thermal Model w/ ANSYS
Component Approximate Change Due to Modeling Methods
Stage 1 Cavity Stator Side +50◦ to +250◦ F Stage 1 Cavity Rotor Side -50◦ to +100◦ F Stage 2 Cavity Rotor Side +50◦ to +200◦ F Stage 2 Cavity Stator Side 0◦ to + 50◦ F
Figure 14: Changes in metal temperatures from implementing the new ingress model
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Overview
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Hot Gas Ingress Model w/ Finesse T250E 2-D Steady State Thermal Model w/ ANSYS T250E Jump Cooling Change Study w/ ANSYS
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T250E Jump Cooling w/ ANSYSGoals Utilize the new ingress model to more accurately estimate the
temperature of the Stage 1 Nozzle of the T250E Model impact of jump cooling flow increases Jump Cooling Overview Compressor air injected directly upstream of the 1st stage
nozzle. Used to cool the first stage nozzle which experiences the
highest temperature flows Has a lower impact on cycle performance than other cooling
methods since jump cooling air is still is processed by the full turbine section.
Effectiveness is given by
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Two Cases Analyzed Med/High cases utilizes less bleed air for cooling the stage 1
nozzle cavity. This gives more air available for other cooling uses, such as
increased jump cooling flow, or to improve the cycle performance.
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Case Change from Previous T250 Phase 4 Engine Version
Low Risk Coolant FlowModerately Decreased 1st Nozzle inner
cavity pressure cuts inner rail leakage flow to stage 1 disk cavity.
Med/High Risk Coolant Flow
Additional decrease in cavity pressure yields a higher leakage flow reduction but
allows more ingress.
Figure 15: Table of Proposed Secondary Cooling Changes
T250E Jump Cooling w/ ANSYS
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Changed Model to have Increased Jump Cooling Provided with experimental data for jump cooling effectiveness Calculated new effectiveness at new jump cooling flow rates for
the new proposed changes by interpolating experimental data New effectiveness was used to back out a new BC
Case Outer JC Change
Inner JC Change
Low Risk +.3% of InletFlow Rate
+.2% of Inlet Flow Rate
Med/HighRisk
+.3% of Inlet Flow Rate
+.4% of Inlet Flow Rate
Figure 17: Proposed Changes to Jump Cooling
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Figure 16: Jump Cooling Effectiveness as a function of cooling flow rate
T250E Jump Cooling w/ ANSYS
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Results Changes to jump cooling resulted in hot spot temperatures
more comfortably below the recommended temperature maximum of 1750°F
Extra jump cooling flow allows the Med/High risk case to have a lower hot spot temperature even with a hotter baseline temperature that resulted from less cooling air leaking into the disk cavity
Case Hot Spot Temperature
Low RiskBaseline 1711°F
w/ Increased JC 1691°FChange -20°F
Med/High Risk
Baseline 1719°Fw/ Increased JC 1684 °F
Change -35°FFigure 18: Results of Jump Cooling Change Study 21
T250E Jump Cooling w/ ANSYS
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Overview
Personal Background Projects at Solar
Hot Gas Ingress Model w/ Finesse T250E 2-D Steady State Thermal Model w/ ANSYS T250E Jump Cooling Change Study w/ ANSYS
San Diego Fun!
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Barbara StanleyBernhard Winkelmann
John MasonMark NovaresiJamie Rhome
Jorge Gonzalez AyalaCharmaine GaryStefania Dzwill
Charmaine GaryReina Maldonado
Noemi Victoria
Thank you!
Dan BurnesHee Koo Moon
Yong KimKevin Liu
Hasan NasirNeil JordanJeff Carullo
Juan YinDan LancasterAnthony FlettJessi Geshay
2016 Summer Interns
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Robert LaFaso(307) 287-3833
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Sources:
[1] R. P. Roy, J. Balasubramanian & M. Michael, Solar Turbines –Disk Cavity Research, Progress report #5 (Experiment Set I –Config. 1B), September, 2015
[2] Scobie JA, Sangan CM, Michael Owen JJ, Lock GD. Review of Ingress in Gas Turbines. ASME. J. Eng. Gas Turbines Power. 2016;138(12):120801-120801-16. doi:10.1115/1.4033938.
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