university turbines systems research fellowship 2012

Presenter: Timothy Repko

Heat Transfer Group Mentor: Yong Kim

Heat Transfer Group Manager: Hee-Koo Moon Aero, Thermal and Performance Manager: John Mason

University Turbines Systems

Research Fellowship 2012

Caterpillar Confidential: Green

Agenda

About Me

Projects

Passage Design

Coriolis Rig

Computations and Analysis - CFD

Transient Liquid Crystal Test

Engine Assembly (Dept 133)

Summary

Questions?


About Me

Education •  M.S. Aerospace Engineering, West Virginia

University, Morgantown WV, May 2013 (In Progress)

-  Advisor: Dr. Andrew Nix

-  Thesis Topic: Effects of Combustor Turbulence on Film Cooling Effectiveness for a Novel Film Cooling Geometry

•  B.S. Aerospace Engineering, West Virginia University, Morgantown WV, December 2011

•  B.S. Mechanical Engineering, West Virginia University, Morgantown WV, December 2011

Membership •  ASME

•  NSCS


Projects

• Design Of New Test Section (Of Internal Cooling Passage Design) For Coriolis Rig

- Interested In The Flow Split’s Sensitivity To Rotation

- Designed For First Stage Turbine Blades

• CFD For New Test Section (4.5x Model)

•  5x Liquid Crystal Test Section

- Material For EI (TC And Pressure Tap Locations)


Coriolis Rig Background

•  First Commissioned in Q4/2008 for Rotating Passage Heat Transfer Investigation

•  Designed to Simulate Rotational Effects on Internal Cooling Passages

•  Large, Enclosed, Rotating Airfoil That Contains the Test Section

•  Powered by 100 Hp Motor

•  Will Be Used to Test the Rotational Effects on the New Internal Cooling Passage

Leading Surface

Trailing Surface

!"

V

2 ! x V


Background on Passage Design

•  This Type of Cooling Passage Design Has Been Applied in Aircraft Applications but Is a New Technology to Solar

•  Provides Very High Cooling Effectiveness and Can Substantially Lower Cooling Flow

- Lower Cooling Flow From by Almost 2%

- Can Provide a Substantial Increase in Power Output


Background on Passage Design

•  New Cooling Passage Has 4 Walls of Cooling to Aid in the Convective Cooling of the Turbine Blade

•  Has a 3D Metal Core that Acts a Cold Sink •  New Cooling Passage Increases Turbulence and Surface Area

for Heat Transfer to Enhance Cooling -  At the Expense of High Pressure Drop Through Pin Fins -  Utilizes Pumping From Rotation to Reduce Pressure Drop

•  Flow Splits from Single Inlet Section into Two Outlet Sections (One Over Pressure Side, Other Over Suction Side)

•  Analysis Was Focused On One Leg Of Passage That Was Found To Have The Most Effect From Rotation (Found In Previous Study)


Why??

•  Analyze Flow Split

•  Mitigate the Potential Risk of Not Considering Rotational Effect on Cooling Performance

•  Validation of CFD Model at Engine Conditions

Static Case Rotating Case


Star CCM+ 7.02.008

•  Star CCM+ Used As a Complete Package For: - Mesh Generation - Solution of RANS (Reynolds Average Navier-

stokes) Equations • Shown Below

- Post-processing

;0=!

!

i

i

xU

0=!

!

i

i

xu

)(1ji

j

i

jj

ij

i uuxU

pxx

UU

tU

!µ!

+"

"#

"

"#=

"

"+

"

"


Coriolis Rig Pressure Test

•  Pressure Data Taken at 50 Rpm Intervals Ramping up the Speed Every Two Minutes

• Confirms Centrifugal Pumping Is Present in Pressure Lines

• Correction Needed for Accurate Reading of Pressure in Test Section

!"

V

2 ! x V


Geometry/Design of Test Section

•  Collaboration With Yong Kim and Ken Ridler to Create Test Section of 4.5x Model -  Model Was Largest Possible to Still Be Able to Fit

Into Coriolis Rig -  Design of Plenum to Allow for Accurate Flow

Representation -  Location of Static Pressure Taps and

Thermocouples for Measurement in Rig


Test Section

•  Test Section Was Designed and Prepared for FEA

•  FEA to Be Completed In Fall Before Production of the Test Section


Mesh Generation (w/ Grid Independence)

•  1st Polyhedral Mesh Created With 2.36 X 106 Cells

•  2nd Polyhedral Mesh Created With 10.3 X 106 Cells -  More Prism Layers Used for Even Higher

Resolution Near Surfaces in Boundary Layer -  Base Size Only Decreased Slightly, ~20%


Flow Scaling

• Reynolds Number and Rotational Number Were the Most Important Parameters to Match to Engine Conditions

• Buoyancy Effects Were Assumed to Be Negligible Due to Highly Turbulent Passage

- Only Fluid Mechanics Considered, Assumed No Heat Transfer Effects

Ro = V!D

Re = VD!


Boundary Conditions (BC’s)

•  Mass Flow Specified at Inlet -  Based on Re and Ro

•  Outlet Pressure Set to Atmospheric Conditions •  Turbulence Was Specified by Length Scale (5 mm) a Intensity 1% -  Representative of Real Engine Conditions in Cooling Flow

•  A New Reference Frame Was Created for the Rotating Models -  Rotating at 750 RPM in the Negative x-direction

•  BC’s Based of Scaling of Real Engine Conditions


Models

•  Steady, 3D, Turbulent Flow

-  RANS

-  Realizable k- # $urbulence Model

-  Segregated Flow Solver

-  Density Found From Ideal Gas Law

-  Dynamic Viscosity and Thermal Conductivity From Sutherland’s Law

-  Molecular Weight, Specific Heat, and Turbulent Prandtl Number Held Constant

•  Convergence Criteria Met After 10000 Iterations


Models Cont.

• Under-relaxation Ramps Used to Aid in Convergence

• Convergence Criteria Met After 10000 Iterations

- No Change in Mass Flow Through Inlet, Outlet, or Either Side of Split for at Least 500 Iterations

- All Residuals Stop Changing in Magnitude for at Least 500 Iterations


Conclusions from Analysis

•  Secondary Flow Vortices Change the Profile of the Flow Through the Inlet Section

•  This Effect Propagates As It Goes Downstream




•  Recirculation Is Much More Pronounced in Rotational Case -  Is Likely to Be One of the

Causes for Flow to Favor the Pressure Side

•  Flow Is Biased Towards the PS and Flow As Can Be Seen From the Streamlines Going From PS to SS

PS SS




•  PS, Shown in Blue, Shows an Increase in in Mass Flow Due to Rotation While the SS, Shown in Yellow, Shows a Decrease in Mass Flows



•  Rotational Effects Tend to Split the Flow to Favor the Pressure Side Channel

•  Rotational Case Matched Flow Split Trend to the Full CFD Model at Engine Conditions -  Increased Flow Through PS Channel -  Decreased Flow Through SS Channel

•  Percentage of Flow Through Each Channel Did Not Match Full Engine Model Although Trends Were Matched

•  Difference in Engine Speed May Account for Difference in Solution

•  Due to Turbulent and Unsteady Nature of the Flow, More Analysis Is Warranted



About Me

Projects

Passage Design

Coriolis Rig




Summary

Questions?



•  Liquid crystal test to map out the heat transfer distribution on 5.0x Model

• Objective is to validate the internal HT coefficients from the design

• Collaborated with Yong Kim to determine the locations of the TCs for the 5x liquid crystal test


Engine Assembly

About Me

Projects

Passage Design

Coriolis Rig




Summary

Questions?


Engine Build Experience

•  July 23-27 •  Titan 130 Teardown - Entire Disassembly

All the Way to the Parts Being Shipped Out to Desoto

•  Excellent Learning Experience for Anyone Working in the Gas Turbine Industry


Solar Experience Summary

• Design of Test Section

•  Introduction to Coriolis Rig and Test Cells

• CFD

- Model ! mesh ! pre-proc. ! solve ! post-proc.

•  Engine Assembly

•  Transient Liquid Crystal Test


Learning Experience

•  Programs - Star CCM+ 7.02.008 - UNIX

• Applied Previous Knowledge of CFD (ANSYS - FLUENT) To Learning New Solver (STAR-CCM+) - Usage of UNIX Servers for Parallel Computing

•  Introduction to the Coriolis Rig •  Engine Build Experience •  Experience With GT Test Cells and Experimental

Setups


Acknowledgements

Solar Turbines • Tim Bridgman • John Mason • Hee-koo Moon • Yong Kim • Ken Ridler • Archie French • Ara Sarhadian • Gail Doore • Archie French • Steve Pointon • Charmaine Gary • Rob Murphy

SwRI – UTSR Fellowship Program •  This Is A Fantastic Program And I

Would Like To Thank Everyone That Works Hard To Make It Possible

WVU – Dr. Andrew Nix

Others Who Helped • Heat Transfer Group • Department 133

university turbines systems research fellowship 2012

Documents