Roberto Claretti

UTSR Fellow - Heat Transfer Intern

Florida Turbine Technologies, Inc.

RClaretti@fttinc.com

www.fttinc.com

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Lunch and Learn Presentation

FTT-UCF Impingement Testing

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Who am I?

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• My name is Roberto Claretti, Graduated from UCF with a BSME in 2011

• I am a Department of Energy University Turbine Systems Research Fellow

• I am a Masters in Mechanical Engineering Student in the Thermofluids Track

• I have worked for the past three years at the Center for Advanced

Turbomachinery and Energy Research located at the Siemens Energy Center in

Orlando

• I have worked on numerous types of heat transfer and flow tests; they

include:

• Film Cooling

• Near Wall Cooling

• Impingement Cooling (Honors in Major Thesis)

• Coupled Impingement/Effusion Cooling

• I have also worked with CFD using Gambit and Fluent

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Overview of Summer Accomplishments

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• Designed and Procured a Seal

Test Rig

• Acquired and post processed

flow data

• Designed, Procured, Built, Tested and Performed

Data Reduction on A Special Impingement Heat

Transfer Test Article.

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Other things I learned…

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• The Boeing 777, powered by two GE90’s, burns 3.9

gallons of fuel every second!

• The energy transfer

rate of a gas pump

pumping 10 gallons a

minute is equivalent to

21 MW!

• The same pump has

the ability to earn

$2200 an hour! Two

orders of magnitude

more than me !

• This 8000 gallon gas tanker truck filled with gasoline

can power the average American home for 15 years!

(with an energy conversion efficiency of 60%, CCGT)

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Impingement Heat Transfer Test

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• We were able to design, machine, assemble and test a heat transfer experiment to better

understand the convective characteristics of four test setups:

• Smooth Channel Validation

• Impingement Validation

• Case B

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Design of Parts

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• All parts were made out of acrylic, 2D

drawings were cut by a, in-house, 3

axis CNC

• Diffuser was made with polystyrene

cut using an electrically heated wire

• Typical measured accuracy ±0.010 in

for non critical dimensions, ±0.006 in

for critical dimensions (diameter)

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Heat Transfer Background

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Newton’s Law of Cooling

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Temperature Sensitive Paint

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Reference Image Test Image

Image of TSP taken without low pass filter using regular camera

TSP is in the center, everything seems to glow in a blue color

Image of TSP taken with the lowpass filter using regular camera

TSP is seen to “glow” compared to the rest of the test section.

This happens due to the TSP emitting light of a lower wavelength

that gets picked up by the scientific grade CCD camera. Pictures

taken with the CCD are shown on the right

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Heat Transfer Test Setup

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Heaters and side walls are attached to the surface Jet Plate is bolted to the test section

Thermocouples are attached to the inlet of the jet plate Thermocouples that measure coolant temperature are shown

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Heat Transfer Test Setup

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Lead Wires

Thermocouple

TSP

Pressure tap lines

Channel exit diffuser

Heater Strips

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Impingement Test Setup

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Venturi Flow meter

Blower under suction

Flow metering valve

Test Section

Piping running through the ceiling

Handheld Manometer

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Smooth Channel Validation

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z

x

• A smooth channel case was tested by blocking the holes of one of the jet plates

• The hydraulic diameter was decreased by attaching a spacer to the wall opposite of the

heaters

• An entrance region of L=23Dh was attached to the channel in order to have a semi-

developed momentum BL before the start of the thermal BL

• Channel dimensions: Dh=.Lheated/Dh=20

• Three Reynolds numbers were run: 60k, 41k and 23k

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Smooth Channel Validation

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0 2 4 6 8 10 12 14 16 18 20

Nu

/Nu

DB

x/Dh

Laterally Averaged Nu/NuDB

Re = 60,000 Re = 41,000 Re = 23,000

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Impingement Validation Case

z/D

y/D x/D

z

y

x

Case z/D x/D xc/D Nx y/D yc/D Ny

Validation 3 3 63 20 8 32 4

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Heated Area

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Impingement Validation Nu Profiles

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Rej=16,000

Rej=13,000

Rej=10,000

Nu

y

x

y

y

x

Nu

z

x

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Case A

y/D ys/D

x/D

Case z/D x/D Nx y/D Ny yc/D ys/D h/D xc/D L/D RejavgB 3 3.0 20 3 4 32 13 0 63 1 17000

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z/D

z

y

x Heated Area

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Case A Local Nu Profiles

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Rej=16,000

Rej=13,000

Rej=10,000 y

x

y

y

Nu

z

x

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Case A Laterally Averaged Nu

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• Case A Nu values increase as x increases contradicting Florschuetz predictions

• Amplitude of fluctuations in Nu remain constant throughout implying little effect of crossflow

Nu

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Impingement Scheme Comparison

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• Case A and impingement validation have similar m.

• The Florschuetz prediction with these geometric parameters is m=0.68 which matches

closely with both Case A and Impingement Validation.

Taking log of both sides

log

Nu

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Thank You!

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• Now FTT has the necessary data to design components that

utilize any of these cooling setups with confidence

• I would like to thank Jim Downs, Gloria Goebel, Bryan Bernier,

Michelle Valentino, An Lee, Ken Landis and everyone else at

FTT for their kind hospitality and for teaching me more about

gas turbine heat transfer!

• I would also like to thank the DoE and UTSR Gas Turbine

Industrial Fellowship Program for giving me this great

opportunity!