Operation Principles of a Closed Loop Continuous and ... · Objective: Component Analysis of HP Turbines in Engine Similar Conditions Turbine scaling parameters: ṁ cor, P 03/P 04,

Turbo & Jet Engine Laboratory

Faculty of Aerospace Engineering

Operation Principles of a Closed Loop Continuous and Heated Micro High Pressure Turbine Facility

Beni Cukurel

Technion - Israel Institute of Technology Aerospace Engineering Haifa, Israel



Objective and Goals

Turbine Test Facility to conduct component Stage Performance Analysis

Test-aided Design

Research & Development

Only Turbine Test bench in Israel

Aerodynamic Blade Performance

Aerodynamic Stage Performance

Efficiency & Operating Map at In-Flight Conditions

Novel cooling configurations

Thermal Cooling Performance

Air Systems Design and Testing

מיקרו טורבינת הנעת

מיקרו טורבינת תאהנ



Exemplary Turbine Power Scaling

𝜂𝜂𝑇𝑇𝑇𝑇 = 1 + 𝜁𝜁𝑅𝑅𝑊𝑊42+𝜁𝜁𝑉𝑉𝐶𝐶3𝑣𝑣2

2 ℎ𝑜𝑜3−ℎ𝑜𝑜4

−1where 𝜁𝜁𝑉𝑉, 𝜁𝜁𝑅𝑅 (Vane and Rotor Losses)

Types of Losses in Detail Entropy Generation in Boundary Layer Entropy Generation in Mixing Processes Entropy Generation in Shock waves Entropy Creation by Heat Transfer Two Dimensional Losses Tip Leakage Losses

𝜁𝜁𝑇𝑇𝑜𝑜𝑇𝑇𝑇𝑇𝑇𝑇 = 𝜁𝜁𝑃𝑃𝑃𝑃𝑜𝑜𝑃𝑃𝑃𝑃𝑇𝑇𝑃𝑃 + 𝜁𝜁𝑆𝑆𝑃𝑃𝑆𝑆𝑜𝑜𝑆𝑆𝑆𝑆𝑇𝑇𝑃𝑃𝑆𝑆 + 𝜁𝜁𝑇𝑇𝑃𝑃𝑇𝑇𝑃𝑃𝑇𝑇𝑃𝑃𝑆𝑆𝑇𝑇 𝐸𝐸𝑆𝑆𝑇𝑇𝑃𝑃 + 𝜁𝜁𝑇𝑇𝑃𝑃𝑇𝑇 𝐶𝐶𝑇𝑇𝑃𝑃𝑃𝑃𝑇𝑇𝑆𝑆𝑆𝑆𝑃𝑃

15% 45% 10% 30%

𝑷𝑷𝑷𝑷�̇�𝒎

= 𝒉𝒉𝒐𝒐𝒐𝒐 − 𝒉𝒉𝒐𝒐𝒐𝒐 = 𝒉𝒉𝒐𝒐𝒐𝒐 − 𝒉𝒉𝒐𝒐𝒐𝒐𝒔𝒔 𝜼𝜼𝑻𝑻𝑻𝑻 = 𝑪𝑪𝒑𝒑𝑻𝑻𝒐𝒐𝒐𝒐 𝟏𝟏 − 𝑷𝑷𝒐𝒐𝒐𝒐𝑷𝑷𝒐𝒐𝒐𝒐

𝜸𝜸−𝟏𝟏𝜸𝜸 𝜼𝜼𝑻𝑻𝑻𝑻

𝜼𝜼𝑻𝑻𝑻𝑻 = f(Geometry, µf, 𝝆𝝆𝒇𝒇 = 𝑷𝑷𝒐𝒐𝒐𝒐𝑹𝑹𝑻𝑻𝒐𝒐𝒐𝒐

, ṁf )



Heat Transfer Characteristic Numbers: Conjugate (Conduction-Convection Coupled)

Buckingham–𝚷𝚷 Similarity: Characteristic Numbers Based on Primary Variables coincide

Turbine Similarity Analysis

PW or : D, N, Po3, Po4, To3, ṁf, µf, 𝜸𝜸𝒇𝒇, Rf, 𝛈𝛈𝐓𝐓, 𝑪𝑪𝒑𝒑𝒇𝒇

ṁcor ṁ𝒇𝒇𝑹𝑹𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐

𝑫𝑫𝟐𝟐𝑷𝑷𝒐𝒐𝒐𝒐 𝜸𝜸𝒇𝒇 Ncor

𝑵𝑵𝑫𝑫𝜸𝜸𝒇𝒇𝑹𝑹𝒇𝒇 𝑻𝑻𝒐𝒐𝒐𝒐

Re 𝑷𝑷𝟎𝟎𝒐𝒐𝑫𝑫 𝜸𝜸𝒇𝒇𝝁𝝁𝒇𝒇 𝑹𝑹𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐

𝜸𝜸𝒇𝒇 Po3/Po4 𝛈𝛈𝐓𝐓 𝑪𝑪𝒑𝒑𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐𝜸𝜸𝒇𝒇𝑹𝑹𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐

q function of External Flow : ṁf, Po3, D, µf, 𝜸𝜸𝒇𝒇, Rf, To3, 𝑪𝑪𝒑𝒑𝒇𝒇, kf Blade Material: d, ks, Ts Internal Flow : ṁc, Poc, L, µc, 𝜸𝜸𝒄𝒄, Rc, Tc,, 𝑪𝑪𝒑𝒑𝒄𝒄, kc

Conjugate Heat Transfer:

Re𝑷𝑷𝟎𝟎𝒐𝒐𝑫𝑫 𝜸𝜸𝒇𝒇𝝁𝝁𝒇𝒇 𝑹𝑹𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐

Ec 𝑽𝑽𝟐𝟐

𝑪𝑪𝒑𝒑𝜟𝜟𝑻𝑻𝒇𝒇 =

ṁ𝒇𝒇𝒐𝒐𝑹𝑹𝒇𝒇𝟐𝟐𝑻𝑻𝒐𝒐𝒐𝒐

𝟐𝟐

𝑷𝑷𝒐𝒐𝒐𝒐𝟐𝟐 𝒒𝒒𝑫𝑫𝟔𝟔

Pr 𝝁𝝁𝒇𝒇𝑪𝑪𝒑𝒑𝒇𝒇𝒌𝒌𝒇𝒇

d/D

𝑩𝑩𝑩𝑩 𝒒𝒒𝒅𝒅

𝒌𝒌𝒔𝒔 𝑻𝑻𝒐𝒐𝒐𝒐−𝑻𝑻𝒔𝒔 𝑲𝑲 𝒌𝒌𝒔𝒔

𝒌𝒌𝒇𝒇 𝑻𝑻𝒇𝒇

𝜟𝜟𝑻𝑻𝒇𝒇= 𝑻𝑻𝟎𝟎𝒐𝒐

𝒒𝒒𝑫𝑫𝟐𝟐/ṁ𝒇𝒇𝑪𝑪𝒑𝒑𝒇𝒇 𝜸𝜸𝒇𝒇

Same Set For Internal Heat Transfer

𝑵𝑵𝑵𝑵 𝒒𝒒𝑫𝑫

𝒌𝒌𝒇𝒇 𝑻𝑻𝒐𝒐𝒐𝒐 − 𝑻𝑻𝒔𝒔

𝑷𝑷𝑷𝑷� = 𝑷𝑷𝑷𝑷/ 𝜸𝜸𝑫𝑫𝟐𝟐 𝑷𝑷𝒐𝒐𝒐𝒐 𝜸𝜸𝑹𝑹𝑻𝑻𝒐𝒐𝒐𝒐

External Flow Characteristic Numbers: Flow parameters



External Aerodynamic Flow Characteristic Numbers:

Turbine Similarity Analysis

𝑷𝑷𝑷𝑷� = 𝒇𝒇(ṁcor,Ncor, Re , γ , Po3/Po4 ,𝜼𝜼T , 𝑪𝑪𝒑𝒑𝒇𝒇 𝑻𝑻𝒐𝒐𝒐𝒐/𝜸𝜸𝒇𝒇𝑹𝑹𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐)

Heat Transfer Characteristic Numbers: Nu = f(Re, d/D, 𝜸𝜸, 𝑻𝑻𝒇𝒇/𝚫𝚫𝐓𝐓𝐟𝐟, Ec, Pr, Bi, K)

𝑻𝑻𝒇𝒇𝜟𝜟𝑻𝑻𝒇𝒇

= 𝑻𝑻𝒐𝒐𝒐𝒐𝑻𝑻𝟎𝟎𝒐𝒐−𝑻𝑻𝒔𝒔

𝑹𝑹𝑹𝑹 𝑷𝑷𝑷𝑷 ṁcor /𝑵𝑵𝑵𝑵 𝑬𝑬𝒄𝒄 = 𝑻𝑻𝒐𝒐𝒐𝒐

𝑻𝑻𝟎𝟎𝒐𝒐−𝑻𝑻𝒔𝒔(𝜸𝜸 − 𝟏𝟏)𝑹𝑹𝑹𝑹 𝑷𝑷𝑷𝑷 �̇�𝒎𝒄𝒄𝒐𝒐𝑷𝑷

𝒐𝒐 /𝑵𝑵𝑵𝑵 𝑩𝑩𝑩𝑩 = (𝒅𝒅/𝑫𝑫) (𝑵𝑵𝑵𝑵/𝑲𝑲)

𝑷𝑷𝑷𝑷𝟎𝟎.𝒐𝒐 𝜶𝜶 𝑵𝑵𝑵𝑵 ∴ Engine to Test ΔPr ~ 4% ΔNu~1.5% (Negligible Pr Influence) Nu = f( Re, ṁcor , d/D, 𝜸𝜸, K, To3/Ts ) For Same Gas, Dimensions, and Materials: Nu = f( Re, ṁcor, To3/Ts )

𝑷𝑷𝑷𝑷� = 𝒇𝒇 ṁcor ṁ𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐𝑷𝑷𝒐𝒐𝒐𝒐

Ncor𝑵𝑵 𝑻𝑻𝒐𝒐𝒐𝒐

𝑷𝑷𝒐𝒐𝒐𝒐/𝑷𝑷𝒐𝒐𝒐𝒐 Re 𝑷𝑷𝟎𝟎𝒐𝒐𝝁𝝁𝒇𝒇 𝑻𝑻𝒐𝒐𝒐𝒐

𝜼𝜼T =f(ṁcor, Ncor, Re ,𝜸𝜸,𝑷𝑷𝒐𝒐𝒐𝒐/𝑷𝑷𝒐𝒐𝒐𝒐 ,𝑪𝑪𝒑𝒑𝒇𝒇 𝑻𝑻𝒐𝒐𝒐𝒐/𝜸𝜸𝒇𝒇𝑹𝑹𝒇𝒇𝑻𝑻𝒐𝒐𝒐𝒐)

For Same Gas, Dimensions, and Materials:



Turbine Test Facility

Objective: Component Analysis of HP Turbines in Engine Similar Conditions

Turbine scaling parameters: ṁcor, P03/P04, Re, Ncor, Tf/Ts

Continuous operation HP turbine facilities include: Graz University – open loop 2.5MW HP turbine, ṁ = 16kg/sec, PR=6, N=11550 rpm, TIT = 450K

Gottingen DLR –closed loop 3.7MW HP turbine, ṁ = 9kg/sec, PR=12, N=13550 rpm, TIT = 700K

Don’t have independent control of all parameters Size Matters: You can NOT scale-down gas turbine

What is “unique” about this facility: Full Performance Characterization including In-Flight (Altitude) Conditions

• Continuously Running (ṁ up to 1kg/sec) • High speed (up to 120,000 rpm)

Allows Aerodynamic AND Thermal Studies Stage Performance in Realistic Conditions Rotor/Stator Interaction Turbine Cooling

• Closed-loop (P range 10– 0.2 bar) • Heated Flow Conditions (up to 600K)



Aerodynamic Operating Considerations Choked nozzle by Design:

• ṁcor =𝛾𝛾+12

− 𝛾𝛾+12 𝛾𝛾−1 = Constant

• P03/ To3 sets Re, ṁ , M3v-is • Before rotor chokes: Ps4 sets M4r • Need to FIX 𝑃𝑃03

𝑇𝑇𝑜𝑜3 AND Po3/Ps4

Design Considerations

ṁ= 𝐴𝐴∗𝑃𝑃𝑜𝑜3 𝛾𝛾𝑅𝑅𝑅𝑅𝑜𝑜3

𝛾𝛾 + 12

− 𝛾𝛾+12 𝛾𝛾−1

3

3v

4

Why Closed Loop? - Altitude Testing Exemplary Loading Po3/Ps4 Rec M3v-is 𝚲𝚲 𝚫𝚫𝚫𝚫/𝐔𝐔𝟐𝟐 Cx/U Vane M4r-is Rotor

Low 2.5 106 1.07 0.15 1.28 0.48 Choked 0.65 - Nominal 3.9 106 1.25 0.27 1.86 0.62 Choked 0.97 -

High 5.2 106 1.25 0.37 2.02 0.70 Choked 1.18 Choked



Design Considerations

T03 @engine=1200K @test=1200K 𝑃𝑃03𝑅𝑅03

�𝑃𝑃𝑆𝑆𝑇𝑇𝑃𝑃𝑆𝑆𝑃𝑃

=𝑃𝑃03𝑅𝑅03

�𝑇𝑇𝑃𝑃𝑡𝑡𝑇𝑇

Greater Than 1.2 km Altitude High loading: Ps4 < Patm Maintain engine similar conditions? Negative Throttle Required

Reality is Worse: Due to Reduced Testing To3: T03 @engine=1200K @test=650K

𝑃𝑃03𝑅𝑅03

�𝑃𝑃𝑆𝑆𝑇𝑇𝑃𝑃𝑆𝑆𝑃𝑃

=𝑃𝑃03𝑅𝑅03

�𝑇𝑇𝑃𝑃𝑡𝑡𝑇𝑇

𝑃𝑃𝑜𝑜3|𝑃𝑃𝑆𝑆𝑇𝑇𝑃𝑃𝑆𝑆𝑃𝑃 > 𝑃𝑃𝑜𝑜3|𝑇𝑇𝑃𝑃𝑡𝑡𝑇𝑇 Further Reduced Test Range

Max. T03 @engine=1200K @test=1200K

Max. T03 @engine=1200K @test=650K

Open Loop Considerations:



Operation Principles: • Fill up Closed System with Air from Reservoir until desired Nominal Pressure Level • Compressor rpm control sets mass flow rate • Adjustable System Pressure Drop Sets Pressure ratio across turbine • Heater controls Turbine inlet temperature

~ Gearbox

Hydraulic Coupling

Plenum with Turbulator Grid

Chiller

Oil-Free Screw

Compressor

Air Flow/Temperature

Variable Speed Motor

Small Heat Exchanger With Pump

Test Section

Test Turbine

Test Section Operation Principles



Objective: Component Analysis Specifics:

~ Gearbox

Hydraulic Coupling

Plenum with Turbulator Grid

Chiller

Oil-Free Screw

Compressor

Air Flow/Temperature

Variable Speed Motor

Small Heat Exchanger With Pump

Test Section

Test Turbine

Test Section Operation Principles

• Stage Aero-Thermal Performance Mapping

• Rotor/Stator Aero-Thermal Coupling

• Conjugate Transfer Studies

• Thermal Barrier Coating Assessment

• Internal / External Blade Cooling

• Cavity Flows

• Air System Design



Control Parameters

Simulation of Operating Conditions

• Ncomp

Transient Response

• Nturb • PWheater • Pin • ∆𝑃𝑃𝑣𝑣𝑇𝑇𝑇𝑇𝑣𝑣𝑃𝑃 (Closure)

• Small Tank (~ 5m3) Decouple Compressor / Turbine Response • Large Tank (~20m3) Maintain Stable Quasi-Steady Turbine Exit Pressure

Independent Variables • Re • ṁcor • Ncor • Tf/Ts • Po3/Po4

Compressor Turbine Matching



Equations of Explicit Algorithm

( )2 1 12/ ( ) .P P i Comp map m i→ → ( )4 5 45/ ( ) .P P i Turb map m i→ →

( )( ) ( ) ( ) ( )( ) ( ) ( )

2 2 12 22

245 2

11M i T i m i tCp T i

T iM i Cpm i tCp T i

+ ∆ + =

− ∆

( ) ( ) ( )2 2 22

11 1 1P i M i R T iV

+ = + +

Operation Maps

Conservation of Mass 1st Law of Thermodynamics Ideal Gas Compressor Pressure / Temperature 2

( ) ( ) ( ) ( )2 21 comp turbM i M i m i t m i t+ = + ⋅∆ − ⋅∆

Chiller ( )6 300T i =

( ) ( ) ( )( )12 1 61coolerPw m i Cp T i T i= − + −

( ) ( ) ( )( )

1

22 1

1

11

1

comp

compP iT i T i

P i

γγ

−

++ = +

Isentropic Relations

1-2 4-5



Equations of Simulation

Heater ( ) ( ) ( )4 45 31 / 1heaterT i Pw Cp m i T i+ = ⋅ + +

Turbine Upstream Pressure / Temperature 2-4 Valve – P. Drop ( ) ( )

2

3 21 12

VP i P i Kρ+ = + −

( ) ( )5 21 1systemM i M M i+ = − +( )

( ) ( ) ( ) ( )( ) ( ) ( )

5 5 45 55

512 5

11M i T i m i tCp T i

T iM i Cpm i tCp T i

+ ∆ + =

− ∆

( ) ( ) ( )5 5 55

11 1 1P i M i R T iV

+ = + +

Conservation of Mass 1st Law of Thermodynamics Ideal Gas 5 Turbine Downstream Pressure/Temperature

Isentropic Relations

( ) ( ) ( )( )

1

55 4

4

11 1

1P i

T i T iP i

γγ−

++ = + ⋅ +

Converge Until: ṁcomp = ṁturb



Convergence of Explicit Algorithm

Aerodynamic Convergence

Turn on Heater Inlet Exit

Valve Heater Cooler

Turbine

Compressor

P [atm]

T [K]

Re-converge



Range of Operating Conditions

TIT [K]

Incr

easi

ng

Alti

tude

R

e



Particle Image Velocimetry Infrared Thermography Solving Inverse Heat Transfer Problem: • Cooling Efficiency • External Heat Transfer • Internal Heat Distribution

• Flow Structures • Secondary Vortices • Aerodynamic Performance

Nusselt Number

Operational Instrumentation • Kulite Pressure Transducers

• Scanivalve Pressure Measurements • Kiel-Head Probes • Thermocouples and RTDs • Heat –flux Gages • Tachometers

New IR Camera Model: SC7600 Waveband: 3.5-5.1μm Resolution: 640x512 Frame Rate: 100Hz – up to 3.4 kHz Integration Time: 200 ns Temperature Range: -20°C – 1500°C

Fixed and Rotating Frame Thermometry

Exemplary Measurement Techniques



Schematic Layout



Conclusions

Full Engine Similar Performance Assessment Independent Control of All Parameters

In Flight Conditions Operational Map (Mission)

Functions Towards:

Test Aided Design

Compressor Turbine Matching

Advanced Turbine Geometry Assessment

Cooling Systems Development

Turbine Pressure Ratio (Differential - Closed Loop)

6:1

Mass Flow Rate [kg/sec] 1

Turbine Inlet Temperature [K] 600

Speed (rpm) 120k

Temperature Ratio (Flow to Blade)

2:1

Test Section Diameter (mm) 200

Operating Conditions

National Turbine Research Center: Equipped with Closed Loop Continuous and Heated High Pressure Turbine Facility



Foresight

We may not be ready TODAY

We Need Foresight!

NOT to end up like this

Documents

Operation Principles of a Closed Loop Continuous and ... · Objective: Component Analysis of HP Turbines in Engine Similar Conditions Turbine scaling parameters: ṁ cor, P 03/P 04,