RECEIVER PULSES AND TEMPERATURE DISTRIBUTION · PDF filetemperature distribution impact on performance of a large bore ... 46 48 50 52 54 56 58 60 ... receiver pulses and temperature

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RECEIVER PULSES AND TEMPERATURE DISTRIBUTION IMPACT ON PERFORMANCE OF A LARGE BORE GAS ENGINE

GT CONFERENCE 2016FRANKFURT, OCTOBER 17

1

Wärtsilä: G. Lo Iacono, G. CaputoPOWERTECH: E. Servetto

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AGENDA

1. Introduction

2. GT-POWER Simulation Model Setup

3. Investigation on Engine Variants

4. Resonator Tuning and Optimization

5. Experimental Measurements

6. Conclusions

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1. Introduction





6. Conclusions

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1. INTRODUCTION

Merchant OffshoreCruise

and FerryNavy

Special

Vessels

Product requirements for Marine engines:

W46DFCO2

NOxSOx

ParticulatesDual-Fuel engine

in gas mode

Diesel

engine

0

10

20

30

40

50

60

70

80

90

100

Emission

values [%]-30%

-85%

-99%

-95%

• Fuel flexibility (Gas, MDO, HFO)

• High output and low fuel consumption

• IMO and EPA compliance

• High power density

• Advanced engine control and diagnostics

• Compact design

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1. INTRODUCTION

6L20DF 1.0 MW

8L20DF 1.4 MW

9L20DF 1.6 MW

8V31DF 4.4 MW

10V31DF 5.5 MW

12V31DF 6.6 MW

14V31DF 7.7 MW

16V31DF 8.8 MW

20V31DF 11.0 MW

6L34DF 3.0 MW

8L34DF 4.0 MW

9L34DF 4.5 MW

12V34DF 6.0 MW

16V34DF 8.0 MW

20V34DF 10.0 MW

6L50DF 5.9 MW

8L50DF 7.8 MW

9L50DF 8.8 MW

12V50DF 11.7 MW

16V50DF 15.6 MW

18V50DF 17.6 MW

6L46DF 6.9 MW

7L46DF 8.0 MW

8L46DF 9.2 MW

9L46DF 10.3 MW

12V46DF 13.7 MW

14V46DF 16.0 MW

16V46DF 18.3 MW

0 5 10 15 20 MW

34DF

50DF

46DF

31DF

20DF

• Charge air system performance in terms of receiver

pressure pulses and charge air temperature distribution

affect remarkably the power output of modern DF engine.

• Huge pressure pulses and large temperature gradient

inside the receiver lead to:

Deteriorated knock resistance in Gas mode reduced max

power output and lower engine brake efficiency

Turbocharger instability unexpected compressor surge

and/or overall lower engine performance

40

42

44

46

48

50

52

54

56

58

60

CA temp cyl 2 CA temp cyl 5 CA temp cyl 6 CA temp cyl 7 CA temp cyl 8 Temp Receivert3

Tem

pera

ture

[ C

]

8L46DF lab engine Receiver Temperature - Diesel mode

100% load No resonator

• Different pressure pulsations behavior for different cylinder

configuration.

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1. Introduction





6. Conclusions

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7

2. GT-POWER MODEL SETUP

• A detailed GT-POWER model representing the 8LW46DF engine was built

• Intake/Exhaust geometries were converted in GEM-3D

The SPEX pulse

converter was

modeled by means of

a FlowSplitGeneral.

EXHAUST SIDEINTAKE SIDE

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• The GT-POWER model was calibrated and extensively validated in both

constant and variable speed conditions on several experimental datasets

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• The GT-POWER model was calibrated and extensively validated in both

constant and variable speed conditions on several experimental datasets

Temperature

along receiver

Gradient as a

function of Load

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1. Introduction





6. Conclusions

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3. INVESTIGATION ON ENGINE VARIANTS

• The other engine variants of the 46DF family were built, scaling the

validated 8L into the 6L, 7L, 9L, 12V, 14V and 16V configurations

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3. INVESTIGATION ON ENGINE VARIANTS

• The natural frequencies of the whole intake system were investigated via

linear analysis for the 8L, 9L, 12V and 16V engines.

~630rpm

8L ~575rpm

9L

~520rpm

16V ~620rpm

12V

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1. Introduction





6. Conclusions

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14

4. RESONATOR TUNING AND OPTIMIZATION

• In order to reduce the pressure fluctuations and

the consequent temperature gradient, an

internal Lambda/4 resonator was proposed

Air Receiver

Internal

Lambda/4

• Resonator Length = 6600mm

• Receiver Length (8L) = 7700mm

• Too tight a fit!

Solution: U-Shaped Resonator

Open End

Closed End

Dividing Wall

Closed End

f=1/4*v/L 1st harmonic order resonator frequency

F=3/2*RPM/60 receiver pulsation frequency

L=10*v/RPM Length resonator

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• Coupled CONVERGE Lite + GT simulations were run, to assess the impact of

the 180° bend at the end of the U-Shaped Lambda/4 on its effectiveness.

High velocity

region around lip

180° bend does

not affect resonator

frequency or

effectiveness

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• Standalone 1D simulations were carried out as well, to prove that GT is

capable of correctly reproducing the effects of the U-shaped Lambda/4

Temperature

along receiver

Gradient at

100%

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• GT-POWER results were used

to determine the optimal

location along the receiver

where to place the Lambda/4

• On the 8L configuration, the

amplitude of the 1.5° order was

found to be maximum close to

cylinder 8

• The resonator was therefore

placed there to maximize its

effectiveness

C8C7C6C5C4C3C2C1

165

170

175

180

185

190

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Am

plit

ud

e [d

B]

Normalized Distance [-]

L/4

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• A trade-off length for the U-shaped Lambda/4 was defined and then tested

on all the “critical” cylinder configurations (8L, 9L, 12V and 16V)

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1. Introduction





6. Conclusions

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5. EXPERIMENTAL MEASUREMENTS

Peak to

peak [bar]Cyl 2 Cyl 4 Cyl 8

No

resonator0,38 0,31 0,82

Resonator

U type0,24 0,28 0,49

• Pressure pulses are reduced along all

the receiver. Huge improvement -40%

on the last cylinder.

• Knocking resistance in Gas mode is

improved. Lower Lambda is possible

to set reducing the fuel consumption.

Pressure pulses damping and higher

volumetric efficiency explains the

improvement.

Receiver Pressure Cyl 2 – 100% load



- U-type Resonator

- No resonator

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• Wider temperature gradient distribution inside the receiver with the U-type resonator than no

resonator case. Result is not in line with GT-power simulation.

• The different behavior is probably due to an uneven wall temperature distribution along the charge air

receiver, which was not modeled in GT.

CA temp cyl 2 CA temp cyl 5 CA temp cyl 6 CA temp cyl 7 CA temp cyl 8

Exp. 100% load no resonator 45.8 47.3 48.0 49.1 51.1

Sim. GT 100% load no resonator 46.3 48.0 48.7 49.5 51.0

40.0

42.0

44.0

46.0

48.0

50.0

52.0

54.0

56.0

58.0

60.0

Tem

pe

ratu

re [

°C]

8L46DF lab engine - NO Resonator Diesel mode

Exp. 100% load no resonator

Sim. GT 100% load no resonator

CA temp cyl 2 CA temp cyl 5 CA temp cyl 6 CA temp cyl 7 CA temp cyl 8

Exp. 100% load U-type 41.8 43.1 44.3 45.3 49.5

Sim. GT 100% load U-type 46.2 47.3 47.7 48.3 50.0

40.0

42.0

44.0

46.0

48.0

50.0

52.0

54.0

56.0

58.0

60.0

Tem

pe

ratu

re [

°C]

8L46DF lab engine - U-type Resonator test Diesel mode

Exp. 100% load U-type

Sim. GT 100% load U-type

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Engine settings No resonator vs U-type

p3 Press In Receiver bar_g -0,10

t3 Temp In Receiver °C 45

Main Engine performance

Engine Efficiency pts % +0,3

Lamda TOT Total Air Ratio - 2,05

NOx Specific At 5% O2 Dry % +35,0

THC Marine Specific As CH4 % -14,0

t5 Temp b Turbine °C -3,0

Firing Pressure max max bar -20

Heat Release 5% Mean °CA -1,1

Heat Release 50% Mean °CA -1,2

Combustion Duration Mean °CA -1,3

IMEP COV Mean pts % -0,45

The installation of the resonator allows:

• +0.3 pts % brake efficiency @ same

knocking margin thanks to the chance to

set a lower receiver pressure setting.

• CoV < 1.5%.

• Faster Combustion duration.

• Lower pmax max -20bar.

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1. Introduction





6. Conclusions

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6. CONCLUSIONS

• GT power well supported in predicting pressure pulses inside the charge air receiver and in

designing the resonator to dump them. Good correlation between experimental data and simulated

one is found on 8L cylinder configuration lab engine.

• Cylinder configurations that needs a resonator and the most critical frequencies have been identified.

• Experimental Temperature distribution along the charge air receiver does not match with the

simulated wider distribution in the real case is found. Difference is most probably due to the

complex design of the charge air receiver, so the wall heat exchange was not well reproduced with

the simplified model used.

• A comparison among overall performance of the U-type resonator with other resonator designs

(external, long internal…) is planned as next step of the study, focusing on the influence of volumetric

efficiency and charge air distribution on knock resistance and engine brake efficiency.

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6. CONCLUSIONS

21.3.2016 Authors: G. Lo Iacono; E. Servetto; G. Caputo

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6. CONCLUSIONS

© Wärtsilä

RECEIVER PULSES AND TEMPERATURE DISTRIBUTION IMPACT ON PERFORMANCE OF A LARGE BORE GAS ENGINE

GT CONFERENCE 2016FRANKFURT, OCTOBER 17

27

Wärtsilä: G. Lo Iacono, G. CaputoPOWERTECH: E. Servetto

Documents

RECEIVER PULSES AND TEMPERATURE DISTRIBUTION · PDF filetemperature distribution impact on performance of a large bore ... 46 48 50 52 54 56 58 60 ... receiver pulses and temperature