Abstract

While turbocharging is a key technology for improving the performance and efficiency of internal combustion engines, the operating behavior of the turbocharger is highly dependent on the rotor temperature distribution as it directly modifies viscosity and clearances of the fluid film bearings. Since a direct experimental identification of the rotor temperature of an automotive turbocharger is not feasible at an acceptable expense, a combination of numerical analysis and experimental identification is applied to investigate its temperature characteristic and level. On the one hand, a numerical conjugate heat transfer (CHT) model of the automotive turbocharger investigated is developed using a commercial CFD-tool and a bidirectional, thermal coupling of the CFD-model with thermohydrodynamic lubrication simulation codes is implemented. On the other hand, experimental investigations of the numerically modeled turbocharger are conducted on a hot gas turbocharger test rig for selected operating points. Here, rotor speeds range from 64.000 to 168.000 rpm. The turbine inlet temperature is set to 600 °C and the lubricant is supplied at a pressure of 300 kPa with 90 °C to ensure practically relevant boundary conditions. Comparisons of measured and numerically predicted local temperatures of the turbocharger components indicate a good agreement between the analyses. The calorimetrically determined frictional power loss of the bearings as well as the floating ring speed are used as additional validation parameters. Evaluation of heat flow of diabatic simulations indicates a high sensitivity of local temperatures to rotor speed and load. A cooling effect of the fluid film bearings is present. Consequently, results confirm the necessity of the diabatic approach to the heat flow analysis of turbocharger rotors.

References

References
1.
Porzig
,
D.
,
Raetz
,
H.
,
Schwarze
,
H.
, and
Seume
,
J. R.
,
2014
, “
Thermal Analysis of Small High-Speed Floating-Ring Journal Bearings
,” Proceedings of 11th International Conference on Turbochargers and Turbocharging (
IMechE
), London, UK, May 13–14.10.1533/978081000342.421
2.
Porzig
,
D.
,
2015
, “
Systemspezifische Schmierfilm-Dissipation in Den Radialen Lagerstellen Von Abgasturboladern
,” Ph.D. thesis,
Clausthal University of Technology
, Clausthal, Germany.
3.
San Andrés
,
L.
,
Barbarie
,
V.
,
Bhattacharya
,
A.
, and
Gjika
,
K.
,
2012
, “
On the Effect of Thermal Energy Transport to the Performance of (Semi) Floating Ring Bearing Systems for Automotive Turbochargers
,”
ASME J. Eng. Gas Turbines Power
,
134
(
10
), p.
102507
.10.1115/1.4007059
4.
Medhioub
,
M.
,
2005
, “
Axialgleitlager Bei Hohen Umfangsgeschwindigkeiten Und Hohen Spezifischen Belastungen
,” Ph.D. thesis,
Technical University of Braunschweig
, Braunschweig, Germany.
5.
Chmielowiec-Jablczyk
,
M.
,
Schubert
,
A.
,
Kraft
,
C.
,
Schwarze
,
H.
,
Wodtke
,
M.
, and
Wasilczuk
,
M.
,
2018
, “
Improvement of Thrust Bearing Calculation Considering the Convectional Heating Within the Space Between the Pads
,”
Lubricants
,
2018
,
6
(
1
), p.
22
.10.3390/lubricants6010022
6.
He
,
M.
,
2003
, “
Thermoelastohydrodynamic Analysis of Fluid Film Journal Bearings
,” Ph.D. thesis,
University of Virginia, Department of Mechanical and Aerospace Engineering
: Charlottesville, VA, USA.
7.
Hagemann
,
T.
,
Kukla
,
S.
, and
Schwarze
,
H.
,
2013
, “
Measurement and Prediction of the Static Operating Conditions of a Large Turbine Tilting-Pad Bearing Under High Circumferential Speeds and Heavy Loads
,”
ASME
Paper No. GT2013-95004.10.1115/GT2013-95004
8.
Deligant
,
M.
,
Podevin
,
P.
, and
Descombes
,
G.
,
2012
, “
Experimental Identification of Turbocharger Mechanical Friction Losses
,”
Energy
,
39
(
1
), pp.
388
394
.10.1016/j.energy.2011.12.049
9.
Perge
,
J.
,
Hoepke
,
B.
,
Uhlmann
,
T.
,
Dohmen
,
J.
, and
Lehmann
,
J.
,
2018
, “
Turbocharger Bearing Friction Measurement and Simulation
,”
Reibungs-Minimierung im Antriebsstrang 2015
,
Springer Vieweg
,
Wiesbaden
.
10.
Hoepke
,
B.
,
Uhlmann
,
T.
,
Pischinger
,
S.
,
Lueddecke
,
B.
, and
Filsinger
,
D.
,
2015
, “
Analysis of Thrust Bearing Impact on Friction Losses in Automotive Turbochargers
,”
ASME J. Eng. Gas Turbines Power
,
137
(
8
), p.
082507
.10.1115/1.4029481
11.
Baines
,
N.
,
Wygant
,
K. D.
, and
Dris
,
A.
,
2010
, “
The Analysis of Heat Transfer in Automotive Turbochargers
,”
ASME J. Eng. Gas Turbines Power
,
132
(
4
), p.
042301
.10.1115/1.3204586
12.
Sirakov
,
B.
, and
Casey
,
M.
,
2013
, “
Evaluation of Heat Transfer Effects on Turbocharger Performance
,”
ASME J. Turbomach.
,
135
(
2
), p.
021011
.10.1115/1.4006608
13.
Tomm
,
U.
,
Weiske
,
S.
,
Coksen
,
A.
,
Rafaa
,
Y.
, and
Münz
,
S.
,
2017
, “
Validation of a Heat Transfer Prediction Approach Inside Turbochargers and Its Application on Turbocharged Engine Performance Analysis
,”
ASME
Paper No. GT2017-63195.10.1115/GT2017-63195
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