Bearing systems in engine-oil lubricated turbochargers (TCs) must operate reliably over a wide range of shaft speeds and withstand severe axial and radial thermal gradients. An engineered thermal management of the energy flows into and out of the bearing system is paramount in order to ensure the component’s mechanical integrity and the robustness of the bearing system. The bearings, radial and thrust type, act both as a load bearing and low friction support with the lubricant carrying away a large fraction of the thermal energy generated by rotational drag and the heat flow disposed from a hot shaft. The paper introduces a thermohydrodynamic analysis for the prediction of the pressure and temperature fields in a (semi) floating ring bearing (S)FRB system. The analysis simultaneously solves the Reynolds equation with variable oil viscosity and the thermal energy transport equation in the inner and outer films of the bearing system. Flow conditions in both films are coupled to the temperature distribution and heat flow through the (semi) floating ring. Other constraints include calculating the fluid films’ forces reacting to the externally applied load and to determine the operating journal and ring eccentricities. The predictions of performance for a unique realistic (S)FRB configuration at typical TC operating conditions reveal a distinct knowledge: (a) the heat flow from the shaft into the inner film is overwhelming, in particular, at the inlet lubricant plane where the temperature difference with the cold oil is largest; (b) the inner film temperature quickly increases as soon as the (cold) lubricant enters the film and is due to the large amount of energy generated by shear drag and the heat transfer from the shaft; (c) a floating ring develops a significant radial temperature gradient; (d) at all shaft speeds, low and high, the thermal energy carried away by the lubricant streams is no less than 70% of the total energy input; the rest is conducted through the TC casing. To warrant this thermal energy distribution, enough lubricant flow must be supplied to the bearing system. The efficient computational model offers a distinct advantage over existing lumped parameters thermal models and there is no penalty in the execution time.

References

References
1.
Malobabic
,
M.
and
Rautenberg
,
M.
, 1987, “
Adiabatic and Non-Adiabatic Efficiencies of Small Turbochargers
,”
International Gas Turbine Congress
, Tokyo, Japan, Oct. 26–31, pp.
57
64
, Paper No. 87-Tokyo-IGTC-105.
2.
Lamquin
,
T.
and
Gjika
,
K.
, 2009, “
Power Losses on a Turbocharger Hydrodynamic Bearing Systems: Test and Prediction
,” ASME Paper No. GT 59599.
3.
Baines
,
N.
,
Wygant
,
K. D.
, and
Antonis
,
D.
, 2010, “
The Analysis of Heat Transfer in Automotive Turbochargers
,”
ASME J. Eng. Gas Turbines Power.
132
, p.
042301
.
4.
Bohn
,
D.
,
Heuer
,
T.
, and
Kusterer
,
K.
, 2003, “
Conjugate Flow and Heat Transfer Investigation of a Turbocharger—Part I: Numerical Results
,” ASME Paper No. GT2003-38445.
5.
Bohn
,
D.
,
Heuer
,
T.
, and
Kusterer
,
K.
, 2003, “
Conjugate Flow and Heat Transfer Investigation of a Turbocharger—Part II: Experimental Results
,” ASME Paper No. GT2003-38449.
6.
Heuer
,
T.
,
Engels
,
B.
, and
Wollscheid
,
P.
, 2005, “
Thermomechanical Analysis of a Turbocharger Based on Conjugate Heat Transfer
,” ASME Paper No. GT2005-68059.
7.
San Andrés
,
L.
and
Kerth
,
J.
, 2004, “
Thermal Effects on the Performance of Floating Ring Bearings for Turbochargers
,”
Proc. Inst. Mech. Eng., Part J: J. Eng. Tribol.
,
218
, pp.
437
450
.
8.
Chun
,
S. M.
, 2008, “
Aeration Effects on the Performance of a Turbocharger Journal Bearing
,”
Trib. Int.
,
41
, pp.
296
306
.
9.
Deligant
,
M.
,
Povedin
,
P.
, and
Descombes
,
G.
, 2011, “
CFD Model for Turbocharger Journal Bearing Performances
,”
Appl. Therm. Eng.
,
31
, pp.
811
819
.
10.
Gjika
,
K.
,
San Andrés
,
L.
, and
LaRue
,
G.
, 2010, “
Nonlinear Dynamic Behavior of Turbocharger Rotor-Bearing Systems With Hydrodynamic Oil Film and Squeeze Film Damper in Series: Prediction and Experiment
,”
ASME J. Comput. Nonlinear Dyn.
,
5
, p.
041006
.
11.
San Andrés
,
L.
,
Maruyama
,
A.
,
Gjika
,
K.
, and
Xia
,
S.
, 2010, “
Turbocharger Nonlinear Response With Engine-Induced Excitations: Predictions and Test Data
,”
ASME J. Eng. Gas Turbines Power
,
132
, p.
032502
.
12.
San Andrés
,
L.
,
Rivadeneira
,
J. C.
,
Gjika
,
K.
,
Groves
,
C.
, and
G.
LaRue
, 2007, “
A Virtual Tool for Prediction of Turbocharger Nonlinear Dynamic Response: Validation Against Test Data
,”
ASME J. Eng. Gas Turbines Power
,
129
, pp.
1035
1046
.
13.
Holt
,
C.
,
San Andrés
,
L.
,
Sahay
,
S.
,
Tang
,
P.
,
LaRue
,
G.
, and
Gjika
,
K.
, 2005, “
Test Response and Nonlinear Analysis of a Turbocharger Supported on Floating Ring Bearings
,”
ASME J. Vibr. Acoust.
,
127
, pp.
107
212
.
14.
Taylor
,
R. I.
, 1999, “
The Inclusion of Lubricant Shear Thinning in the Short Bearing Approximation
,”
Proc. Inst. Mech. Eng.
,
213
(
1
), pp.
35
46
.
15.
San Andrés
,
L.
, 2010, “
Thermohydrodynamic Bulk-Flow Model in Thin Film Lubrication
,” Notes 10, Modern Lubrication Theory, Texas A&M University Digital Libraries, http://repository.tamu.edu/handle/1969.1/93197http://repository.tamu.edu/handle/1969.1/93197
16.
San Andrés
,
L.
,
Yang
,
Z.
, and
Childs
,
D.
, 1993, “
Thermal Effects in Cryogenic Liquid Annular Seals, I: Theory and Approximate Solutions
,”
ASME J. Tribol.
,
115, 2
, pp.
267
276
.
17.
Li
,
C. H.
and
Rhode
,
S. M.
, 1981,“
On the Steady State and Dynamic Performance Characteristics of Floating Ring Bearings
,”
ASM, J. Lubr. Technol.
,
103
, pp.
389
397
.
18.
San Andrés
,
L.
, 2010, “
Thermal Analysis of Finite Length Journal Bearings Including Fluid Inertia
,” Notes 7, Modern Lubrication Theory, Texas A&M University Digital Libraries, http://repository.tamu.edu/handle/1969.1/93197http://repository.tamu.edu/handle/1969.1/93197
19.
Launder
,
B. E.
and
Leschziner
,
M.
, 1978, “
Flow in Finite Width Thrust Bearings Including Inertial Effects—I: Laminar Flow, II: Turbulent Flow
,”
ASME J. Lubr. Technol.
,
100
, pp.
330
345
.
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