Session: 34-07 Centrifugal, combustor, and bearing methods

Paper Number: 128783

128783 - CFD Study of Journal Bearing Flow Physics and the Influence of Oil Feed Condition Within a Planetary Gearbox 

Increasingly strict emission regulations and continuous pressure on cost per flying hour require further reduction in fuel consumption of modern gas-turbines in aviation industry. One promising technology is the geared turbofan, enabling for slower fan speeds, hence, larger bypass ratios for better thrust efficiency, as well as more efficient and smaller (lighter) turbine and compressor designs. Such a gearbox must handle very high torques and, for compactness, may be a planetary gear box. However, high torques and centrifugal loads may overload commonly used ball bearings and make usage of journal bearings necessary. The flow physics in such bearings is usually described as Couette-Poiseuille flow, a two-dimensional simplification of the Navier-Stokes equations. However, during testing it has been observed that, depending on the feed oil temperature and the oil feed flow condition, w.r.t. positioning of oil bores and flow split among these, has significant three-dimensional influence onto measurements, which cannot be predicted without full three-dimensional CFD simulation. Within the scope of this paper, the journal bearing flow physics will be assessed based on a journal bearing which has a static inner and a rotating outer cylinder with its axis additionally rotating around a center axis. Full three-dimensional CFD is performed, including centrifugal force, thermal conduction to the metal parts, two-phase flow (air/oil), cavitation from oil to oil-vapor as well as evaporation of dissolved air within the oil phase. It will be shown how the feed flow distribution within the oil feed pocket and the feed oil temperature affect the gap flow and temperature distribution along the circumference of the journal bearing.

Presenting Author: Ivo Martin Rolls-Royce Deutschland Ltd & Co KG

Presenting Author Biography: CFD and System Analyst, Fuel, Oil & Heat Management Sytems
Rolls-Royce Germany, Dahlewitz, Brandenburg
October 2019 – present
 Develop capability for simulation of oil distribution within gearboxes and
bearing chambers
 Develop capability for simulation of oil flow within journal bearings
 Coordinating research activities with partner universities
 Definition and support of test activities
 Requirement and design definition

Controls Engineer
Rolls-Royce Germany, Dahlewitz, Brandenburg
October 2017 – 2019
 Controls engineer for system verification
 Develop requirement and risk based test procedures
 Support software and system testing
 Develop tools for test automization
 Analyze test data and support investigation of test issues
 miscellaneous project work for BR700NG and RB2043

Research Assistant
BTU-Cottbus-Senftenberg, Cottbus, Brandenburg
October 2013 – February 2017
 Development of a robust structural dynamic design process for airfoils
 Automatic eigenmode recognition using machine learning
 Enhancing machine learning through data preparation and reduction
 Development of an automatic surface projection methods using Kohonen
maps
 Improvement of neural network performance by incorporating principlecomponent
analysis (or kernel PCA) between the input and hidden layer
 Rapid hot-to-cold transformation of centrifugal loaded airfoil geometries within
FEM environment

Fluid Systems Engineer
Rolls-Royce Germany, Dahlewitz, Brandenburg
October 2011 – October 2013
 CFD specialist for secondary air and oil systems
 Sub-system responsibility for lean burn, rear bearing chamber and low
pressure turbine during the development of BR700NG engine
 Definition and management of system requirements and definitions for air
system of BR700NG
 Numeric simulations and test bed definitions for investigation of engine issues
 Coordinating collaborative activities with HQ in Derby (England) and with
external suppliers in Spain and Italy
 miscellaneous project work for Trent1000, BR725, BR710, and BR700NG

Working Student – Rolls-Royce Compressor Department
Rolls-Royce Germany, Dahlewitz, Brandenburg
March 2010 – July 2010
 Development of an automatic design optimization process for tandem
compressor airfoils
 Using Python, Fortan, and C++ to make process communicating platform
independent and executable on different clusters simultaneously

Engineering Student
Technical University of Berlin (Germany)
2004-2011

Authors:

Ivo Martin Rolls-Royce Deutschland Ltd & Co KG
Wolfram Kurz-Hardjosoekatmo Rolls-Royce Deutschland Ltd & Co KG
Sebastian Schrewe Rolls-Royce Deutschland Ltd & Co KG