Reduced Convective Combustion Chamber Wall Heat Transfer Losses of Hydrogen-Fueled Engines by Vortex-Stratified Combustion - Part 1: Background and Optical Engine Observations

2017 ◽  
Vol 10 (5) ◽  
pp. 2248-2258 ◽  
Author(s):  
David Oh ◽  
Martin Brouillette ◽  
Jean-Sebastien Plante
Keyword(s):  
Heat Transfer ◽  
Combustion Chamber ◽  
Chamber Wall ◽  
Wall Heat Transfer ◽  
Convective Combustion ◽  
Optical Engine ◽  
Stratified Combustion

Internal Bearing Chamber Wall Heat Transfer as a Function of Operating Conditions and Chamber Geometry

1999 ◽  
Author(s):  
Stefan Busam ◽  
Axel Glahn ◽  
Sigmar Wittig
Keyword(s):  
Heat Transfer ◽  
Operating Conditions ◽  
Chamber Wall ◽  
Test Facility ◽  
Detailed Knowledge ◽  
Wall Heat Transfer ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Dimensional Parameter ◽  
Secondary Air

Increasing efficiencies of modern aero-engines are accompanied by rising turbine inlet temperatures, pressure levels and rotational speeds. These operating conditions require a detailed knowledge of two-phase flow phenomena in secondary air and lubrication oil systems in order to predict correctly the heat transfer to the oil. It has been found in earlier investigations that especially at high rotational speeds the heat transfer rate within the bearing chambers is significantly increased with negative effects on the heat to oil management. Furthermore, operating conditions are reached where oil coking and oil fires are more likely to occur. Therefore, besides heat sources like bearing friction and churning, the heat transfer along the housing wall has to be considered in order to meet safety and reliability criteria. Based on our recent publications as well as new measurements of local and mean heat transfer coefficients, which were obtained at our test facility for engine relevant operating conditions, an equation for the internal bearing chamber wall heat transfer is proposed. Nusselt numbers are expressed as a function of non-dimensional parameter groups covering influences of chamber geometry, flow rates and shaft speed.

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