Geared Turbine Heat Split for Gearbox and Bearing Cooling
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Solution Overview
Problem
Gas turbine engines, particularly geared gas turbine engines with lean burn combustors, face challenges in managing heat generated by components like the power gearbox and turbomachinery bearings, leading to energy waste and potential fuel thermal degradation, which complicates efficient operation and Specific Fuel Consumption (SFC).
Innovation Solution
A heat management system is implemented with a pipe assembly, air-lubricant and fuel-lubricant heat exchangers, configured to dissipate specific proportions of heat to air and fuel, optimizing lubrication and cooling of the power gearbox and turbomachinery bearings, minimizing heat exchanger size and weight, and maximizing SFC benefits across varying operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat is dissipated to fuel to improve SFC, then fuel efficiency improves, but fuel thermal degradation risk increases
Solution Approach 1:
The heat dissipation function is segmented into two independent paths: one to fuel (via fuel-lubricant heat exchanger) and one to air (via air-lubricant heat exchanger). This allows selective heat rejection to fuel within safe temperature limits while routing excess heat to air, preventing fuel thermal degradation while maintaining SFC benefits
Solution Approach 2:
The lubricant system acts as an intermediary carrier that collects heat from gearboxes and bearings, then transfers it through heat exchangers to either fuel or air. This intermediary mechanism enables controlled heat transfer, preventing direct harmful thermal contact between hot components and fuel while still allowing beneficial heat recovery
2Reliability
If heat dissipation capacity is increased to ensure proper functioning, then component cooling improves, but system complexity and energy waste increase
Solution Approach 1:
The lubricant system performs multiple functions simultaneously: it lubricates gearboxes and bearings, collects heat from these components, and transfers heat to either fuel or air based on operating conditions. This multi-functionality reduces the need for separate cooling systems, thereby reducing overall system complexity while ensuring reliable component functioning
Solution Approach 2:
The heat management system dynamically adjusts the proportion of heat dissipated to fuel versus air based on real-time operating conditions such as fuel temperature, engine load, and ambient temperature. This dynamic adaptation ensures adequate cooling under all conditions while avoiding unnecessary system complexity through intelligent control rather than oversized fixed-capacity equipment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively provides adequate lubrication and cooling, reduces energy waste, and avoids fuel thermal degradation, thereby enhancing engine efficiency and reducing fuel consumption under all operating conditions.
Implementation Method 1
at least one air-lubricant heat exchanger to dissipate a first amount of heat to a first heat sink
Implementation Method 2
dissipate a first amount of heat to a first heat sink, wherein the first heat sink is air
Implementation Method 3
at least one fuel-lubricant heat exchanger to dissipate a second amount of heat to a second heat sink, wherein the second heat sink is fuel
Implementation Method 4
a pipe assembly adapted to provide a lubricant flow to the gearbox and turbomachinery bearings
Data Source
AI summary
A geared gas turbine engine includes a heat management system configured to provide lubrication and cooling to a power gearbox and turbomachinery bearings, and including a pipe assembly adapted to provide a lubricant flow to the power gearbox and turbomachinery bearings to remove the heat generated by the power gearbox and turbomachinery bearings, an air-lubricant heat exchanger to dissipate a first amount of heat, and a fuel-lubricant heat exchanger to dissipate a second amount of heat wherein the heat management system is configured to provide the first amount of heat and the second amount of heat such that at cruise conditions a proportion of heat generated by the gearbox and the turbomachinery and dissipated to air is in the range of from 0.35 to 0.80.