Gas Turbine Seal Runner Cooling via Centrifugal Recirculation
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Solution Overview
Problem
Gas turbine engine seal runners face damage due to thermal and mechanical stresses, which can affect the sealing efficiency over time, and existing solutions do not effectively manage temperature gradients to maintain coolant circulation.
Innovation Solution
An annular seal runner with a sealed cavity filled with a temperature-dependent liquid coolant that recirculates due to centrifugal forces and density variations, enhancing cooling efficiency across a range of operating temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal runner is used in a gas turbine engine, then sealing function is provided, but thermal and mechanical stresses damage the runner and seals over time
Solution Approach 1:
A liquid coolant is introduced as an intermediary substance filling the sealed cavity within the seal runner. This coolant acts as a thermal mediator, absorbing heat from the runner and seals through thermal contact, thereby protecting these components from thermal damage while maintaining the sealing function between the runner and static seals
Solution Approach 2:
The invention utilizes hydraulic principles by employing a liquid coolant within the sealed cavity. The coolant circulation system leverages fluid dynamics, where centrifugal forces generated by runner rotation and density variations driven by temperature gradients create continuous coolant flow. This hydraulic approach efficiently removes thermal energy from critical components
2Temperature
If a coolant is used to cool the seal runner, then thermal stress damage is reduced, but coolant circulation must be maintained across temperature gradients
Solution Approach 1:
The coolant circulation system is designed to be self-sustaining without requiring external pumps or complex control mechanisms. The rotation of the seal runner itself generates centrifugal forces that drive coolant circulation, while temperature-dependent density variations create natural convection currents. The system serves itself by converting the mechanical energy of rotation and thermal energy differences directly into coolant flow
Solution Approach 2:
The invention exploits changes in physical parameters of the coolant, specifically its density as a function of temperature. As the coolant experiences temperature gradients within the sealed cavity, its density varies accordingly, creating buoyancy-driven convection currents. This parameter change mechanism, combined with centrifugal effects from rotation, automatically maintains coolant circulation throughout the system
3Ease of operation
If the seal runner is exposed to temperature gradients, then sealing operation is maintained, but thermal stresses increase and damage the runner
Solution Approach 1:
The liquid coolant serves as a thermal intermediary, positioned between the heat source (temperature gradients from sealing operation) and the seal runner structure. It absorbs excess thermal energy through conduction and convection, preventing direct thermal stress on the runner and seals while allowing the sealing operation to proceed under controlled thermal conditions
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 solution effectively recirculates coolant within the seal runner, maintaining sealing efficiency and reducing damage from thermal stresses by utilizing a coolant with varying density across temperature gradients, ensuring consistent performance across the engine's operating range.
Implementation Method 1
inducing recirculation of the coolant in the sealed cavity, the recirculation being a combined resultant of centrifugal loads caused by a rotation of the seal runner
Implementation Method 2
variations in a density of the coolant across the temperature gradient
Data Source
AI summary
A seal runner for a gas turbine engine, the seal runner including an annular body having a sealed cavity defined therein, the cavity being elongated along an axial direction of the body and being annular, the cavity at least partially filled with a coolant, the coolant being liquid across a range of operating temperatures of the gas turbine engine, the coolant having a temperature dependent density across the range of operating temperatures of the gas turbine engine. A gas turbine engine and a method of cooling a seal runner exposed to a temperature gradient are also discussed.