Turbine Case Cooling Annular Duct Fire Zone Decoupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing turbine case cooling systems in gas turbine engines face issues where the cooling air flow from manifolds affects the pressurization of the fire zone, leading to inconsistent fire extinguishing capabilities and interference with the bypass nozzle pressure, which can impact engine performance.
Innovation Solution
A turbine case cooling system with an annular duct that is radially spaced from the turbine casing, featuring impingement holes and a sealingly coupled design that separates the cooling chamber from the fire zone, allowing controlled pressure drop and increased cooling capacity by aligning with the static pressure of the bypass flow or turbine assembly outlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If separate annular manifolds are provided around the turbine case for cooling different turbine stages, then the turbine case can be selectively cooled to reduce clearance and improve engine performance, but the cooling air flow from the manifolds affects the pressurisation of the fire zone and interferes with bypass nozzle pressure
Solution Approach 1:
The turbine case cooling system is segmented into multiple separate annular manifolds, each axially aligned with specific turbine stages (high pressure, intermediate pressure, and low pressure turbines). Each manifold can be independently controlled to cool specific sections of the turbine case, allowing selective cooling while managing the overall impact on fire zone pressurisation.
Solution Approach 2:
The patent introduces a fire zone pressurisation control system that acts as an intermediary between the turbine case cooling manifolds and the fire zone. This control system regulates the cooling air flow to maintain adequate pressurisation in the fire zone, ensuring fire extinguishing capability is not compromised while still achieving the desired cooling effect.
2Temperature
If turbine case cooling air is exhausted into the fire zone from manifolds, then the turbine case is cooled effectively, but the fire zone pressurisation becomes dependent on the amount of cooling air, affecting fire extinguishing requirements
Solution Approach 1:
The system employs feedback control mechanisms that monitor fire zone pressurisation and cooling air flow rates. Based on this feedback, the control system adjusts the cooling air supply to maintain optimal pressurisation levels, decoupling the fire extinguishing requirements from direct dependence on cooling air quantity and simplifying the overall system design.
3Productivity
If the fire zone pressure is higher than the manifold pressure, then the cooling air flow is impeded from exhausting into the fire zone, but if the fire zone pressure is lower, then the cooling air is drawn through more quickly
Solution Approach 1:
The system uses dynamic control of the cooling air supply to manifolds, adjusting flow rates in real-time based on operating conditions. This dynamic adjustment compensates for pressure variations in the fire zone, maintaining stable and predictable cooling air flow through the turbine case regardless of whether fire zone pressure is higher or lower than manifold pressure.
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
This design enhances cooling capacity and flow per unit area without interfering with the fire zone or bypass flow, simplifies fire extinguishing requirements, and reduces weight and fuel consumption by decoupling pressure dynamics between the cooling system and fire zone.
Implementation Method 1
the at least one manifold having impingement holes through its radially inner wall to selectively impingement cool at least part of the turbine casing
Implementation Method 2
the duct sealingly coupled to the turbine casing at a first end towards the inlet of the axially first turbine stage of the turbine assembly
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A turbine case cooling system (53) comprising a turbine assembly (44) having an inlet (46) and an outlet (48) and surrounded by a turbine casing (50). The turbine case cooling system (53) is arranged to selectively impingement cool at least part of the turbine casing (50). The system (53) includes an annular structure (38) that is radially spaced from the turbine casing (50) and comprises a downstream end (39). The system (53) includes an annular duct (54) that is spaced radially outwardly from the turbine casing (50) and radially inwardly from the annular structure (38). The duct (54) is sealingly coupled to the turbine casing (50) at a first end (56) towards the turbine inlet (46), and a second end (58) extends axially towards the downstream end (39) of the annular structure (38) and the turbine outlet (48).