Gas Turbine Stator Vane Restrictor for Altitude Ignition
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Solution Overview
Problem
Gas turbine engines face challenges in starting at altitude due to difficulties in achieving ignition at low combustor loading, which requires increasing combustor volume, leading to increased size and weight, and thus higher fuel and material costs.
Innovation Solution
A gas turbine engine design featuring a stator vane ring with passageways that include a restrictor, which temporarily reduces the operational flow area and ablates at combustor exit temperatures between 200 °C to 600 °C to reveal an operational gas washed surface, allowing for efficient combustion initiation and sustained operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If combustor volume is increased to reduce combustor loading for ignition at altitude, then ignition capability at altitude is improved, but engine size and weight increase
Solution Approach 1:
A restrictor is installed in the passageway of the stator vane ring before engine operation to reduce combustor loading during the critical ignition phase at altitude. The restrictor is temporarily present during start-up and then removed through ablation at controlled temperatures (200-600°C), allowing the combustor to ignite successfully without requiring a permanently larger combustor volume
Solution Approach 2:
The restrictor material is selected to undergo ablation at specific temperature ranges (200-600°C), transforming from a flow-restricting state to a removed state. This parameter change allows the system to dynamically adjust combustor loading: high restriction during cold start, then complete removal during operation, achieving low combustor loading temporarily without permanent structural changes
2Reliability
If combustor volume is increased to reduce combustor loading for ignition at altitude, then ignition capability at altitude is improved, but engine size increases
Solution Approach 1:
The restrictor is pre-installed in the stator vane ring passageway to temporarily reduce combustor loading during the ignition phase. This allows the combustor to maintain its original compact volume while achieving the necessary low loading conditions for altitude ignition through the restrictor's flow limitation
Solution Approach 2:
The restrictor is designed as a temporary, consumable component that serves its purpose during start-up and then ablates away. This disposable element enables the combustor to function with small volume permanently, while temporarily achieving the flow conditions needed for ignition without requiring permanent structural modifications
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 enables effective ignition and operation at altitude by reducing combustor loading, maintaining engine efficiency, and minimizing size and weight increments, thus addressing the challenges of starting a gas turbine engine at varying in-flight conditions.
Implementation Method 1
the restrictor commences to ablate when the combustor exit temperature is from 200 °C to 600 °C and reveal an operational gas washed surface of the stator vane ring
Data Source
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AI summary
A gas turbine engine comprising: a combustor configured to initiate combustion; and a turbine comprising a stator vane ring defining a plurality of passageways between adjacent vanes; wherein at least one of the passageways is provided with a restrictor which defines a temporary gas washed surface for the stator vane ring and is configured to be ablated upon initiation of combustion to reveal an operational gas washed surface of the stator vane ring. A method of starting a gas turbine engine is also described.