Gas Turbine Rotor Assembly Flow Restrictor for Cooling Air Control
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Solution Overview
Problem
The controlling of airflow through gaps of form-fitting torque transmitting means in gas turbine rotor assemblies is complex, especially when multiple decentralized tie bolts are used, and the airflow management is challenging.
Innovation Solution
A rotor assembly design featuring a first rotor disc with a center through hole and a second rotor disc without a center through hole, where the second rotor disc incorporates a flow restrictor assembly that reduces the effective flow cross section of the center through hole, thereby controlling the cooling air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple decentralized tie bolts are used for clamping rotor discs, then the torque transmission reliability is improved, but the complexity of controlling airflow through gaps of form-fitting torque transmitting means increases
Solution Approach 1:
The invention extracts the airflow control function from the complex multi-bolt connection system and relocates it to a dedicated flow restrictor assembly. This separate component specifically manages cooling air flow through the center through-hole, independent of the torque transmission function performed by the curvic coupling and tie bolts. The flow restrictor assembly includes adjustable elements that can control airflow without interfering with the mechanical connection, thereby reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The flow restrictor assembly acts as an intermediary component between the cooling air supply and the turbine rotor discs. It mediates the airflow by providing a controlled passage through the center through-hole, regulating the amount of cooling air that reaches the gaps of the form-fitting torque transmitting means. This intermediary structure simplifies airflow control by centralizing the regulation function rather than requiring complex coordination of multiple decentralized elements.
2Temperature
If cooling air flow through center through hole is increased, then turbine rotor blade cooling is improved, but pressure of cooling air upstream of rotor disc is reduced
Solution Approach 1:
The flow restrictor assembly incorporates adjustable elements that allow dynamic control of the flow cross-section area. This enables the system to adapt the cooling air flow rate and upstream pressure according to varying operational conditions. By adjusting the restrictor opening, operators can optimize the balance between cooling effectiveness and available pressure, rather than being constrained by a fixed flow path.
Solution Approach 2:
The invention changes the flow parameters by introducing a variable restriction in the center through-hole. The flow restrictor assembly modifies the flow cross-section area, which directly affects both the cooling air flow rate and the upstream pressure. This parameter adjustment capability allows the system to achieve desired cooling effects while maintaining sufficient pressure for effective airflow through the torque transmitting means gaps.
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 flow restrictor assembly increases the pressure of cooling air upstream of the first rotor disc, enhancing the cooling air flow through gaps of the torque transmitting means on one side while reducing it on the other side, thus allowing for controlled airflow management.
Implementation Method 1
the flow restrictor assembly restricts the effective flow cross section of the center through hole of the first disc... the effective flow cross section is reduced. This throttling of the effective flow cross section reduces the cooling air flow through the center through hole in such a way, that the pressure of the cooling air being next to the first rotor disc is increased significantly
Data Source
Figure 1
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AI summary
The invention relates to a rotor assembly (RA), especially for a gas turbine, comprising at least a first rotor disc (FRD) and a second rotor disc (SRD), the two rotor discs (FRD, SRD) are arranged directly next to each other, wherein the first rotor disc (FRD) comprises a center through hole (CTH) and the second rotor disc (SRD) comprises no center through hole but a rotor disc center (RH). To control or to adjust the cooling air through gaps of a form-fitting torque transmitting means it is proposed to use a flow restrictor assembly (FRA) which restricts the effective flow cross section of the center through hole of the first disc (FRD).