Turbine Case Cooling Conduit with Ejector Section
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Solution Overview
Problem
Conventional cooling systems for gas turbine engines require large pipe diameters and long routing with multiple bends, leading to flow perturbations and potential leakage of pressurized cool air, necessitating improved flow control measures.
Innovation Solution
A turbine case cooling system utilizing a cooling conduit with an ejector section to draw bypass air into the conduit using a motive air flow, mixing it with the bypass air to form a cooling gas flow, and a diffuser section that increases in cross-sectional area to convey the cooling gas flow perpendicular to the engine's center axis, reducing pipe size and flow disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional cooling techniques are used with large pipe diameter and long routing, then the cooling system can supply sufficient cool air flow, but the system creates flow perturbations in the main gas path and requires multiple bends
Solution Approach 1:
The cooling conduit is oriented perpendicular to the engine's longitudinal center axis, utilizing a transverse dimension for cooling air supply instead of the conventional longitudinal routing. This dimensional change allows the cooling system to be integrated without creating flow perturbations in the main axial gas path, as the cooling flow is extracted radially rather than axially
Solution Approach 2:
The system employs pneumatic principles by using a motive air flow to create a low-pressure region that draws bypass air through the cooling conduit via pressure differential. This pneumatic drawing mechanism eliminates the need for large diameter pipes and complex flow control valves, as the flow is controlled by pressure gradients rather than mechanical components
2Stress or pressure
If conventional cooling techniques are used with pressurized cool air source, then the cooling system can maintain cooling pressure, but the cool air may be supplied inadvertently in case of leakage requiring flow control measures
Solution Approach 1:
Instead of pressurizing the cooling air source and using valves to prevent inadvertent supply, the system inverts the approach by using a low-pressure drawing mechanism. The motive air flow creates a low-pressure region that actively draws bypass air through the cooling conduit, meaning cooling air is supplied only when the motive air flow is actively drawing it, eliminating the risk of inadvertent supply from a pressurized source
Solution Approach 2:
The cooling system is self-regulating through the pneumatic drawing mechanism. The motive air flow automatically controls the bypass air flow through pressure differential, eliminating the need for external flow control valves and complex control systems. The system self-regulates based on the interaction between motive air flow and bypass air pressure
3Ease of operation
If conventional cooling techniques are used with large valve size and long routing, then the system can control and supply cool air, but the device complexity increases
Solution Approach 1:
The system replaces mechanical flow control valves with a pneumatic drawing mechanism controlled by motive air flow. The flow control is achieved through pressure differential and entrainment effects rather than mechanical valve adjustment, significantly reducing device complexity while maintaining ease of operation through active flow management
Solution Approach 2:
The invention extracts and eliminates the complex flow control valve system from the conventional cooling arrangement. By using the motive air flow to actively draw bypass air through the cooling conduit, the system removes the need for valves, reducing device complexity while maintaining effective cooling air supply control
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 a compact, efficient, and leak-resistant cooling system with smaller piping and control valves, maintaining optimal engine efficiency and preventing unintended bypass air supply, while ensuring consistent static pressure in the cooling manifold.
Implementation Method 1
an ejector section of the cooling conduit disposed downstream of the inlet, the ejector section in use supplying a motive air flow radially into the cooling conduit to draw a bypass air flow from the bypass duct into the cooling conduit via the inlet
Implementation Method 2
the motive air flow mixing with the bypass air flow to form the cooling gas flow in the conduit
Implementation Method 3
a diffuser section of the cooling conduit disposed downstream of the ejector section and extending along a diffuser length of the conduit between the ejector section and the outlet, the diffuser section defining a gas flow path through the conduit and in use conveying the cooling gas flow toward the outlet, the diffuser section increasing in cross-sectional area along the diffuser length
Data Source
AI summary
A turbine case cooling system and a method for supplying a cooling gas flow are provided. The cooling system has a turbine case and a turbine case cooling manifold. The cooling system also has a fluid or cooling conduit. The cooling conduit has an inlet in fluid communication with the bypass duct, and an outlet in fluid communication with the cooling manifold. The cooling conduit also has an ejector section which in use supplies a motive air flow radially into the cooling conduit to draw a bypass air flow from the bypass duct. The motive air flow mixes with the bypass air flow to form the cooling gas flow. The cooling conduit also has a diffuser section which in use conveys the cooling gas flow toward the outlet in a direction substantially perpendicular to the center axis of the gas turbine engine.