Metering Plate With Exit Diffuser For Gas Turbine Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High turbine inlet temperatures in gas turbine engines lead to gas path temperatures exceeding the melting points of turbine component materials, necessitating cooling, but existing metering plates used for cooling flow control induce pressure losses and degrade heat transfer due to flow attachment issues.
Innovation Solution
A thin wall meter plate with an exit diffuser and optional inlet bellmouth is used to control the flow from an upstream to a downstream channel, facilitating even flow distribution and reducing pressure losses by aligning the flow axis and spreading the flow area, thereby enhancing heat transfer and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a traditional metering plate with a hole is used to control cooling flow, then flow metering is achieved, but pressure losses increase and heat transfer degrades due to flow detachment
Solution Approach 1:
The metering plate is segmented into multiple components: an inlet bellmouth section, a diffuser section, and an outlet section. This segmentation allows each section to perform its specific function - the bellmouth captures flow, the diffuser gradually expands to align flow direction, and the outlet delivers flow to the downstream channel, collectively reducing pressure losses while maintaining flow control
Solution Approach 2:
The inlet bellmouth features a curved, rounded leading edge instead of a sharp edge, which smoothly captures incoming flow and reduces flow separation. The diffuser section also employs curved surfaces to gradually change flow direction, preventing abrupt transitions that cause detachment and pressure losses
2Quantity of substance
If a traditional metering plate with a hole is used to control cooling flow, then flow metering is achieved, but heat transfer on the non-flow attached wall degrades
Solution Approach 1:
The curved diffuser section gradually redirects flow to align with the downstream channel direction, ensuring smooth flow attachment to the wall. This curved transition prevents the formation of dead zones and maintains continuous flow contact with the wall surface, preserving heat transfer efficiency
Solution Approach 2:
The diffuser angle and expansion ratio are carefully designed to optimize flow alignment. By controlling the geometric parameters of the diffuser section, the flow direction is gradually changed to match the downstream channel, ensuring attachment and maintaining heat transfer performance
3Device complexity
If a simple hole in a thin plate is used, then device complexity is low, but flow attachment to downstream channel is poor
Solution Approach 1:
The metering plate is divided into functional sections (inlet bellmouth, diffuser, outlet) that work together to progressively guide and attach flow to the downstream channel. This segmented approach achieves stable flow attachment through gradual geometric transitions rather than abrupt changes
Solution Approach 2:
Curved surfaces in the bellmouth and diffuser sections create smooth flow paths that promote attachment. The rounded geometry naturally guides flow to follow the contour and align with the downstream channel, ensuring stable flow composition and attachment
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 significantly reduces pressure losses and improves cooling efficiency by ensuring even flow distribution and attachment to the downstream channel, maintaining desired downstream pressure and heat transfer levels.
Implementation Method 1
A thin wall meter plate with an exit diffuser and optional inlet bellmouth is used to control the flow from an upstream to a downstream channel, facilitating even flow distribution and reducing pressure losses by aligning the flow axis and spreading the flow area
Implementation Method 2
dedicated cooling air is extracted from a compressor section and is used to cool the gas path components in the turbine
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A cooling device for a gas turbine engine component comprises a gas turbine engine component having an upstream channel (74) and a downstream channel (76) that define a cooling flow path. A meter feature (70) includes at least one hole (78) to meter flow from the upstream channel (74) to the downstream channel (76), and has an upstream side (80) and a downstream side (82). An exit diffuser (84) extends outwardly from the downstream side (80) of the meter feature (70) to control flow in a desired direction into the downstream channel (76).