Bleed Valve Ringed Flow Path for Quieter Gas Turbine Venting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines generate undesirable noise due to the venting of high pressure air, which is disruptive during low-power operations like aircraft approach or ground operations, affecting nearby residents and ground crew.
Innovation Solution
A bleed valve with a tortuous path defined by concentrically positioned rings and swirl vanes that reduce the pressure of the fluid flow, incorporating serrations on the terminal segments of the rings to minimize turbulent kinetic energy and noise, is used to vent high pressure air from the compressor section into the outer bypass duct.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure air is vented directly from the compressor section, then the venting function is achieved, but undesirable noise is generated due to mixing with lower pressure air in the fan bypass duct
Solution Approach 1:
The venting path is segmented into multiple sections using a series of rings (first ring, second ring, third ring, fourth ring) spaced apart from each other. This segmentation creates a tortuous path that divides the direct high-pressure jet into multiple smaller flow sections, reducing the intensity of noise-generating mixing with bypass air.
Solution Approach 2:
The tortuous path defined by the spaced-apart rings forces the high-pressure air to follow a curved, non-linear trajectory rather than a straight path. This curvature increases flow path length and promotes gradual pressure equalization, reducing turbulent mixing noise when the air enters the bypass duct.
2Object-generated harmful factors
If a tortuous path is introduced to reduce noise, then noise levels decrease, but the device complexity increases due to multiple rings and swirl vanes
Solution Approach 1:
The rings serve multiple functions simultaneously: they define the tortuous flow path, provide mounting surfaces for swirl vanes, and act as flow control elements. The swirl vanes themselves perform dual functions of inducing rotation and further defining the tortuous path. This multi-functionality reduces the need for separate noise-reduction components.
Solution Approach 2:
The swirl vanes are nested within the spaces between the rings, with first swirl vanes mounted on the first ring and second swirl vanes mounted on the second ring. This nested arrangement integrates multiple flow control features into a compact structure, achieving complex flow management without proportionally increasing overall device size or complexity.
3Object-generated harmful factors
If swirl vanes are added to further reduce noise, then turbulent kinetic energy decreases, but manufacturing complexity increases
Solution Approach 1:
Swirl vanes are strategically placed only at specific locations where they provide maximum benefit for reducing turbulent kinetic energy. The first swirl vanes are positioned on the first ring and the second swirl vanes on the second ring, creating localized flow control zones rather than requiring swirl control throughout the entire venting path. This selective placement optimizes noise reduction while minimizing manufacturing complexity.
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 bleed valve significantly reduces noise by lowering turbulent kinetic energy levels and peak Mach numbers, thereby minimizing the disruptive noise associated with the venting of high pressure air from gas turbine engines.
Implementation Method 1
The housing defines a tortuous path for the fluid flow from the inlet to the outlet configured to reduce a pressure of the fluid flow from the inlet to the outlet within the housing
Implementation Method 2
The terminal segment includes a plurality of serrations. The bleed valve includes at least one swirl vane coupled within the housing downstream of the inlet... significantly reduces noise by lowering turbulent kinetic energy levels
Implementation Method 3
The at least one swirl vane is coupled within the housing at an angle relative to a central axis that extends through the housing... The at least one second swirl vane is coupled within the housing at the angle relative to the central axis
Data Source
AI summary
A bleed valve for a gas turbine engine includes a housing that defines an inlet upstream from an outlet. The bleed valve includes a poppet movable relative to the housing between a first position, in which the poppet closes the inlet, and a second position, in which the inlet is open and configured to receive a fluid flow. The housing defines a tortuous path for the fluid flow from the inlet to the outlet configured to reduce a pressure of the fluid flow from the inlet to the outlet within the housing. The tortuous path is defined by a plurality of rings positioned about the poppet, with each ring of the plurality of rings spaced apart from an adjacent ring of the plurality of rings between the inlet and the outlet to define the tortuous path.