Axially Translatable Gaspath Bleed Valve Ring
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Solution Overview
Problem
Conventional compressor bleed off valve (BOV) arrangements in gas turbine engines suffer from pressure losses and inefficiencies in extracting water and hail particles, especially at low engine operating conditions due to reliance on static pressure differences and limited effectiveness in redirecting particles trajectories.
Innovation Solution
A bleed off valve (BOV) with a ring that is axially translatable between retracted and deployed positions, positioned in a converging portion of the radially outer annular wall, mechanically scoops water and hail particles from the core gaspath by using total pressure and a ramp to deflect the flow, enhancing extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional radial off take BOV arrangement is used, then the sealing piston can close off the bleed passage, but pressure losses occur as core flow passes under the piston even when closed
Solution Approach 1:
The invention extracts the sealing function from the flow path by positioning the sealing piston in a retracted location away from the core flow passage. The seal engages with the radial off take opening rather than blocking the main flow path, eliminating pressure losses while maintaining sealing effectiveness.
Solution Approach 2:
The invention introduces a seal as an intermediary element that transfers the sealing function from the piston to the radial off take opening. The seal engages with the opening when the piston is retracted, allowing the piston to be positioned optimally without compromising sealing.
2Device complexity
If conventional BOV relies on static pressure differential to extract water and hail, then the system is simple, but extraction efficiency is limited especially at low engine operating conditions
Solution Approach 1:
The invention makes the BOV system dynamic by enabling axial translation of the ring between retracted and deployed positions. At low power conditions, the ring can deploy forward to mechanically scoop particles, while at high power conditions it retracts to rely on pressure differential, optimizing performance across all operating ranges.
Solution Approach 2:
The invention changes the operational parameters of the BOV system by introducing axial position as a controllable variable. The ring's axial position is adjusted based on engine operating conditions, transforming the system from a static pressure-based extractor to a dynamic system that can switch between mechanical scooping and pressure-driven extraction modes.
3Productivity
If the ring protrudes into the gaspath to mechanically scoop particles, then extraction efficiency improves, but device complexity increases
Solution Approach 1:
The invention merges the particle extraction function with the existing BOV structure by integrating the ring directly into the valve assembly. The ring is axially translatable along with the piston, combining sealing and particle extraction functions in a single integrated mechanism rather than adding separate components.
Solution Approach 2:
The ring serves multiple functions: it acts as a sealing element when retracted and as a mechanical scooping device when deployed. This multi-functionality reduces the need for separate components and simplifies the overall system while improving extraction efficiency.
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 achieves efficient extraction of air, water, and hail particles, particularly at low power conditions, with up to 80% hail extraction, by mechanically redirecting particles and reducing core flow losses, resulting in improved water-to-air ratio management and preventing combustor flameouts.
Implementation Method 1
mechanically scoops water and hail particles from the core gaspath by using total pressure
Implementation Method 2
a ramp to deflect the flow, enhancing extraction efficiency
Data Source
AI summary
A bleed of valve comprises a ring axially translatable between a retracted position in which the ring is configured to close an annular bleed off opening defined in a converging portion of a radially outer annular wall of a gas turbine engine gaspath and a deployed position in which the ring protrudes into the gaspath to mechanically scoop out incoming air and water/hail particles.