Bleed Air Duct Central Insert Venturi Effect
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Solution Overview
Problem
Gas turbine engines face pressure loss challenges when tapping air for bleed applications, which affects air supply efficiency and aircraft performance, particularly as thrust increases.
Innovation Solution
A bleed air supply system with a duct featuring a central insert that creates a venturi effect by reducing the cross-sectional flow area upstream and increasing it downstream, along with strategically spaced inlet ends and the use of a diffuser with an outer and inner shroud, and part-circular radius portions to minimize pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If air is tapped from a high pressure port downstream of the compressor section, then sufficient air supply is achieved, but pressure loss increases and engine efficiency decreases
Solution Approach 1:
The patent applies parameter changes by modifying the physical parameters of the duct system - specifically changing the cross-sectional area distribution along the duct length and the angle of inlet ports. The duct cross-section transitions from a smaller upstream area to a larger downstream area, and inlet ports are angled between 45-90 degrees relative to the duct axis. These parameter optimizations reduce flow resistance and pressure loss while maintaining adequate air supply quantity.
2Quantity of substance
If air is tapped from a high pressure port, then air supply is sufficient, but the pressure at the port rises until a shutoff valve closes
Solution Approach 1:
The patent implements dynamics by making the duct cross-sectional area variable along its length rather than constant. The duct transitions from a smaller cross-section at the upstream end to a larger cross-section at the downstream end, creating a gradual expansion that accommodates varying pressure conditions. This dynamic geometric adaptation allows the system to maintain stable air supply without excessive pressure buildup that would trigger shutoff valves.
3Loss of energy
If a central insert is added to create a venturi effect, then pressure loss is reduced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the duct interior into distinct zones using a central insert. The insert creates a venturi effect by defining a restricted upstream section that transitions to an expanded downstream section. This segmentation of the flow path into zones of different cross-sectional areas generates the beneficial pressure recovery effect while keeping the overall duct structure relatively simple.
Solution Approach 2:
The patent employs curvature principles by designing the central insert with smooth, rounded contours rather than sharp edges. The insert features a curved venturi profile that gradually narrows and then expands the flow passage, minimizing flow separation and turbulence. This curved geometry optimizes the venturi effect for pressure loss reduction while maintaining manufacturing feasibility.
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 loss and enhances the efficiency of air delivery to aircraft systems, ensuring sufficient air supply without compromising engine efficiency.
Implementation Method 1
the central insert provides a venturi effect by reducing the cross-sectional flow area between the insert and an inner wall of the duct of the upstream end
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A bleed air supply system for a gas turbine engine (10) comprising a duct (50) having an inlet end (79) and extending to an outlet end (400). The inlet end (79) of the duct (50) is provided with a central insert (82). In another feature, there may be a plurality of ducts (50), and inlet ends (79) of the plurality of ducts (50) being spaced by at least 90°. In another feature, a compressor (12) may have a diffuser (118) with a shroud ending upstream of the downstream end of an inner shroud (54), having an outer shroud (58) ending at a location upstream of a downstream end of an inner shroud (54) at locations circumferentially aligned with an inlet (79) end of the duct (50).