Compressor Bleed Air NACA Inlet Pressure Recovery
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Solution Overview
Problem
Conventional gas turbine engines experience pressure loss due to flow separation in the compressor bleed air system, which reduces the efficiency of bleed air utilization for cooling and environmental control purposes.
Innovation Solution
Incorporating a sloped upstream portion in the inlet of the compressor bleed air system, utilizing NACA submerged inlets and stator vanes with flow passages and apertures to facilitate a gradual transition of bleed air flow, thereby reducing flow separation and recovering pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional compressor bleed air system is used, then the structure is simple, but pressure loss occurs due to flow separation
Solution Approach 1:
The patent applies curvature by replacing the conventional sharp-edged inlet with a sloped upstream portion that gradually transitions the flow direction. This curved/sloped geometry reduces flow separation and minimizes pressure loss, directly addressing the technical contradiction between energy loss and structural simplicity.
Solution Approach 2:
The sloped upstream portion performs preliminary flow conditioning before the air enters the bleed air duct. By pre-adjusting the flow direction and reducing turbulence upstream, the system minimizes subsequent pressure losses, embodying the preliminary action principle.
2Productivity
If the bleed air flow is redirected sharply, then the device complexity is low, but flow separation occurs reducing efficiency
Solution Approach 1:
The sloped upstream portion uses a curved transition geometry instead of sharp angles to redirect the bleed air flow. This curved path maintains attached flow, reduces separation, and improves system efficiency while adding only moderate geometric complexity.
Solution Approach 2:
The patent changes the geometric parameters of the inlet, specifically introducing a slope angle in the upstream portion. This parameter modification optimizes the flow transition, reducing flow separation and improving productivity with a relatively simple design change.
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 effectively reduces flow separation and pressure loss, enhancing the pressure within the bleed air cavity and improving the efficiency of the compressor bleed air system for cooling and environmental control applications.
Implementation Method 1
The elbow of the inlet may generally result in a pressure loss of the bleed air flow on an upstream side of the inlet due to flow separation of the bleed air from the upstream surface of the inlet
Data Source
AI summary
A gas turbine engine includes a compressor section having rotor shaft assembly and a stator shroud assembly including a stator shroud casing surrounding the compressor rotor shaft assembly, a compressor flow passage being defined between the compressor rotor shaft assembly and the stator shroud casing. A compressor bleed air system includes a compressor bleed air duct that includes a sloped inlet portion, such as a NACA submerged inlet portion, in the stator shroud casing. Alternatively, stator vanes at a compressor bleed air passage may have a NACA inlet scoop and an airflow passage through the stator vane providing a bleed airflow to a cavity, which has airflow passages providing bleed air to an upstream side of the bleed air passage.