Aeronautic Propulsion System Inlet Channel Radius Optimization
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Solution Overview
Problem
Aeronautic propulsion systems with high bypass ratios face challenges in optimizing propulsion efficiency while minimizing mass and drag penalties, particularly due to increased dimensions of the secondary flow space, which lead to mechanical integration issues and aerodynamic losses in the inlet channel.
Innovation Solution
The proposed solution involves an aeronautic propulsion system with a reduction mechanism having a specific ratio between the mean radius of the inlet channel and the low-pressure compressor, and a reduction ratio greater than 4.5, which reduces the size of the reduction mechanism and gentles the slope of the inlet channel, improving the supply of the low-pressure compressor and optimizing the fan and turbine dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the fan pressure ratio is reduced to improve propulsion efficiency, then the propulsion efficiency is improved, but the fan diameter and external dimensions of the propulsion system increase
Solution Approach 1:
The patent applies parameter changes by optimizing the fan pressure ratio to a specific range (1.04-1.29) and adjusting the fan diameter within 266.7-342.9 inches to achieve the optimal balance between propulsion efficiency and compact dimensions. This involves changing the operational parameters of the fan system to resolve the contradiction between efficiency and size.
Solution Approach 2:
The patent resolves the contradiction by introducing the reduction mechanism with a specific reduction ratio (4.5-6.0) that operates in a different dimensional space, allowing the fan to rotate at higher speeds while delivering the required thrust at lower effective speeds, thus maintaining compact fan diameter while achieving high propulsion efficiency.
2Force
If the secondary flowrate is increased to maintain thrust, then the thrust is maintained, but the external diameter and mass of the low-pressure modules increase
Solution Approach 1:
The patent changes the operational parameters by optimizing the secondary flowrate within specific ranges (20,000-80,000 kg/s) and adjusting the low-pressure module dimensions to achieve the optimal balance between thrust generation and mass. This involves changing the flow parameters to resolve the contradiction between thrust and mass.
3Speed
If the reduction ratio is increased to reduce fan speed, then the fan speed is reduced, but the reduction mechanism size increases
Solution Approach 1:
The patent applies parameter changes by optimizing the reduction ratio to a specific range (4.5-6.0) and adjusting the reduction mechanism dimensions to achieve the optimal balance between fan speed reduction and compact mechanism size. This involves changing the reduction ratio parameter to resolve the contradiction between speed reduction and mechanism size.
4Volume of moving object
If the inlet channel slope is steepened to reduce its size, then the inlet channel size is reduced, but aerodynamic losses increase
Solution Approach 1:
The patent changes the geometric parameters of the inlet channel by optimizing the slope angle and cross-sectional area to achieve the optimal balance between compact size and low aerodynamic losses. This involves changing the shape parameters to resolve the contradiction between size and energy losses.
Data Source
AI summary
A propulsion system includes a drive shaft movable in rotation about an axis of rotation, a low-pressure compressor driven in rotation by the drive shaft, the low-pressure compressor having a mean radius, a fan shaft, a fan driven in rotation by the fan shaft, a reduction mechanism coupling the drive shaft and the fan shaft, having a reduction ratio, and an inlet channel which extends between the fan and the low-pressure compressor, the inlet channel having an inlet adjacent to the fan and an outlet opposite the inlet and adjacent to the low-pressure compressor, the inlet having a mean radius. A first ratio between a ratio of a mean radius of the inlet channel and the mean radius of the low-pressure compressor, and the reduction ratio of the reduction mechanism, is strictly less than 0.35.