Fuselage Divot Layout for Unducted Engine Inlet Flow Control
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Solution Overview
Problem
Unducted turbine engines experience undesirable noise levels and increased Thrust Specific Fuel Consumption (TSFC) due to accelerated inlet airflow, which is not efficiently managed by conventional methods like extending the pylon, leading to structural issues and heavier aircraft.
Innovation Solution
Incorporating a divot in the fuselage near the unducted turbine engine to control the inlet airflow speed, optimizing its geometric shape and location to match or reduce it to the freestream airflow speed, thereby reducing TSFC and minimizing structural stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the pylon is extended to move the unducted turbine engine away from the fuselage, then the inlet airflow acceleration is reduced, but the structural weight and complexity increase
Solution Approach 1:
A divot is introduced as an intermediary aerodynamic feature in the fuselage to manage inlet airflow. The divot acts as a flow conditioning element that reduces airflow acceleration to the engine inlet, replacing the need for extended pylons and achieving energy efficiency without additional structural weight
Solution Approach 2:
The shape and geometry of the divot are optimized to control airflow parameters. By adjusting the divot's depth, length, and curvature, the inlet airflow Mach number is reduced to match or fall below freestream conditions, thereby reducing TSFC without structural modifications
2Loss of energy
If the pylon is extended to reduce inlet airflow acceleration, then TSFC decreases, but structural stress and aircraft complexity increase
Solution Approach 1:
The airflow management function is merged into the fuselage structure itself through the divot feature. This integration eliminates the need for separate structural modifications like extended pylons, reducing both complexity and weight while achieving the same aerodynamic benefit
Solution Approach 2:
The divot's geometric parameters are optimized to control inlet airflow characteristics. By changing the fuselage contour locally, the inlet Mach number is reduced without requiring complex structural extensions or modifications to the engine mounting system
3Object-affected harmful factors
If conventional methods are used to manage inlet airflow, then structural integrity is maintained, but noise levels and TSFC increase
Solution Approach 1:
The divot modifies inlet airflow parameters by reducing acceleration and controlling Mach number. This aerodynamic parameter change simultaneously reduces both noise generation from high-speed inlet flow and TSFC from inefficient compression, achieving dual benefit without structural compromise
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 divot effectively controls inlet airflow Mach number, reducing TSFC by up to 5% and mitigating structural issues, resulting in a more efficient and lightweight aircraft design.
Implementation Method 1
Incorporating a divot in the fuselage near the unducted turbine engine to control the inlet airflow speed, optimizing its geometric shape and location to match or reduce it to the freestream airflow speed
Data Source
AI summary
An aircraft comprising a fuselage and an unducted turbine engine. The fuselage having a divot with an upstream edge and a downstream edge. The divot is defined by a straight reference line having a length (L) and a maximum depth (h) relative to the straight reference line. The unducted turbine engine having an engine core, a nacelle, and a set of blades. A first flow ratio (FR1) is equal to: h/L.