Fluidic Barrier on Fan Blade Low Pressure Side
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Solution Overview
Problem
Current turbofan engines face limitations in maintaining constant operating pressure ratios and efficiently reducing fan pressure ratios while minimizing core pressure loss due to bypass/core pressure leakage, especially at reduced power settings, which affects engine performance.
Innovation Solution
A fluid barrier is created between the core and bypass streams using high-pressure jets and vortices generated by splitters or fan blades, inhibiting pressure leakage by imparting momentum to resist flow from the higher pressure core stream into the bypass stream, with mechanisms like fluid jets and vortex generators positioned at the interface between the streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan pressure ratio is reduced to improve low power flight efficiency, then the engine can operate more efficiently at reduced power settings, but core pressure loss due to bypass/core pressure leakage increases
Solution Approach 1:
A fluid barrier is introduced as an intermediary between the core and bypass streams. This fluid barrier, generated by injecting fluid into the region between the streams, acts as a mediator that prevents direct pressure leakage from the core stream to the bypass stream, thereby reducing core pressure loss while allowing the fan pressure ratio to be reduced for improved low power flight efficiency.
Solution Approach 2:
The invention uses pneumatic principles by injecting high-pressure fluid (typically air from the compressor) into the region between the core and bypass streams. This injected fluid creates a pressurized barrier that physically blocks the pressure leakage path, utilizing gas dynamics and pressure differential principles to maintain core pressure while enabling reduced fan pressure ratio operation.
2Adaptability or versatility
If the fan pressure ratio is reduced to allow flexible operation at diverse power settings, then the engine can adapt to varying flight conditions, but pressure leakage from core to bypass stream increases
Solution Approach 1:
The fluid barrier serves as a dynamic intermediary that can be activated or adjusted based on operating conditions. When the engine operates at reduced power settings where pressure leakage becomes problematic, the fluid barrier is injected to block the leakage path. This allows the engine to maintain adaptability across diverse power settings while suppressing the harmful pressure leakage effect when necessary.
Solution Approach 2:
The fluid barrier system is dynamic in nature, allowing the engine to adapt its internal flow structure based on operating conditions. The barrier can be injected, adjusted, or deactivated depending on the power setting and flight condition, enabling the engine to optimize performance across the full range of mission adaptive requirements while preventing pressure leakage when operating at reduced power ratios.
3Loss of energy
If a fluid barrier is introduced to prevent pressure leakage, then core pressure loss is reduced, but the device complexity increases
Solution Approach 1:
Rather than introducing complex mechanical barriers or physical structures, the invention uses pneumatic principles to create the barrier. High-pressure fluid is injected through relatively simple nozzles or injectors into the region between the core and bypass streams, where it naturally expands and forms a pressure barrier. This approach achieves effective pressure leakage prevention while minimizing structural complexity compared to mechanical barrier solutions.
Solution Approach 2:
The fluid barrier system utilizes the engine's own compressed air from the compressor to create the barrier, rather than requiring external power sources or complex control systems. The high-pressure fluid is drawn from the compressor output and injected where needed, allowing the system to self-regulate and maintain the barrier using the engine's existing pneumatic resources, thereby reducing overall system complexity.
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 fluid barrier effectively limits pressure loss in the core engine, maintaining efficient engine operation and reducing unnecessary loading on the turbine, thereby enhancing propulsion system performance across varying flight conditions and power settings.
Implementation Method 1
A fluid barrier is created between the core and bypass streams using high-pressure jets and vortices generated by splitters or fan blades, inhibiting pressure leakage by imparting momentum to resist flow from the higher pressure core stream into the bypass stream
Implementation Method 2
A fluid barrier is created between the core and bypass streams using high-pressure jets and vortices generated by splitters or fan blades
Data Source
AI summary
A turbofan engine has a fan portion in fluid communication with a core stream and a bypass stream of air separated by splitters disposed both upstream and downstream of the fan portion. A fluid passage is defined between the splitters. The turbofan engine has a plurality of high pressure fluid jets originating from the low pressure side of the fan blades, the jets restricting the migration of the core stream into the bypass stream through the fluid passage.