Bi-directional Pump Nacelle Flow Control
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Solution Overview
Problem
Current gas turbine engine propulsion systems lack efficient integrated flow control mechanisms for optimizing airflow distribution and thrust reversal, leading to suboptimal performance in terms of size, weight, and efficiency.
Innovation Solution
The integration of a bi-directional pump and perforated surfaces within the nacelle assembly, which includes a thrust reverser and inlet lip, allows for selective airflow direction in response to operability conditions, enhancing airflow distribution and reducing drag by controlling boundary layers and flow separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate flow control systems are used for inlet lip and thrust reverser, then each component can be optimized independently, but the overall system size and weight increase
Solution Approach 1:
The patent combines separate flow control systems into a single integrated system where one pump serves both the inlet lip boundary layer control and the thrust reverser efflux flow control. This merging eliminates redundant components and reduces overall system weight while maintaining the ability to independently control each function through selective pump operation.
2Weight of stationary object
If a single integrated flow control system is used, then system weight is reduced, but the complexity of controlling multiple functions increases
Solution Approach 1:
The patent employs a bi-directional pump that can dynamically switch between different flow directions and operational modes based on flight conditions. The system transitions between boundary layer control mode (drawing flow from inlet lip) and thrust reverser mode (discharging flow over cascade), with the ability to operate in either direction or both simultaneously, reducing mechanical complexity compared to multiple fixed-function pumps.
Solution Approach 2:
The single pump is designed to perform multiple functions: it can draw airflow from the inlet lip for boundary layer control, discharge airflow over the thrust reverser cascade for efflux control, or perform both functions simultaneously. This multi-functionality eliminates the need for separate dedicated pumps for each control function.
3Productivity
If boundary layer control is applied at the inlet lip, then airflow distribution is optimized, but additional energy consumption occurs
Solution Approach 1:
The boundary layer control system operates periodically or intermittently rather than continuously, activating the pump only when boundary layer control is needed (such as during high-angle-of-attack conditions or thrust reversal deployment) and deactivating it during normal cruise conditions, thereby reducing overall energy consumption while maintaining airflow distribution efficiency when required.
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
This solution improves the overall performance of the propulsion system by optimizing airflow distribution, reducing drag, and enhancing thrust reversal efficiency, resulting in a more compact and efficient design.
Implementation Method 1
controlling boundary layers and flow separation
Implementation Method 2
controlling boundary layers and flow separation
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A nacelle assembly (16) for a gas turbine engine includes a fan nacelle (62) bounding a bypass flow path (B). The fan nacelle (62) includes a first nacelle section (68A) and a second nacelle section (68B). The second nacelle section (68B) includes a moveable portion (79) movable relative to a forward portion (81) to define a secondary flow passage (74). The first nacelle section (68A) includes an inlet lip (71). A thrust reverser (72) is configured to selectively communicate a portion of bypass airflow between the bypass flow path (B) and the secondary flow passage (74). A pump (88) is configured to selectively communicate airflow between the inlet lip (71) and the secondary flow passage (74).