Adjustable Bloom Mixer for Turbofan Engine
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bloom mixers in turbofan engines have a fixed mixing ratio between cold and hot airflows, which is suboptimal for varying flight conditions, leading to inefficiencies in engine performance, noise levels, and fan flutter risks, and existing adjustable solutions are costly and complex.
Innovation Solution
An adjustable bloom mixer that utilizes an air-guiding element and air control device to radially adjust the mixer's corrugated part based on temperature differences, altering the airflow paths to change the mixing ratio by deflecting the corrugated part inward or outward, thereby adjusting the cold and hot flow cross-sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cold flow cross-section is increased to reduce fan flutter, then fan flutter is reduced, but thrust is reduced and noise level increases
Solution Approach 1:
The bloom mixer is designed with a dynamically adjustable cold flow cross-section that can be modified during operation. The mixer includes a movable partition wall that can shift position to change the cross-sectional area, allowing the system to adapt between high thrust conditions (smaller cross-section) and fan flutter prevention conditions (larger cross-section).
Solution Approach 2:
The invention changes the geometric parameter of the cold flow cross-section by adjusting the position of the partition wall within the bloom mixer. This parameter change allows the cross-sectional area to vary continuously, enabling optimization of both thrust and fan flutter characteristics under different operating conditions.
2Reliability
If the cold flow cross-section is increased to reduce fan flutter, then fan flutter is reduced, but noise level increases
Solution Approach 1:
The bloom mixer incorporates a movable partition wall that dynamically adjusts the cold flow cross-section. During takeoff or high-speed conditions, the partition wall positions to increase the cross-section, reducing fan flutter. During cruise conditions, it repositions to minimize the cross-section, thereby reducing noise levels.
Solution Approach 2:
The invention modifies the geometric parameter of the cold flow cross-section through partition wall movement. This allows continuous adjustment of the cross-sectional area to balance between fan flutter reduction (requiring larger area) and noise reduction (requiring smaller area) based on operational requirements.
3Device complexity
If a fixed mixing ratio is used in the bloom mixer, then the structure is simple, but the mixing ratio cannot be adapted to varying flight conditions
Solution Approach 1:
The bloom mixer employs a movable partition wall that can shift position to dynamically adjust the mixing ratio between cold and hot airflows. This simple mechanical movement enables the system to adapt to varying flight conditions without requiring complex control systems or multiple adjustable components.
Solution Approach 2:
The invention changes the mixing ratio parameter by adjusting the position of the partition wall, which alters the relative cross-sectional areas available for cold and hot airflow. This allows continuous variation of the mixing ratio to optimize engine performance across different operating conditions while maintaining relatively simple structure.
4Adaptability or versatility
If existing adjustable mixing apparatus with multiple segments are used, then the mixing ratio can be adjusted, but maintenance expenditure and costs are high
Solution Approach 1:
Instead of using complex multi-segment articulated structures, the invention employs a single movable partition wall that can shift position to adjust the mixing ratio. This simplified dynamic structure reduces the number of moving parts, lowers maintenance requirements, and decreases operational costs while still enabling effective mixing ratio adjustment.
Solution Approach 2:
The invention extracts and eliminates the complex multi-segment structure from the adjustable mixing apparatus. By using a single partition wall instead of multiple articulated segments, the design removes unnecessary complexity, reduces maintenance expenditure, and lowers costs while maintaining the essential function of mixing ratio adjustment.
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 allows for optimal adaptation of the mixing ratio to flight conditions, reducing fan flutter, minimizing noise, and influencing thrust at lower maintenance and operational costs by leveraging temperature-induced expansion to adjust the mixer's geometry.
Implementation Method 1
the bloom mixer is thus radially adjusted outwards or inwards due to the temperature difference at the inner and outer surfaces and due to the expansion behavior this entails
Data Source
AI summary
An adjustable bloom mixer for a turbofan engine for setting a mixing ratio, adapted to the respective flight condition, between cold airflow in the bypass duct and hot airflow in the core flow duct includes an air-guiding element (13) arranged upstream of a thin-walled, corrugated part (6b) of the bloom mixer (6) for branching off a cold partial airflow and/or a hot partial airflow from the bypass duct and from the core flow duct of the engine. An air control device (14) is assigned to the air-guiding element (13) for leading the branched-off cold airflow or hot airflow along the inner surface and/or the outer surface of the bloom mixer (6) in order to deflect its corrugated part (6b) radially inwards or outwards on the basis of a temperature difference between an inner and an outer surface effected by the hot and/or cold partial airflow.