Variable Motive Nozzle Ejector for Turbine Engine Bleed Air
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to parasitic flows from compressor bleeds, where extracted air is often at too high a pressure and temperature, leading to energy loss and varying performance across different ambient conditions.
Innovation Solution
A variable motive nozzle ejector system is integrated into the turbine engine, featuring a ram within a primary nozzle and an actuator to adjust the nozzle area based on sensed pressure, mixing high and low pressure airflow to optimize intermediate pressure and temperature, and communicating with pressure sensors to adapt to ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed ejector is used to mix compressor bleed airflows, then the system structure is simple, but the ejector cannot adapt to daily temperature variations and delivers inconsistent airflow
Solution Approach 1:
The ejector incorporates a movable ram positioned within the primary nozzle that can adjust the nozzle area dynamically. This dynamic adjustment allows the ejector to adapt to varying ambient temperatures and maintain optimal performance across different operating conditions, resolving the contradiction between adaptability and structural simplicity.
2Productivity
If the ejector nozzle area is fixed, then the device is simpler, but the airflow delivery varies with temperature causing overflow on hot days and insufficient flow on cold days
Solution Approach 1:
The primary nozzle includes a movable ram that adjusts the nozzle area based on operating conditions. This dynamic adjustment ensures consistent airflow delivery across varying temperatures, preventing overflow on hot days and ensuring sufficient flow on cold days, while maintaining relatively simple device architecture.
3Temperature
If compressor bleed air is extracted at high pressure, then cooling effectiveness is improved, but energy loss increases due to throttling requirements
Solution Approach 1:
The ejector utilizes the high-pressure compressor bleed air that would otherwise be throttled and wasted, converting this high-pressure flow into a beneficial motive flow that drives the mixing process. This converts what was previously a harmful energy loss into a useful function, providing both cooling effectiveness and energy recovery.
Solution Approach 2:
The ejector acts as an intermediary device that mixes high-pressure bleed air with lower-pressure airflow, creating an intermediate pressure airflow suitable for turbine cooling. This eliminates the need for direct throttling of high-pressure air while achieving the required cooling parameters.
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 enhances the overall efficiency of the turbine engine by optimizing compressor bleeds, reducing energy loss, and maintaining performance across varying ambient temperatures without the need for bypass lines or throttling valves.
Implementation Method 1
mixing the first airflow with a portion of the second airflow in the ejector to form a third airflow
Implementation Method 2
adjusting the variable motive nozzle ejector based upon the sensed pressure. The variable motive nozzle ejector increases the third airflow therethrough based upon a sensed low pressure and decreases the third airflow therethrough based upon a sensed high pressure
Data Source
AI summary
A gas turbine engine system. The system includes a compressor with a first compressor stage and a second compressor stage, a turbine with a first turbine stage and a second turbine stage, a first flow path connecting the first compressor stage and the first turbine stage, a second flow path connecting the second compressor stage and the second turbine stage, a crossover flow path connecting the first flow path and the second flow path, and an ejector positioned about the crossover flow path and the first flow path. The ejector may be a variable motive nozzle ejector.