Ram Air Turbine Exhaust Compression Walls for Pressure Ratio
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Solution Overview
Problem
Conventional ram-air turbines (RATs) located internally suffer from pressure losses in inlet ducting, limiting their power generation capability and being restricted to ambient static pressure, which hinders their ability to generate mechanical or electrical power efficiently and results in larger, heavier systems.
Innovation Solution
The integration of an axial turbine with a permanent magnet alternator and the use of aerodynamic compression walls in the exhaust ducting to increase the total-to-static pressure ratio across the turbine, allowing for enhanced power extraction and reduced size and weight by accelerating free-stream air to create a lower static pressure region at the turbine discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a RAT is located internally to minimize system size and weight, then system integration is improved, but pressure losses occur in the inlet ducting which decreases turbine output power
Solution Approach 1:
The harmful pressure losses in the inlet ducting are extracted and eliminated by positioning the turbine directly in the free stream airflow, removing the inlet ducting component entirely. This allows the turbine to operate at its maximum power potential while maintaining compact system integration.
Solution Approach 2:
A diffuser component is introduced as an intermediary element that manages the transition from the compact internal housing to the free stream airflow. The diffuser optimizes flow conditions to the turbine inlet, enabling high power extraction while maintaining a compact overall system volume.
2Device complexity
If conventional RAT designs are used with ambient static pressure on the turbine discharge, then system simplicity is maintained, but power generation capability is limited
Solution Approach 1:
A vacuum exhaust system is implemented using pneumatic principles to create a pressure differential at the turbine discharge. The vacuum pump actively removes exhaust gases, creating a low-pressure region that increases the pressure ratio across the turbine and thereby significantly enhances power generation capability beyond what is achievable with passive ambient pressure discharge.
3Power
If the turbine is directly exposed to free-stream air for maximum power extraction, then power generation is optimized, but the system cannot be integrated internally and requires larger installation space
Solution Approach 1:
The turbine is nested within a compact housing structure that is integrated into the aircraft body. The housing contains the vacuum pump, diffuser, and other components in a space-efficient arrangement, allowing the high-power turbine to be installed in an internal location without requiring excessive installation space.
Solution Approach 2:
The system utilizes the third dimension by vertically integrating components and utilizing the space above and below the turbine. The vacuum pump and exhaust system are arranged in a compact vertical configuration, maximizing power extraction while minimizing the overall installation footprint within the aircraft structure.
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 configuration results in a significant increase in power generation, with experimental results showing at least 65.8% more power output compared to conventional RATs, while also reducing system size and weight by eliminating unnecessary components and stabilizing rotational speed.
Implementation Method 1
aerodynamic compression walls in the exhaust ducting to increase the total-to-static pressure ratio across the turbine
Implementation Method 2
accelerating free-stream air to create a lower static pressure region at the turbine discharge
Implementation Method 3
An axial turbine is used for demonstration purposes
Implementation Method 4
the alternator is the only driven mechanism of the turbine
Data Source
AI summary
A method for increasing the total-to-static pressure ratio across a Ram Air Turbine (RAT) has designed and experimentally tested. The invention develops a localized accelerated flow of free-stream air near the discharge of the turbine rotor exhaust. This localized accelerated flow decreases the static pressure at the exit of the turbine and allows for additional power generation for a given free-stream flight condition. Full-scale wind tunnel experimenting testing shows that creating this low static pressure region behind the turbine resulted in significant increases in turbine output power when compared to a turbine that is not subjected to this invention. The invention showed the ability to increase the total-to-static pressure ratio across the turbine.