Post-swirl Propulsor Side Force Generation via Stator Pitch Control
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Solution Overview
Problem
Existing underwater vehicle control systems, such as torpedoes and UUVs, face challenges in generating sufficient control forces at low speeds, as thrust vectoring diminishes effectiveness with increased flow velocity and tunnel thrusters increase drag and occupy valuable volume, while complex designs like the Haselton bow propulsor interfere with sonar systems.
Innovation Solution
A post-swirl propulsor system is configured with individually adjustable downstream stator blade pitch angles, utilizing servo-motors and a controller to vary the pitch, generating perpendicular forces for vehicle control without significant volume reduction or sonar interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If thrust vectoring is used to generate side forces, then control is effective at zero speeds, but effectiveness is significantly diminished above five knots
Solution Approach 1:
The propulsor system dynamically adjusts the pitch angles of stator blades to vary the direction and magnitude of thrust vectors in real-time, enabling effective side force generation across a wide speed range from zero to high velocities
Solution Approach 2:
The system changes the operational parameters by varying stator blade pitch angles to alter the flow characteristics and thrust vector direction, allowing the same propulsor to generate effective side forces at both low and high speeds without performance degradation
2Ease of operation
If tunnel thrusters are used to provide lateral and vertical control, then low speed control requirements are met, but drag increases and maximum velocities are reduced
Solution Approach 1:
The invention merges the propulsion function and control function into a single integrated propulsor system, where the same rotor and stator assembly provides both forward thrust and lateral/vertical control forces, eliminating the need for separate tunnel thrusters and their associated drag penalties
3Ease of operation
If tunnel thrusters are used for control, then lateral and vertical control is provided, but considerable volume is occupied
Solution Approach 1:
The propulsor system is designed as a multi-functional device that simultaneously provides forward propulsion, lateral control, and vertical control, replacing multiple separate control devices (tunnel thrusters, control surfaces) with a single universal system that accomplishes all control tasks
Solution Approach 2:
The control functions are merged into the main propulsor assembly, utilizing the rotor-stator configuration to generate control forces in multiple directions without requiring additional dedicated control thrusters, thereby conserving vehicle volume
4Force
If Haselton bow propulsor is used to generate side forces, then substantial side force component is achieved, but mechanical complexity increases and forward looking sonar is interfered with
Solution Approach 1:
The invention extracts the control function from complex mechanical mechanisms (swashplates, cyclic pitch actuators) and implements it through a simpler rotor-stator propulsor configuration, reducing mechanical complexity while maintaining side force generation capability
Solution Approach 2:
The system replaces complex mechanical pitch control mechanisms with a more streamlined rotor-stator configuration where stator blade pitch angles are adjusted to achieve side forces, reducing mechanical complexity and eliminating interference with forward looking sonar
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 post-swirl propulsor system effectively generates side forces and moments for vehicle control at reasonable speeds, improving propulsive efficiency and avoiding the limitations of pre-swirl and thrust vectoring methods, with significant side forces achievable even at higher velocities.
Implementation Method 1
A thrust flow from the rotor combines with a circumferentially varying flow from the stator blades to produce a force on the vehicle that is perpendicular to a main axis of the vehicle
Implementation Method 2
By sinusoidally varying the stator blade pitch distribution about the circumference, it is possible to generate significant side forces
Data Source
AI summary
Systems and methods for maneuvering an underwater vehicle by generating vehicle maneuvering forces from a propulsor of the vehicle are provided. A post-swirl propulsor is configured such that pitch angles of downstream stator blades can be individually varied. The variation in pitch results in the generation of multiple forces and moments for vehicle control.