Variable Pitch Marine Thruster Power Optimization
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Solution Overview
Problem
Conventional lateral tunnel thrusters in marine vehicles become ineffective at intermediate forward speeds due to decreased side force production, as the propeller blades operate off-design with increased fluid velocity, leading to reduced maneuvering capabilities.
Innovation Solution
A system that monitors and adjusts the electrical power to the thruster motor to maintain a predetermined level of lateral thrust by varying the pitch of the propeller blades, using voltage and current meters to provide feedback for a computer-controlled pitch actuator, ensuring optimal thrust regardless of forward velocity and ambient currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the propeller rotates at fixed speed to provide lateral thrust, then the thruster is simple to control, but the side force decreases significantly at intermediate forward velocities
Solution Approach 1:
The propeller pitch is made dynamically adjustable through a variable pitch mechanism that allows the blades to change their angle of attack in real-time. This dynamic adjustment enables the propeller to adapt to varying forward velocities and maintain optimal thrust production across different operating conditions, resolving the contradiction between simple control and effective force generation.
Solution Approach 2:
The system changes the operational parameters of the propeller by varying the pitch angle in response to detected forward velocity. When forward velocity increases, the pitch angle is adjusted to compensate for the off-design operating conditions, thereby maintaining effective side force production. This parameter change approach transforms a fixed-parameter system into an adaptive one that overcomes the performance degradation at intermediate speeds.
2Productivity
If the propeller pitch is adjusted to maintain optimal thrust at high forward speeds, then thrust efficiency improves, but the control system complexity increases
Solution Approach 1:
The system employs a feedback mechanism where a sensor detects the actual forward velocity of the vehicle, and this information is fed back to the control system. The control system then adjusts the propeller pitch based on this feedback to maintain optimal thrust efficiency. This feedback approach enables automatic adaptation to operating conditions while keeping the control logic relatively simple and rule-based.
Solution Approach 2:
The system performs self-adjustment by automatically detecting its own operating conditions (forward velocity) and autonomously modifying its parameters (propeller pitch) to maintain optimal performance. This self-service capability eliminates the need for complex external control systems or manual intervention, achieving thrust efficiency through autonomous adaptation.
3Device complexity
If conventional control surfaces are used for maneuvering, then the structure is simple, but maneuvering effectiveness decreases at low speeds due to insufficient flow
Solution Approach 1:
The lateral tunnel thruster acts as an intermediary device between the vehicle's propulsion system and the water medium. Instead of relying solely on the vehicle's forward motion to generate flow over control surfaces, the thruster actively pumps water through a tunnel and over the propeller blades, creating the necessary flow conditions for effective maneuvering force generation even at low speeds.
Solution Approach 2:
The system uses hydraulic principles by employing a pumped flow system that forces water through a tunnel and over the propeller blades. This hydraulic approach creates controlled water flow independent of vehicle speed, enabling the generation of effective maneuvering forces at low speeds where conventional aerodynamic control surfaces would be ineffective.
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 maneuverability and thrust efficiency at intermediate speeds by maintaining optimal blade pitch, compensating for increased fluid velocity and currents, thereby improving the overall performance of lateral thrusters and extending effective control beyond the limitations of conventional systems.
Implementation Method 1
The rotating propeller creates a pressure differential across the blades and drives a jet of water through the tunnel and out one side. The integrated pressure force on the blades is transferred as a force to the vehicle
Implementation Method 2
The rotating propeller creates a pressure differential across the blades and drives a jet of water through the tunnel and out one side. The integrated pressure force on the blades is transferred as a force to the vehicle that acts in the opposite direction of the jet flow
Data Source
AI summary
A system and method of use for a marine vehicle to compensate for the effects of forward velocity of the vehicle and ambient currents of a water medium on lateral thrust from a lateral tunnel in the vehicle. A thruster in the tunnel has a variable pitch propeller rotated by a motor at a maintained constant speed to produce lateral thrust of flowing water through the tunnel. A power supply provides input power to the motor, and voltage and amp meters provide signals representative of the power. A computer generates pitch control signals from the representative signals, and a pitch actuator connected to the propeller and the computer is responsive to the pitch control signals to change the blade pitch of the propeller in order to maintain the lateral thrust at a predetermined level.