Underwater Propulsion Device Low-Vibration Control

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Solution Overview

Problem

Underwater exploration apparatuses face challenges with propeller-driven systems causing vibration and disturbing observation targets, and pump-jet systems struggling with low-speed propulsion force and fine attitude control.

Innovation Solution

A pump-jet-driven underwater propulsion apparatus with a diffuser and direction control wings, where the jet flow blasts along the direction control wings, and entrained flow introducing channels and grooves enhance propulsion force and control, allowing for reduced vibration and efficient low-speed operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a propeller-driven system is used for underwater propulsion, then propulsion force is generated, but the apparatus body vibrates and water around the apparatus body is agitated, disturbing observation targets

Engineering Contradiction:
Improvepropulsion forceVSAvoidvibration and water agitation disturbing observation targets
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical propeller system with a pump-jet system. The pump-jet apparatus uses an impeller enclosed within a diffuser structure to generate thrust through fluid dynamics rather than direct mechanical propeller rotation, thereby reducing vibration and water agitation that disturbs observation targets like planktons.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The diffuser structure acts as an intermediary between the impeller and the external water environment. It encloses the impeller and gradually expands to convert kinetic energy into pressure, mediating the interaction between the rotating impeller and surrounding water to minimize turbulence and vibration while maintaining propulsion effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the number of revolutions of the impeller is decreased in a pump-jet system, then energy consumption is reduced, but the pressure of the blasted flow decreases, making it difficult to produce necessary propulsion force in low-speed operation

Engineering Contradiction:
Improveenergy consumptionVSAvoidpropulsion force in low-speed operation
Core Design Contradiction:
Use of energy by moving objectVSForce

Solution Approach 1:

The patent optimizes geometric parameters of the diffuser structure, including the expansion angle and length of the diffuser channels, to enhance flow guidance and pressure recovery. This allows the system to maintain effective propulsion force even at lower impeller rotation speeds, enabling energy-efficient low-speed operation without sacrificing thrust capability.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If a conventional pump-jet system is used, then vibration is reduced compared to propeller-driven systems, but fine attitude control including backward movement and quick pivotal movement is difficult to achieve

Engineering Contradiction:
Improvevibration levelVSAvoidfine attitude control capability
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent divides the single pump-jet propulsion system into multiple independent pump units (typically three or four), each capable of independent operation. This segmentation enables differential thrust generation, allowing the apparatus to achieve fine attitude control, backward movement, and quick pivotal movements by independently adjusting the speed and direction of each pump unit, while maintaining the low-vibration benefits of pump-jet propulsion.

Inventive Principle:
Principle #1Segmentation

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 solution provides a low-vibration, efficient propulsion system capable of fine attitude control and maintaining necessary propulsion force during low-speed operations, suitable for forward, backward, and pivotal movements.

Implementation Method 1

jet flow (F) blasted via the nozzle flows along an outer surface of the plurality of direction control wings

Methodology Applied
Scientific EffectJet flow: Jet

Implementation Method 2

a first entrained flow introducing channel that passes through the diffuser and introduces water flow flowing along an outer side of the diffuser into a propulsion channel sandwiched between the diffuser and the direction control wings

Methodology Applied
Scientific EffectEntrained flow: Entrainment

Data Source

PatentEP3202658B1Underwater propulsion device and underwater search device
Publication Date: 2019.11.06 NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF MARINE SCIENCE AND TECHNOLOGY
  • EP3202658B1 patent drawingFigure 1(a)~1(b)
  • EP3202658B1 patent drawingFigure 2
  • EP3202658B1 patent drawingFigure 3(a)~3(b)

AI summary

There are provided an underwater propulsion apparatus and an underwater exploration apparatus producing a small amount of vibration and capable of ensuring propulsion force necessary in low-speed operation and performing fine attitude control. [Solution] An underwater propulsion apparatus 1 according to an embodiment includes a main body 2 having a conical tail portion, a channel 4 having an inlet 6 in the outer circumferential surface of the main body 2 and a nozzle 7 on the side downstream of the inlet 6 and in the tail portion, at least one pump 3 having an impeller 5 provided in the channel 4, a diffuser 8 attached to the main body 2 so as to surround the outer circumference of the nozzle 7, and a plurality of direction control wings 9 attached to the outer surface of the main body 2 and located in positions downstream of the nozzle 7 and close thereto, each of the plurality of direction control wings 9 having an upstream end pivotally supported by the main body 2.