Marine Drivetrain Fluid-Shear Load Testing Without Propeller Thrust
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Solution Overview
Problem
Testing drive trains and components of marine propulsion systems is challenging due to the need for sea-based testing, which is time-consuming, expensive, and risky, and existing land-based methods face difficulties with thrust issues and low engine speed limitations.
Innovation Solution
A testing device comprising two disks with radial depressions and a securing mechanism that allows for fluid communication, enabling load testing without thrust by shearing fluid between the disks, allowing for secure mounting on driven shafts and adjustable sealing to manage fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If testing is performed at sea, then comprehensive propulsion system testing is achieved, but time consumption and expense increase substantially
Solution Approach 1:
A water-filled tank acts as an intermediary medium between the propeller and the drive train. The tank contains the propeller and absorbs its thrust, allowing the drive train to be tested on land without actual sea trials. This mediator enables comprehensive testing while eliminating the need for time-consuming sea voyages.
2Reliability
If the watercraft is moored to a dock for testing, then sea-based testing risks are avoided, but testing is limited to low engine speeds due to substantial thrust
Solution Approach 1:
The water-filled tank serves as a thrust-absorbing intermediary that allows high-speed engine operation without generating dangerous external thrust. The water mass provides resistance that contains the propeller's thrust force, enabling safe testing across the full engine speed range while maintaining land-based safety.
3Loss of time
If service tanks are used for land-based testing, then sea-based testing is avoided, but substantial thrust from the propeller creates management difficulties
Solution Approach 1:
The water-filled tank acts as a thrust-managing intermediary that absorbs and contains propeller thrust. This allows the system to be operated on land with full engine power without the management difficulties associated with traditional service tanks, as the water provides natural thrust containment.
4Adaptability or versatility
If the propeller is submerged in a service tank, then land-based testing becomes possible, but the propeller still creates substantial thrust that is difficult to manage
Solution Approach 1:
The water-filled tank provides a controlled environment where the propeller operates submerged but its thrust is absorbed by the water mass rather than being transmitted to the external environment. This intermediary arrangement enables testing location flexibility while controlling propeller thrust forces.
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
Enables efficient load testing of marine propulsion systems on land, reducing costs and risks by eliminating the need for sea-based testing and allowing for testing at various engine speeds without producing thrust, thus facilitating component evaluation and optimization.
Implementation Method 1
enabling load testing without thrust by shearing fluid between the disks
Implementation Method 2
a first portion of the first disk inner side radially inward of the first radially outer edge and a second portion of the second disk inner side radially inward of the second radially outer edge define a seal in fluid communication with the space
Data Source
Figure 1~2B
Figure 3
Figure 4
AI summary
A testing device for testing a drive train or components within a marine propulsion system is provided and includes a first disk with a plurality of first disk depressions that faces a second disk with a plurality of second disk depressions. The first disk and the second disk are secured relative to each other so that they define a space, and a seal at outer edges of the disks is in fluid communication with the space. One of the first disk and the second disk is secured to a driven shaft. Upon rotation of the driven shaft, a load is produced due to shearing of fluid between the disks, yet no thrust is produced.