Marine Driven Shaft Load Testing With Thrust-Free Fluid Shear
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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 management.
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 production by shearing fluid between the disks, facilitating testing on land or in a tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If testing is performed during runs at sea, then the drive train can be tested under real operating conditions, but the testing requires substantial time and expense and involves substantial risk
Solution Approach 1:
The patent introduces an intermediary testing device consisting of two disks with radial depressions that creates fluid shear resistance. This intermediary mechanism allows the drive train to be tested under controlled conditions on land by simulating load through fluid dynamics, eliminating the need for sea-based testing while maintaining testing accuracy.
2Ease of manufacture
If the watercraft is moored to a dock and the engine is operated without moving the watercraft, then testing can be performed on land, but the turning propeller creates substantial thrust making testing difficult
Solution Approach 1:
The patent extracts the propeller from the testing system by using a disk-based fluid shear mechanism instead. The propeller is removed entirely from the test setup, and its function of creating resistance is replaced by fluid shear between rotating and stationary disks, eliminating the thrust problem while maintaining land-based testing accessibility.
3Ease of manufacture
If a service tank is used to submerge the propeller for testing, then testing can be performed on land, but the propeller still creates substantial thrust making testing difficult to manage
Solution Approach 1:
The patent replaces the propeller-submerged-in-water configuration with an intermediary disk-based fluid shear system. Instead of submerging the propeller in a service tank, the invention uses two disks with radial depressions that create fluid resistance through shear, providing the same loading effect without the problematic thrust generation.
4Adaptability or versatility
If testing is performed at sea, then comprehensive load testing can be conducted, but the device complexity and operational requirements increase substantially
Solution Approach 1:
The patent creates a simplified copy of the marine propulsion testing environment using disk mechanisms that replicate load conditions without requiring actual marine operations. The radial depressions in the disks copy the fluid dynamic effects needed for testing, providing comprehensive load testing capability with reduced system complexity.
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 and safe load testing of marine propulsion systems on land or in a tank, reducing costs and risks associated with sea-based testing while avoiding thrust issues.
Implementation Method 1
enabling load testing without thrust production 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
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.