Adjustable Flow Tunnel for Vessel Propeller Efficiency
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Solution Overview
Problem
Conventional inland vessels with fixed flow tunnels face inefficiencies in both shallow and deep water conditions due to increased drag and reduced propeller efficiency when loaded, as the tunnels are not adaptable to varying draft conditions and propeller designs.
Innovation Solution
A vessel with a rotatably mounted propeller and adjustable tunnel members that can form a sealing engagement with a nozzle to create an adjustable flow tunnel, allowing for efficient water flow in shallow water while retracting to reduce drag in deeper water, utilizing a sealing engagement and longitudinal seal arrangement to maintain underpressure and prevent air inflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed flow tunnel is provided on the hull, then water flow towards the propeller is improved in shallow draft conditions, but drag force on the hull increases when the vessel moves through deeper water
Solution Approach 1:
The flow tunnel is designed with movable tunnel members that can be extended or retracted relative to the hull. In shallow water conditions, the tunnel members are extended to form a flow tunnel that improves water flow towards the propeller. In deeper water conditions, the tunnel members are retracted to reduce drag force, allowing the vessel to adapt to varying draft conditions optimally
2Productivity
If the vessel operates in shallow water with the flow tunnel extended, then propeller efficiency is improved, but the tunnel members create increased drag when retracted in deeper water
Solution Approach 1:
The system dynamically adjusts the tunnel member position based on operating conditions. The tunnel members are extended in shallow water to maximize propeller efficiency and retracted in deeper water to minimize energy loss from drag, optimizing the balance between propulsion efficiency and energy consumption
3Adaptability or versatility
If tunnel members are made movable to adapt to varying draft conditions, then the system becomes more complex, but operational flexibility is improved
Solution Approach 1:
The flow tunnel is divided into multiple separate tunnel members that can move independently relative to the hull. This segmentation allows each tunnel member to be controlled separately, providing adaptability to varying draft conditions while keeping the complexity of individual components manageable and the overall system modular
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 adjustable tunnel member system enhances propeller efficiency by maintaining underpressure and reducing drag, enabling efficient propulsion in both shallow and deep water conditions without the need for constant tunnel deployment.
Implementation Method 1
the tunnel member forms a sealing engagement with the nozzle for maintaining an underpressure inside the flow tunnel
Implementation Method 2
the rotating propeller generates a suction effect in the region before the propeller. When the flow tunnel is formed, the propeller motion creates a partial vacuum (underpressure) inside the flow tunnel. This partial vacuum helps to draw in surrounding water towards the propeller
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
A tunnel member assembly (41a) adapted for attaching in or onto a hull of a vessel with a propeller that is rotatably mounted with respect to the hull and a nozzle (30) surrounding the propeller. The tunnel member assembly comprises a casing (64) adapted for mounting the tunnel member assembly in or onto the hull, and a tunnel member (42a), which is coupled to and moveable with respect to the casing between: - a retracted state, wherein the tunnel member is removed from the nozzle, and - an extended state, wherein the tunnel member defines at least a part of an adjustable flow tunnel (40) for conveying a flow of water towards the propeller, and wherein the tunnel member abuts the nozzle to form a sealing engagement for maintaining an undeipressure inside the flow tunnel.