Variable Area Journal Bearing for Drag Reduction
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Solution Overview
Problem
Hydrodynamic journal bearings are overdesigned in areas not exposed to maximum loads, leading to inefficiencies in drag and fuel efficiency due to uniform load-bearing capacity around the circumference, which results in higher viscous drag and reduced energy efficiency.
Innovation Solution
The journal bearing's effective surface area is varied and adjusted to match instantaneous load conditions by rotating the bearing within a support structure, allowing the load-bearing capacity to change around the circumference, reducing frictional losses and optimizing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the journal bearing is designed with uniform load-bearing capacity around the circumference, then the bearing can accommodate the greatest (maximum) load, but the bearing is overdesigned in areas not exposed to maximum loads, leading to increased drag and reduced fuel efficiency
Solution Approach 1:
The bearing inner lining is designed with non-uniform thickness around the circumference, creating variable load-bearing capacity that matches the local load requirements. The thicker section provides enhanced load-bearing capacity where maximum loads occur, while thinner sections reduce drag in areas experiencing lower loads, thereby resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The bearing is designed to rotate within the support structure, dynamically adjusting the position of the variable thickness profile relative to the journal. This allows the bearing to adapt its load-bearing characteristics to varying operational conditions, optimizing the match between load-bearing capacity and actual load requirements while minimizing drag losses.
2Force
If the journal bearing provides uniform hydrodynamic load-bearing capacity around its circumference, then the bearing can handle worst case maximum loads, but the bearing is not optimized for drag and fuel efficiency in areas not exposed to greatest applied loads
Solution Approach 1:
The bearing inner lining features locally varied thickness, with thicker sections positioned to provide enhanced load-bearing capacity where maximum journal loads are applied, and thinner sections in areas experiencing lower loads. This local differentiation optimizes the balance between force-bearing capability and fuel efficiency by reducing unnecessary material and drag in low-load zones.
Solution Approach 2:
The bearing design intentionally introduces asymmetry in the inner lining thickness around the circumference, breaking the uniform symmetry of conventional bearings. This asymmetric profile is strategically configured to match the asymmetric load distribution experienced by the journal, thereby improving fuel efficiency without compromising the ability to handle maximum loads when required.
3Reliability
If the surface area of the journal bearing is increased to provide greater load-bearing capacity, then the bearing can accommodate higher loads, but the viscous drag forces increase, reducing energy efficiency
Solution Approach 1:
Rather than uniformly increasing the bearing surface area, the invention applies increased thickness (and thus load-bearing capacity) only in the specific circumferential regions where maximum loads are applied. This localized approach provides the necessary reliability for high load conditions while minimizing the overall surface area that generates viscous drag, thereby preserving energy efficiency.
Solution Approach 2:
The invention changes the geometric parameter of the bearing inner lining from uniform thickness to variable thickness. This parameter change allows the bearing to provide greater load-bearing capacity through increased thickness in critical load zones, while maintaining smaller surface area in non-critical zones, thus reducing viscous drag and improving energy efficiency.
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 approach minimizes viscous friction losses, enhancing energy efficiency by matching the bearing surface area to the instantaneous load, thereby reducing drag and improving fuel economy.
Implementation Method 1
Hydrodynamic (fluid film) journal bearings are designed to provide uniform hydrodynamic load-bearing capacity around the circumference of the journal bearing
Implementation Method 2
rotating the hydrodynamic plain journal bearing within the support structure to change a position of the load-bearing capacity of the journal bearing relative to the journal
Data Source
AI summary
A method of adjusting a load-bearing capacity of a hydrodynamic plain journal bearing for a journal is provided comprising providing a hydrodynamic plain journal bearing having a circumference, wherein a load-bearing capacity of the journal bearing varies around the bearing circumference; providing the hydrodynamic plain journal bearing in a journal bearing support structure, wherein the support structure supports the hydrodynamic plain journal bearing around the journal; and rotating the hydrodynamic plain journal bearing within the support structure to change a position of the load-bearing capacity of the journal bearing relative to the journal.