Angled Disc Inner Surface for Soot Prevention in Centrifugal Separators
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Solution Overview
Problem
Centrifugal separators for cleaning crankcase gases from internal combustion engines face reduced separation performance due to accumulation of soot and solid combustion residues at the inner circumference of separation discs, especially under conditions of high EGR or engine wear, which blocks the interspaces between the discs.
Innovation Solution
The centrifugal separator design features a stack of separation discs with a circumferential inner end surface angled at least 20 degrees to the center axis, preventing soot and solid residues from building up on the inner surface, allowing them to slide into adjacent interspaces under centrifugal force, thus maintaining separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separation discs are arranged in a disc stack with small interspaces, then separation efficiency is improved, but soot and solid residues accumulate and block the interspaces
Solution Approach 1:
The inner circumferential surface of the separation disc is given a specific angled geometry (20-45 degrees) that differs from the rest of the disc surface. This local geometric modification creates a self-cleaning zone where soot and residues are prevented from accumulating, while the rest of the disc maintains its separation function. The angled surface locally changes the flow characteristics to prevent blockage in the interspaces.
2Ease of manufacture
If the inner circumferential surface is made parallel to the center axis, then manufacturing is simplified, but soot and residues accumulate on the surface
Solution Approach 1:
The angle parameter of the inner circumferential surface is changed from 0 degrees (parallel to center axis) to a specific range of 20-45 degrees. This parameter modification fundamentally changes the behavior of soot and residues on the surface, causing them to be directed away from the disc and into the interspaces, thereby preventing accumulation while maintaining manufacturing feasibility.
3Object-generated harmful factors
If the angled surface is set too steep (above 45 degrees), then soot prevention is improved, but manufacturing complexity increases
Solution Approach 1:
The angle parameter is optimized within a specific range (20-45 degrees) to achieve the desired effect without excessive complexity. Angles below 20 degrees are insufficient for preventing accumulation, while angles above 45 degrees create unnecessarily complex geometry and potential manufacturing difficulties. The selected range represents an optimal compromise that achieves effective soot prevention with reasonable manufacturing 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
This design effectively prevents the accumulation of soot and solid residues, ensuring consistent separation performance by directing them into interspaces between the discs, thereby maintaining the separation efficiency of the centrifugal separator.
Implementation Method 1
a surface parallel with the centre axis, i.e. a surface perpendicular to the centrifugal forces acting on the crankcase gases in the centrifugal separator, is avoided. Accordingly, soot and other solid combustion residues together with oil and/or other hydrocarbons will slide along the first surface portion into an adjacent separation disc interspace.
Data Source
AI summary
A centrifugal separator is configured for cleaning of crankcase gases from an internal combustion engine. The centrifugal separator includes a rotor rotatably arranged inside a stationary housing. The stationary housing includes an inlet for crankcase gases, a gas outlet, and a liquid outlet. The rotor includes a stack of separation discs, each separation disc of the stack of separation discs having a center axis, an inner surface, and an outer surface. A circumferential inner end surface extends between the inner surface and the outer surface. The circumferential inner end surface of at least one separation disc of the stack of separation discs includes a substantially flat first surface portion extending at an angle of at least 20 degrees to the center axis.