Honeycomb Filter Deformed Square Cell Geometry
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Solution Overview
Problem
Honeycomb filters face challenges in achieving both high thermal shock resistance and low pressure loss, as measures to enhance one often compromise the other, such as thinning the wall or increasing porosity, which can lead to reduced isostatic strength and increased pressure loss.
Innovation Solution
A honeycomb filter design featuring a deformed square cell shape with specific curved corners, a porosity of 45-65%, and a partition wall thickness of 0.15-0.26 mm, which includes a first curved portion with a radius of 40-80 μm and a second curved portion with a radius of 40-80 μm, connected by a straight portion, to balance thermal shock resistance and pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the wall thickness is reduced to decrease pressure loss, then pressure loss is reduced, but thermal shock resistance and isostatic strength deteriorate
Solution Approach 1:
The partition wall incorporates local quality variations through different porosity regions: a first region with lower porosity (higher density) near the cell corners for strength, and a second region with higher porosity in the cell center for flow efficiency. This spatial variation in material properties allows the wall to simultaneously achieve low pressure loss and high thermal shock resistance without reducing overall wall thickness.
2Loss of energy
If the porosity is increased to decrease pressure loss, then pressure loss is reduced, but thermal shock resistance and isostatic strength deteriorate
Solution Approach 1:
The partition wall uses local quality differentiation by creating regions with distinct porosity values. The first region (lower porosity) provides structural strength and thermal shock resistance, while the second region (higher porosity) reduces flow resistance. This localized variation in porosity allows the filter to achieve low pressure loss without compromising overall strength.
3Reliability
If R-shaped reinforcing portions are added to improve thermal shock resistance, then thermal shock resistance is improved, but pressure loss increases
Solution Approach 1:
Instead of adding R-shaped reinforcing portions that increase pressure loss, the invention uses local quality variation within the partition wall itself. By creating a lower porosity region at cell corners and a higher porosity region in the center, the partition wall achieves thermal shock resistance through material property differentiation rather than geometric additions, thereby avoiding increased pressure loss.
Data Source
AI summary
A honeycomb filter includes a honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion disposed at one end of the cells, wherein the plurality of cells are arranged in a square grid pattern along a first direction and a second direction in a section orthogonal to an extending direction of the cells, the shape in the section is a deformed square having a specific corner, the specific corner includes a first curved portion, a second curved portion, and a connecting portion, a radius of curvature R1 of the first curved portion and a radius of curvature R2 of the second curved portion are 40 to 80 μm, respectively, and a center distance between a center of curvature O1 of the first curved portion and a center of curvature O2 of the second curved portion is 80 to 200 μm.