Ceramic Honeycomb Heat Exchanger Surface Roughness
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Solution Overview
Problem
Existing heat exchangers face challenges in achieving high heat exchange performance, particularly in automotive applications where efficient heat transfer is crucial for fuel efficiency and catalyst activation.
Innovation Solution
A heat exchange member with a honeycomb structure body and a covering member, where the partition walls and outer peripheral wall are made of ceramic containing silicon carbide, and the outer peripheral wall surface has a peak count RPc of 55 pks/cm or larger, along with a specific manufacturing method involving high-speed grinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the outer peripheral wall surface is made smooth, then the manufacturing process is simpler, but the number of contact points between the honeycomb structure body and covering member decreases, reducing heat exchange performance
Solution Approach 1:
The invention changes the surface roughness parameter of the outer peripheral wall to optimize heat exchange. By controlling the arithmetic mean roughness Ra to be 9.5 μm or less while maintaining a peak count Rp of 55 pks/cm or more, the invention achieves both manufacturability and enhanced heat transfer through increased contact points with the covering member.
Solution Approach 2:
The invention applies local quality by creating specific surface characteristics only on the outer peripheral wall that contacts the covering member. The surface is designed with controlled roughness and peak distribution in the contact region, while other parts of the honeycomb structure maintain their standard properties, thus improving heat exchange at the critical interface without complicating the entire manufacturing process.
2Reliability
If the peak count of the outer peripheral wall surface is increased to improve heat exchange performance, then the number of contact points with the covering member increases, but the surface becomes more difficult to manufacture with consistent quality
Solution Approach 1:
The invention establishes specific parameter ranges for surface roughness (Ra ≤ 9.5 μm) and peak count (Rp ≥ 55 pks/cm) that balance heat exchange performance with manufacturing feasibility. These parameter specifications provide clear manufacturing targets while ensuring sufficient contact points for effective heat transfer.
Solution Approach 2:
The invention applies partial action by focusing surface roughness control specifically on the outer peripheral wall region that contacts the covering member, rather than requiring precise control over the entire honeycomb structure surface. This targeted approach achieves the necessary contact points for heat exchange without unnecessarily complicating the manufacturing of the entire component.
3Reliability
If a ceramic material is used for the partition walls and outer peripheral wall, then the durability and heat resistance are improved, but the manufacturing complexity increases due to the need for specialized grinding processes
Solution Approach 1:
The invention optimizes the grain size parameter of the grindstone to 90 or finer and sets the circumferential speed to 3.0 m/second or higher, achieving the required surface roughness and peak count for ceramic materials. These parameter specifications enable consistent production of the desired surface characteristics while maintaining manufacturing efficiency.
Solution Approach 2:
The invention performs preliminary action by pre-specifying the optimal grinding parameters (grain size ≤ 90, circumferential speed ≥ 3.0 m/s) before the actual manufacturing process. This advance determination of processing parameters simplifies the manufacturing workflow by providing clear guidelines for achieving the required surface quality on ceramic honeycomb structures.
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 proposed solution enhances heat exchange performance by increasing the number of contact points between the honeycomb structure body and the covering member, leading to improved heat transfer efficiency and durability.
Implementation Method 1
cutting the outer peripheral wall surface with use of a grindstone having a grit size of 90 or finer and a diameter of 20 mm or larger at a circumferential speed of 3.0 m/second or higher
Implementation Method 2
The partition walls and the outer peripheral wall contain ceramic as a main component, and the outer peripheral wall surface has a peak count RPc according to JIS B 0601:2013 set to 55 pks/cm or larger
Data Source
AI summary
A heat exchange member including: a honeycomb structure body including: partition walls extending from a first end surface to a second end surface to define cells forming flow passages for a first fluid; and an outer peripheral wall; and a covering member configured to cover the outer peripheral wall of the honeycomb structure body. The partition walls and the outer peripheral wall contain ceramic as a main component, and the outer peripheral wall surface has a peak count RPc according to JIS B 0601:2013 set to 55 pks/cm or larger.