Ngk Insulators, Inc.

Teruyoshi Mori

Yukio Miyairi

Naomi Noda

Shinichi Miwa

Hiroyuki Suenobu

Kazuhiko Kumazawa

Masayuki Hironaga

Kazuhiko Hamatsuka

Yuji Deguchi

Tatsuo Kawaguchi

Takao Saito

Takehide Shimoda

A heat/acoustic wave conversion component having a first end face and a second end face, includes a partition wall that defines a plurality of cells extending from the first end face to the second end face, inside of the cells being filled with working fluid that oscillates to transmit acoustic waves, the heat/acoustic wave conversion component mutually converting heat exchanged between the partition wall and the working fluid and energy of acoustic waves resulting from oscillations of the working fluid. Hydraulic diameter HD of the heat/acoustic wave conversion component is 0.4 mm or less, where the hydraulic diameter HD is defined as HD=4&#xd7;S/C, where S denotes a cross-sectional area of each cell perpendicular to the cell extending direction and C denotes a perimeter of the cross section, and the heat/acoustic wave conversion component has three-point bending strength of 5 MPa or more.

Heat/acoustic wave conversion component and heat/acoustic wave conversion unit

A heat/acoustic wave conversion component includes a plurality of monolithic honeycomb segments each including a partition wall that defines a plurality of cells extending between both end faces, and the plurality of monolithic honeycomb segments each mutually converts heat exchanged between the partition wall and the working fluid in the cells and energy of acoustic waves resulting from oscillations of the working fluid. In the heat/acoustic wave conversion component including the plurality of honeycomb segments each being monolithic configured, hydraulic diameter HD of the cells is 0.4 mm or less, open frontal area of the honeycomb segments is 60% or more and 93% or less, heat conductivity of the honeycomb segments is 5 W/mK or less, and a ratio HD/L of the hydraulic diameter HD to the length L of the honeycomb segment is 0.005 or more and less than 0.02.

A heat/acoustic wave conversion component includes a partition wall that defines a plurality of cells, inside of the cells being filled with fluid that oscillates to transmit acoustic waves, the heat/acoustic wave conversion component mutually converting heat exchanged between the partition wall and the fluid and energy of acoustic waves resulting from oscillations of the fluid. The plurality of cells have an average of hydraulic diameters HDs that is 0.4 mm or less in a plane perpendicular to the cell extending direction, the heat/acoustic wave conversion component has an open frontal area at each end face of 60% or more and 93% or less, and distribution of hydraulic diameters HDs of the plurality of cells has relative standard deviation that is 2% or more and 30% or less.

A heat/acoustic wave conversion unit includes a heat/acoustic wave conversion component and two heat exchangers. Hydraulic diameter HD of the cells in the heat/acoustic wave conversion component is 0.4 mm or less, and a ratio HD/L of HD to the length L of the heat/acoustic wave conversion component is from 0.005 to 0.02. One of the heat exchangers includes a heat-exchanging honeycomb structure and an annular tube that surrounds a circumferential face of the heat-exchanging honeycomb structure. The annular tube includes a structure body that is disposed in the channel to increase a contact area with the heated fluid, an inflow port into which the heated fluid flows, and an outflow port through which the heated fluid flows out. At least one of the heat-exchanging honeycomb structure and the structure body is made of a ceramic material that contains SiC as a main component.

Heat/acoustic wave conversion unit

There is provided a mold for extrusion forming of ceramic articles which is excellent in wear resistance and can remarkably decrease forming defects in the vicinity of outer peripheries thereof. The mold for the extrusion forming of the ceramic articles includes a diehaving a plurality of back holesand slitsa back pressing plateand a back spacerto adjust the amount of the kneaded clay to be supplied; and a pressing plateand a spacerto regulate the shape and size of the formed ceramic article. At least a portion of the supply endof the diewhich overlaps with the back pressing plateis flattened, and a surface roughness (Ra) thereof is in a range of 0.05 &#x3bc;m to 10 &#x3bc;m.

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Nagoya, Japan

Teruyoshi Mori