Heat/acoustic wave conversion unit

Patent metadata

Field	Value
Publication number	US-9759157-B2
Application number	US-201514849984-A
Country	US
Kind code	B2
Filing date	Sep 10, 2015
Priority date	Sep 19, 2014
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

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.

First claim

What is claimed is:

1. A heat/acoustic wave conversion unit, comprising:
a heat/acoustic wave conversion component having a first end face and a second end face, the heat/acoustic wave conversion component including 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;
a low-temperature side heat exchanger that is disposed adjacent to a first end part of the heat/acoustic wave conversion component on the first end face side, the low-temperature side heat exchanger exchanging heat with the first end part; and
a high-temperature side heat exchanger that is disposed adjacent to a second end part of the heat/acoustic wave conversion component on the second end face side, the high-temperature side heat exchanger receiving inflow of heated fluid and absorbing heat from the heated fluid, and supplying the heat to the second end part so as to keep the second end part at a state of higher temperature than at the first end part, wherein
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×S/C, where S denotes an area of a cross section of each cell perpendicular to the cell extending direction and C denotes a perimeter of the cross section,
let that the heat/acoustic wave conversion component has a length L from the first end face to the second end face, a ratio HD/L of the hydraulic diameter HD to the length L of the heat/acoustic wave conversion component is 0.005 or more and less than 0.02, and
the high-temperature side heat exchanger includes:
a heat-exchanging honeycomb structure having a partition wall that defines two or more cells which extend in the extending direction between two end faces, an opposed end face facing to the second end face of the heat/acoustic wave conversion component and a non-opposed end face facing to an opposite side from the heat/acoustic wave conversion component when viewed from the opposed end face, and which are filled with the working fluid internally so as to be a propagation path of acoustic waves due to oscillations of the working fluid; and
an annular tube that surrounds a circumferential face of the heat-exchanging honeycomb structure, which extends between the two end faces, and that defines a channel through which the heated fluid flows, the annular tube including 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,
wherein 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.

2. The heat/acoustic wave conversion unit according to claim 1 , wherein the heat/acoustic wave conversion component has an open frontal area at an end face of 93% or less.

3. The heat/acoustic wave conversion unit according to claim 1 , wherein the cells in the heat/acoustic wave conversion component have a triangular shape in the cross section.

4. The heat/acoustic wave conversion unit according to claim 1 , wherein let that D denotes an equivalent circle diameter of a cross section of the heat/acoustic wave conversion component in a plane perpendicular to the extending direction, the equivalent circle diameter D is 30 mm or more and 100 mm or less, and a ratio L/D of the length L of the heat/acoustic wave conversion component to the equivalent circle diameter D is 0.3 or more and 1.0 or less.

5. The heat/acoustic wave conversion unit according to claim 1 , wherein the heat/acoustic wave conversion component includes:
a plurality of monolithic honeycomb segments, each including the partition wall that defines some of the plurality of cells, and mutually converting heat exchanged between the partition wall and the working fluid and energy of acoustic waves resulting from oscillations of the working fluid;
a bonding part that mutually bonds side faces of the plurality of honeycomb segments; and
a circumferential wall that surrounds a circumferential face of a honeycomb structure body made up of the plurality of honeycomb segments and the bonding part, wherein
an open frontal area at each end face of the honeycomb segments is 60% or more and 93% or less, and
heat conductivity of a material making up the honeycomb segments is 5 W/mK or less.

6. The heat/acoustic wave conversion unit according to claim 5 , wherein the cells have the cross section of a triangular shape, and a cross section of the honeycomb segments that is parallel to the cross section of the cells has a hexagonal shape.

7. The heat/acoustic wave conversion unit according to claim 5 , wherein the cells have the cross section of a triangular shape, and a cross section of the honeycomb segments that is parallel to the cross section of the cells has a triangular shape.

8. The heat/acoustic wave conversion unit according to claim 5 , wherein Young's modulus of materials making up the bonding part and the circumferential wall are both less than 30% of Young's modulus of a material making up the honeycomb segments, a thermal expansion coefficient of the material making up the bonding part is 70% or more and less than 130% of a thermal expansion coefficient of the material making up the honeycomb segments, and heat capacity of the material making up the bonding part is 50% or more of heat capacity of the material making up the honeycomb segments.

9. The heat/acoustic wave conversion unit according to claim 5 , wherein a bonding width of two of the honeycomb segments bonded mutually is 0.2 mm or more and 4 mm or less, and in a plane perpendicular to the extending direction, a ratio of a total cross-sectional area of the bonding part to a cross-sectional area of the heat/acoustic wave conversion component is 10% or less.

10. The heat/acoustic wave conversion unit according to claim 5 , wherein each of the plurality of honeycomb segments has a cross-sectional area in a plane perpendicular to the extending direction that is 3 cm 2 or more and 12 cm 2 or less.

11. The heat/acoustic wave conversion unit according to claim 5 , wherein let that D denotes an equivalent circle diameter of a cross section of the heat/acoustic wave conversion component in a plane perpendicular to the extending direction, the equivalent circle diameter D is 30 mm or more and 100 mm or less, and a ratio L/D of the length L of the honeycomb segments to the equivalent circle diameter D is 0.3 or more and 1.0 or less.

12. The heat/acoustic wave conversion unit according to claim 1 , wherein the heat-exchanging honeycomb structure directly comes in contact with heated fluid flowing through the channel at the circumferential face to absorb heat from the heated fluid, and transmits the absorbed heat from the opposed end face to the second end part of the heat/acoustic wave conversion component.

13. The heat/acoustic wave conversion unit according to claim 1 , wherein the opposed end face of the heat-exchanging honeycomb structure is in contact with the second end face of the heat/acoustic wave conversion component.

14. The heat/acoustic wave conversion unit according to claim 1 , wherein
the plurality of cells in the heat/acoustic wave conversion component and the two or more cells in the heat-exchanging honeycomb structure

Assignees

• Ngk Insulators Ltd

Inventors

• Miyairi Yukio
• Miwa Shinichi
• Kawaguchi Tatsuo
• Noda Naomi
• Deguchi Yuji
• Mori Teruyoshi
• Hamatsuka Kazuhiko
• Suenobu Hiroyuki
• Hironaga Masayuki
• Kumazawa Kazuhiko

Classifications

• F02G1/043

  the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines · CPC title

• F02G1/02

  of open-cycle type · CPC title

• F02G5/02 Primary

  Profiting from waste heat of exhaust gases · CPC title

• F25B9/145

  pulse-tube cycle · CPC title

• F03G7/002 Primary

  using the energy of vibration of fluid columns · CPC title