JPH0244158A - Cooling device - Google Patents

Abstract

PURPOSE: To improve thermal conduction between a reheater and a working fluid and increase heat phase delay between the surface of the working fluid and balk of a member, by providing at least one surface through which and with which the working fluid passes and makes contact on a reheater, and further providing many protrusions protruding into the working fluid on the foregoing surface. CONSTITUTION: A thermal/acoustic condenser includes an elongated organ pipe 1 in which there are accommodated a working fluid and a reheater composed of many thin flat plates 2, and the many thin flat plates 2 are disposed parallely to an axis of the organ pipe 1 and to each other. The working fluid flows through the surface of the flat plate 2 and is rendered to expansion and compression such that cooling effect is produced at one end of the organ pipe 1. Each flat plate 2 includes many pads 3 that protrude into a layer flow boundary layer 4 of the working fluid to divide the layer flow boundary layer for improvement of thermal conduction thereof. The many pads 3 further form a series of heat absorption areas or heat source areas on the flat plate whereby heat phase delay between the surface of each flat plate and the body is made maximum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cooling device, and more specifically, this thermoacoustic cooler.
SIC3TODAY, August 1985,
r IJnderstandina Some
5iule Phenonena In Therl
lo-Acoustics With Applica
tions To Acoustical Heat
Engines” ^I1. J. Phys., 53
(2) February 1985, rTheory
and CalculatOn for an
Intrinsically Irreversi
ble ACOLIStCprile HOVer
using LiQ! Jid Sod! 1111 As
Primary Working FILlidJJ,
^coust, soc, An, 78(2), Aug
ust1985, and “Heat Tr ansf8r
) 1955 Edition, v.

tulle 1. Hax Jacob, John W.
The present invention relates to so-called thermoacoustic coolers which operate on the basis of thermodynamic phenomena, such as those described in Ill Iy and 5ons, page 291. However, it is not limited to thermoacoustic coolers.

Simply put, this type of cooler is an organ pipe (o
It operates by the movement, compression, and expansion of a working fluid, such as gas or steam, within an enclosure, similar to the movement of air within an rgan pipe.

The movement of the working fluid is actually somewhat different due to the presence of a structure known as a reheater ("6gcnerator") placed within the thermoacoustic cooler enclosure or pipe, but the physics of the air within the organ pipes are It follows the same law as the law of.

Reheater is a kind of heat exchanger in which the working fluid flows,
The heat is transferred to the part called the "cold end" of the thermoacoustic cooler, the other part of the reheater, whose function is to receive thermal energy from the working fluid, temporarily store it, and then give it away. carried to. Reheaters are also used for similar purposes in refrigeration systems operating on the Stirling cycle.

The performance of a thermoacoustic cooler depends on the time lag between the working fluid pressure cycle and the temporary storage of energy by the reheater, and the efficiency with which thermal energy can be transferred into and out of the reheater.

The present invention comprises a reheater and a working fluid in contact with the reheater and which is moved, compressed and expanded to produce a cooling effect, the working fluid passing through and contacting the reheater. A surface is provided that protrudes into the working fluid to create a number of partial discontinuities in the laminar boundary layer flow thereby improving heat transfer between the reheater and the working fluid. and further to provide a cooling device provided with a number of protrusions creating partial heat source or heat sink areas increasing the thermal phase lag between said surface and the bulk of the component forming said surface. be.

Hereinafter, for a better understanding of the present invention, description will be made with reference to the accompanying drawings.

The thermoacoustic cooler of FIG. 1 has an elongated enclosure or organ pipe 1 containing a working fluid and a reheater consisting of a number of thin flat plates 2. The thermoacoustic cooler of FIG.

A number of thin flat plates 2 are arranged parallel to the axis of the organ pipes 1 and parallel to each other 6 The working fluid flows through the reheater or the surface of the flat plates 2 and at the same time the cooling effect is applied to the organ pipes. 1 (not shown) undergoes expansion and compression as occurs. The means for flowing, expanding and compressing the fluid are not shown.

As shown in FIG. 2, each flat plate 2 has a number of pads 3 on both surfaces thereof that protrude into the laminar boundary layer 4 of the working fluid to disrupt the laminar boundary layer and improve its heat conduction. is provided. The large number of pads 3 also forms a series of heat absorption or heat source areas on the plates, maximizing the thermal phase lag between the surface of each plate and its body. (The theoretical optimum for a thick reheater is 45 mm, see the above-mentioned fourth publication) Instead of the pad 3, it extends transversely to the direction of flow of the working fluid, i.e. in cross-section as shown in FIG. A series of strips (not shown) may be provided that look like pads.

The flat plate 2 of the reheater is made of quartz, silicon or ceramic and has a thickness of approximately 0.5 mm.

The pads and strips are made of aluminum and are deposited on the flat plate 2 by any suitable method and have a thickness of about 0.5 microns.6 The working fluid is nitrogen at 10 atmospheres, and the local bulk movement of the nitrogen (the Iokal bulk no.
vclent of the N1troen), ie the movement indicated by the arrows in FIGS. 1 and 2 is 0.5 mm or more.

Instead of flat plates, the reheater may also comprise a number of cylindrical plates coaxially nested in one another, with pads or strips on their surfaces.

As will be clear to those skilled in the art, to obtain the best Ie efficiency, the reheater plates should be tapered at their ends or of different lengths to reduce acoustic reflections. Alternatively, the ends may be tapered and their lengths may vary.

(This creates overtones.) It also goes without saying that the cross-section of the gas flow path should be as constant as physically possible over the entire length of the organ pipe; The surface dimensions are made larger than other parts to accommodate the flat plate.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a thermoacoustic cooler, and FIG. 2 is a partial sectional view of a reheater used in the thermoacoustic cooler of FIG. Surrounding wall or organ pipe 2: Flat plate 3: Pad 4: Laminar boundary layer procedure auxiliary device (marshal) August 18, 1999

Claims (1)

[Claims] 1) A reheater and a working fluid that is in contact with the reheater and is moved, compressed, and expanded to produce a cooling effect, and the working fluid passes through and comes into contact with the reheater. at least one surface is provided, the surface protruding into the working fluid to create a number of partial discontinuities in the laminar boundary layer flow to thereby conduct heat between the reheater and the working fluid; A cooling device provided with a number of protrusions creating a partial heat source or heat sink that improves the temperature and also increases the thermal phase lag between said surface and the volume of the component forming said surface. 2) The cooling device of claim 1, wherein the cooling device has an elongated enclosure. 3) The cooling device according to claim 1 or 2, wherein the reheater has a large number of thin flat plates arranged parallel to each other in the axial direction of an elongated surrounding wall. 3. The cooling device according to claim 1, comprising a large number of coaxially nested cylindrical plates. 5) A cooling device according to any one of claims 1 to 4, wherein the protrusion protruding into the working fluid has a number of pads. 6) The cooling device according to any one of claims 1 to 5, wherein the working fluid is nitrogen.