Be used to stride critical CO
2The micro-channel parallel flow heat exchanger and the manufacture method of circulation
Technical field
The present invention relates to a kind of being used for CO
2Be the cross-critical steam compression type refrigerating of working medium, the micro-channel parallel flow heat exchanger in the heat pump assembly, be specifically related to the gas cooler or the evaporimeter that in refrigeration, heat pump assembly, use.
Background technology
At CO
2Stride in the heat exchanger of critical cycle refrigeration, heat pump assembly use, wherein a kind of heat exchanger is operated in the high-pressure side of system, supercritical CO
2Heat release cooling in the pipe of heat exchanger, pressure can reach more than the 10MPa, and surrounding air heats up by the outer fin heat exchange of pipe, and this heat exchanger is called as gas cooler; Another kind of heat exchanger is operated in the system low-voltage side, subcritical CO
2Heat absorption evaporation in Tube Sheet of Heat Exchanger, pressure is about 4MPa and be in room temperature or the more air heat exchange of low ambient temperature, and this heat exchanger is called as evaporimeter.Since in these two kinds of heat exchangers, CO
2Pressure is very high, if remove to design heat exchanger according to stock size, it is a lot of to cause the heat exchanger tube wall thickness to increase, and makes whole heat exchanger weight very heavy, bulky.
Because MCA can solve the problem of proof pressure, CO in the heat exchanger
2Pipeline wall thickness can not need too thick; And because supercritical CO
2Viscosity is little, and flowing pressure loss is little in MCA; CO
2Coefficient of heat transfer height, same heat exchange amount only needs less heat exchange area, so the heat exchanger of use MCA is at CO
2Stride reasonable application prospect is arranged in the critical cycle.
A kind of micro-channel parallel flow heat exchanger is disclosed in the prior art, this micro-channel parallel flow heat exchanger has had use on air conditioning for automobiles, the working medium of using mostly is R134a, and its operating pressure is below 3MPa, and the heat exchanger channels in the flat tube adopts the shapes such as rectangle that needn't bear high pressure; The cross dimensions of heat exchanger channels is in 2 * 3mm, and its header adopts single circular tube structure.
Man-Hoe Kim etc. are at document " Fundamental process and system design issues in CO
2Vaporcompression systems ", Progress in Energy and Combustion Science.2004 has introduced the critical CO of striding of external design among the 30:144-149
2The gas cooler (see figure 1) that recycles, material is an aluminium matter, adopts the flat heat exchange pipe of 8 font bitubular header (see figure 2)s and microchannel; The evaporimeter of introducing in this article, material are aluminium matter, adopt the flat heat exchange pipe of 4 header (see figure 3)s and microchannel.Adopt this many header structures, can provide and flat tube between enough weld width; Simultaneously, compare with single header, each channel diameter of many headers reduces, and with respect to the large diameter pipeline of single channel, can tolerate higher pressure.But, the bitubular header of this 8 fonts or 4 headers, because the shape tendency of its arc-shaped surface has fluctuating, scolder is not easy docile and obedient at welding surface, the welding of header and flat tube bundle has difficulties; Temperature also has the inhomogeneous of part in welding process, and welding quality is not easy control.Along with the quantity increase of bundle of parallel tubes, the yield rate of heat exchanger significantly reduces.
Summary of the invention
The purpose of this invention is to provide a kind of critical CO that is used to stride
2The micro-channel parallel flow heat exchanger and the manufacture method of circulation to guarantee the welding quality of header and flat tube interfascicular, improve the yield rate of micro-channel heat exchanger.
Technical scheme of the present invention is as follows:
A kind ofly be used to stride critical CO
2The micro-channel parallel flow heat exchanger of circulation, comprise many headers and be welded on two flat heat exchange pipe bundles between header, flat heat exchange pipe adopts MCA, header adopts many barrel structures of at least two runners, it is characterized in that: header one side of described many barrel structures has the integral planar structure of extrusion modling, and the flat heat exchange pipe bundle is welded on this integral planar structure.
The present invention also provides the manufacture method of described micro-channel parallel flow heat exchanger, it is characterized in that this method carries out as follows:
1) with the header and the flat heat exchange pipe extrusion modling respectively of many barrel structures, making a side of described header is planar structure;
2) leave parallel flat heat exchange pipe groove in the planar side of described header;
3) superscribe scolder at the position to be welded of every flat heat exchange pipe, insert respectively in the flat heat exchange pipe groove, fix flat heat exchange pipe bundle position after, the overall vacuum soldering.
The present invention compared with prior art, have the following advantages and the high-lighting effect: many headers that adopt planar structure, the planar side of many headers has obtained thickening on the one hand, and intensity has obtained enhancing, has offset because the influence that the intensity that one group of flat heat exchange pipe troughed belt leaving slackens.On the other hand, in welding process, at flat tube position to be welded parcel scolder, make scolder docile and obedient at welding surface easily earlier, it is more even to be heated, and welding quality is controlled easily, thereby has effectively improved the yield rate of heat exchanger integral body.
Description of drawings
Fig. 1 is the appearance assumption diagram of the micro-channel parallel flow heat exchanger of available technology adopting.
Fig. 2 is the sectional drawing of the bitubular header of micro-channel parallel flow heat exchanger in the prior art at flat heat exchange pipe groove weld.
Fig. 3 is that four headers of micro-channel parallel flow heat exchanger of available technology adopting are at the sectional drawing of flat heat exchange pipe groove weld.
Fig. 4 is a flat heat exchange pipe section structure schematic diagram.
Fig. 5 is a micro-channel parallel flow heat exchanger perspective view provided by the invention.
Fig. 6 a is many header sectional drawings of micro-channel parallel flow heat exchanger provided by the invention.
Fig. 6 b is the sectional drawings of many headers of micro-channel parallel flow heat exchanger provided by the invention at flat heat exchange pipe groove weld.
The specific embodiment
Below in conjunction with accompanying drawing structure of the present invention, manufacture method are described further.
Fig. 5 is the perspective view of micro-channel parallel flow heat exchanger provided by the invention, and this micro-channel parallel flow heat exchanger contains many headers 1, is welded on two flat heat exchange pipe bundles 2 between header, and parallel flat tube interfascicular is welded with fin 3.Fig. 6 a is the section structure schematic diagram of many headers provided by the invention, and the one side is designed to the plane, by extrusion modling; In order to weld, on the welding plane, mill out the parallel flat heat exchange pipe groove 4 that has flat tube thickness and width (Fig. 6 b) with the flat tube bundle.
CO
2Working medium at first enters the many headers 1 (inlet header) of this heat exchanger one side, again from many headers 1 enter the parallel micro-channel flat bundle 2 with the flat tube bundle outside air carry out heat exchange.CO after the heat exchange
2Working medium flows out from the many headers (outlet header) of heat exchanger opposite side.
Preparation method provided by the invention is as follows: at first with the header 1 and flat heat exchange pipe extrusion modling respectively of many barrel structures, general many headers adopt 2~5 barrel structures, and making a side of header is planar structure; The microchannel diameter of section of flat heat exchange pipe is 0.7~1.2mm.During welding, earlier leave parallel flat heat exchange pipe groove 4 in the planar side of many headers, then at the thin scolder of position parcel one deck to be welded of every flat heat exchange pipe of flat heat exchange pipe bundle 2, pack in the flat heat exchange pipe groove of on many headers, having held successfully 4, after all flat heat exchange pipe bundles 2 and many headers 1 are fixed the welding position, adopt the overall vacuum soldering to finish the welding of 1 of flat tube bundle 2 and many header.It is more even to be heated like this, and welding quality is controlled easily, thereby has effectively improved the yield rate of heat exchanger integral body.