Three, summary of the invention
The objective of the invention is to overcome the shortcoming of above-mentioned prior art, a kind of heat exchanger flow circuit method for arranging and device thereof that can improve heat exchange efficiency is provided.
For achieving the above object, the method that the present invention adopts is:
1, a kind of method for arranging of heat exchanger flow circuit is characterized in that:
1) according to pure counter-flow arrangement principle, arrange and select the import and the outlet position in the horizontal direction of cold-producing medium, promptly the flow tendency direction of cold-producing medium is opposite with air-flow direction;
2), on the fin between the import and export of cold-producing medium, carry out part and crack according to the principle that prevents the reverse heat conduction in the fin;
3) arrange the import and export of heat exchanger according to the phase of refrigerant, arrange and select the import and the outlet position in vertical direction of cold-producing medium, if cold-producing medium is a gaseous state, the import and export position of refrigerant flow path is in the heat exchanger lower end, and promptly its inlet flow direction is opposite with gravity direction; If liquid, the import and export position of refrigerant flow path is in the heat exchanger upper end, and promptly inlet flow direction is identical with gravity direction;
4) according to the approaching principle uniformly of local heat flux density, take the stage teeth riffled tube of good effect of heat exchange in the monophase field, strengthen monophase field intraductal heat exchange effect; And adopt the less single riffled tube of resistance at two-phase section;
5) principle that is complementary according to heat exchange reinforcement and the pressure loss in the incipient stage of two-phase section, adopts dual flow path to arrange;
6) principle of working in coordination with according to the field, in the fin zone that air has just flowed into, adopt the method for not cracking or cracking less, or the employing reinforcing degree is weak, the relatively low fin of pressure drop, and, adopt the fin surface of high heat-transfer performance such as the doube bridge fin that cracks in the hind wing panel region that air flows.
The heat exchanger of making according to said method is: the refrigerant flow direction is opposite with air-flow direction; During as condenser, the side-entrance of heat exchanger refrigerant is a gaseous state, and the refrigerant import is arranged on the heat exchanger lower end; Exit refrigerant liquefy, outlet is arranged on the lower end, and heat exchanger is then opposite when using as evaporimeter, and import and export all is arranged on the upper end, has seam in the middle of condenser and evaporimeter two array of pipes; Be provided with strengthening effect riffled tube preferably in the monophase field, be provided with the less thermoexcell of resistance at two-phase section; Adopt the doube bridge sheet that cracks at the air outlet slit place,, adopt crack less fin or flat sheet at the air intlet place.
Adopt stream of the present invention to arrange that the heat exchanger of making can significantly improve the heat exchange property of heat exchanger in refrigeration and the air-conditioning equipment, and along with the increase of mass velocity, the effect that improves can be more obvious, thereby reduce to freeze and the volume of air-conditioning equipment, reduced the cost of product.
Five, the specific embodiment
Referring to Fig. 1, stream method for arranging of the present invention is as follows:
1) pure counter-flow arrangement
According to the thermal conduction study basic principle, the mean temperature difference maximum of adverse current under identical out temperature condition, the mean temperature difference minimum of following current.So under identical cold fluid and hot fluid temperature, adopt counter-flow arrangement to be better than following current and arrange that promptly the refrigerant flow direction is opposite with air-flow direction;
2) prevent reverse heat conduction in the fin
The import of cold-producing medium and outlet all are in of heat exchanger together, have the bigger temperature difference in the fin at this place, inevitably reverse heat conduction can take place.For fear of reverse heat conduction, the way of employing is that two comb mid portions at heat exchanger crack.The employing part is cracked rather than whole cracking is because the temperature difference in the part fin that do not crack is very little, can ignore the influence of reverse heat conduction.In addition, part is cracked and is convenient to make and installation.
3) layout of heat exchanger inlet and outlet
Because gravity can make liquid automatically flow to lower from eminence, so should allow liquid enter the lower outflow in the stream as much as possible, to reduce flow resistance from eminence.When heat exchanger was done the condenser use, because condenser refrigerant side-entrance place phase is a gaseous state, the exit was liquid, so the import and the outlet of heat exchanger is arranged on the lower end optimum; When using as evaporimeter, because the import refrigerant of evaporimeter is liquid, thus opposite with condenser, import and export and all be arranged on the upper end.
4) make heat exchanger local heat flux density near even
According to waiting hot-fluid principle, if the local heat flux density of heat exchanger can be everywhere near even, then the overall heat exchange effect of heat exchanger is best.Need to make analysis-by-synthesis to managing the inside and outside thermal resistance and the temperature difference for this reason.According to q=k Δ t, q is approached evenly, can realize by adjusting overall heat transfer coefficient k and temperature difference t.
With the heat exchange in the general condenser is example, and the thermal resistance of refrigerant side and the coefficient of heat transfer distribute along journey and be shown in qualitatively among Fig. 2, Fig. 3.Obviously, the refrigerant thermal resistance of monophase field is much larger than the thermal resistance of two-phase section, and wherein the thermal resistance with air side is suitable in steam side monophase field, for making whole exchanger heat current density near evenly, can consider suitably to reduce the coefficient of heat transfer of two-phase section.The line arrangement that employing is divided into two reduces the mass velocity of cold-producing medium by this method, thereby reaches the purpose that suitably reduces the coefficient of heat transfer and reduced the two-phase section resistance.
Because the refrigerant thermal resistance of monophase field is much larger than the refrigerant thermal resistance of two-phase section, and the on-way resistance of monophase field is relatively low.Therefore, take the reasonable pipe of heat exchange effect,, strengthen the monophase field intraductal heat exchange and also can receive certain effect as the stage teeth riffled tube.And needn't too much consider the consequence that the resistance that causes increases.
5) take all factors into consideration the heat exchange reinforcement and the pressure loss
General condenser along the distribution of journey pressure drop as shown in Figure 4.Obviously, in the incipient stage of two-phase section, because flow velocity is very high, pressure drop is very big, and the local coefficient of heat transfer in this area is also very big simultaneously, and from reducing pressure drop and waiting the hot-fluid principle, this area can adopt dual flow path to arrange, coolant distribution to reduce flow velocity.The result who does like this reduces the too high local coefficient of heat transfer, reduces pressure drop simultaneously.The distributor that this moment is suitable and the selection of branch chalaza position are crucial, need to come by experiment to determine.Experimental technique is very simple, and the position that only needs to change the branch chalaza under identical test condition is tested.By the branch chalaza position of relatively selecting the best to experimental result.
6) follow a synergistic principle
Area (the air side flow direction first comb subarea) velocity that enters fin at air is more consistent with the direction ratio of localized temperature gradients, the collaborative degree that is two fields, this area is better, the measure of augmentation of heat transfer (cracking) DeGrain as fin, but resistance can obviously increase.But at the fin rear portion, since the fluid separation, the collaborative degree variation of temperature gradient field and velocity field, and the measure of enhanced heat exchange can be received obvious effects.From this viewpoint, can not crack or crack less in the air intlet place, or adopting that reinforcing degree is weak, the relatively low fin (as the less flat sheet of even not cracking of cracking) of pressure drop, the air outlet slit place then can adopt the fin surface of high heat-transfer performance such as the doube bridge fin that cracks.
Above-mentioned 6 basic principles proposed by the invention both had been adapted to condenser, also were applicable to evaporimeter.When the more heat exchanger of deployment tube row number, these several principles are suitable for too.When specifically arranging stream, repugnance may occur between the different principles, need take all factors into consideration, catch principal element.
Referring to Fig. 1, the heat exchanger refrigerant flow direction that method for designing according to the present invention is made is opposite with air-flow direction; When the import refrigerant is gaseous state, utilize the lift of gas to reduce on-way resistance, this moment, cold media gas was entered by heat exchanger lower end import 1; In the time of the refrigerant liquefy, utilize the gravity of liquid to reduce on-way resistance, the outlet 2 of heat exchanger also is placed on the lower end; When the import refrigerant was liquid state, refrigerant liquid was entered by heat exchanger upper end import 1; When refrigerant became gaseous state, the outlet 2 of heat exchanger also was arranged on the upper end; Adopted the measure that reduces reverse heat conduction, had seam 3 in the centre of two combs to reach the purpose that reduces reverse heat conduction; Make heat flow density as far as possible evenly by the form of selecting the inside and outside heat exchange surface of pipe; Because the refrigerant thermal resistance of monophase field 7 is much larger than the refrigerant thermal resistance of two-phase section 6, and the on-way resistance of monophase field 7 is relatively low.Therefore, the 7 stage teeth riffled tubes of taking good effect of heat exchange are strengthened monophase field intraductal heat exchange effect in the monophase field; And adopt the less single riffled tube of resistance at two-phase section 6.Air side fins is followed a synergistic principle, adopts the doube bridge sheet 4 that cracks at the air outlet slit place; At the air intlet place, adopt crack less fin even flat sheet 5.
The method for arranging of heat exchanger flow circuit also can be designed the heat exchanger of other concrete structure according to the present invention.