CN200965433Y - A heat exchanger with crossing spiral tube - Google Patents

Abstract

The utility model discloses a heat-exchanger applied for a cross helix-pipe, relating to an exhausted-gas recycling heat-exchanger of an engine and aiming at improving the exhausted-gas recycling heat-exchanger of the engine and raising the heat-exchanging rate. The exchanger comprises a heat-exchanging pipe, a casing and a pipe board, wherein the heat-exchanging pipe is a stainless steel pipe body which is provided with an inward-raised cross helix groove at the surface of the heat-exchanging pipe, and the section of the pipe takes a shape of a flat. The height and the width of the section of the flat heat-exchanging pipe are different and the helix lines with the opposite revolving directions are interlaced on the long-edge against the pipe, as an X-shape. Because the utility model adopts the cross helix heat-exchanging pipe, the dirty is not easy to be accumulated in the pipe and at the outside of pipe and the heat-exchanging effect can be enhanced. The heat-exchanger is especially suitable for the exhausted-gas recycling cooling device of the automobile engine to reduce the emitting temperature of exhausted gas and also to raise the off-gas emitting capability index and to meet the environment-protection requirements which gradually becomes stricter. And simultaneously, the utility model is also suitable for the turbine pressure-rising system to raise the capability of the engine.

Description

A kind of heat exchanger of employing crossed spiral tube

Technical field

The heat exchanger of a kind of employing crossed spiral tube of the utility model relates to a kind of waste gas recycle heat exchanger of engine, is a kind of inlet and outlet attachment device of engine, is the heat exchanger of the passage traversed by of a kind of heat exchanger tube and heat exchange medium.

Background technology

Heat exchanger is very general in sector applications such as petrochemical industry, machine-building, oil refining, metallurgy, light industry, pharmacy, food, account for 40%～60% of whole technological equipment investment, so the development of heat exchanger has very big influence to these industries.Because the continuous growth of the energy and Master Cost has promoted the development of energy-efficient heat exchanger widely.In automobile manufacture industry, along with countries in the world are more and more stricter to the requirement of automobile exhaust emission standard, the optimal design of the heat exchanger in the automobile exhaust gas recirculation cooling device will play an important role.

Waste gas recirculation cooling technology be heat exchanger applications in gas recirculation system, after the part waste gas that automobile engine is discharged cools off by cooler for recycled exhaust gas, again pass back to cycling and reutilization in the combustion chamber of engine, so both introduced not active gases to the combustion chamber, reduce the content of nitrogen in the combustion chamber, can reduce the temperature of combustion chamber again, because the generation of oxynitrides is closely-related with combustion peak and oxygen content, thereby adopt waste gas recirculation cooling technology to suppress oxynitrides generation and discharging.Wherein, heat exchanger is the key element in the cooling system for recycled exhaust gas, the height of its heat exchange efficiency has determined the temperature height of EGR gas, therefore, guaranteeing under the prerequisite that engine performance does not reduce, the heat exchange efficiency that improves cooler for recycled exhaust gas is particularly important to automobile industry, the primary and foremost purpose when heat exchange efficiency that improves heat exchanger simultaneously is the design heat exchanger.

At present, heat exchanger commonly used has two big classes in the vehicle engine exhaust gas recirculation system.

The first kind is a shell-and-tube heat exchanger, arranges many parallel pipes (claiming these parallel pipes to be tube bank) exactly in a circular shell, and the waste gas that temperature is high is walked tube side, and cooling agent is then walked shell side, carries out the exchange of heat by two kinds of fluids of tube wall; Usually can be at shell-side device longitudinal baffle parallel or the deflection plate vertical with tube bank with tube bank, with the flow velocity that improves shell-side fluid and strengthen disturbance, the raising heat exchange efficiency.This type of heat exchanger structure is simple, but heat exchange efficiency is not too high;

At present, the circular heat exchanger tube that a kind of surface has inwardly protruded helical groove mainly is set in this heat exchanger, heat exchange efficiency has improved much relatively, but the increasingly stringent that requires along with automobile emissions standards, the heat exchange effect of this heat exchanger can not meet the demands gradually, has used the shell-and-tube heat exchanger advantage of simple structure in the design of the present utility model.

Second class is a plate-fin heat exchanger, dividing plate, fin and strip of paper used for sealing three parts are elementary cells of plate-fin heat exchanger, cold and hot fluid flows in the runner of adjacent basic unit body, reach the dividing plate that fuses with fin by fin and carry out heat exchange, fin can play the tube sheet spacing and strengthen the effect of rigidity.This type of heat exchanger structure compactness, heat exchange efficiency height, but complex structure, the manufacturing cost height.Used the advantage of plate-fin heat exchanger compact conformation in the utility model design.

In a word, for improving the discharge performance index of engine, making waste gas recirculation cooling system have higher heat exchange efficiency, is the transformation key of heat exchanger.

The content of invention

The purpose of this utility model is exactly the heat exchanger of a kind of employing crossed spiral tube of design, for improving the engine exhaust recycle heat exchanger, improves exchange efficiency, with the discharge capacity of less oxynitrides, satisfies the environmental requirement that improves day by day; The utility model also is suitable for the charge air cooler as turbo charge system simultaneously, to improve the performance of engine.

The purpose of this utility model is achieved in that a kind of heat exchanger of employing crossed spiral groove heat exchange tube comprises: housing, heat exchanger tube, tube sheet; Heat exchanger tube is arranged and is fixed on the tube sheet of housing in some way, and axis is parallel to each other, it is characterized in that: the cross sectional shape of described heat exchanger tube is special flat-shaped, its height and the width are unequal, the cross section is made up of with two relative minor faces two relative long limits, wherein, in serving as reasons in described long limit to the camber line or the straight line of outer lug, in also serving as reasons, described minor face, grows linking to each other of limit and minor face slyness to the camber line or the straight line of outer lug; The outer surface of described heat exchanger tube body have inwardly recessed interrupted or continuously, one or more helical groove is arranged in a crossed manner, and the inner surface of body has the cross-helicity projection with the corresponding projection of outer surface groove, the two ends of body are smooth section.

The two ends of described heat exchanger tube are weldingly fixed on the tube sheet in the housing, and body is placed all parallel with housing sidewall.Described heat exchanger tube is made up of the opposite helical groove of direction of rotation, and the intersection is " X " shape.The long limit and the minor face of described heat exchanger tube all are made up of circular arc, and long limit arc radius is more a lot of greatly than minor face arc radius, the linking to each other of four circular arc slynesses.The long limit of described heat exchanger tube and minor face are all by rectilinear(-al), and long limit is connected by circular arc chamfering with minor face.The long limit of described heat exchanger tube is a straight line, and minor face is the cross sectional shape ovalize of the described heat exchanger tube of semi arch, and the ratio of major axis and minor axis is not more than 4.Described lead angle is 20～75 degree.Described depth of groove is greater than 0.4mm.Housing be shaped as rectangle, circle, form such as square.With certain angle or vertical mutually the setting, the mode that promptly adopts in-line arrangement, wrong row or in-line arrangement and wrong row to use is simultaneously arranged heat exchanger tube to the end face of described heat exchanger tube on the tube sheet of heat exchanger.Deflection plate is set in the described heat exchanger shell as required.

The beneficial effects of the utility model are: owing to used crossing spiral recess heat-exchanging pipe, when waste gas flows in pipe by heat exchanger tube, be subjected to the guiding of cross-helicity groove line, near wall crisscross motion vertically, the projection of cross-helicity shape also makes the fluid of crisscross motion produce periodic disturbance mutually simultaneously, tube fluid is substantially based on turbulent flow, telling on is the raising of heat exchanger effectiveness, the faster cooling of waste gas in the pipe, in other words the gas temperature at heat exchanger exit is lower, can produce better exhaust gas utilization effect.The utility model had both had the convenience simple in structure of traditional shell-and-tube heat exchanger, adaptability is strong, disposal ability is big, advantages such as reliable operation, the compact conformation that has plate-fin heat exchanger again, characteristics such as volume is little, heat transfer efficiency height, this heat exchanger is particularly useful for cooler for recycled exhaust gas, improves the discharge standard of engine.Equally also can be used as the turbocharging charge air cooler, improve supercharging efficient, thereby the performance of automobile engine is improved.

Below by drawings and Examples, the technical solution of the utility model is elaborated.

Description of drawings

Fig. 1 is the perspective view of the utility model first embodiment;

Fig. 2 is the cross sectional shape schematic diagram at the utility model first embodiment tube sheet place;

Fig. 3 is the perspective view of flat-shaped crossing spiral recess heat-exchanging pipe for cross sectional shape that the utility model adopted;

Fig. 4 is the schematic diagram under first kind of cross sectional shape of heat exchanger tube shown in Figure 3;

Fig. 5 is the schematic diagram under second kind of cross sectional shape of heat exchanger tube shown in Figure 3;

Fig. 6 is the schematic diagram under the third cross sectional shape of heat exchanger tube shown in Figure 3;

Fig. 7 is the schematic diagram under the 4th kind of cross sectional shape of heat exchanger tube shown in Figure 3;

Fig. 8 is the three-dimensional schematic cross-section of the utility model second embodiment.

The specific embodiment

Embodiment one:

Be respectively the perspective view of the utility model first embodiment and the cross sectional shape schematic diagram at tube sheet place shown in Fig. 1,2.What the sequence number among the figure was represented is: 1. housing, 2. heat exchanger tube, 3. tube sheet.As shown in Figure 1, when the housing 1 of heat exchanger is the square-section, a kind of arrangement of flat-shaped crossing spiral recess heat-exchanging pipe 2 in housing 1; Being arranged in the housing 1 of heat exchanger tube 2 compactnesses, and the dual mode according to parallel and vertical of heat exchanger tube 2 is staggered in housing, and the mouth of pipe two ends of heat exchanger tube 2 are weldingly fixed on the tube sheet 3 at housing two ends.The application of flat-shaped cross-helicity pipe and arrangement as shown in Figure 1, the flow strength of reinforced pipe inner fluid not only, the disturbance of the fluid of the outer cooling agent of pipe has also obtained reinforcement, make inside and outside the pipe all less scaling, thereby also improved the heat exchange situation of the interior outer fluid of pipe.

Heat exchanger tube is provided with direction of rotation opposite helical line, and the intersection is " X " shape, and helicla flute concaves at outer surface, the inner surface projection, and its shape is corresponding with groove shapes.When the cross sectional shape of body when being flat-shaped, the place that two helixes intersect is at relative Chang Bianchu.Lead angle is 20～75 degree.Described depth of groove is greater than 0.4mm.

The housing of heat exchanger, its profile can be rectangle, circle, shape such as square.Heat exchanger tube is according to the shape of housing, and axis is parallel to each other, and is arranged in the shell with in-line arrangement, wrong row or in-line arrangement and the common mode of using of wrong row.The two ends of heat exchanger tube are fixed on the tube sheet in the housing, and the end face of heat exchanger tube on the tube sheet of heat exchanger with certain angle or vertical mutually the setting, the heat exchanger tube axis is arranged parallel to each other and is fixed in the housing.

The utility model employing crossed spiral groove heat exchange tube can obviously improve the inside and outside heat transfer coefficient of pipe in diabatic process, play the effect of bilateral reinforcement, and comparing with the pipe that traditional heat exchangers is adopted has very big advantage.The mechanism of its augmentation of heat transfer is: when waste gas enters heat exchanger tube, because the guiding function of cross-helicity, make that enter tube fluid rotates along the direction of symmetry and move, formed the eddy flow layer, produce complicated secondary stream simultaneously, all converge along fluid that the groove line rotates and direction is different and the fluid that moves vertically in the cross one another place of spiral, bump, the disturbance of fluid obviously strengthens, attenuate and destroyed the boundary layer of fluid not only, the exchange capability of heat of outer fluid in the pipe is improved, also make simultaneously to produce metathesis between core flow and the close fluid of tube wall, the heat exchange effect of tube fluid and extratubal fluid is strengthened, and effectively reduced the temperature value in whole flow field, improve the ability of heat exchanger tube, and then increase the heat exchange efficiency of cooler for recycled exhaust gas.Simultaneously, the enhancing of flow disturbance makes critical Reynolds number reduce, promptly take place ahead of time from the transformation of laminar flow to turbulent flow, tube fluid produces and rotatablely moves strongly, and the heat exchanging tube wall has souring strongly, and spiral grooved tube itself has the thermal compensation ability, expand with heat and contract with cold, tube wall is less scaling, and, even fouling, snaking are also more convenient.In addition, the fin of this intersection has strengthened the mechanical strength of heat exchanger tube.

Simultaneously, the utility model improves performance as starting point to save cost, for organically integrating, engine exhaust recirculated cooling system and dynamical system provide technology platform, saved between engine air greatly and volume, reduced unnecessary setting effectively, when improving engine performance, greatly save manufacturing cost for the producer.

Figure 3 shows that cross sectional shape that the utility model adopts is the perspective view of flat-shaped crossing spiral recess heat-exchanging pipe; As shown in the figure, the cross sectional shape of body is flat-shaped, and the cross section is made up of with two relative minor faces two relative long limits, wherein, in serving as reasons, described long limit, to the camber line or the straight line of outer lug, grows linking to each other of limit and minor face slyness in described minor face is also served as reasons to the camber line or the straight line of outer lug; The outer surface of the body of heat exchanger tube has inwardly recessed cross one another helical groove, and the inner surface of body has and the corresponding cross-helicity projection of outer surface groove, and the helical groove infall is " X " shape, and the two ends of body are smooth section; The cross sectional shape of helical groove can be set to " U " shape, " V " shape or circular arc, is beneficial to the generation of small size shape face; The groove lead angle is designed between 20～75 degree; Depth of groove is not less than 0.4mm.This set of crossing spiral recess pipe can make fluid produce turbulent flow fully in pipe; Simultaneously, use, simplify difficulty of processing,, make all surface all can carry out heat exchange fully well, thoroughly eliminated the heat exchange dead angle so all acute angles of cross section all are designed to arc transition in order to ensure economy.

Fig. 4 is the schematic cross-section of flat-shaped crossing spiral recess heat-exchanging pipe shown in Figure 3.What sequence number was represented among the figure is: 21. helical grooves, 22. groove infalls, long limit, 23. cross sections, 24. cross section minor faces.Realize the heat exchange of maximal efficiency for the surface that makes full use of heat exchanger tube, and be easy to production and processing, present embodiment has the heat exchanger tube body under helical groove 21 situations, and long limit 23, its cross section and cross section minor face 24 all are arranged to arc, and the linking to each other of long limit, cross section and cross section minor face slyness.As shown in Figure 4, the arc radius on long limit, cross section is far longer than the radius of minor face, the phenomenon that the surface " subsides " can not occur like this.

Arrange in the cooler for recycled exhaust gas that cross sectional shape is that flat-shaped spiral heat exchange tube is compared with currently used round screw thread heat exchanger tube.At first, under the constant prerequisite of the volume that guarantees cooler and exhaust gas flow, just under the situation that the heat exchanger tube area of section is constant, the perimeter of section of flat pipe is affirmed the perimeter of section greater than pipe, thereby the heat exchange area of flat pipe is greater than the heat exchange area of pipe, and then improved the heat exchange area of whole heat exchanger, make heat exchanger reach higher heat exchange effect.

Embodiment two:

The cross sectional shape of the heat exchanger tube in the present embodiment is another kind of oblate, as shown in Figure 5.The difference of present embodiment and the described embodiment one of above-mentioned Fig. 4 is that the cross sectional shape of stainless steel body is flat, and two relative long limits are straight line, and relative minor face is the semicircle cambered surface of curved projection from inside to outside, and such setting can improve heat exchange efficiency.

The flat-shaped spiral heat exchange tube of being arranged in the cooler for recycled exhaust gas not only increases to some extent than the heat exchange area of pipe, and the disturbance of tube fluid is played the effect of reinforcement.Because flat pipe is not centrosymmetric shape with respect to pipe, the geometric center of flat-shaped helix tube is littler than the distance of round screw thread tube and tube wall with the distance of tube wall, most of fluid in the pipe can participate in heat exchange, and the shape of flat pipe makes the disturbance of fluid strengthen, the heat exchange effect strengthens, thereby wanting that the temperature of tube fluid descends is fast, and the temperature difference of import and export increases, and heat exchange efficiency improves.

Embodiment three:

Fig. 6 is the heat exchanger tube profile in the present embodiment.Present embodiment is a distortion on the basis of the described embodiment of above-mentioned Fig. 4, with coupling together of the whole cross section slyness of heat exchanger tube, promptly, under the situation of the cross sectional shape of removing helical groove, the cross sectional shape of body is arranged to ellipse for aspect processing.

Embodiment four:

Fig. 7 is the heat exchanger tube profile in the present embodiment.The semicircular arc transition is set between present embodiment the two sides that heat exchanger tube is adjacent connects, the cross sectional shape of helical groove is removed in this heat exchanger tube cross section, and the cross sectional shape of stainless steel body is rectangle, and links to each other by circular arc chamfering between the adjacent two sides; This set makes heat exchange efficiency effectively to be increased.

The non-centrosymmetry of flat-shaped helix tube is with respect to the helix tube of circle, different arrangement modes can produce different effects, therefore according to different demands, can have multiple on the mode of the layout of heat exchanger tube, heat exchanger tube in-line arrangement, wrong row or in-line arrangement and wrong row use simultaneously, the effect difference that different arrangement modes makes the outer flow of coolant generation disturbance of pipe, thereby the heat exchange of outer fluid in also can reinforced pipe, the heat exchange efficiency of enhancing heat exchanger.

Embodiment five:

Figure 8 shows that the stereogram of the utility model the 5th embodiment; This embodiment is a housing when being the square-section, and flat-shaped crossing spiral recess heat-exchanging pipe is with the staggered a kind of arrangement schematic diagram of certain angle.Every row heat exchanger tube is arranged in parallel with identical angle, and adjacent two tubulation bundles are symmetrical distribution, and the mouth of pipe two ends of heat exchanger tube are weldingly fixed on the tube sheet at housing two ends.This arrangement has made full use of the advantage of flat-shaped heat exchanger tube, because the non-centrosymmetry of flat-shaped heat exchanger tube, being staggered of pipe makes the disturbance of the outer cooling agent of pipe aggravate, the heat exchange effect strengthens, the heat exchange amount increases, the heat exchange efficiency of cooler increases, thereby improves the discharge performance index of automobile engine, satisfies the stricter environment protection emission requirement that improves day by day.

Below just shown the arrangement of several typical flat-shaped crossing spiral recess heat-exchanging pipes in the two-tube-pass heat exchanger, wherein can revise about length, number and the heat exchanger tube arrangement mode in housing of heat exchanger tube, but the pipe number of different journey heat exchanger tubes then will be determined according to actual conditions, differ too great disparity, also a certain distance will be arranged.

It should be noted last that, below only unrestricted in order to the explanation the technical solution of the utility model, although the utility model is had been described in detail with reference to the preferred arrangement scheme, those of ordinary skills are to be understood that, can make amendment or be equal to replacement the technical solution of the utility model (such as the arrangement mode of heat exchanger tube in housing), and not break away from the spirit and scope of technical solutions of the utility model.

Claims (12)

1, a kind of heat exchanger of employing crossed spiral tube comprises: housing, heat exchanger tube, tube sheet; Heat exchanger tube is arranged and is fixed on the tube sheet of housing in some way, and axis is parallel to each other, it is characterized in that: the cross sectional shape of described heat exchanger tube is special flat-shaped, its height and the width are unequal, the cross section is made up of with two relative minor faces two relative long limits, wherein, in serving as reasons in described long limit to the camber line or the straight line of outer lug, in also serving as reasons, described minor face, grows linking to each other of limit and minor face slyness to the camber line or the straight line of outer lug; The outer surface of described heat exchanger tube body have inwardly recessed interrupted or continuously, one or more helical groove is arranged in a crossed manner, and the inner surface of body has the cross-helicity projection with the corresponding projection of outer surface groove, the two ends of body are smooth section.

2, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: the two ends of described heat exchanger tube are weldingly fixed on the tube sheet in the housing, and body is placed all parallel with housing sidewall.

3, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: described heat exchanger tube is made up of the opposite helical groove of direction of rotation, and the intersection is " X " shape.

4, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: the long limit and the minor face of described heat exchanger tube all are made up of circular arc, and long limit arc radius is more a lot of greatly than minor face arc radius, the linking to each other of four circular arc slynesses.

5, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: the long limit of described heat exchanger tube and minor face are all by rectilinear(-al), and long limit is connected by circular arc chamfering with minor face.

6, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: the long limit of described heat exchanger tube is a straight line, and minor face is a semi arch.

7, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: the cross sectional shape ovalize of described heat exchanger tube, and the ratio of major axis and minor axis is not more than 4.

8, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: the lead angle of described helical groove is 20～75 degree.

9, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: described depth of groove is greater than 0.4mm.

10, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: housing be shaped as rectangle, circle, square.

11, the heat exchanger of a kind of employing crossed spiral tube according to claim 1, it is characterized in that: with certain angle or vertical mutually the setting, the mode that promptly adopts in-line arrangement, wrong row or in-line arrangement and wrong row to use is simultaneously arranged heat exchanger tube to the end face of described heat exchanger tube on the tube sheet of heat exchanger.

12, the heat exchanger of a kind of employing crossed spiral tube according to claim 1 is characterized in that: deflection plate is set in the described heat exchanger shell as required.

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