CN108398041A - A kind of UTILIZATION OF VESIDUAL HEAT IN hot-pipe system in trapezoidal air channel - Google Patents

Abstract

The present invention provides a waste heat utilization heat pipe system for a trapezoidal air passage, the system includes a heat pipe, and the heat pipe includes a vertical part, a horizontal part and a vertical pipe, wherein the bottom end of the vertical part communicates with the horizontal part, and the horizontal part The part extends from the bottom end of the vertical part to the direction away from the vertical part, and the lower part of the horizontal part communicates with a plurality of vertical pipes, wherein the vertical pipe is the evaporation end of the heat pipe, and the vertical part is the condensation end of the heat pipe. The vertical pipe is located in the flue gas passage, the vertical part is located in the air passage, the flue gas passage is a circular arc structure, the air passage is a trapezoidal structure, and the upper bottom of the trapezoidal structure is located on the upper part of the vertical part, The lower bottom is the upper wall of the flue gas channel. By setting a new type of trapezoidal structure, the heat exchange efficiency can be further improved, and by setting the trapezoidal structure, the external structure can be made compact, and the external space can be fully utilized. For example, the position of the waist of the trapezoidal structure can be set to other components, such as pipes.

Description

A trapezoidal air channel waste heat utilization heat pipe system

technical field

The invention relates to a heat pipe technology, in particular to a heat pipe with a new structure.

Background technique

Heat pipe technology is a heat transfer element called "heat pipe" invented by George Grover of Los Alamos National Laboratory in the United States in 1963. It makes full use of the principle of heat conduction and phase change medium. The rapid heat transfer properties of the heat pipe quickly transfer the heat of the heating object to the heat source, and its thermal conductivity exceeds that of any known metal.

Heat pipe technology was widely used in aerospace, military and other industries before. Since it was introduced into the radiator manufacturing industry, people have changed the traditional radiator design ideas and got rid of the single heat dissipation mode that only relies on high air volume motors to obtain better heat dissipation. The use of heat pipe technology enables the radiator to obtain a satisfactory heat exchange effect, opening up a new world in the heat dissipation industry. At present, heat pipes are widely used in various heat exchange equipment, including the power field, such as waste heat utilization of power plants.

In the prior art, the shape of the heat pipe affects the heat-absorbing area of the evaporating end, so the heat-absorbing range of the evaporating end is generally relatively small, and sometimes it is necessary to install multiple heat pipes in the heat source to meet the heat-absorbing demand; and when there are multiple evaporating ends, Because each evaporation end is in a different position of the heat source, there will be uneven heat absorption.

In addition, in the prior art, the waste heat utilization heat pipe device all extends the condensation end to the outside of the pipe, which takes up an external area and makes the structure of the heat pipe waste heat utilization system not compact.

In view of the above problems, the present invention improves on the previous invention, and provides a new heat pipe structure, which makes full use of the heat source, reduces energy consumption, and improves the smoke exhaust effect.

Contents of the invention

In view of the above problems, the present invention improves on the basis of the previous invention, and provides a new heat pipe structure to realize full utilization of waste heat.

In order to achieve the above object, the technical scheme of the present invention is as follows:

A waste heat utilization heat pipe system for a trapezoidal air channel, the system includes a heat pipe, and the heat pipe includes a vertical part, a horizontal part and a vertical pipe, wherein the bottom end of the vertical part communicates with the horizontal part, and the horizontal part connects with the vertical part. The bottom end of the part extends away from the vertical part, and the lower part of the horizontal part is connected to a plurality of vertical pipes, wherein the vertical pipe is the evaporation end of the heat pipe, and the vertical part is the condensation end of the heat pipe. It is characterized in that the The vertical pipe is located in the flue gas passage, the vertical part is located in the air passage, the flue gas passage is a circular arc structure, the air passage is a trapezoidal structure, and the upper bottom of the trapezoidal structure is located at the upper part of the vertical part, The lower bottom is the upper wall of the flue gas channel. By setting the new trapezoidal structure shown in Figure 2, the heat exchange efficiency can be further improved.

Preferably, the length of the upper base of the trapezoidal structure is 40-60% of the length of the lower base.

Preferably, the length of the upper base of the trapezoidal structure is 50% of the length of the lower base.

Preferably, the trapezoid is an isosceles trapezoid.

Preferably, the angle formed between the bottom of the trapezoid and the waist is 29-67°, preferably 40-50°.

Preferably, along the flow direction of the flue gas, the diameter of the vertical pipe increases continuously with decreasing diameter.

Advantageously, said vertical portion is arranged in the air channel.

Preferably, the heat pipe is arranged in a round pipe, and the round pipe is divided into two parts, an upper part and a lower part, the upper part is an air channel, and the lower part is a flue gas channel.

As preferably, along the flue gas flow direction, the length of the horizontal part is L, and along the flue gas flow direction, the pipe diameter of the vertical pipe at the tail of the heat pipe is D _tail , and the distance from the tail of the heat pipe is the vertical pipe at the position l The law of diameter D is as follows: D ² =b*(D _tail ) ² +c*(D _tail ) ² *(l/L) ^a , where a, b, and c are coefficients, which meet the following requirements:

1.085<a<1.125, 0.985<b+c<1.015, 0.485<b<0.645.

Preferably, as l/L increases, a decreases gradually.

Preferably, 1.093<a<1.106, b+c=1, 0.548<b<0.573. Advantageously, said vertical portion is arranged in the air channel.

Preferably, the heat pipe is arranged in a round pipe, and the round pipe is divided into two parts, an upper part and a lower part, the upper part is an air channel, and the lower part is a flue gas channel.

Preferably, the horizontal part is a flat tube structure, the vertical tube is a round tube structure, and the horizontal part is a square structure; the vertical tubes are in multiple rows, and two adjacent rows are arranged in a staggered arrangement; the vertical tubes The center of the circle and the centers of two adjacent vertical tubes in the adjacent row form an isosceles triangle, and the centers of the vertical tubes are located at the points of the vertices of the isosceles triangle.

Preferably, the outer diameter of the vertical tube is d, the distance between the centers of adjacent vertical tubes in the same row is L, and the center of the vertical tube forms an isosceles with the centers of adjacent two vertical tubes in the adjacent row The vertex of the triangle is A, then the following requirements are met:

Sin(A)=a*( d/L) ² -b* (d/L)+c, where a, b, and c are parameters, meeting the following requirements:

1.03<a<1.09, 1.73<b<1.74; 0.895<c<0.906, 0.1<d/L<0.7.

Preferably, a=1.07, b=1.735, c=0.901.

As preferably, 0.3<d/L<0.5.

Preferably, as d/L gradually decreases, a becomes larger, b becomes smaller, and c becomes larger.

Compared with the prior art, the present invention has the following advantages:

1) By setting a new type of trapezoidal structure air channel, the heat exchange efficiency can be further improved, and by setting a trapezoidal structure, the external structure can be made compact and the external space can be fully utilized. For example, the position of the waist of the trapezoidal structure can be set to other components, such as pipes.

2) The present invention provides a new heat pipe structure. By improving the structure of the evaporation end of the heat pipe, it can further meet the heat absorption and improve the waste heat absorption capacity according to the different diameters of the vertical pipes at different positions.

3) The present invention improves the structure of the evaporation end of the heat pipe in waste heat utilization, extends the evaporation end of the heat pipe to a farther direction, and makes the heat absorption area of the evaporation end of the heat pipe without changing the volume of the condensation end of the heat pipe Increase, so that the heat absorption range of the heat pipe can be expanded, and the heat at the farthest end of the heat source can be absorbed. Compared with the prior art, the evaporating end and the condensing end of the heat pipe keep the same size. At the same time, the volume and footprint of the heat exchanger are reduced, making the structure compact.

4) A large number of numerical simulation and experimental researches have been carried out, and the optimal structure of the distribution structure of heat pipes in waste heat utilization has been carried out, and the optimal relational expression of heat pipe distribution has been obtained through research, and the distribution of heat pipes has been further improved to achieve the optimum Excellent heat absorption, lower cost.

5) In the present invention, connecting pipes are arranged at adjacent evaporating ends, which can make the fluid in the evaporating end with high pressure quickly flow to the evaporating end with low pressure when the vertical pipes are heated differently and cause different pressures, thereby maintaining The overall pressure is balanced to avoid local overheating or overcooling.

Description of drawings

Fig. 1 is a schematic diagram of the first embodiment of the heat pipe structure arranged in the flue according to the present invention.

Fig. 2 is a schematic diagram of the second embodiment of the heat pipe structure arranged in the flue according to the present invention.

Fig. 3 is a schematic diagram of the structure of the heat pipe of the present invention.

FIG. 4 is a schematic view of FIG. 3 viewed from the bottom.

Fig. 5 is a schematic diagram of a partial structure of a heat pipe provided with a communication pipe according to the present invention.

Fig. 6 is a schematic diagram of the third embodiment of the heat pipe structure arranged in the flue according to the present invention.

FIG. 7 is a partially enlarged and annotated schematic diagram of FIG. 4 .

In the figure: 10-heat pipe, 101-vertical part, 102-horizontal part, 103-vertical pipe, 104-round pipe, 105-air channel, 106-flue gas pipe, 107-communicating pipe, 108-dividing wall.

Detailed ways

The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

In this article, if there is no special explanation, when it comes to formulas, "/" means division, and "×" and "*" mean multiplication.

The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figures 1-6, a heat pipe 10 arranged in a flue and using a flue waste heat device, the heat pipe includes a vertical part 101, a horizontal part 102 and a vertical pipe 103, wherein the bottom end of the vertical part 101 communicate with the horizontal part 102, the horizontal part 102 extends from the bottom end of the vertical part 101 toward the direction away from the vertical part 101, and the lower part of the horizontal part 102 communicates with a plurality of vertical pipes 103, wherein the vertical pipes 103 are heat pipes The evaporating end, vertical section 101 is the condensing end of the heat pipe. At least a part of the vertical part is arranged in the air channel, and the vertical pipe and the horizontal part are arranged in the flue gas duct 106

During operation, the heat pipe of the present invention absorbs heat from the flue gas through the vertical pipe 103, then the fluid in the vertical pipe 103 evaporates, enters the vertical part through the horizontal part, and then releases heat to the air in the vertical part, The fluid condenses and then enters the vertical tube 103 by gravity.

The invention improves the structure of the heat pipe by setting the evaporating end of the heat pipe, extends the evaporating end of the heat pipe to a farther direction, and increases the heat absorption area of the evaporating end of the heat pipe without changing the volume of the condensing end of the heat pipe. In this way, the heat absorption range of the heat pipe can be expanded, and the heat at the farthest end of the heat source can be absorbed. Compared with the heat pipe evaporating end and condensing end in the prior art keeping the same size, the heat exchange efficiency can be increased by more than 45%. At the same time, the volume and footprint of the condensing end are reduced, making the structure compact.

Preferably, there are multiple vertical tubes, and along the flow direction of the smoke, the diameters of the vertical tubes become smaller and smaller. Numerical simulations and experiments have found that along the flow direction of the flue gas, the heat received by the vertical tubes is getting smaller and smaller, and the temperature of the vertical tubes at different positions is also different, resulting in uneven local heating. Because with the continuous heat exchange of the flue gas, the temperature of the flue gas is also continuously decreasing, resulting in a decrease in the heat exchange capacity. Therefore, the present invention sets the diameters of the vertical pipes at different positions of the flue gas passage to be different, As a result, along the flue gas flow direction, the heat absorption capacity of the vertical tubes continues to decrease, so that the overall heat pipe temperature remains basically the same, thereby improving the overall heat exchange efficiency, saving materials, avoiding local damage caused by uneven temperature, and extending service life of the heat pipe.

Preferably, along the flow direction of the flue gas, the diameter of the vertical pipe increases continuously with decreasing diameter. As the change of the diameter of the vertical pipe, the present invention has carried out a large number of numerical simulations and experiments, so as to obtain the above-mentioned change law of the diameter of the vertical pipe. Through the above-mentioned change rule, materials can be saved, and at the same time, the heat exchange efficiency can be increased by about 8%.

Preferably, the distribution density and length of all the vertical pipes 103 are the same.

Along the flue gas flow direction, the length of the horizontal part is L, and along the flue gas flow direction, the diameter of the vertical pipe at the tail of the heat pipe is D _tail , then the diameter of the vertical pipe at the distance from the tail of the heat pipe is D. as follows:

D ² ＝b*(D- _tail ) ² +c*(D _-tail ) ² *(l/L) ^a , where a, b, and c are coefficients, meeting the following requirements:

1.085<a<1.125, 0.985<b+c<1.015, 0.485<b<0.645.

Preferably, as l/L increases, a decreases gradually.

As preferred, 1.093<a<1.106, b+c=1, 0.548<b<0.573;

The above-mentioned optimized formula is obtained through a large number of experiments and numerical simulations, which can make the distribution density of the vertical tubes of the heat pipes reach an optimal distribution, uniform heat distribution on the whole, good heat exchange effect, and save materials at the same time.

Preferably, the vertical portion 101 is arranged in the air channel. By heating the air channels, the heated air is used directly for combustion.

Preferably, as shown in FIG. 1 , the heat pipe 10 is arranged in a circular tube 104 , and the circular tube is divided into an upper part and a lower part by a partition wall 108 , the upper part is an air channel 105 , and the lower part is a flue gas channel 106 . Through the above arrangement, all the heat pipes and heat exchange fluids can be arranged in the circular pipe, so that the external space can be fully utilized and the purpose of compact structure can be achieved.

Preferably, as shown in FIG. 1 , the cross-sectional area of the upper part is 50-80% of the cross-sectional area of the lower part, more preferably 60-70%. Through the above-mentioned area distribution, the heat absorption and heat dissipation of the heat pipe can be evenly coordinated.

Preferably, as shown in FIG. 1 , two heat pipes are arranged in the circular pipe, and the vertical part 101 of the heat pipe 10 is arranged close to each other.

Preferably, the distance between the opposite surfaces of the vertical portion 101 is 20-40%, preferably 30%, of the width of the vertical portion of the heat pipe (the distance between the vertical portion of the heat pipe in the left and right direction in FIG. 3 is the width).

Figure 2 shows a second example of the distribution of heat pipes in the flue. As shown in Fig. 2, the air channel is a trapezoidal structure. The upper base of the trapezoidal structure is located on the upper part of the vertical part 101 , and the lower base is the upper wall of the flue gas channel. By setting the new trapezoidal structure shown in Figure 2, the heat exchange efficiency can be further improved. Because as the vertical part of the heat pipe goes upward, the vertical part of the heat pipe continuously participates in heat exchange, so the lower part of the vertical part has the highest temperature. By setting the trapezoidal structure, the air flow in the lower part can be increased, and the air flow in the upper part can be less, so as to achieve uniform heat exchange the goal of. Moreover, by setting the trapezoidal structure, the external structure can be made compact, and the external space can be fully utilized. For example, the position of the waist of the trapezoidal structure can be set to other components, such as pipes.

Preferably, the upper base of the trapezoidal structure is 40-60% of the lower base, more preferably 50%.

Preferably, the trapezoid is an isosceles trapezoid.

Further preferably, the angle formed between the lower base of the trapezoid and the waist is 29-67°, preferably 40-50°.

Through the above structural optimization, the uniformity of heat exchange and the improvement of heat exchange efficiency can be achieved to the greatest extent.

Figure 6 shows a third embodiment of the distribution of heat pipes in the flue. As shown in Figure 6, the air channel is a rectangular structure. The upper base of the rectangular structure is located on the upper part of the vertical part 101 , and the lower base is a part of the upper wall of the flue gas channel. By setting the new rectangular structure shown in FIG. 6 , the external structure can be further made compact, and the external space can be fully utilized. For example, other components, such as pipes, can be positioned outside the rectangular structure.

Preferably, the long side of the rectangular structure is parallel to the vertical part.

Preferably, the long side of the rectangular structure is 1.5-3 times, preferably twice, the short side.

Preferably, the short side of the rectangular structure is 0.6-0.8 times, preferably 0.72 times, the radius of the flue gas channel 106 . Through the above structure optimization, the heat exchange efficiency can be improved to the greatest extent.

In addition, the present invention sets multiple vertical tubes 103 as the evaporating ends of the heat pipes, so that each vertical tube 103 adds heat absorption as an independent heat absorbing tube, and also increases the heat absorbing area of the evaporating end of the overall heat pipe.

Preferably, the horizontal part 102 is a flat tube structure, and the vertical tube 103 is a round tube structure. By setting the horizontal part as a flat tube structure, the distribution of the vertical tubes 103 can be increased to further improve heat absorption.

Further preferably, the horizontal portion 102 is a square structure.

Preferably, as shown in FIG. 4 , the vertical pipes 103 are arranged in multiple rows, and two adjacent rows are arranged in a staggered arrangement. Through the staggered arrangement, the heat absorption of the heat pipes can be further improved.

Preferably, the vertical tubes 103 are located on the extension line of the midlines of the connecting line segments between the centers of adjacent vertical tubes 103 in adjacent rows. That is, the center of the vertical tube 103 and the centers of two adjacent vertical tubes 103 in the adjacent row form an isosceles triangle, and the center of the vertical tube is located at the point of the vertex of the isosceles triangle.

Preferably, as shown in FIG. 5 , a communication pipe 107 is provided between at least two adjacent vertical pipes 103 . In the research, it is found that in the process of absorbing heat in the vertical section, the heat absorbed by the heat-absorbing tubes in different positions will be different, resulting in different pressures or temperatures between the vertical tubes 103, which will cause some of the vertical tubes 103 to be heated If it is too high, the service life will be shortened. Once a problem occurs in one vertical pipe 103, the whole heat pipe may become unusable. In the present invention, through a large number of researches, connecting pipes 107 are arranged in adjacent vertical pipes, which can make the fluid in the vertical pipe 103 with high pressure quickly flow to the pressure when the vertical pipes are heated differently and cause different pressures. Small vertical pipes 103, so as to maintain overall pressure balance and avoid local overheating or overcooling.

Preferably, a plurality of communication pipes 107 are arranged between adjacent vertical pipes 103 from the lower part of the vertical pipe 103 to the upper part of the vertical pipe 103 . By arranging a plurality of connecting pipes, the pressure of the fluid can be continuously equalized during the process of absorbing heat and evaporating, and the pressure in the entire vertical pipe can be ensured to be equalized.

Preferably, from the bottom of the vertical pipe 103 to the top of the vertical pipe 103, the distance between adjacent communication pipes 107 decreases continuously. The purpose of this is to set up more connecting pipes, because as the fluid flows upwards, the fluid is continuously heated, and as the fluid is continuously heated, the heating in different heat collecting tubes becomes more and more uneven, so through the above settings, it can be guaranteed Achieve pressure equalization as quickly as possible during fluid flow.

Preferably, from the lower part of the vertical pipe 103 to the upper part of the vertical pipe 103, the distance between adjacent communicating pipes decreases continuously and becomes larger and larger. It is found through experiments that the above setting can ensure better and faster pressure equalization in the process of fluid flow. This is also the best connection method obtained through a large number of studies on the law of pressure distribution changes.

Preferably, the diameter of the communication pipe 107 increases continuously from the lower part of the vertical pipe 103 to the upper part of the vertical pipe 103 . The purpose of this is to ensure a larger communication area, because as the fluid flows upwards, the fluid is continuously heated, and as the fluid is continuously heated, the heating in different heat collecting tubes becomes more and more uneven. Therefore, through the above settings, it can be Ensure that pressure equalization is achieved as soon as possible during fluid flow.

Preferably, from the lower part of the vertical pipe 103 to the upper part of the vertical pipe 103, the diameter of the communication pipe 107 increases more and more. It is found through experiments that the above setting can ensure better and faster pressure equalization in the process of fluid flow. This is also the best connection method obtained through a large number of studies on the law of pressure distribution changes.

Through numerical simulation and experiments, it is found that the distance between the vertical pipes 103, including the distance between the same row and the distance between adjacent rows, cannot be too small, too small will lead to excessive distribution of heat pipes, resulting in the heat absorption of each heat pipe Insufficient, too large will lead to too little distribution of heat pipes, resulting in overheating of heat pipes, so this application through a large number of numerical simulations and experiments, summed up the optimal distribution of heat pipe vertical pipe 103 distribution, so that heat pipes can neither absorb heat enough nor can Excessive heat absorption.

As shown in Figure 7, the outer diameter of the vertical tube 103 is d, the distance between the centers of adjacent vertical tubes 103 in the same row is L, and the center of the vertical tube 103 is the same as the adjacent two vertical tubes of the adjacent row. The apex angle of the isosceles triangle formed by the center of the straight pipe 103 is A, which meets the following requirements:

Sin(A)=a*( d/L) ² -b* (d/L)+c, where a, b, and c are parameters, meeting the following requirements:

1.03<a<1.09, 1.73<b<1.74; 0.895<c<0.906, 0.1<d/L<0.7.

Preferably, a=1.07, b=1.735, c=0.901.

Preferably, as d/L gradually decreases, a becomes larger, b becomes smaller, and c becomes larger.

Preferably, 15°<A<80°.

More preferably, 20°<A<40°.

More preferably, 0.3<d/L<0.5.

The above empirical formula is obtained through a large number of numerical simulations and experiments. The structure obtained through the above relational formula can realize the optimal heat pipe structure, and the error is basically within 3% after experimental verification.

The heat absorption capacity of the heat pipe is 900-1100W, more preferably 1000W;

The temperature of the flue gas is 90-110 degrees Celsius, more preferably 100 degrees Celsius.

The horizontal portion of the heat pipe shown in FIG. 3 is preferably a square, with a side length of 400-600 mm, more preferably 500 mm.

The outer diameter d of the vertical pipe 103 is 9-12 mm, more preferably 11 mm.

Preferably, as shown in FIG. 4 , the system includes two heat pipes, and the horizontal parts 102 of the two heat pipes respectively extend towards opposite directions. By arranging two symmetrical heat pipes, heat can be absorbed in different directions , to meet the needs of heat exchange.

Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be based on the scope defined in the claims.

Claims (10)

1. a kind of UTILIZATION OF VESIDUAL HEAT IN hot-pipe system in trapezoidal air channel, the system comprises heat pipe, the heat pipe includes vertical portion Point, horizontal component and VERTICAL TUBE, the wherein bottom end of vertical portion is connected to horizontal component, and the horizontal component is from the bottom of vertical portion The direction away from vertical portion is held to extend, the horizontal component lower part is connected to multiple VERTICAL TUBEs, and wherein VERTICAL TUBE is heat pipe Evaporation ends, vertical portion is the condensation end of heat pipe, which is characterized in that the VERTICAL TUBE is located in exhaust gases passes, described vertical Part is located in air duct, and the exhaust gases passes are arc structures, and the air duct is trapezium structure, trapezium structure Upper bottom is located at the top of vertical portion, and bottom is the upper wall surface of exhaust gases passes.

2. hot-pipe system as described in claim 1, which is characterized in that the upper bottom length of the trapezium structure is bottom length 40-60%。

3. hot-pipe system as claimed in claim 3, which is characterized in that the upper bottom length of the trapezium structure is bottom length 50%。

4. hot-pipe system as described in claim 1, which is characterized in that it is described it is trapezoidal be isosceles trapezoid.

5. hot-pipe system as claimed in claim 4, which is characterized in that the trapezoidal bottom and kidney-shaped at angle be 29- 67 °, preferably 40-50 °.

6. hot-pipe system as described in claim 1, which is characterized in that the VERTICAL TUBE is multiple, along the flowing of flue gas The caliber in direction, the VERTICAL TUBE is smaller and smaller.

7. hot-pipe system as claimed in claim 6, which is characterized in that along the flow direction of flue gas, the pipe of the VERTICAL TUBE The smaller and smaller amplitude of diameter constantly increases.

8. hot-pipe system as claimed in claim 6, which is characterized in that along flow of flue gas direction, the length of horizontal component is L, along flow of flue gas direction, the caliber of the VERTICAL TUBE of heat pipe tail portion is D_Tail, then apart from heat pipe tail portion, distance is the vertical of the positions l Pipe caliber D rules are as follows：D²=b*（D_Tail）²+c*（D_Tail）²*（l/L）^a, wherein a, b, c is coefficient, meets following require：

1.085<a<1.125,0.985<b+c<1.015 0.485<b<0.645.

9. heat pipe as claimed in claim 8, which is characterized in that as l/L increases, a is gradually reduced.

10. heat pipe as claimed in claim 8, which is characterized in that 1.093<a<1.106, b+c=1,0.548<b<0.573.