CN110017495B

CN110017495B - Combustion waste heat exchange device with optimized tube spacing and outer diameter

Info

Publication number: CN110017495B
Application number: CN201910241789.2A
Authority: CN
Inventors: 刘海涛; 王东杰; 吕志鸿; 胡煦东; 靳雁松; 贾川; 贾大鹏; 李源浩
Original assignee: China North Vehicle Research Institute
Current assignee: China North Vehicle Research Institute
Priority date: 2017-05-11
Filing date: 2017-05-11
Publication date: 2020-05-12
Anticipated expiration: 2037-05-11
Also published as: CN107192282B; CN110017495A; CN109990307B; CN107192282A; CN109990307A

Abstract

The invention provides a combustion waste heat exchange device with optimized tube spacing and outer diameter, which comprises a heat exchange core body, wherein the heat exchange core body comprises a cover plate and a plurality of heat exchange tubes, the heat exchange tubes comprise round tubes, the round tubes are arranged in a plurality of rows along the flow direction of flue gas, the round tubes are in a staggered structure, the spacing between the circle centers of the adjacent round tubes is 1.1-1.3 times of the outer diameter of the round tubes, and the outer diameter of the round tubes is the average value of the outer diameters of the two adjacent heat exchange tubes. The invention is the optimal proportional relation through a large number of experiments through the proportional relation. Through the setting of the pipe diameter and the space size, the pressure distribution can be optimal.

Description

Combustion waste heat exchange device with optimized tube spacing and outer diameter

Technical Field

The invention belongs to the field of heat exchange, and particularly relates to a shell-and-tube heat exchange device for waste heat utilization.

Background

In the last decade, energy conservation work is further carried out due to energy shortage. Various novel advanced energy-saving furnaces are gradually improved, and the heat dissipation loss of the furnace is obviously reduced after the novel high-quality heat-insulating materials such as refractory fibers are adopted. The advanced combustion device is adopted to strengthen the combustion, the incomplete combustion amount is reduced, and the air-fuel ratio is also reasonable. However, techniques for reducing the heat loss of flue gas and recovering the residual heat of flue gas have not been developed rapidly. In order to further improve the heat efficiency of the kiln and achieve the purposes of energy conservation and consumption reduction, the recovery of the flue gas waste heat is also an important energy-saving way.

The smoke is the main way of wasting energy of general energy consumption equipment, for example, the energy consumption of boiler smoke is about 15%, and other equipment such as setting machine, drying-machine and kiln of printing and dyeing industry all consume energy through the smoke. The flue gas waste heat recovery mainly converts the heat carried by the flue gas into the heat which can be utilized through a certain heat exchange mode.

The flue gas waste heat recovery method generally adopts two methods, one is to preheat a workpiece; the second is to preheat air to support combustion. The flue gas preheats the work piece and need occupy great volume and carry out the heat exchange, often receives the restriction in operation place. The preheating air combustion supporting is a better method, is generally arranged on a heating furnace, can also strengthen combustion, accelerates the temperature rise of the furnace and improves the thermal performance of the furnace.

The power transmission system of the special vehicle is subject to adverse factors such as friction pair locking, poor lubrication, reduction of the power supply capacity of a storage battery, difficulty in engine ignition in a low-pressure environment and the like in an extremely cold environment, and the reliability of the vehicle is greatly reduced. The warmer is used as a combustion heat exchange device, heat is transferred through cooling liquid, and a cooling system, a lubricating system, a transmission system, a power system and the like of a vehicle can be warmed under an extreme environment, so that each system reaches an optimal working state, and adverse factors faced by vehicle starting are eliminated. Meanwhile, the light weight of the vehicle and the adaptability to various extreme environmental conditions put forward the requirements of high power density, high integration, high efficiency, low consumption and high adaptability to the heater. Thus, the requirements of the process are met, and finally, a remarkable comprehensive energy-saving effect can be obtained.

The traditional heater generally faces the problems of low heat flux density and low heat exchange efficiency, the key points of solving the problems are to increase the heat exchange area, reduce the flow resistance, improve the temperature difference of a heat exchange medium, the convection heat exchange coefficient and the like, and under the condition of the same volume, the traditional heat exchange structure cannot meet the practical requirement.

Disclosure of Invention

The invention aims to solve the problems of low heat exchange efficiency, heavy weight, large occupied volume and poor high temperature resistance of the existing waste heat utilization heat exchange device, and provides a heat exchange device with compact structure, high temperature resistance, high power density and high heat exchange efficiency.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a waste gas waste heat utilization heat exchange device comprises a heat exchange core body, a heat exchange core body front support body and a heat exchange core body rear support body, wherein the heat exchange core body, the front support body and the rear support body are arranged in a waste gas flue; the heat exchange device comprises a front support body, a rear support body, a heat exchange core body cover plate, a flue pipe wall, a liquid inlet header and a liquid outlet header, wherein the front support body is connected with the heat exchange core body cover plate and the flue pipe wall, the rear support body is connected with the heat exchange core body cover plate and the flue pipe wall, and the front support body, the rear support body, the heat exchange core body cover plate and the flue pipe wall jointly form.

Preferably, the front support body and the rear support body are of tubular structures, two ends of the tube wall of the front support body are connected with the cover plate and the flue tube wall, and two ends of the tube wall of the rear support body are connected with the cover plate and the flue tube wall.

Preferably, the inlet pipe and the outlet pipe of the heat exchange device are respectively arranged on the wall of the flue and are respectively communicated with the inlet header and the outlet header.

Preferably, the inlet header is located at a lower portion of the flue and the outlet header is located at an upper portion of the flue.

Preferably, the waste gas flue is a combustion chamber installation cylinder, and the waste gas inlet temperature of the heat exchange device is 1200-1400 ℃.

Preferably, the heat exchange device is provided with a first exhaust port and a second exhaust port, the first exhaust port is arranged on the pipe wall of the waste gas flue of the upper header, and the second exhaust port is arranged on the water outlet pipe.

Preferably, the front support and the rear support are of a hollow square-round transition structure, one side end face is square, and one side end face is round, wherein the square end face of the front support is connected with one side end face of the round tube of the heat exchange core body and is fixed and sealed, and the round end face is fixed and sealed with the air outlet at the rear end face of the front combustion chamber mounting cylinder; the square end face of the rear supporting body is connected with one side end face of the flat tube of the heat exchange core body and is fixed and sealed, and the round end face of the rear supporting body is fixed and sealed with the air outlet of the rear flange device.

Preferably, the heat exchange tube includes the pipe, the section sets up a plurality of dispersion heat transfer structures in the pipe, dispersion heat transfer structure includes core and shell, the core sets up in the shell, the shell is fixed with heat exchange tube inner wall connection, the core includes that the grid piece by a plurality of quantity arranges the combination and forms, connects between the grid piece and forms the check and cut the hole.

Preferably, the inner wall of the heat exchange tube is provided with a groove, the shell of the dispersed heat exchange structure is arranged in the groove, and the inner wall of the shell is aligned with the inner wall of the circular tube.

Preferably, the distance between the adjacent dispersed heat exchange structures is L, the length of each dispersed heat exchange structure is C, the diameter of each heat exchange tube is D, the fluid circulation area of each grid hole is A, and the circumference of each grid hole in fluid circulation is Z, so that the following requirements are met:

L/C＝a-b*LN(D/E)；

E＝4*A/Z；

wherein LN is a logarithmic function, a, b are parameters, wherein 4.9< a <6.1,1.3< b < 2.1;

the distance between the dispersed heat exchange structures is the distance between two opposite ends of the adjacent dispersed heat exchange structures;

10<D<18mm；

8<C<15mm；

25<L<35mm。

preferably, the grid holes are square.

Preferably, the waste heat utilization heat exchange device is arranged in an exhaust gas flue of the combustor, preferably a flue of the heater.

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

1) according to the heat exchange device, the flue pipe wall is used for forming the inlet header and the outlet header of the heat exchange device, so that the inlet header and the outlet header are not separately arranged, the heat exchange device occupies less space, the volume and the weight of the heat exchange core are reduced, and the structure is compact.

2) According to the heat exchange device, the heat exchange core body adopts the round tube-shaped heat exchange tube, the diameter of the heat exchange tube is gradually reduced along the flow direction of flue gas, the film boiling phenomenon at the water side can be effectively reduced, the convective heat exchange strength at the water side is increased, the heat load of the heat exchange core body is reduced, and the heat exchange efficiency is improved.

3) According to the heat exchange device, the distance between the dispersed heat exchange structures in the circular tube is continuously reduced along with the distance from the inlet of the circular tube, so that the film boiling phenomenon of the water side can be effectively reduced, the convective heat exchange strength of the water side is increased, the heat load of the heat exchange core is reduced, and the heat exchange efficiency is improved.

4) According to the heat exchange device, the length of the dispersed heat exchange structure in the circular tube is continuously reduced along with the distance from the inlet of the circular tube, so that the film boiling phenomenon of the water side can be effectively reduced, the convective heat exchange strength of the water side is increased, the heat load of the heat exchange core is reduced, and the heat exchange efficiency is improved.

5) According to the heat exchange device, the grid type dispersed heat exchange structure is arranged in the heat exchange tube, so that a steam-water mixture in the heat exchange tube is separated, the film boiling phenomenon on the water side is effectively reduced, the convective heat exchange strength on the water side is increased, the heat load of the heat exchange core is reduced, and the heat exchange efficiency is improved.

6) The invention optimizes the structure of the heat-exchanging structure, obtains the optimal optimized size of the heat-exchanging structure through a large amount of numerical simulation and experiments, and further improves the heat-exchanging efficiency.

7) According to the heat exchange device, the heat exchange core body is a circular tube-flat tube combined type heat exchange structure, the front end of the heat exchange core body is of a thin-wall circular tube type heat exchange structure, the rear end of the heat exchange core body is of a plurality of rows of thin-wall flat tube type heat exchange structures, different heat exchange structures are adopted at different positions according to different heat absorption capacities, the film boiling phenomenon at the water side is effectively reduced, the heat load of the heat exchange core body is reduced, and the heat exchange efficiency is improved.

8) According to the heat exchange device, the upper shell and the lower shell of the heat exchange body are provided with the baffle plates and the guide plates, the baffle plates and the guide plates are used for guiding the liquid on the water side to flow according to the numerical simulation optimization conclusion, most of the liquid entering the water inlet pipe enters the water side channel around the heat exchange core under the blocking action of the bottom surface of the lower shell and the side baffle plates, flows down by the two guide plates of the half notch on the bottom surface of the lower shell, flows through the circular pipe and the flat pipe from bottom to top from the bottom of the heat exchange core and enters the water outlet pipe, and the heat load of the heat exchange core is. Meanwhile, the liquid entering between the front support body and the heat exchange body shell plays a role in cooling the front support body, the reliability of the heat exchange body is improved, the liquid around the rear support body exchanges heat with combustion exhaust gas, and the heat utilization rate is improved.

9) According to the heat exchange device, the upper shell and the lower shell of the heat exchange body adopt the covering structures at the butt joint parts, so that the effect of strengthening the structural stability can be achieved, the outward square groove is arranged in the middle area of the square structure of the upper shell, and the through holes are formed in the baffle plates arranged at the front end and the rear end of the square structure, so that gas in the heat exchange device can be conveniently gathered and discharged to the water outlet pipe, and the increase of the heat load of the heat exchange device caused by gas accumulation is avoided.

10) According to the heat exchange device, the front end is provided with the combustion chamber installation structure, and the rear end is provided with the smoke exhaust device fixing flange structure, so that the integration level of the combustion heat exchange device is improved, and the maintenance of the combustion heat exchange device and the maintenance of the heat exchange device are facilitated.

Drawings

FIG. 1 is a front view of one embodiment of a heat exchange device of the present invention;

FIG. 2 is a right side view of one embodiment of the heat exchange device of the present invention;

FIG. 3 is a water side view of the heat exchange core of the present invention;

FIG. 4 is a gas side structural view of the heat exchange core of the present invention;

FIG. 5 is a view showing the construction of the upper case of the heat exchange body of the present invention;

FIG. 6 is a view showing the construction of a lower shell of the heat exchange body of the present invention;

FIG. 7 is a schematic cross-sectional view of a dispersed heat exchange structure according to the present invention;

FIG. 8 is a schematic view of the arrangement of the dispersed heat exchange structure of the present invention within a heat exchange tube;

fig. 9 is another schematic view of the arrangement of the divergent heat exchange structure of the present invention within a heat exchange tube.

Fig. 10 is a schematic cross-sectional view of the arrangement of the dispersed heat exchange structure of the present invention in the heat exchange tube.

In the figure: 1. a heat exchange core body; 2. a front support; 3. a rear support body; 4. a heat exchange body upper shell; 5. a heat exchanger lower shell; 6. a front frame type baffle of the upper shell; 7. a rear frame type baffle of the upper shell; 8. a lower housing side baffle; 9. a lower shell rear frame type baffle; 10. a front flow guide plate; 11. a rear baffle; 12. a combustion chamber mounting cylinder; 13. a fixed flange; 14. a water outlet pipe; 15. a front air release port; 16. a rear air release port; 17. a circular tube; 18. flat tubes; 19. a water side cover plate; 20. a gas side cover plate; 21. straight tooth-shaped turbulence sheets; 22. a serrated fin; 23. an upper baffle of the upper shell; 24. an upper housing side baffle; 25. a lower housing side baffle; 26. an upper baffle plate of the lower shell; 27. a front guide plate of the lower shell; 28. a lower housing rear baffle; 29. an axial lower baffle; 30. an axial side baffle; 31. a water inlet pipe; 32. the heat exchanger comprises a dispersed heat exchange structure, a 33 dispersed heat exchange structure shell, 34 grid holes, 35 grid pieces, 36 heat exchange core body upper cover plates, 37 inlet header, 38 outlet header, a middle part 39 and a lower cover plate 40.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

In this document, "/" denotes division and "×", "denotes multiplication, referring to formulas, if not specifically stated.

The waste gas waste heat utilization heat exchange device shown in fig. 1-6 comprises a heat exchange core body 1, a heat exchange core body front support body 2 and a heat exchange core body rear support body 3, wherein the heat exchange core body 1, the front support body 2 and the rear support body 3 are arranged in a waste gas flue 12, the heat exchange core body 1 comprises an upper cover plate 36, a lower cover plate 40 and a plurality of heat exchange tubes, the heat exchange tubes penetrate through the upper cover plate 36 and the lower cover plate 40 in a connecting manner, the front support body 2 and the rear support body 3 are respectively positioned at two ends of the heat exchange core body 1 and form a gas side channel of the heat exchange device together with the heat exchange core body 1; the heat exchange device comprises a front support body 1, a heat exchange core body upper cover plate 36, a lower cover plate 40 and a flue 12 pipe wall, wherein the front support body 1 is connected with the heat exchange core body upper cover plate 36, the lower cover plate 40 and the flue 12 pipe wall, and the front support body 2, a rear support body 3, the heat exchange core body cover plate 36 and the flue 12 pipe wall jointly form a liquid inlet header 37 and an outlet header 38 of the heat exchange device.

According to the heat exchange device, the pipe wall is used as one part of the inlet header and the outlet header of the heat exchange device, the inlet header and the outlet header of the heat exchange device are formed by utilizing the pipe wall of the flue, the whole heat exchange device is arranged in the waste gas flue, the independent arrangement of the inlet header and the outlet header is avoided, the heat exchange device occupies less space, the volume and the weight of a heat exchange core body are reduced, and the structure is compact.

Preferably, the front support 2 and the rear support 3 are tubular structures, the two ends of the tube wall of the front support 2 are connected with the

cover plates

36 and 40 and the tube wall of the flue, and the two ends of the tube wall of the rear support 3 are connected with the

cover plates

36 and 40 and the tube wall of the flue.

Through so setting up for preceding supporter 2 and back supporter 3 form the waste gas entry and the waste gas export of heat transfer device waste gas side respectively, further make compact structure.

Preferably, the duct walls of the front and rear supports 2, 3 are connected to the duct wall of the flue 12 by an intermediate member 39, and the intermediate member 39 has a curved plate-like structure, as shown in fig. 1.

Preferably, the water inlet pipe 31 and the water outlet pipe 14 of the heat exchange device are respectively arranged on the pipe wall of the flue 12 and are respectively communicated with the inlet header and the outlet header.

Preferably, inlet header 38 is located in the lower portion of the flue and outlet header 37 is located in the upper portion of the flue.

Preferably, the heat exchange pipe includes a circular pipe 17, the circular pipe 17 is arranged perpendicular to the flow direction of the exhaust gas, and the diameter of the circular pipe 17 is smaller along the flow direction of the exhaust gas. If the distance from the exhaust gas inlet is S, the inner diameter of the circular tube is D, and if D is F (S), F '(S) <0, and F' (S) is the first derivative of F (S).

Because the inlet waste gas temperature of the waste heat utilization heat exchange device is very high, the liquid in the heat exchange pipe forms a steam-water mixture, and the proportion of a vapor phase in the steam-water mixture is lower and higher and the proportion of a liquid phase is higher and higher along the flowing direction of flue gas. Because the vapor phase proportion of front end is high, the space that consequently occupies is inevitable big, consequently through the change of pipe diameter for the pipe cross-sectional area of heat transfer device's front end is big, thereby makes inner space be enough to satisfy the distribution of liquid phase and satisfy the requirement of heat transfer pipe pressure, avoids anterior heat exchange tube pressure too big, thereby makes whole all heat exchange tube internal pressure of heat transfer core even, avoids having pressure too big, extension heat transfer device's life.

Preferably, F "(S) >0, F" (S) is the second derivative of F (S). That is, the diameter of the circular tube is gradually decreased along the flowing direction of the exhaust gas.

Experiments show that the pressure distribution in the round pipes at different positions can be further met by arranging the upper F (S) >0, and the pressure distribution in the heat exchange pipe is further ensured to be uniform.

Preferably, as shown in fig. 3, the round tubes 17 are arranged in a plurality of rows along the flow direction of the flue gas, the round tubes 17 are in a staggered structure, and the distance between the centers of the adjacent round tubes 17 is 1.1 to 1.3 times of the outer diameter of the round tubes 17. The outer diameter of the round pipe 17 is the average value of the outer diameters of two adjacent heat exchange pipes.

Preferably, the diameter of the rear row of tubes 17 is 0.93 to 0.98 times the diameter of the adjacent front row of tubes in the exhaust gas flow direction.

The above proportional relationship is the optimum proportional relationship through a large number of experiments. Through the setting of the pipe diameter and the space size, the pressure distribution can be optimal.

Preferably, the front support 2 forms an inlet channel on the gas side and the rear support 3 forms an outlet channel on the gas side.

Preferably, the heat exchange tube comprises a round tube 17, a plurality of separated heat exchange structures 32 are arranged in the round tube 17 in a segmented manner, each separated heat exchange structure 32 comprises a core body and a shell 33, the core body is arranged in the shell 33, the shell 33 is fixedly connected with the inner wall of the round tube 17, the core body comprises a plurality of grid pieces 35, and grid holes 34 are formed between the grid pieces 35 in a connected manner.

Because the temperature of the waste gas is very high, the flow in the round pipe can form a gas-liquid two-phase flow, the grid heat exchange dispersion heat exchange structure is arranged in the round pipe, the liquid phase and the gas phase in the two-phase fluid are separated through the dispersion heat exchange structure, the liquid phase is dispersed into small liquid masses, the gas phase is dispersed into small bubbles, the backflow of the liquid phase is inhibited, the gas phase flows smoothly, the flow stabilizing effect is achieved, and the vibration reduction and noise reduction effects are achieved. Meanwhile, the grid dispersed heat exchange structure is arranged, namely, the inner fins are additionally arranged in the heat exchange tube, so that heat exchange is enhanced, and the heat exchange effect is improved.

The invention disperses the gas-liquid two phases at all cross section positions of all heat exchange tubes, thereby realizing the dispersion of gas-liquid interface and gas phase boundary layer on the whole heat exchange tube section and the contact area of the cooling wall surface and enhancing the disturbance, greatly reducing the noise and the vibration and strengthening the heat transfer.

Preferably, the core of the partitioned heat exchange structure 32 is integrally formed.

Preferably, the core of the heat exchange structure 32 is welded by the grid sheets 35.

Preferably, the grid pieces 35 are provided with communication holes. Communication between the grating holes 34 is achieved by the communication holes.

Through setting up the intercommunicating pore, can guarantee to communicate each other between the adjacent grid hole, can the pressure between the even grid hole for the fluid flow direction low pressure of high pressure runner, also can further separate liquid phase and gaseous phase when the fluid flows simultaneously, be favorable to further stabilizing two-phase flow.

Preferably, a plurality of the dispersed heat exchange structures 32 are arranged in the circular tube 17 along the flowing direction (i.e. the height direction of fig. 8) of the fluid in the circular tube 17, and the distance between the adjacent dispersed heat exchange structures is shorter and shorter from the inlet of the circular tube to the outlet of the circular tube. Set the distance from the inlet of the circular tube toH, the distance between the adjacent dispersed heat exchange structures is L, and L is equal to F₁(H) I.e. L is a function of the height H as a variable and L' is the first derivative of L, the following requirements are met:

L’<0；

the main reason is that the gas in the circular tube carries liquid in the rising process, the circular tube is continuously heated in the rising process, so that more and more gas in gas-liquid two-phase flow is caused, the heat exchange capacity in the circular tube is relatively weakened along with the increase of the gas phase because more and more gas phases in the gas-liquid two-phase flow, and the vibration and the noise thereof are also continuously increased along with the increase of the gas phase. The distance between adjacent dispersed heat exchange structures needs to be set shorter and shorter.

In addition, the section from the outlet of the round tube to the upper collecting tube is suddenly enlarged in space, the change of the space can cause the gas to rapidly flow out and gather upwards, so the change of the space can cause the gathered vapor phase (vapor mass) to enter the condensing collecting tube from the position of the round tube, the vapor mass leaves the position of the connecting tube and rapidly moves upwards due to the poor liquid density of the vapor (vapor), and the liquid at the original space position of the vapor mass pushed away from the wall surface by the vapor mass also rapidly rebounds and impacts the wall surface to form an impact phenomenon. The more discontinuous the gas (vapor) liquid phase, the larger the gas mass accumulation and the larger the water hammer energy. The impact phenomenon can cause larger noise vibration and mechanical impact, and damage to equipment. Therefore, in order to avoid the phenomenon, the distance between the adjacent dispersed heat exchange structures is set to be shorter and shorter, so that the gas phase and the liquid phase are continuously separated in the fluid conveying process, and the vibration and the noise are reduced to the maximum extent.

Through the experiment discovery, through foretell setting, both can reduce vibrations and noise to the at utmost, can improve the heat transfer effect simultaneously.

It is further preferred that the distance between adjacent discrete heat exchange structures from the inlet of the circular tube 17 to the outlet of the circular tube 17 is increasingly shorter. I.e. S "is the second derivative of S, the following requirements are met:

L”>0；

experiments show that the vibration and the noise can be further reduced by about 10% and the heat exchange effect can be improved by about 11% by the arrangement.

Preferably, the length of each of the discrete heat exchange structures 32 remains constant.

Preferably, other parameters of the decentralized heat exchange structures (such as length, tube diameter, etc.) are kept constant, except for the distance between adjacent decentralized heat exchange structures 32.

Preferably, a plurality of the dispersed heat exchange structures 32 are arranged in the circular tube 17 along the height direction of the circular tube 17, and the length of the dispersed heat exchange structures 32 is longer from the inlet of the circular tube 17 to the outlet of the circular tube 17. That is, the length of the dispersed heat exchange structure is C, and C is F₂(X), C' is the first derivative of C, and meets the following requirements:

C’>0；

further preferably, the length of the dispersing heat exchange structure is increased from the inlet of the circular tube to the outlet of the circular tube. I.e., C "is the second derivative of C, the following requirement is satisfied:

C”>0；

for example, the distance between adjacent dispersed heat exchange structures may vary.

Preferably, the distance between adjacent dispersed heat exchange structures is kept constant.

Preferably, other parameters of the decentralized heat exchange structure (such as adjacent spacing, pipe diameter, etc.) are kept constant, in addition to the length of the decentralized heat exchange structure.

Preferably, a plurality of dispersing heat exchange structures are arranged in the circular tube 17 along the height direction of the circular tube 17, and the hydraulic diameters of the grid holes 41 in different dispersing heat exchange structures 32 are smaller from the inlet of the circular tube 17 to the outlet of the circular tube 17. That is, the hydraulic diameter of the grid holes of the dispersed heat exchange structure is Z, and Z is F₃(X), Z' is the first derivative of Z, satisfying the following requirements:

Z’<0；

preferably, the hydraulic diameter of the grid holes of the dispersed heat exchange structure is gradually increased from the inlet of the circular tube to the outlet of the circular tube. Namely, it is

Z' is the second derivative of Z, and meets the following requirements:

Z”>0。

Preferably, the length of the dispersive heat exchange structure and the distance between adjacent dispersive heat exchange structures are kept constant.

Preferably, other parameters of the dispersive heat exchange structure (such as length, distance between adjacent dispersive heat exchange structures, etc.) are kept constant, except for the hydraulic diameter of the grid openings of the dispersive heat exchange structure.

Further preferably, as shown in fig. 3, a groove is formed inside the circular tube 17, and the shell 33 of the dispersed heat exchange structure 32 is disposed in the groove.

Preferably, the inner wall of the housing 33 is aligned with the inner wall of the barrel 17. Through alignment, the inner wall surface of the circular tube is on the same plane, and the smoothness of the surface is guaranteed.

Preferably, the thickness of the housing 33 is smaller than the depth of the groove, so that the inner wall surface of the circular tube is formed with the groove, thereby performing enhanced heat transfer.

More preferably, as shown in fig. 4, the circular tube 17 is formed by welding in a multi-stage structure, and the dispersed heat exchange structure 32 is provided at the joint of the multi-stage structure. The circular tube with the dispersed heat exchange structure is simple to manufacture and low in cost in the mode.

Through analysis and experiments, the distances among the dispersed heat exchange structures cannot be too large, the vibration and noise reduction effect is poor if the distances are too large, meanwhile, the distances cannot be too small, the resistance is too large if the distances are too small, and similarly, the outer diameters of the grid holes cannot be too large or too small, the vibration and noise reduction effect is poor or the resistance is too large, so that the vibration and noise reduction is optimized under the condition that normal flow resistance (the total pressure bearing is less than 2.5Mpa, or the on-way resistance of a single round pipe is less than or equal to 5Pa/M) is preferentially met through a large number of experiments, and the optimal relation of each parameter is arranged.

L/C＝a-b*LN(D/E)；

E＝4*A/Z；

10<D<18mm；

8<C<15mm；

25<L<35mm。

preferably, 5.4< a <5.8,1.6< b < 1.9;

preferably, a is 5.52 and b is 1.93.

The space S of the dispersed heat exchange structures is the distance between two opposite ends of the adjacent dispersed heat exchange structures; namely the distance between the tail end of the front dispersed heat exchange structure and the front end of the rear dispersed heat exchange structure. See in particular the label of fig. 9.

The diameter D of the heat exchange tube means an average of the inner diameter and the outer diameter.

Preferably, the length S of the round tube is between 140 and 200 mm. More preferably, 160-180 mm.

By optimizing the optimal geometric dimension of the formula, the optimal effect of shock absorption and noise reduction can be achieved under the condition of meeting the normal flow resistance.

Further preferably, a is continuously decreased and b is continuously increased as D/E is increased.

For other parameters, such as the wall thickness of the pipe and the wall thickness of the shell, the parameters are set according to normal standards.

Preferably, the grid apertures 34 extend the entire length of the distributed heat exchange structure 32. I.e., the length of the grid apertures 34 is equal to the length of the dispersive heat exchange structure 32.

Through the arrangement, heat transfer can be further enhanced, and the heat exchange efficiency can be improved.

Preferably, the grid openings, except for the grid openings formed by the housing 33, are square.

Preferably, the heat exchange tube comprises a round tube 17 and a flat tube 18, and the round tube 17 is distributed at the front end of the flat tube 18. I.e. along the flow direction of the exhaust gases, round tubes 17 and flat tubes 18 are distributed in succession.

The main reason lies in that waste gas inlet side temperature is high, therefore liquid boils easily, thereby form vapour-liquid two-phase flow, because the shape of pipe is circular, even under the same heat transfer area condition, pipe flow area is big, make the bearing capacity reinforce, and along with the heat transfer of flue gas, the flue gas temperature of rear end is lower relatively, consequently, can use flat pipe, flat pipe is long and flat because the shape is prolate, the circulation space is little, liquid can not boil at the rear end, consequently, do not need the big passageway can satisfy the pressure requirement, and flat pipe heat transfer area is big, thereby make the intensive heat transfer. Therefore, the distribution of the flat pipes and the round pipes enables the pressure distribution of the heat exchange device to be relatively uniform on the whole, the phenomenon that the pressure is too large is avoided, and the heat exchange capacity is relatively increased.

Preferably, the fluid flow area of a single round tube is larger than that of a single flat tube.

Preferably, the fluid flow area of a single round tube is 2-3 times the flow area of a single flat tube.

Preferably, the circular tube 17 is placed on the front side of the heat exchange core body, the circular tube 17 has a plurality of rows, each row comprises a plurality of circular tubes 17, and two adjacent rows of circular tubes 17 are distributed in a staggered manner. Flat pipe 18 divide the multirow next-door neighbour pipe heat transfer structure arrange in heat transfer core rear side, every row contains a plurality of flat pipes 18, and two adjacent rows of flat pipes preceding, back one-to-one.

The extension direction of the flat tubes 18 is parallel to the flow direction of the flue gas.

Preferably, the flow direction of the liquid in the circular tubes 17 and the flat tubes 18 is perpendicular to the flow direction of the exhaust gas.

Preferably, the fins are arranged in the flat tubes to divide the liquid flow channels in the flat tubes into a plurality of small flow channels. Preferably, the hydraulic diameters of the small flow channels in the different flat tubes become smaller along the direction of the flow of the exhaust gas. And if the distance from the waste gas inlet is S, the hydraulic diameter of the flat tube small flow passage is d, and if d is F (S), F '(S) <0, and F' (S) is the first derivative of F (S).

The main reason is along the flow direction of waste gas, and the pressure that needs bear in the flat intraductal pipe is littleer and more, consequently can diminish the water conservancy diameter, diminishes through diminishing the water conservancy radius moreover, can increase heat transfer area, improves heat transfer ability. Therefore, by means of the arrangement of the characteristics, the pressure requirement can be met, and the enhanced heat transfer can be realized.

Preferably, the hydraulic diameter d of the flat tube small flow channel increases continuously along the flow direction of the waste gas. I.e. F "(S) >0, F" (S) being the second derivative of F (S).

For F (S) >0, the heat exchange effect can be obviously improved, and pressure balance is realized. The above results are obtained by a number of numerical simulations and experiments.

Preferably, the small flow channels in the same flat tube have a smaller hydraulic radius along the direction of liquid flow. And if the distance from the waste gas inlet is S, the hydraulic diameter of the flat tube small flow passage is d, and if d is F (S), F '(S) <0, and F' (S) is the first derivative of F (S).

Preferably, the hydraulic diameter d of the same flat tube small flow channel along the flowing direction of the waste gas is increased continuously. Then F "(S) >0, F" (S) is the second derivative of F (S). For the same reasons as before.

Preferably, the small flow channels in the flat tubes are rectangular in cross-section and have dimensions of 2x4 mm.

Preferably, the cross section of the small flow channel between the flat tubes is triangular.

Preferably, the exhaust gas flue 12 is a combustion chamber installation cylinder 12.

Preferably, the exhaust gas inlet temperature of the heat exchange device is 1200-1400 degrees Celsius, preferably 1300 degrees Celsius. Preferably, the front row of round tubes is made of high-temperature resistant stainless steel.

Preferably, the heat exchange device is provided with exhaust ports 15 and 16, the exhaust port 15 is arranged on the pipe wall of an exhaust gas flue 17 of the upper header, and the exhaust port 16 is arranged on the water outlet pipe. Preferably, the exhaust ports 15, 16 are automatically exhausted according to the pressure condition.

Specific preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The heat exchange device related in the preferred embodiment comprises a heat exchange core body 1, a front support body 2, a rear support body 3, a heat exchange body upper shell 4 and an upper shell front frame type baffle 6 and an upper shell rear frame type baffle 7 which are arranged on the heat exchange body upper shell 4, a heat exchange body lower shell 5 and a lower shell side baffle 8 and a lower shell rear frame type baffle 9 which are arranged on the heat exchange body lower shell 5, a front guide plate 10, a rear guide plate 11, a water inlet pipe 31, a water outlet pipe 14, a combustion chamber installation cylinder 12, a fixing flange 13 and the like.

The heat exchange core body 1 is a thin-wall round tube-tube strip combined heat exchange structure, liquid flowing areas are arranged inside the round tubes 17 and the flat tubes 18, areas between the round tubes and between the flat tubes are gas flowing areas, the zigzag fins 22 are arranged between adjacent flat tubes of each row of flat tubes and used for increasing the heat exchange area of a gas side channel, and the straight-tooth-shaped turbulence sheets 21 are arranged inside the flat tubes and used for increasing disturbance to flowing liquid. The square end face of preceding supporter 2, back supporter 3 passes through welded fastening with the regional both ends face of 2 gas flow of heat exchange core respectively, the circular terminal surface of preceding supporter 2 is connected, is fixed with the rear end face gas outlet of combustion chamber installation section of thick bamboo 12, the circular terminal surface of back supporter 3 aligns and fixes with mounting flange minor diameter terminal surface round hole, casing 4 is relative with heat exchange core water side passageway on the heat exchange body, is located heat exchange core 1 and supporter (2, 3) upside, casing 5 is located heat exchange core 2 and supporter (2, 3) downside under the heat exchange body, and is fixed in both sides free limit department with heat exchange body on casing 4. The front end face and the rear end face of the upper shell (4) and the lower shell (5) are respectively fixed and sealed with the outer side face of the combustion chamber installation cylinder (12) and the outer side face of the small-diameter end of the fixed flange (13). The heat exchanger comprises a heat exchanger upper shell, a front frame type baffle 6 and a rear frame type baffle 7, wherein the front frame type baffle 6 and the rear frame type baffle 7 are transversely fixed at the front end and the rear end of a square part according to the shape of the shell, the heat exchanger lower shell side baffle 25 is positioned at the front end of the square part, the left side and the right side are respectively fixed with one baffle, the heat exchanger lower shell rear frame type baffle 9 is transversely fixed at the rear end of the square part according to the shape of the shell, the stepped front guide plate 10 and the stepped rear guide plate 11 are fixed at the bottom surface of the heat exchanger lower shell 5 and the corresponding area of the round. The water inlet pipe 31 and the water outlet pipe 14 are respectively connected with the upper shell 4 and the lower shell 5 of the heat exchange body, are used as a heat exchange device to be connected with the outside to form a bridge, and form a water side flow channel together with the shells 4 and 5 of the heat exchange body, the liquid flowing area of the heat exchange core body 1 and the core body supporting bodies 2 and 3. The combustion chamber installation cylinder 12, the front support body 2, the heat exchange core body 1, the gas flowing area, the rear support body 3 and the fixed flange 13 jointly form a gas side flow channel. The heat exchange device realizes flowing heat exchange and has the characteristics of high temperature resistance, compact structure, high heat exchange efficiency and high power density.

Specifically, as shown in fig. 3 and 4, the heat exchange core body comprises 3 rows of high-temperature-resistant stainless steel round tubes 17 which are staggered in front and back, 2 rows of stainless steel flat tubes 18 which are aligned in front and back, 2 water side cover plates 19, 2 air side cover plates 20, 42 saw-tooth-shaped

fins

22 and 40 straight-tooth-shaped turbulence plates 21, wherein the number of the first row and the third row of round tubes in the round tube heat exchange structure is 9, the number of the second row of round tubes is 8, the wall thickness of each round tube is 1mm, the number of each row of flat tubes in the flat tube heat exchange structure is 21, the wall thickness of each flat tube is 0.5mm, the straight-tooth-shaped turbulence plates 21 and the saw-tooth-shaped fins 22 are of independent structures, and the straight-tooth-shaped turbulence plates 21 and the flat-. Round holes and long holes with the same number as the round pipes 17 and the flat pipes 18 are arranged on the water side cover plate 19, the hole diameter is matched with the sizes of the round pipes and the flat pipes, and 90-degree folded edges are arranged at the cover plate edges of the water side cover plate 19 and the air side cover plate 20, so that the water side cover plate and the air side cover plate are convenient to fix. All parts of the heat exchange core body 1 are fixed and sealed through a brazing process, and the heat exchange core body has good strengthWith the technical characteristics, the volume of the welded heat exchange core body 1 is 160 multiplied by 180 multiplied by 168(mm), and the heat exchange area is 3.62m²And the heat exchange efficiency can reach 92%.

Specifically, the front support body 2 and the rear support body 3 are in a hollow square-round transition structure, one side end face is square, and one side end face is round, wherein the square end face of the front support body 2 is connected with the front end face of the heat exchange core body 1 and is welded, fixed and sealed, and the round end face is sleeved in the small-diameter cylinder of the combustion chamber installation cylinder 12 and then is welded, fixed and sealed; the square end face of the rear supporting body is in butt joint with the rear end face of the heat exchange core body and is welded, fixed and sealed, the circular end face is welded and fixed and sealed at the air inlet of the front end face of the fixing flange 13, and preferably, the thickness of the front supporting body and the thickness of the rear supporting body are 1.5 mm.

Specifically, the shapes of the upper shell 4 and the lower shell 5 of the heat exchanger are similar to those of the fixed front support 2, the heat exchange core 1 and the fixed rear support 3, the front part of the upper shell 4 and the front part of the lower shell of the heat exchanger are of a round-square transition structure, the middle part of the upper shell is of a square structure, and the rear part of the lower shell is of a square-round transition structure, so that the core supports (2 and 3) and the heat exchange core 1 can be surrounded in the upper shell 4 and the lower shell after the free edges of the two side surfaces of the upper shell and the lower shell 5 are butted, and the upper shell and the lower shell are fixed with the outer side surface of a.

Specifically, see fig. 2, the butt joint of the free edges of the two side surfaces of the upper shell 4 and the lower shell 5 of the heat exchange body is of a covering fixing structure, namely, one side plane of the upper shell is outwards expanded near the butt joint and is provided with a downward extending part, the distance is the same as the thickness of the shell as the optimal expansion distance, the other side plane of the lower shell is provided with the downward extending part, the two extending parts are fixed, and when the upper shell and the lower shell are in butt joint, the butt joint edges form a mutually covering structure, so that the welding fixation is facilitated, and meanwhile, the effect of strengthening the stability of the.

Specifically, an exhaust auxiliary seat is arranged on the bottom surface of the round-square transition structure of the upper shell 4 of the heat exchange body close to the front end face, so that air in a front end water side flow channel can be conveniently exhausted. The middle area of the square structure of the shell 4 on the heat exchange body is provided with an outward square groove, so that the gas in the heat exchange device can be conveniently collected and discharged. A circular water outlet hole and a sensor attaching seat mounting hole are formed in the central area of a square groove of an upper shell 4 of the heat exchange body, a circular water inlet hole is formed in a circle-square transition structure at the front end of the right end face of a lower shell, the diameter of the water inlet hole is the same as that of the water outlet hole and used for mounting a water pipe, and meanwhile, a sensor attaching seat mounting hole is formed beside the water inlet hole and the water outlet hole and used for mounting a sensor attaching seat and facilitating collection of inlet water temperature and outlet water temperature of the heat. The water outlet pipe 14 arranged on the upper shell 4 of the heat exchange body is provided with an exhaust auxiliary seat which is convenient for the heat exchange device to exhaust air.

Specifically, as shown in fig. 5, the upper shell 4 of the heat exchanger is provided with an upper shell front frame type baffle 6 and an upper shell rear frame type baffle 7 which have the same structure and respectively comprise 1 upper shell upper baffle 23 and 2 upper shell side baffles 24, and a semicircular hole penetrating through the baffles is formed in the middle area of the upper part of the upper baffle 23, so that gas in the front space of the upper baffle 23 can be conveniently discharged out of the heat exchanger through the hole. The upper baffle 23 of the front frame type baffle 6 is transversely placed on the plane where the front end of the square structure of the upper shell 4 of the heat exchanger body and the front end surface of the heat exchange core 1 are located, the length of the upper baffle is the distance between the two side surfaces of the upper shell, the height of the upper baffle is the same as the distance between the upper shell and the upper cover plate of the heat exchange core 1, and the upper baffle is fixed on the inner side surface of the upper shell 4 of; the side baffle 24 of preceding frame baffle 6 is located preceding frame baffle 6 overhead gage 23 rear portion, the heat exchange core left and right sides, and its height is unanimous with the square structure side in place, and the width is the same with the distance of last casing 4 side to the heat exchange core with the side, is fixed in on the heat exchange body 4 medial surface and preceding terminal surface of overhead gage 23 of preceding frame baffle 6. Similarly, the front end surface of the upper baffle plate 23 of the back frame type baffle plate 7 is located on the plane of the back end surface of the heat exchange core body 1, and the front end surface of the side baffle plate 24 of the back frame type baffle plate 7 is located on the plane of the back end surface of the upper baffle plate 23 of the back frame type baffle plate 7.

Specifically, referring to fig. 6, the lower heat exchange unit shell 5 is provided with a lower shell side baffle 25, a lower shell upper baffle 26, a lower shell front baffle 27 (i.e., baffle 11 of fig. 1), a lower shell rear baffle 28 (i.e., baffle 12 of fig. 1), an axial lower baffle 29, and an axial side baffle 30. The lower shell 5 of the heat exchange body is provided with side baffles 25 at positions close to the left side and the right side of the front end and the rear end of the square structure of the upper shell, the structural characteristics of the lower shell are the same as those of the side baffles 24 of the upper shell, when the upper shell and the lower shell are butted, the side baffles at the same positions of the two shells are overlapped in the front and the rear directions, namely, the rear side surface of the baffle of the upper shell is superposed with the front side surface of the baffle of the lower. The lower shell upper baffle 26 is transversely arranged on the bottom surface of the rear end of the lower shell and in front of the rear side baffle 25, the rear side surface of the upper baffle 26 is superposed with the front end surface of the side baffle and is fixed on the inner side of the bottom surface of the lower shell, and no hole is formed in the middle of the lower baffle. The axial lower baffle 29 is fixed in the middle area of the inner side of the bottom surface of the round-square transition section at the front end of the lower shell 5 of the heat exchange body in a welding mode, the axial side baffle 30 is fixed in the middle height of the right side face of the lower shell in a welding mode, the water inlet is located at the lower portion of the baffle, and the axial lower baffle 29 and the axial side baffle 30 are consistent in length with the axial length of the front support body. The front guide plate 27 of the lower shell and the rear guide plate 28 of the lower shell are transversely fixed on the bottom surface of the lower shell 5 of the heat exchange body, the length of the front guide plate is consistent with the width of the bottom surface of the lower shell of the heat exchange body, and the height of the right part of the guide plate, which is positioned on the vertical surface of the central shaft of the heat exchange device, is 1/2 with the height of the. In the axial direction of the heat exchanger, the front guide plate 27 of the lower housing is placed on a plane parallel to and equidistant from the plane where the axes of the two rows of round tubes in the front of the heat exchange core 1 are located, and the rear guide plate 28 of the lower housing is placed on the plane where the axes of the round tubes in the second row of the heat exchange core 1 are located.

Preferably, the height of the lower baffle 29 varies in the axial direction with the distance between the bottom surface of the front support 2 and the lower heat exchange shell 5 to ensure that the distance between the lower baffle 29 and the front support remains uniform in the axial direction, and the flow rate of the fluid passing therethrough meets the design requirements.

Preferably, the height of the axial side baffle 30 varies axially with the distance between the right side of the front support 2 and the lower heat exchange shell 5 to ensure that the distance between the axial side baffle 30 and the front support remains axially consistent, and the fluid flow therethrough meets design requirements.

The purpose of the baffle and baffle is to distribute the flow. The axial downward baffle plate is aligned with the middle position of the trapezoidal guide plate, most of liquid entering from the water inlet pipe enters the heat exchange core body through the lower edge of the trapezoidal structure, and a small part of liquid enters the region between the front support body and the heat exchange body through the gap between the axial downward baffle plate and the axial upward baffle plate and the front support body, so that the combustion chamber and the shell are cooled, and the fluid flows into the water outlet space of the heat exchange core body through the small hole in the center of the baffle plate arranged on the upper shell.

In the aspect of functions, flow distribution is carried out according to the position of breakwater after the coolant liquid gets into the heat transfer core by the water inlet, the one-level heat transfer pipe accounts for whole discharge 42%, the flat pipe of second grade heat transfer accounts for flow 30%, the flat pipe of tertiary heat transfer accounts for flow 20%, the one-level heat transfer pipe mainly carries out the forced heat exchange with high temperature gas, reduces high temperature gas temperature, guarantee two, the flat pipe life of tertiary heat transfer, two, the flat pipe of tertiary heat transfer is because internally mounted has the heat transfer fin, heat transfer area improves by a wide margin, has guaranteed complete machine heat. In order to realize the flow distribution, corresponding guide plates and baffles are arranged on the upper shell and the lower shell. Wherein, axial lower baffle and axial side shield are fixed in down on the casing, and the baffle height is along with preceding supporter shape change and with preceding supporter lateral surface interval 2mm, and about 8% gets into the space between last casing and preceding supporter through this gap in the fluid that gets into heat transfer device to the gap inflow core upper portion space between frame baffle and the heat exchange core before the last casing, and then flows out heat transfer device by the delivery port, and this partial fluid mainly used cools off preceding supporter, improves heat transfer device reliability. The lower shell at the bottom of the first-stage heat exchange circular tube of the heat exchange core body is provided with a front guide plate of the lower shell and a rear guide plate of the lower shell, the front guide plate is positioned between the first row of heat exchange tubes and the second row of heat exchange tubes, the rear backflow plate is positioned on the central plane of the second row of heat exchange tubes, and the two guide plates are in a trapezoidal structure and start from the central position to be higher than the left side of the guide plate on the right side along the flowing direction of. The purpose of setting up the trapezium structure guide plate lies in with some fluid interception in order to improve one-level heat transfer pipe flow in heat transfer pipe bottom, releases some fluid and ensures heat transfer flat pipe flow. The flow of a second row of heat exchange tubes and a third row of heat exchange tubes in the first-stage heat exchange circular tube is ensured by the combined action of the front guide plate and the rear guide plate of the lower shell, and meanwhile, the rear guide plate is placed on the central plane of the second row of heat exchange tubes to ensure the required flow and balance the heat load of each row of heat exchange tubes through numerical simulation calculation and experimental verification.

Preferably, the upper and lower housings form a portion of the wall of the exhaust gas passage.

1. According to the heat exchange device, high-temperature waste gas generated by combustion flows through the heat exchange device from the air side channel, heat is transferred to liquid in the water side channel through the wall surface of the air side channel and the heat exchange core fins, so that the liquid is heated, the adopted thin-wall heat exchange structure can effectively reduce heat exchange thermal resistance and reduce the volume and weight of the heat exchange core, and the heat exchange device has the characteristics of high temperature resistance, compact structure, high heat exchange efficiency and high power density.

2. According to the heat exchange device, the front end of the heat exchange core body is of a thin-wall round-tube-shaped heat exchange structure, and the round tube is made of high-temperature-resistant stainless steel, so that the high-temperature-resistant strength of the heat exchange core body can be improved, and the volume of the combustion heat exchange device is effectively reduced.

3. According to the heat exchange device, the rear end of the heat exchange core body is of a multi-row thin-wall flat tube type heat exchange structure, and the straight-tooth fins are arranged between the flat tubes, so that the heat exchange area of the air side channel is increased, and the heat exchange efficiency of the heat exchange device is improved. The zigzag turbulence sheets are arranged in the flat tubes, so that the film boiling phenomenon of the water side can be effectively reduced, the convective heat transfer strength of the water side is increased, the heat load of the heat transfer core body is reduced, and the heat transfer efficiency is improved.

4. According to the heat exchange device, the upper shell and the lower shell of the heat exchange body are provided with the baffle plates and the guide plates, the baffle plates and the guide plates are used for guiding water side liquid to flow according to a design mode, most of the liquid entering the water inlet pipe enters the water side channel around the heat exchange core under the blocking action of the bottom surface of the lower shell and the side baffle plates, flows down by the two guide plates of the half notch on the bottom surface of the lower shell, flows through the circular pipe and the flat pipe from bottom to top from the bottom of the heat exchange core and enters the water outlet pipe, and the heat load of the heat exchange core is reduced while the heat exchange. Meanwhile, the liquid entering between the front support body and the heat exchange body shell plays a role in cooling the front support body, the reliability of the heat exchange body is improved, the liquid around the rear support body exchanges heat with combustion exhaust gas, and the heat utilization rate is improved.

5. According to the heat exchange device, the upper shell and the lower shell of the heat exchange body adopt the covering structures at the butt joint parts, so that the effect of strengthening the structural stability can be achieved, the outward square groove is arranged in the middle area of the square structure of the upper shell, and the through holes are formed in the baffles arranged at the front end and the rear end of the square structure, so that gas in the heat exchange device can be conveniently gathered and discharged to the water outlet pipe, and the increase of the heat load of the heat exchange device caused by gas accumulation is avoided.

6. According to the heat exchange device, the front end is provided with the combustion chamber installation structure, and the rear end is provided with the smoke exhaust device fixing flange structure, so that the integration level of the combustion heat exchange device is improved, and the maintenance of the combustion and heat exchange device is facilitated.

Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. The heat exchange device comprises a heat exchange core body, wherein the heat exchange core body comprises a cover plate and a plurality of heat exchange tubes, the heat exchange tubes comprise round tubes, the round tubes are arranged in a plurality of rows along the flowing direction of flue gas, the round tubes are of a staggered structure, the distance between the circle centers of the adjacent round tubes is 1.1-1.3 times of the outer diameter of the round tube, and the outer diameter of the round tube is the average value of the outer diameters of the two adjacent heat exchange tubes; the circular tube is internally provided with a plurality of dispersed heat exchange structures in a segmented manner, each dispersed heat exchange structure comprises a core body and a shell, the core body is arranged in the shell, the shell is fixedly connected with the inner wall of the heat exchange tube, the core body comprises a plurality of grid pieces which are arranged and combined, and grid holes are formed between the grid pieces in a connected manner.

2. The heat exchange device of claim 1 wherein the diameter of the tubes of the subsequent row is 0.93 to 0.98 times the diameter of the tubes of the adjacent preceding row in the direction of flow of the exhaust gas.