CN111006189B

CN111006189B - Square outer-layer steam generator

Info

Publication number: CN111006189B
Application number: CN201910038630.0A
Authority: CN
Inventors: 黄雪涛; 王海霞; 毋青松; 董新婷; 刘宗泽
Original assignee: Shandong Jiaotong University
Current assignee: Shandong Jiaotong University
Priority date: 2019-01-16
Filing date: 2019-01-16
Publication date: 2021-03-30
Anticipated expiration: 2039-01-16
Also published as: CN111006189A

Abstract

The invention provides a steam generator which comprises a box body and an inner tube body, wherein the inner tube body comprises an outer tube and a core body arranged in the outer tube, the core body consists of a square through hole and a regular octagonal through hole, the side length of the square through hole is equal to that of the regular octagonal through hole, four sides of the square through hole are respectively sides of four different regular octagonal through holes, and four mutually spaced sides of the regular octagonal through hole are respectively sides of four different square through holes; the outmost layer of the core body is a square through hole, and the vertex angle of the square through hole is fixedly connected with the inner wall of the inner pipe body. According to the steam generator with the novel structure, the vertex angle position of the square is fixed on the inner pipe body, so that the heating space in the inner pipe can be fully utilized, the space between the outermost layer and the inner wall of the inner pipe body can be fully heated, the inner pipe body and the core body are fully fixed, and the heating efficiency is improved.

Description

Square outer-layer steam generator

Technical Field

The invention relates to the technical field of boilers, in particular to a steam generator with a novel structure.

Background

Steam generators are mechanical devices that utilize the heat energy of a fuel or other energy source to heat water into steam. The steam generator has wide application field and is widely applied to places such as clothing factories, dry cleaning shops, restaurants, bunkers, canteens, restaurants, factories and mines, bean product factories and the like.

The existing steam generator mostly adopts gas or fuel oil for heating, and the heating efficiency is low, and the existing electric heating steam generator mostly adopts an electric heating pipe arranged at the bottom of a water supply tank for directly heating water in the water supply tank to generate steam. The electric heating steam generator has the problems of slow heating and low heat efficiency.

For example, chinese patent document CN2071061U discloses a steam generator for beauty treatment and health care, which comprises a metal electrode plate, a housing made of heat-resistant plastic, a steam outlet cover plate, an internal baffle plate, and a movable handle, wherein the metal electrode plate must be connected to a power supply through a power line, the housing is provided with an internal baffle plate, the upper opening is provided with the steam outlet cover plate, and the housing is provided with a socket groove at the bottom outside for connecting with the movable handle with a socket. An improved electric heating steam generator for generating steam, as disclosed in chinese patent document CN2651594Y, comprises a main body cavity and an electric heater, wherein the electric heater is disposed in the main body cavity, a partition board is disposed in the main body cavity to separate the cavity from the upper and lower parts, the upper cavity is a steam cavity, the lower cavity is a heating water cavity, and a steam through hole is disposed on the partition board; the partition boards have 2-6 layers, transition chambers are formed among the partition boards, and the steam through holes on the adjacent partition boards are arranged in a staggered mode. The electric heater heats water in the heating water cavity, and steam enters the steam cavity for standby through the partition plate and the transition chamber formed by the partition plate. The electric heating steam generators disclosed in the above two patent documents belong to the product.

The steam generator in the prior art has uneven heating, low efficiency of overall steam generation and single heater structure.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the multifunctional steam generator with the novel structure, which can quickly provide steam, has the functions of quick heating, uniform temperature distribution, safety and reliability, and improves the heating efficiency.

In order to achieve the purpose, the invention adopts the following technical scheme:

a steam generator comprises a box body, an inner pipe body, a cold water inlet and a steam outlet, wherein the cold water inlet is formed in the side wall of the box body, an exhaust port is formed in the upper portion of the box body, the inner pipe body is arranged in the box body and comprises an outer pipe and a core body arranged in the outer pipe, the inner pipe body is arranged in the vertical direction, a water inlet channel is formed in the lower portion of the inner pipe body, water in the box body can enter the inner pipe body to be heated, and the upper portion of the inner pipe body is connected with the steam outlet; the core body is arranged at the upper part of the water inlet channel, and the core body extends in the vertical direction of the inner pipe body; the core body is composed of a square through hole and a regular octagonal through hole, the side length of the square through hole is equal to that of the regular octagonal through hole, four sides of the square through hole are respectively sides of four different regular octagonal through holes, and four mutually spaced sides of the regular octagonal through hole are respectively sides of four different square through holes; an electric heater is arranged in the square through hole; the core body is characterized in that the outermost layer of the core body is a square through hole, and the vertex angle of the square through hole is fixedly connected with the inner wall of the inner pipe body.

Preferably, the top angle of the square through hole is fixedly connected with the inner wall of the inner pipe body in a welding mode.

Preferably, the inner wall of the inner tube body is provided with a groove, and the vertex angle of the square through hole is arranged in the groove.

Preferably, the inner wall of the inner tube body is provided with a concave part, and the top angle of the square through hole is provided with a convex part which is arranged in the concave part.

Preferably, the inner tube has elasticity, and the inner tube may elastically surround the core.

Preferably, the cross-section of the inner tube body is square.

Preferably, the inner wall of the inner tube body is provided with a groove, and the outer end of the core body is arranged in the groove.

Preferably, the inner pipe body is formed by welding a multi-section structure, and the core body is arranged at the joint of the multi-section structure.

Preferably, the steam outlet is hermetically connected with the outer pipe of the inner pipe body.

Preferably, the cross-sectional area of the vapor outlet conduit is less than the cross-sectional area of the outer tube of the inner tube.

Preferably, the inner pipe is disposed at an intermediate position of the case.

Preferably, the water inlet channel is a strip-shaped slit.

Preferably, the water inlet channel is arranged below 50% of the water level of the box body.

Preferably, the electric heater is a resistance heater.

Preferably, the resistive heater fills the entire square channel.

Preferably, the core bodies are arranged in a plurality along the vertical direction, and a water inlet channel is arranged on the outer pipe between every two adjacent core bodies.

Preferably, the farther the center of the square through-hole is from the center of the core, the greater the heating power of the resistance heater per unit length in the vertical direction.

Preferably, the heating power of the resistance heater per unit length in the vertical direction is continuously increased by a larger and larger margin the farther the center of the square through hole is from the center of the core.

Preferably, the center of the core body is a regular octagonal channel, the regular quadrilateral channel is of a two-layer structure surrounding the core body, the outermost layer is a regular octagonal channel, and the side length of the outer tube is 8 times that of the square channel.

Preferably, the heating power of each electric heater of the first layer is W1, the heating power of each electric heater of the second layer is W2, the height of the core is H, and the side length of the regular quadrangle is L, so that the following requirements are met:

W2/W1= a-b LN (H/L); wherein a, b are parameters, 3.3< a <3.4,0.90< b < 0.95;

1.15<W2/W1<1.75；5.9< H/L<10.1；

the total heating power of the first and second layers is M, 2500W < M < 5500W.

Preferably, a =3.343 and b = 0.921.

The invention has the following advantages:

1) according to the steam generator with the novel structure, the vertex angle position of the square is fixed on the inner pipe body, so that the heating space in the inner pipe can be fully utilized, the space between the outermost layer and the inner wall of the inner pipe body can be fully heated, the inner pipe body and the core body are fully fixed, steam can be generated quickly and efficiently, and the steam generator has the functions of quick heating, uniform temperature distribution, safety and reliability, and the heating efficiency is improved.

2) The invention further improves the heating uniformity and the heating efficiency by setting the change of the heating power of the electric heater in the inner tube body away from the center of the core body.

3) According to the invention, the inner core bodies of the inner pipe body are distributed at intervals in the vertical direction, and the water inlet channels are arranged on the spaced inner pipe bodies, so that water at different positions can be ensured to enter the inner pipe for heating in time, and the heating efficiency can be further improved.

4) The invention designs the change of the heating power of different electric heaters in the inner tube body along the height direction, and can further improve the safety performance and the heating performance of the device.

5) The invention determines the optimal proportional relation of the electric heating powers of different layers through numerical simulation and a large number of experiments, further improves the heating uniformity and the heating efficiency, and also provides an optimal reference basis for the design of the inner tube body with the structure.

6) According to the invention, through numerical simulation and a large number of experiments, the optimal relation of each size of the core body is determined, and the heating uniformity and the heating efficiency are further improved.

Description of the drawings:

fig. 1 is a schematic view of a preferred structure of a steam generator for generating hot water and steam according to the present invention.

Fig. 2 is a schematic view of a preferred structure of the steam generator for generating only steam according to the present invention.

Fig. 3 is a schematic cross-sectional structure of the inner tube body.

Figure 4 is a schematic cross-sectional view of the inner body core a-a of the tube of figure 3.

Fig. 5 is a schematic longitudinal sectional view of the inner tube body.

Figure 6 is a schematic cross-sectional view of a modified innertube core.

In the figure: 1-a box body; 2-an inner tube; 3-a cold water inlet; 4-hot water outlet; 5-a steam outlet; 6-an exhaust port;

7-a core body; 71-regular quadrilateral; 72-regular octagon; 73-edge; 8-opening the hole; 9-electric heater.

Detailed Description

Fig. 1-6 illustrate a steam generator. As shown in fig. 1, the steam generator includes a tank 1, an inner pipe 2, a cold water inlet 3, a hot water outlet 4, and a steam outlet 5, the cold water inlet 3 being provided at a lower portion of the tank 1, and the hot water outlet 4 being provided at an upper portion of the tank 1. The inner pipe body 2 is arranged in the box body, the inner pipe body 2 is arranged in the vertical direction (perpendicular to the plane of the bottom of the water tank), the inner pipe body 2 comprises an outer pipe and a core body 7 arranged in the outer pipe, a water inlet channel 8 is arranged at the lower part of the inner pipe body 2, so that water in the box body 1 can enter the inner pipe body 2 to be heated, and the upper part of the inner pipe body 2 is connected with a steam outlet 5; the core body 7 is arranged at the upper part of the water inlet channel 8, and the core body 7 extends in the vertical direction of the inner pipe body 2; the core body 7 is composed of a square through hole 71 and a regular octagonal through hole 72, the side length of the square through hole is equal to that of the regular octagonal through hole, four sides 73 of the square through hole 71 are respectively sides of four different regular octagonal through holes 72, and four mutually spaced sides 73 of the regular octagonal through hole 72 are respectively sides of four different square through holes 71; the electric heater 9 is provided in the square through hole 71.

Preferably, referring to fig. 6, the outermost layer of the core body is a square through hole 71, and the top corner of the square through hole is fixedly connected to the inner wall of the inner pipe body 2.

Compared with the prior application, the steam generator with a novel structure is designed, the heating space in the inner pipe can be fully utilized by fixing the vertex angle position of the square on the inner pipe body, so that the space between the outermost layer and the inner wall of the inner pipe body can be fully heated, the inner pipe body and the core body are fully fixed, steam can be generated quickly and efficiently, and the steam generator has the functions of quick heating, uniform temperature distribution, safety and reliability, and the heating efficiency is improved.

Further preferably, the vertex angle of the square through hole is fixedly connected with the inner wall of the inner pipe body in a welding mode. Preferably, the method can be realized by arranging the welding layer in the inner tube body and then carrying out integrated heating in a manner that the top angle of the square through hole is fixedly connected with the inner wall of the inner tube body in a welding manner.

Preferably, the inner tube has elasticity, and the inner tube may elastically surround the core. Through setting up elastic inner tube for the core can be through the mode setting such as inserting in the inner tube body, through the elasticity parcel core of inner tube body.

According to the steam generator with the novel heating structure, the electric heaters are uniformly distributed around the regular octagonal channels through the heating structure, so that fluid can enter the regular octagonal channels and can be uniformly heated through the electric heaters.

Preferably, the through-holes are formed on the sides of the regular octagonal through-hole but not the regular quadrangular through-hole. Through setting up the through-tube hole, can guarantee that the water that gets into the inner tube is free flow in the inner tube. For example, the pressure increase caused by the large heating of water in one octagonal through hole can flow into the adjacent octagonal through hole through the pipe through hole, so that the uniform heating and the uniform pressure balance of the whole body are ensured.

Preferably, the plurality of through holes are provided along a height direction from top to bottom.

The distribution density of the through holes 74 increases along the height direction from the bottom to the top. Because the water is heated more and more along the height direction, the water heating distribution is more and more uneven, and the internal pressure distribution is more and more uneven. This arrangement ensures that the through-hole 74 has a larger through-hole area along the height, and further ensures uniform heating and pressure equalization as a whole.

The distribution density of the through holes 74 increases in the height direction from the bottom to the top. It has been found through a large number of experiments and numerical simulations that such an arrangement ensures that the through-opening area of the through-opening 74 is larger and larger along the height, further ensuring uniform heating and overall pressure equalization.

The area of the single through-hole 74 increases along the height direction from the bottom up. Because the water is heated more and more along the height direction, the water heating distribution is more and more uneven, and the internal pressure distribution is more and more uneven. This arrangement ensures that the through-hole 74 has a larger and larger through-area distribution along the height, and further ensures uniform heating and pressure equalization as a whole.

The area of the individual through-holes 74 increases in the height direction from the bottom to the top. It has been found through a large number of experiments and numerical simulations that such an arrangement ensures that the through-opening area of the through-opening 74 is larger and larger along the height, further ensuring uniform heating and overall pressure equalization.

Preferably, the steam outlet 5 is connected with the outer pipe of the inner pipe body 2 in a sealing way.

Preferably, the cross-sectional area of the conduit of the steam outlet 5 is smaller than the cross-sectional area of the outer pipe of the inner pipe body 2. This can ensure the steam discharge speed.

Cold water enters the tank through cold water inlet 3. When the steam heating device works, the inner pipe body 2 is arranged in the box body 1, water in the box body 1 enters the inner pipe body 2 through the water inlet channel 8 on the outer pipe, then the water is heated through the electric heater in the regular quadrilateral through hole of the core body 7 in the inner pipe body 2 in the regular octagonal through hole, and steam generated after heating is discharged through the steam outlet 5. Meanwhile, the inner pipe body generates steam and simultaneously heats water in the box body, and hot water generated after heating can be utilized through the hot water outlet.

Preferably, the square through holes are sealed up and down, and water cannot enter the square through holes.

Through foretell structure setting, can produce steam and hot water simultaneously for steam generator has multiple functions, has expanded the scope of its utilization, and the steam that produces is direct discharges through the steam outlet with interior body coupling moreover, because heat the outside water of interior body through the outer tube, consequently outside water can not the boiling evaporation, has also guaranteed the security of heating.

According to the invention, the inner pipe body 2 is arranged in the vertical direction, so that water can be heated in the vertical direction, the water is continuously heated in the rising process, and the heating efficiency is further improved compared with the inner pipe body arranged in the horizontal direction.

Preferably, the outer pipe of the inner pipe body is an outer wall surface of the core body. Preferably, the inner tube and the core are integrally manufactured.

As a modification, the hot water outlet 4 may be eliminated, for example as shown in fig. 2, with the steam generator acting as a single function evaporator for generating steam.

Preferably, an exhaust port 6 is provided at the upper part of the case 1. Through setting up gas vent 6, avoid 1 internal pressure of box too big, can guarantee safety.

Preferably, the cross section of the box body 1 is circular.

Preferably, the cross section of the inner tube 2 is square.

Preferably, the inner tube 2 is disposed at an intermediate position of the case 1. Through so setting up, guarantee hot water heating's homogeneity.

Preferably, the side of the cross-sectional area of the outer tube of the inner tube body 2 is 0.01 to 0.15 times the cross-sectional area of the case body 1. Further preferably 0.11 to 0.13 times.

Preferably, the water inlet channel 8 is a strip-shaped slit.

Preferably, the water inlet channel 8 is open. As shown in fig. 5. It should be noted that fig. 5 is only a schematic diagram, and although fig. 5 shows only 1 or one row of holes, it is actually not limited to one or one row, and a plurality of or a plurality of rows may be provided at upper and lower positions between adjacent electric heating rods 9.

Preferably, the shape of the opening may be circular or square.

Preferably, the opening is provided at 50% or less of the water level of the tank 1. Through so setting up, can guarantee that hydroenergy is enough timely inside the entering interior pipe body 2 heats, also avoid the trompil to set up too high steam that leads to from the trompil to spill over simultaneously, avoid whole box internal pressure too big, also avoid the water of eminence to get into interior pipe body simultaneously, cause the moisture that the steam that produces carried too much.

Preferably, the wire connecting the electric heater 9 enters through the water inlet channel.

Preferably, a lead wire connected to the electric heater 9 is inserted into the inner tube 2 through the bottom of the inner tube 2.

Preferably, the inner wall of the inner tube 2 is provided with a groove, and the outer wall of the core 7 is arranged in the groove. Through so setting up can further improve the fastness of core installation.

Preferably, the inner tube 2 is formed by welding a multi-stage structure, and the core 7 is provided at the joint of the multi-stage structure. Through such setting, can be so that processing is convenient, save the cost.

Preferably, the electric heater 9 is a resistance heater.

Preferably, the resistive heater 9 fills the entire square channel. Through so setting up can guarantee the wall contact of electric heater and square passageway, further improve heating efficiency.

Preferably, the core bodies 7 are arranged in a plurality at intervals along the vertical direction, and water inlet channels are arranged on the outer pipes at intervals between two adjacent core bodies 7. According to the invention, the cores in the inner pipe body are distributed at intervals in the vertical direction, and the water inlet channels are arranged on the spaced inner pipe bodies, so that water at different positions can be ensured to enter the inner pipe for heating in time, and the heating efficiency can be further improved.

Preferably, the farther the center of the square through-hole is from the center of the core 7, the greater the heating power of the resistance heater per unit length in the vertical direction. For example, in fig. 3, the heating power of the first layer is smaller than that of the second layer, but the heating power of the second layer is also different, specifically, the heating power of the four corners is larger than that of the non-corners. It was found by vertical simulations and experiments that the further away from the center, the more heating power is needed, especially in the outermost layer, because the larger the area involved in heating, and the more heating power per unit length in the vertical direction is needed, because the water outside the inner pipe body is also heated. The invention further improves the heating uniformity and the heating efficiency by setting the change of the heating power of the electric heater in the inner tube body away from the center of the core body.

Preferably, the heating power of the resistance heater per unit length in the vertical direction is continuously increased by a larger and larger amount the farther the center of the square through hole is from the center of the core 7. The above-mentioned variation of the heating amplitude is also obtained through a large number of numerical simulations and experiments, and is not common knowledge in the art. Through the change of above-mentioned range, can further improve heating efficiency and heating degree of consistency.

Preferably, the core body 7 is a regular octagonal central core body, and the regular octagonal through hole is located in the center of the core body. As shown in fig. 3.

Preferably, the center of the core body 7 is a regular octagonal channel, the regular quadrilateral channel is of a two-layer structure surrounding the core body, the outermost layer is the regular octagonal channel, and the side length of the outer pipe is 8 times that of the regular octagonal through hole.

Through a large number of numerical simulations and experiments, the purpose that the electric heaters on different layers can achieve uniform heating only through different heating power requirements can be known, and the longer the side length of the regular quadrangle is, the larger the volume to be heated is, the larger the external space is, and the larger the heating power ratio of the inner layer to the outer layer is; the longer the core in the vertical direction, the larger the heating area over the entire length, the more uniform the heating distribution, and therefore the smaller the required heating power ratio between the inner and outer layers. Therefore, the invention carries out a great deal of research on the heating power of each layer, the side length and the height thereof through a great deal of vertical simulation and experiments to obtain the optimal heating power relation. For the above-described configuration of fig. 3, the ratio of the heating power of the outermost layer to the heating power of the innermost layer satisfies the following requirements:

preferably, in a structure similar to fig. 3, the electric heater is a regular octagon located at the center, the electric heater has two layers, the heating power of each electric heater of the first layer is W1, the heating power of each electric heater of the second layer is W2, and the height of the core is H, and the side length of the regular quadrangle is L, so that the following requirements are satisfied:

W2/W1= a-b LN (H/L); wherein a, b are parameters, 3.3< a <3.4,0.90< b < 0.95;

1.15<W2/W1<1.75；5.9< H/L<10.1；

the total heating power of the first and second layers is M, 2500W < M < 5500W.

Preferably, a =3.343 and b = 0.921.

Preferably, 1.3< W2/W1< 1.5; 7.1< H/L < 8.1;

the first and second layers are inner and outer layers, respectively.

Preferably, a is gradually decreased and b is gradually increased as H/L is increased. Through so setting up can further make the heating even, improve heating efficiency.

Preferably, the pipe diameter of the inner pipe body 2 is continuously enlarged along the vertical direction from bottom to top. The main reasons are as follows: 1) by increasing the diameter of the inner pipe 2, the resistance to upward flow of the steam can be reduced, so that the steam evaporated in the inner pipe 2 continuously moves towards the direction of increasing the diameter of the pipe, thereby further promoting the rising of the steam. 2) Because along with the continuous flow of fluid, liquid evaporates in interior body 2 to make vapour volume bigger and bigger, the pressure is also bigger and bigger, consequently satisfies the change of the vapour volume that constantly increases and pressure through increasing the pipe diameter, thereby makes pressure distribution even on the whole.

Preferably, the pipe diameter of the inner pipe body 2 is continuously increased in a larger and larger range along the vertical direction from bottom to top. The amplitude change of the pipe diameter is a result obtained by a large number of experiments and numerical simulation of the applicant, and through the arrangement, the steam flow can be further promoted, and the pressure is integrally uniform.

Preferably, a plurality of cores 7 are provided in the inner tube 2, and the larger the interval between the cores 7 from the bottom end of the inner tube 2 to the upper end of the inner tube 2. Let the distance from the bottom end of the inner tube body 2 be H, the distance between adjacent core bodies be S, S = F₁(H) I.e. S is a function with distance H as a variable, S' is the first derivative of S, satisfying the following requirements:

S’>0;

the main reason is to avoid drying out caused by the rapid heating of the upper steam. Heating power through setting up the lower part is greater than upper portion heating power for water is fully heated in the lower part, and the water on rise in-process reheating upper portion can guarantee the abundant homogeneous mixing of heating on the one hand, and on the other hand can also avoid the heating dry phenomenon that leads to because the water on the upper portion that the upper portion heating is too big evaporates earlier. The distance between adjacent cores that needs to be provided becomes shorter and shorter.

Through the experiment, the heating is kept uniform to the greatest extent by the arrangement, and the heating effect can be improved.

It is further preferred that the distance between adjacent cores increases in a larger and larger range from the inlet of the inner tube 2 to the outlet of the inner tube 2. I.e. S "is the second derivative of S, the following requirements are met:

S”>0;

through the experiment discovery, through so setting up, can further keep the whole even of heating, can improve the heating effect simultaneously. It should be noted that the above rule is a rule obtained by a large number of experiments and numerical simulations, and is not common knowledge or conventional means in the field.

Preferably, a plurality of cores are provided in the inner tube 2, and the heating power of the electric heaters arranged in each of the regular quadrangles of the different cores is gradually reduced from the bottom end of the inner tube 2 to the upper end of the inner tube 2. Assuming that the distance from the bottom end of the inner tube 2 is H, the power of the electric heater disposed in each regular quadrangle of the adjacent cores is W, S = F₃(H) I.e. W is a function of the distance H as a variable, W' is the first derivative of W, satisfying the following requirements:

W’<0;

Further preferably, the electric heater power arranged in each of the regular quadrangles of the adjacent cores is decreased by an increasing magnitude from the inlet of the inner tube 2 to the outlet of the inner tube 2. I.e., W "is the second derivative of S, the following requirement is satisfied:

W”>0；

Preferably, a plurality of cores are provided in the inner tube 2, and the side length of the square shape is gradually reduced from the bottom end of the inner tube 2 to the upper end of the inner tube 2. The distance from the inlet of the inner pipe body 2 is H, the side length of the square is C, and C = F₂(H) And C' is the first derivative of C, and meets the following requirements:

C’<0；

the main reason is because the smaller the square edge length, the more difficult the fabrication, but the better the uniformity of the overall heating. Since the overall heating of the water should be kept uniform the further up, avoiding partial drying due to non-uniform heating, and the further up, since the steam is to exit through the outlet, the more uniform the steam out and heating. Through the setting, the cost can be saved, the best heating uniformity and steam output efficiency are achieved, and meanwhile, the dry burning is avoided.

It is further preferred that the side length of the square increases with decreasing amplitude from the inlet of the inner tube 2 to the outlet of the inner tube 2. C' is the second derivative of C, and meets the following requirements:

C”>0。

preferably, the distance between adjacent cores is kept constant.

Since it can be seen through experiments and numerical simulations that the more outward the larger the volume to be heated, especially the outermost side, the peripheral water and the water in the inner tube. The invention further improves the heating uniformity and the heating efficiency by setting the change of the heating power of the electric heater in the inner tube body away from the center of the core body.

Preferably, the heating power of the resistance heater per unit length in the vertical direction is continuously increased to a greater and greater extent the farther the square through-hole is from the center of the core. Through such rule setting, heating degree of consistency and heating efficiency have further been improved.

Preferably, the openings are arranged in a plurality of rows in the height direction (i.e., from bottom to top, hereinafter appearing in the height direction, if not otherwise specified, from bottom to top).

Through setting up the multirow, can guarantee that different high positions intake, avoid a single position to intake, cause the inhomogeneous of heating, avoid the water that gets into simultaneously to be evaporated, cause the heating tube dry up.

Preferably, the distribution density of the open pores becomes smaller and smaller along the height direction. The density of the distribution of the openings is smaller and smaller, that is, the distribution of the openings is smaller and smaller, and the area of the openings is smaller and smaller.

Through a large amount of numerical simulation and experimental research thereof, it is found that the distribution density is smaller and smaller by arranging the open pores, the main reason is to ensure that most of water is heated at the lower part, and water continuously enters the inner pipe body 2 in the rising process of the water changed into steam and is continuously heated. If the water inflow in the lower part is small, the water in the lower part can be quickly vaporized, the pressure in the inner pipe body 2 is too high, and the water in the upper part can not enter the inner pipe body due to the pressure. The drying of the inner tube body is reduced, and the heating efficiency is improved.

Further preferably, the distribution density of the openings is continuously increased with a smaller and smaller amplitude along the height direction.

Through a large amount of experiments and numerical simulation, through the change of foretell trompil distribution density, can further improve heating efficiency, improve the output efficiency of steam, can reduce the internal dryout of inner tube simultaneously.

Preferably, the area of the individual openings becomes smaller and smaller along the height direction. Further preferably, the area of the individual openings increases progressively in the height direction to a smaller and smaller extent. For specific reasons see the variation in the open cell distribution density.

Preferably, the sum of the areas of the openings in each row is smaller and smaller along the height direction. Preferably, the sum of the areas of the openings in each row is smaller and smaller along the height direction. For specific reasons see the variation in the open cell distribution density.

Preferably, the distance between each row of the open holes is larger along the height direction. Preferably, the spacing between each row of the holes increases along the height direction. For specific reasons see the variation in the open cell distribution density.

Preferably, the heating power per unit length of the electric heating rod 9 is continuously reduced along the height direction. The heating power of the electric heating rod 9 is continuously reduced, so that the fluid at the lower part is rapidly heated, then the hot fluid flows to the upper part through natural convection, and the fluid at the upper part and the fluid outside the inner pipe body 2 at the lower part rapidly enter, so that the heating efficiency can be further improved. Through a large amount of experiments and numerical simulation, the heating efficiency can be further improved by about 10% through the change of the heating power of the inner pipe body, and the heating time is saved.

Preferably, the magnitude of the continuous decrease in the heating power per unit length of the electric heating rod 9 is continuously increased along the height direction.

Through a large amount of experiments and numerical simulation, the heating efficiency can be further improved by 5% through the change of the heating power amplitude of the electric heating rod 9, and the heating time is further saved.

Preferably, the same electric heating rod 9 in the same core is divided into a plurality of sections, and the heating power per unit length of the different sections is different along the height direction. Wherein the heating power per unit length of the different segments is continuously reduced along the height direction. Further preferably, the magnitude of the decrease is continuously increased.

Preferably, the length of each segment is the same.

Preferably, the heating power per unit length of each segment is the same.

The specific reason is as described above.

By providing the segments, manufacturing can be further facilitated.

Learn through analysis and experiment that the interval between the vertical direction core can not be too big, too big the effect that leads to steam to produce is not good, simultaneously also can not the undersize, the undersize leads to the interior easy of burning dry of pipe, and on the same hand, the length of a side of square also can not be too big or the undersize, and too big heating that leads to is inhomogeneous, and the undersize leads to regular tetragon and octagon to distribute too densely, causes flow resistance to increase and the processing cost increases. Therefore, the resistance is optimized through a large number of experiments under the condition that the steam outlet amount of the steam is preferentially met, and the optimal relation of each parameter is arranged.

Preferably, for a regular octagonal central structure, the distance between adjacent cores is S1, the side length of a square is L, the core is a square section, and the side length of the square section of the core is B2, so that the following requirements are met:

10*L/B2=a-b*(S1/B2);

wherein a, b are parameters, wherein 0.95< a <0.96,0.158< b < 0.165;

90<B2<240mm；

8<L<30mm；

29<S1<110mm。

further preferably, a =0.956, b =0.163;

further preferably, a is larger and B is smaller as L/B2 is increased.

Preferably, the length L of the square through hole is an average of the length of the inner side and the length of the outer side of the square through hole, and the length B2 of the square section of the core is an average of the length of the inner side and the length of the outer side of the square section of the core.

The distance between adjacent cores is S1, which is the distance between the facing surfaces of the adjacent cores. Such as the distance between the upper end surface of the lower core and the lower end surface of the upper core.

Preferably, L also increases with increasing B2. But as B2 increases, L increases by a lesser and lesser magnitude. The change of the rule is obtained through a large amount of numerical simulation and experiments, and the heat exchange effect and the noise are further improved and reduced through the change of the rule.

Preferably, S1 decreases as B2 increases. However, as B2 increases, the magnitude of the decrease of S1 becomes smaller and smaller. The change of the rule is obtained through a large amount of numerical simulation and experiments, and the heat exchange effect and the noise are further improved and reduced through the change of the rule.

For a square-centered structure like that of fig. 6, the distance between adjacent cores is S1, the side length of the square is L, the core is a square section, and the side length of the square section of the core is B2, which preferably satisfies the following requirements:

10*L/B2=c*(S1/B2)^d(ii) a Wherein c, d are parameters, wherein 1.225<c<1.235,-0.065<d<-0.060；

90<B2<240mm；

11<L<34mm；

29<S1<110mm。

Further preferably, c =1.228, d = -0.063;

further preferably, c is larger and d is smaller as L/B2 is increased.

The height H of the core is preferably 100-500 mm, and more preferably 200-300 mm.

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. A steam generator comprises a box body, an inner pipe body, a cold water inlet and a steam outlet, wherein the cold water inlet is formed in the side wall of the box body, an exhaust port is formed in the upper portion of the box body, the inner pipe body is arranged in the box body and comprises an outer pipe and a core body arranged in the outer pipe, the inner pipe body is arranged in the vertical direction, a water inlet channel is formed in the lower portion of the inner pipe body, water in the box body can enter the inner pipe body to be heated, and the upper portion of the inner pipe body is connected with the steam outlet; the core body is arranged at the upper part of the water inlet channel, and the core body extends in the vertical direction of the inner pipe body; the core body is composed of a square through hole and a regular octagonal through hole, the side length of the square through hole is equal to that of the regular octagonal through hole, four sides of the square through hole are respectively sides of four different regular octagonal through holes, and four mutually spaced sides of the regular octagonal through hole are respectively sides of four different square through holes; an electric heater is arranged in the square through hole; the core body is characterized in that the outermost layer of the core body is a square through hole, and the vertex angle of the square through hole is fixedly connected with the inner wall of the inner pipe body.

2. The steam generator of claim 1, wherein the top corners of the square through holes are fixedly connected to the inner wall of the inner tube by welding.

3. The steam generator of claim 1, wherein the inner wall of the inner tube body is provided with a groove, and a top corner of the square through hole is provided in the groove.

4. The steam generator of claim 1, wherein the inner wall of the inner tube body is provided with a recess, and the top corner of the square through hole is provided with a protrusion, the protrusion being disposed in the recess.

5. The steam generator of claim 1, wherein the inner tube is resilient and resiliently surrounds the core.

6. The steam generator of claim 1, wherein the inner tube is square in cross-section.