A micro-charged spray burner suitable for large flow and combustion method thereof

Abstract

The present invention relates to the technical field of micro liquid combustion devices, and discloses a micro charged spray burner suitable for large flow, including a combustion chamber, an atomization unit, a multi-nozzle nozzle, a combustion mesh plate, a fuel supply box and a high-voltage DC power supply; the atomization unit includes an atomization chamber and a metal grid; the combustion chamber and the atomization chamber are separated by a combustion mesh plate, and the metal grid is arranged in the atomization chamber; the multi-nozzle nozzle includes a feed pipe and a plurality of spray layers arranged on the feed pipe, the top end of the feed pipe is sealed, and the plurality of spray layers are arranged at intervals along the axial direction of the feed pipe and close to the top end of the feed pipe, and the plurality of spray layers are all located in a cavity surrounded by the metal grid, and the bottom end of the feed pipe passes through the bottom end opening of the atomization chamber and is connected to the fuel supply box. The present invention also discloses a combustion method suitable for a micro charged spray burner with large flow, and its beneficial effects are: compact structure, high combustion efficiency, and broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of micro liquid combustion devices, and in particular to a micro charged spray burner suitable for large flow and a combustion method thereof. Background Art

[0002] In recent decades, with the rapid development of MEMS micro-machining technology, a large number of micro-devices such as micro-medical equipment, micro-robots, micro-aircraft and portable electronic devices have emerged due to the needs of social development. At present, the vast majority of micro-devices and systems are powered by traditional chemical batteries, but traditional chemical batteries have disadvantages such as low energy density, short service life and long charging time, which are insufficient to meet the requirements of micro-power equipment for endurance. The energy density of liquid hydrocarbon fuel is dozens of times that of traditional chemical batteries. If liquid hydrocarbon fuel is used as fuel for micro burners, it can meet the characteristics of high energy density, small size and long endurance, and is expected to replace chemical batteries.

[0003] The combustion rate of liquid fuel mainly depends on the evaporation rate of liquid fuel. How to make liquid fuel evaporate quickly and burn stably has become the key to the successful development of micro burners. The droplets produced by charged atomization of liquid fuel have good monodispersity characteristics, which greatly increases the contact area with air and greatly increases the evaporation rate. The coaxial single nozzle charged atomization has a small flow rate and low heat generation. The coaxial multi-nozzle (the direction of the nozzle is consistent with the direction of the nozzle) charged atomization has a large flow rate and high heat generation, but the nozzles affect each other, resulting in a long atomization jet range, a large nozzle diameter, and a wide atomization area, making the size of the micro burner larger. Therefore, for equipment that requires high-power energy supply, a large flow rate is required. If coaxial multi-nozzle charged atomization is used, the size of the burner will be greatly increased. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above prior art and provide a micro-charged spray burner with reasonable size and high fuel efficiency suitable for large flow. Another purpose of the present invention is to provide a combustion method for a micro-charged spray burner with large flow that effectively improves the combustion efficiency.

[0005] The object of the present invention is achieved through the following technical solutions: a micro-charged spray burner suitable for large flow, comprising a combustion chamber, an atomization unit, a multi-nozzle nozzle, a combustion mesh plate, a fuel supply box and a high-voltage direct current power supply; the atomization unit comprises an atomization chamber and a metal grid; the combustion chamber and the atomization chamber are both cylindrical with openings at both ends, the combustion chamber and the atomization chamber are arranged up and down and connected, the combustion chamber and the atomization chamber are separated by the combustion mesh plate, the metal grid is arranged around the atomization chamber, and the top of the metal grid is connected to the combustion mesh plate; the multi-nozzle nozzle comprises a feed pipe and a plurality of spray layers arranged on the feed pipe, the top of the feed pipe is sealed, the plurality of spray layers are arranged at intervals along the axial direction of the feed pipe and close to the top of the feed pipe, the plurality of spray layers are located in a cavity surrounded by the metal grid, the bottom end of the feed pipe passes through the bottom end opening of the atomization chamber and is connected to the fuel supply box, the multi-nozzle nozzle is connected to the positive electrode of the high-voltage direct current power supply, and the metal grid is connected to the negative electrode of the high-voltage direct current power supply.

[0006] Furthermore, each of the spraying layers comprises a plurality of nozzles uniformly distributed along the radial direction of the material conveying pipe, and the nozzles between two adjacent spraying layers are aligned vertically.

[0007] Furthermore, the atomization unit also includes a fuel recovery groove, which is arranged at the bottom end of the atomization chamber and forms an air inlet of the atomization chamber. The bottom end of the metal grid is located in the fuel recovery groove, and the fuel recovery groove is connected to the fuel supply tank. The bottom end of the feed pipe passes through the air inlet and is connected to the fuel supply tank.

[0008] Furthermore, the fuel recovery groove is an annular groove, the middle of which is hollowed out to form an air inlet, the outer edge of the fuel recovery groove is connected to the bottom end of the atomization chamber, and the bottom end of the multi-nozzle nozzle passes through the rear air inlet and is connected to the fuel supply tank.

[0009] Furthermore, the diameter of the air inlet is larger than the outer diameter of the feed pipe.

[0010] Furthermore, a porous medium layer is filled between the metal grid and the inner wall of the combustion chamber, the top end of the porous medium layer is connected to the combustion mesh plate, and the bottom end of the porous medium layer is located in the fuel recovery tank.

[0011] Furthermore, the combustion chamber comprises an upper chamber and a lower chamber which are arranged one above the other, the inner diameter of the upper chamber is smaller than the inner diameter of the lower chamber, and the connection transition between the upper chamber and the lower chamber is a right-angle transition.

[0012] Furthermore, the surface of the combustion mesh plate is coated with a catalyst.

[0013] Furthermore, it also includes a supply pump, and the bottom end of the feed pipe is connected to the fuel supply tank through the supply pump.

[0014] Furthermore, the combustion mesh plate includes a circular mesh portion and a sealing plate arranged on the periphery of the mesh portion, and the combustion chamber and the atomization chamber are respectively connected to the upper and lower sides of the sealing plate.

[0015] Furthermore, it also includes an igniter, which is close to the combustion mesh plate and the lead of the igniter is connected to an external power source.

[0016] Furthermore, it also includes an air intake pipe, a lower cover plate and a heat exchange sleeve, the bottom end of the heat exchange sleeve is sealed by the lower cover plate, the combustion chamber and the atomization chamber are both located in the heat exchange sleeve, the top end of the combustion chamber is connected to the top end of the heat exchange sleeve, the inner cavity of the combustion chamber is connected to the outside, and there are gaps between the outer wall of the combustion chamber and the outer wall of the atomization chamber and the inner wall of the heat exchange sleeve, and there is a gap between the bottom end of the atomization chamber and the lower cover plate to form an air flow channel between the atomization chamber and the heat exchange sleeve, the air intake pipe passes through the heat exchange sleeve to be connected to the air flow channel, and the bottom end of the multi-nozzle nozzle passes through the lower cover plate and is connected to the fuel supply tank.

[0017] Furthermore, it also includes an outer sleeve and an upper cover plate; the outer sleeve is sleeved on the outer periphery of the heat exchange sleeve, the top end of the outer sleeve is sealed by the upper cover plate, and the bottom end of the outer sleeve is sealed by the lower cover plate, a gap is left between the top end of the heat exchange sleeve and the upper cover plate, and a gap is left between the outer wall of the heat exchange sleeve and the inner wall of the outer sleeve, so that an exhaust gas discharge channel is formed between the inner cavity of the combustion chamber, the heat exchange sleeve and the outer sleeve, and an exhaust gas discharge port is opened on the wall of the outer sleeve.

[0018] A combustion method suitable for a large-flow micro-charged spray burner comprises the following steps:

[0019] Turn on the supply pump and the high-voltage DC power supply, wherein the multi-nozzle nozzle is connected to the positive electrode of the high-voltage DC power supply, and the metal grid is connected to the negative electrode of the high-voltage DC power supply;

[0020] Under the action of the supply pump, the liquid fuel is sprayed out from the multi-nozzle nozzle at a flow rate of 20 to 100 ml / h, atomized into fine droplets in the atomization chamber, and captured by the metal grid under the traction of the electric field force;

[0021] Air flows into the air flow channel through multiple symmetrically distributed intake pipes, flows into the atomization chamber along the outer wall of the fuel recovery tank to mix with the fuel; the mixed gas composed of fuel vapor and air is ignited by the igniter at the combustion mesh plate and fully burns in the combustion chamber. The exhaust gas after combustion is discharged after passing through the exhaust gas emission channel and the exhaust gas outlet.

[0022] The present invention has the following advantages over the prior art:

[0023] 1. The discharge direction of the spray layer of the porous nozzle in this burner is perpendicular to the axial direction of the feed pipe, and more spray layers can be arranged in a limited space, thereby increasing the flow rate of liquid fuel and controlling the size of the burner; the porous nozzle and the metal grid in this burner are respectively connected to the positive and negative electrodes of the high-voltage DC power supply, and the axially distributed spray layer is combined with the technical means of charged atomization, so that the fuel droplets sprayed from the multi-nozzle nozzle are atomized and flow toward the metal grid, with a wide atomization area and a short atomization jet. This burner has a simple and compact structure, can achieve full and stable combustion of liquid, has high combustion efficiency, and has broad application prospects.

[0024] 2. The spray layer of the multi-nozzle nozzle in this burner includes multiple nozzles uniformly distributed radially along the feed pipe, which effectively increases the fuel flow rate. The radially distributed nozzles have little mutual influence, the spray jet is shorter and more divergent, and the evaporation flow of the droplets is accelerated, which is conducive to organizing combustion. When the fuel flow rate and the number of nozzles are the same, compared with the coaxial multi-nozzle (the direction of the nozzle is consistent with the direction of the nozzle), the multi-nozzle nozzle has a greater mutual influence between the coaxial multi-nozzle, a long atomization jet range and a wide atomization area, and the corresponding atomization chamber has a larger volume. It can be seen that this multi-nozzle design can effectively reduce the size of the burner.

[0025] 3. In this burner, a fuel recovery tank is arranged at the bottom of the atomization chamber to recycle the incompletely evaporated droplets, thereby improving the fuel utilization rate. The present invention fills a porous medium layer between the metal grid and the inner wall of the atomization chamber, thereby expanding the contact surface area between the fuel droplets and the air and accelerating the evaporation rate of the droplets. The surface of the combustion mesh plate is coated with a catalyst to increase the combustion efficiency of the fuel, and the combustion mesh plate plays a role in stabilizing the flame surface.

[0026] 4. The combustion chamber in the present invention is divided into an upper chamber and a lower chamber. The inner diameter of the upper chamber is smaller than the inner diameter of the lower chamber. The connection transition between the upper chamber and the lower chamber is a right-angle transition. This structure prolongs the residence time of the fuel inside the combustion chamber and improves the combustion efficiency.

[0027] 5. The exhaust gas after combustion in the combustion chamber of the present invention is not discharged directly, but flows from top to bottom through the exhaust gas discharge channel and is discharged from the exhaust gas exhaust port at the bottom. In the exhaust gas discharge channel, the high-temperature exhaust gas and the newly-intake air continuously exchange heat through the heat exchange sleeve, which can not only preheat the air, but also keep the burner warm, forming an effective insulation layer, reducing heat loss, and greatly improving the combustion efficiency. At the same time, the preheated air heats the porous medium layer through the wall of the atomization chamber, and the metal grid conducts heat to the porous medium layer, so that the droplet temperature increases and accelerates evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 It shows a schematic structural diagram of a micro charged spray burner suitable for large flow according to the present invention;

[0030] Figure 2 Shows Figure 1 Schematic diagram of the structure in the AA direction;

[0031] Figure 3 Shows Figure 1 Schematic diagram of the structure in the middle BB direction;

[0032] Figure 4 It shows a schematic structural diagram of a multi-nozzle nozzle according to the present invention;

[0033] Figure 5 Shows Figure 4 Schematic diagram of the structure in the CC direction;

[0034] Figure 6 A schematic diagram showing the structure of a porous medium layer filled between a metal grid and a combustion chamber according to the present invention is shown;

[0035] Figure 7 It shows a schematic structural diagram of a combustion screen plate according to the present invention;

[0036] In the figure, 1 is a combustion chamber; 2 is a fuel supply box; 3 is a multi-nozzle nozzle; 4 is a high-voltage DC power supply; 5 is an atomization chamber; 6 is a combustion mesh plate; 7 is a metal grid; 8 is a fuel recovery tank; 9 is an air inlet; 10 is a feed pipe; 11 is a nozzle; 12 is a porous medium layer; 13 is an upper chamber; 14 is a lower chamber; 15 is a mesh portion; 16 is a sealing plate; 17 is an igniter; 18 is a lead; 19 is a supply pump; 20 is an air inlet pipe; 21 is a lower cover plate; 22 is a heat exchange sleeve; 23 is an outer sleeve; 24 is an upper cover plate; 25 is an exhaust gas outlet; 26 is a return port; 27 is a fuel recovery pipe; 28 is an air flow channel; 29 is an exhaust gas discharge channel. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0038] like Figure 1-Figure 3As shown, a micro charged spray burner suitable for large flow rate includes a combustion chamber 1, an atomization unit, a multi-nozzle nozzle 3, a combustion mesh plate 6, a fuel supply box 2 and a high-voltage DC power supply 4; the atomization unit includes an atomization chamber 5 and a metal mesh 7; the combustion chamber 1 and the atomization chamber 5 are both cylindrical with openings at both ends, the combustion chamber 1 and the atomization chamber 5 are arranged up and down and connected, the combustion chamber 1 and the atomization chamber 5 are separated by the combustion mesh plate 6, the metal mesh 7 is arranged around the atomization chamber 5, and the top of the metal mesh 7 is connected to the combustion mesh plate 6 connection; the multi-mouth nozzle 3 includes a feed pipe 10 and several spray layers arranged on the feed pipe 10, the top of the feed pipe 10 is sealed, and several spray layers are arranged at intervals along the axial direction of the feed pipe 10 and close to the top of the feed pipe 10, and several spray layers are located in the cavity surrounded by the metal grid 7, the bottom end of the feed pipe 10 passes through the bottom opening of the atomizing chamber 5 and is connected to the fuel supply box 2, the multi-mouth nozzle 3 is connected to the positive electrode of the high-voltage DC power supply 4, and the metal grid 7 is connected to the negative electrode of the high-voltage DC power supply 4. The bottom end of the combustion chamber 1 and the top end of the atomizing chamber 5 are both sealed with the edge of the combustion mesh plate 6, and the inner cavities of the two are connected, the bottom opening of the atomizing chamber 5 is used to flow in air, and the top opening of the combustion chamber 1 is used to discharge combustion exhaust. Turning on the high-voltage DC power supply 4 forms an electrostatic field between the multi-mouth nozzle 3 and the metal grid 7, which helps to atomize and collect fuel droplets and improve the utilization rate of fuel.

[0039] A multi-nozzle nozzle 3 is provided in the micro-charged spray burner, and the discharge direction of the spray layer is perpendicular to the axial direction of the feed pipe. The fuel sprayed out of the spray layer is atomized into small droplets in the atomization chamber 5. The small droplets flow to the metal grid 7 under the action of the electrostatic field, and then evaporate after mixing with the air, and burn on the combustion mesh plate 6. In this device, the spray layer is perpendicular to the feed pipe, so that as many spray layers as possible can be arranged in a limited space to increase the fuel flow rate. The sprayed fuel droplets flow to the metal grid under the action of the electrostatic field, which can reduce the mutual influence between the spray layers, and solve the problems of low heat generation of coaxial single nozzles, large heat generation but large size of multi-nozzles, poor fuel atomization effect, and low fuel utilization in the prior art.

[0040] like Figure 4 and Figure 5 As shown, the spraying layers each include a plurality of nozzles 11 uniformly distributed along the radial direction of the feed pipe 10, and the nozzles 11 between two adjacent spraying layers are aligned vertically. The spraying direction of the nozzles 11 is perpendicular to the feed pipe 10, and the jets sprayed from the two adjacent layers of nozzles do not interfere with each other. With this spoke structure, the influence between the nozzles is small, the flow rate of the fuel is increased, the spray jet is shorter and more divergent, the evaporation flow of the droplets is accelerated, the heat release is increased, and the size of the burner is reduced.

[0041] like Figure 6As shown, a porous medium layer 12 is filled between the metal grid 7 and the inner wall of the combustion chamber 1, and the top of the porous medium layer 12 is connected to the combustion mesh plate 6. The fuel droplets in the atomization chamber 5 are dispersed and flow to the metal grid 7 under the action of the electrostatic field, and then flow into the porous medium layer 12 behind the metal grid 7, thereby increasing the contact area between the fuel droplets and the air and improving the evaporation rate of the fuel. The connection between the porous medium layer 12 and the metal grid 7 and the combustion mesh plate 6 is sealed to prevent fuel leakage.

[0042] like Figure 1 and Figure 6 As shown, the atomization unit further includes a fuel recovery tank 8, which is arranged at the bottom end of the atomization chamber 5 and forms an air inlet 9 of the atomization chamber 5. The bottom ends of the metal grid 7 and the porous medium layer 12 are both located in the fuel recovery tank 8. A return port 26 is provided at the bottom end of the fuel recovery tank 8. One end of a fuel recovery pipe 27 extends into the return port 26 and enters the fuel recovery tank 8, and the other end thereof extends into the fuel supply tank 2. The bottom end of the feed pipe 10 passes through the air inlet 9 and is connected to the fuel supply tank 2. The liquid droplets that are not completely evaporated in the metal grid 7 and the porous medium layer 12 flow into the fuel recovery tank 8 under the action of gravity, and finally return to the fuel supply tank 2 through the fuel recovery pipe 27, so that the liquid fuel is recycled.

[0043] The fuel recovery groove 8 is an annular groove, the middle of which is hollowed out to form the air inlet 9 of the atomizing chamber 5. The outer edge of the fuel recovery groove 8 is integrally connected with the bottom end of the atomizing chamber 5. The bottom end of the feed pipe 10 of the multi-nozzle nozzle 3 passes through the rear air inlet 9 and is connected with the fuel supply tank 2. The diameter of the air inlet 9 is larger than the outer diameter of the feed pipe 10. This arrangement facilitates the inflow of air and improves the combustion efficiency of the burner.

[0044] like Figure 1 As shown, the combustion chamber 1 includes an upper chamber 13 and a lower chamber 14 arranged in a vertical direction, the inner diameter of the upper chamber 13 is smaller than the inner diameter of the lower chamber 14, and the connection transition between the upper chamber 13 and the lower chamber 14 is a right-angle transition. This arrangement can increase the residence time of the combustion gas in the combustion chamber, promote its full combustion, and thus improve the combustion efficiency.

[0045] A supply pump 19 is also included, and the bottom end of the delivery pipe 10 is connected to the fuel supply tank 2 through the supply pump 19. Liquid fuel is pumped into the delivery pipe 10 through the supply pump 19.

[0046] The combustion mesh plate 6 includes a circular mesh portion 15 and a sealing plate 16 arranged on the periphery of the mesh portion 15, and the combustion chamber 1 and the atomization chamber 5 are respectively connected to the upper and lower sides of the sealing plate 16. The combustion chamber 1 and the atomization chamber 5 are arranged up and down, the bottom end of the combustion chamber 1 is sealed and connected to the upper side of the sealing plate 16, and the top end of the atomization chamber 5 is sealed and connected to the lower side of the sealing plate 16. This arrangement can effectively prevent fuel leakage and improve the combustion efficiency of the fuel. The surface of the combustion mesh plate 6 is coated with a catalyst to catalyze combustion and stabilize the flame surface.

[0047] The burner also includes an igniter 17, which is close to the combustion mesh plate 6, and a lead 18 of the igniter 17 is connected to an external power supply. There is a small gap between the igniter 17 and the combustion mesh plate 6. The igniter is provided to facilitate ignition and facilitate the use of the burner.

[0048] It also includes an air intake pipe 20, a lower cover plate 21 and a heat exchange sleeve 22, the bottom end of the heat exchange sleeve 22 is sealed by the lower cover plate 21, the combustion chamber 1 and the atomizing chamber 5 are both located in the heat exchange sleeve 22, the top end of the combustion chamber 1 is connected to the top end of the heat exchange sleeve 22, the inner cavity of the combustion chamber 1 is connected to the outside, there is a gap between the outer wall of the combustion chamber 1 and the outer wall of the atomizing chamber 5 and the inner wall of the heat exchange sleeve 22, and there is a gap between the bottom end of the atomizing chamber 5 and the lower cover plate 21, so that an air flow channel is formed between the combustion chamber 1, the atomizing chamber 5 and the fuel recovery tank 8 and the heat exchange sleeve 22, and one end of the air intake pipe 20 passes through the heat exchange sleeve 22 and communicates with the air flow channel, so as to transport the outside air to the inner cavity of the atomizing chamber 5. The bottom end of the multi-nozzle nozzle and the fuel recovery pipe 27 are both connected to the fuel supply tank 2 after passing through the lower cover plate 21. The exhaust gas generated by combustion is discharged through the inner cavity of the combustion chamber 1.

[0049] It also includes an outer sleeve 23 and an upper cover plate 24; the outer sleeve 23 is sleeved on the outer periphery of the heat exchange sleeve 22, the top of the outer sleeve 23 is sealed by the upper cover plate 24, the bottom of the outer sleeve 23 is sealed by the lower cover plate 21, a gap is left between the top of the heat exchange sleeve 22 and the upper cover plate 24, and a gap is left between the outer wall of the heat exchange sleeve 22 and the inner wall of the outer sleeve 23, so that an exhaust gas discharge channel 29 is formed between the inner cavity of the combustion chamber 1, the heat exchange sleeve 22 and the outer sleeve 23, and the outer sleeve 23 is provided with uniformly distributed exhaust gas outlets 25 on the wall. The exhaust gas generated by combustion is discharged through the exhaust gas discharge channel 29 and the exhaust gas outlet 25 in sequence. Among them, the exhaust gas outlet 25 is arranged close to the lower cover plate 21.

[0050] By providing the lower cover plate 21, the upper cover plate 24, the heat exchange sleeve 22 and the outer sleeve 23, the combustion chamber 1 and the atomization chamber 5 are encapsulated to prevent external interference, which helps to improve the stability of combustion. By providing the tail gas discharge channel 29 and the air flow channel 28, the high-temperature tail gas is used to heat the incoming air, which is beneficial to the evaporation of the liquid fuel and improves the utilization rate of the liquid fuel.

[0051] Specifically:

[0052] The upper cover plate 24 and the outer sleeve 23 are both made of ceramic materials with low thermal conductivity and high temperature resistance. The diameter of the upper cover plate 24 is 75mm and the thickness is 3mm. The diameter of the outer sleeve is 70mm and the thickness is 2mm. The overall height of the upper cover plate 24 and the outer sleeve 23 is 83mm. A 1mm small hole is opened on the top of the upper cover plate 24 for the lead wire 18 (igniter lead wire) to pass through. The diameter of the exhaust gas outlet 25 is about 2-3mm, and the distance from the lower cover plate 21 is 4-5mm, and it is symmetrical along the central axis of the burner.

[0053] The lower cover plate 21 is circular, made of low thermal conductivity, insulating silicon carbide, with a diameter of 78 mm and a thickness of 3 mm. A 3 mm small hole is opened at the center of the circle, and the feed pipe 10 passes through the small hole to communicate with the fuel supply tank 2. A 2-3 mm small hole is opened 10 mm away from the center of the circle, and the fuel recovery pipe 27 passes through the small hole and extends into the fuel recovery tank 8 by 0.5 mm.

[0054] The outer diameter of the feed pipe 10 is 4mm, the inner diameter is 3.5mm, the interval between each spray layer is 15mm, and the four nozzles in each layer are symmetrically distributed. The inner diameter of each nozzle is 0.5-0.8mm, the outer diameter is 0.8-1.2mm, and the height is 3mm. The material is stainless steel, and the lower end of the multi-nozzle nozzle has an interference fit with the small hole. The top of the multi-nozzle nozzle 3 is 8mm away from the combustion mesh plate 6, and the bottom nozzle 11 is 20mm away from the lower cover plate 21.

[0055] The multi-nozzle nozzle 3 is connected to the positive electrode of the high-voltage DC power supply 4, the voltage of the high-voltage DC power supply 4 is 2-15 kV, and the metal grid 7 is connected to the negative electrode of the high-voltage DC power supply 4. By arranging the multi-nozzle nozzle 3, the metal grid 7 and the high-voltage DC power supply, the fuel droplets in the atomization chamber 17 can be atomized. The feed pipe 10 and the multi-nozzle nozzle 3 are both made of materials with good conductivity and certain strength, such as stainless steel.

[0056] The heat exchange sleeve 22 is made of stainless steel with high thermal conductivity and high temperature resistance, has a height of 77 mm, is spaced 2 to 3 mm from the upper cover plate 1 , and is connected to the lower cover plate 7 , thereby forming an exhaust gas discharge channel 29 .

[0057] The diameter of the combustion mesh plate 6 is 50 mm, the material is stainless steel, the thickness is 0.5 mm to 1 mm, and the mesh density of the mesh portion 15 is 100 holes / cm 2 The surface is coated with a catalyst, which is used to catalyze fuel combustion and stabilize the flame surface. The sealing plate 16 is seamlessly connected to the atomization chamber 5 and the combustion chamber 1 and is sealed. The outer diameter of the metal grid 7 is 42 mm, the thickness is 1 mm, the height is 53 mm, and the lower end thereof is spaced 1 mm from the fuel recovery tank 8.

[0058] The porous medium layer 12 is tightly attached to the metal grid 7, has an outer diameter of 46 mm and a thickness of 2 to 3 mm. The material is a sintered material with excellent air permeability, such as silicon carbide, with an air permeability of 35%. Its function is to expand the surface area of ​​the fuel droplets and accelerate evaporation. It also has the functions of heat storage and heat conduction to promote fuel evaporation.

[0059] The atomizing chamber 5 and the fuel recovery groove 8 are an integral body, the atomizing chamber 5 has an outer diameter of 50 mm and a thickness of 2 mm, the fuel recovery groove 8 is an annular groove with an outer diameter of 46 mm and an inner diameter of 15 mm, and a groove height of 3 mm. A 2-3 mm small hole is opened at the bottom of the fuel recovery groove 8, which is interference fit with the fuel recovery pipe 27.

[0060] The outer diameter of the lower chamber 14 of the combustion chamber 1 is 50 mm, the height is 10 mm, the outer diameter of the upper chamber 13 is 40 mm, the height is 7 mm, and the wall thickness of the combustion chamber 1 is 2 mm. The material is low thermal conductivity, high temperature resistant ceramics, which can increase the residence time of the mixed steam in the combustion chamber 1, reduce the heat loss during the combustion process, improve the combustion efficiency of the fuel, and maintain the temperature of the combustion chamber.

[0061] The heat exchange sleeve 22, the combustion chamber 1, the atomization chamber 5, the fuel recovery tank 8 and the lower cover plate 21 form an air flow channel 28, and an exhaust gas discharge channel 29 is formed between the combustion chamber 1, the upper cover plate 24 and the heat exchange sleeve 22. The exhaust gas in the exhaust gas discharge channel 29 continuously exchanges heat with the air in the air flow channel 28, so as to preheat the air with the waste heat in the exhaust gas, and at the same time keep the burner warm to reduce heat loss.

[0062] The intake pipe 20 passes through the outer sleeve 23 and the heat exchange sleeve 4, and is connected to the air flow channel 16, and the center of the outlet end of the intake pipe 20 faces the right-angle transition step of the upper and lower chambers of the combustion chamber 1. The outlet end of the intake pipe 20 faces the right-angle transition step of the combustion chamber 1, so that the newly entered air is diverted and the disturbance is increased, thereby increasing the residence time of the air, exchanging more heat with the exhaust gas, and making the air temperature distribution more uniform.

[0063] The volume of the fuel supply tank 2 is 300 ml, and the fuel recovery pipe 27 extends into the fuel supply tank 2 and is immersed in the fuel therein. The consumed fuel is replenished by the fuel feed pipe, and the material is selected to be a plastic pipe.

[0064] The burner has the advantages of compact size, high fuel recovery rate, high thermal efficiency of exhaust gas preheating air, porous medium structure to accelerate fuel evaporation, combustion mesh plate catalytic combustion to improve combustion stability, combustion chamber can increase the residence time of gas to improve combustion efficiency, etc., and has broad application prospects.

[0065] A combustion method suitable for a large-flow micro-charged spray burner comprises the following steps:

[0066] Turn on the supply pump 19 and the high-voltage DC power supply 4, wherein the multi-nozzle nozzle 3 is connected to the positive electrode of the high-voltage DC power supply 4, and the metal grid 7 is connected to the negative electrode of the high-voltage DC power supply 4;

[0067] Under the action of the supply pump 19, the liquid fuel is sprayed out from the multi-nozzle nozzle at a flow rate of 20 to 100 ml / h, atomized into fine droplets in the atomization chamber 5, and captured by the metal grid 7 under the traction of the electric field force;

[0068] Air flows into the air flow channel 28 through multiple symmetrically distributed intake pipes 20, flows into the atomization chamber 5 along the outer wall of the fuel recovery tank 8 to mix with the fuel; the mixed gas composed of fuel vapor and air is ignited by the igniter 17 at the combustion mesh plate 6, and is fully burned in the combustion chamber 20. The exhaust gas after combustion is discharged after passing through the exhaust gas exhaust channel 29 and the exhaust gas outlet 25.

[0069] The above specific implementation modes are preferred embodiments of the present invention and cannot be used to limit the present invention. Any other changes or other equivalent replacement methods that do not deviate from the technical solution of the present invention are included in the protection scope of the present invention.

Claims

1. A micro charged spray burner suitable for large flow, characterized by: It comprises a combustion chamber, an atomization unit, a multi-nozzle nozzle, a combustion mesh plate, a fuel supply box and a high-voltage direct current power supply; the atomization unit comprises an atomization chamber and a metal grid; the combustion chamber and the atomization chamber are both cylindrical with openings at both ends, the combustion chamber and the atomization chamber are arranged up and down and are connected, the combustion chamber and the atomization chamber are separated by a combustion mesh plate, the metal grid is arranged around the atomization chamber, and the top of the metal grid is connected to the combustion mesh plate; the multi-nozzle nozzle comprises a feed pipe and a plurality of spray layers arranged on the feed pipe, the top of the feed pipe is sealed, the plurality of spray layers are arranged at intervals along the axial direction of the feed pipe and close to the top of the feed pipe, the plurality of spray layers are all located in a cavity surrounded by the metal grid, the bottom end of the feed pipe passes through the bottom end opening of the atomization chamber and is connected to the fuel supply box, the multi-nozzle nozzle is connected to the positive electrode of the high-voltage direct current power supply, and the metal grid is connected to the negative electrode of the high-voltage direct current power supply; Each of the spraying layers comprises a plurality of nozzles uniformly distributed along the radial direction of the feed conveying pipe, and the nozzles between two adjacent spraying layers are aligned vertically; It also includes an air intake pipe, a lower cover plate and a heat exchange sleeve, the bottom end of the heat exchange sleeve is sealed by the lower cover plate, the combustion chamber and the atomization chamber are both located in the heat exchange sleeve, the top end of the combustion chamber is connected to the top end of the heat exchange sleeve, the inner cavity of the combustion chamber is connected to the outside, there are gaps between the outer wall of the combustion chamber and the outer wall of the atomization chamber and the inner wall of the heat exchange sleeve, there is a gap between the bottom end of the atomization chamber and the lower cover plate, so that an air flow channel is formed between the atomization chamber and the heat exchange sleeve, the air intake pipe passes through the heat exchange sleeve and is connected to the air flow channel, and the bottom end of the multi-nozzle nozzle passes through the lower cover plate and is connected to the fuel supply tank; It also includes an outer sleeve and an upper cover plate; the outer sleeve is sleeved on the outer periphery of the heat exchange sleeve, the top end of the outer sleeve is sealed by the upper cover plate, and the bottom end of the outer sleeve is sealed by the lower cover plate, a gap is left between the top end of the heat exchange sleeve and the upper cover plate, and a gap is left between the outer wall of the heat exchange sleeve and the inner wall of the outer sleeve, so that an exhaust gas discharge channel is formed between the inner cavity of the combustion chamber, the heat exchange sleeve and the outer sleeve, and an exhaust gas discharge port is opened on the wall of the outer sleeve.

2. The micro charged spray burner suitable for large flow rate according to claim 1 is characterized in that: The atomization unit also includes a fuel recovery groove, which is arranged at the bottom end of the atomization chamber and forms an air inlet of the atomization chamber. The bottom end of the metal grid is located in the fuel recovery groove, and the fuel recovery groove is connected to the fuel supply tank. The bottom end of the feed pipe passes through the air inlet and is connected to the fuel supply tank.

3. The micro charged spray burner suitable for large flow rate according to claim 1 is characterized in that: A porous medium layer is filled between the metal grid and the inner wall of the combustion chamber, and the top of the porous medium layer is connected to the combustion mesh plate.

4. The micro charged spray burner suitable for large flow rate according to claim 1 is characterized in that: The combustion chamber comprises an upper chamber and a lower chamber which are arranged one above the other. The inner diameter of the upper chamber is smaller than the inner diameter of the lower chamber. The connection transition between the upper chamber and the lower chamber is a right-angle transition.

5. The micro charged spray burner suitable for large flow rate according to claim 1 is characterized in that: The combustion mesh plate comprises a circular mesh portion and a sealing plate arranged on the periphery of the mesh portion, and the combustion chamber and the atomization chamber are respectively connected to the upper and lower sides of the sealing plate.

6. The micro charged spray burner suitable for large flow rate according to claim 1 is characterized in that: It also includes an igniter, which is close to the combustion mesh plate and has a lead wire connected to an external power source.

7. A combustion method for a micro-charged spray burner with a large flow rate based on any one of claims 1 to 6, characterized in that: The steps include: Turn on the supply pump and the high-voltage DC power supply, wherein the multi-nozzle nozzle is connected to the positive electrode of the high-voltage DC power supply, and the metal grid is connected to the negative electrode of the high-voltage DC power supply; Under the action of the supply pump, the liquid fuel is sprayed out from the multi-nozzle nozzle at a flow rate of 20-100 ml / h, atomized into fine droplets in the atomization chamber, and captured by the metal grid under the traction of the electric field force; Air flows into the air flow channel through multiple symmetrically distributed intake pipes, flows into the atomization chamber along the outer wall of the fuel recovery tank to mix with the fuel; the mixed gas composed of fuel vapor and air is ignited by the igniter at the combustion mesh plate and fully burns in the combustion chamber. The exhaust gas after combustion is discharged after passing through the exhaust gas emission channel and the exhaust gas outlet.

Images