Flow heating system of constant-volume combustion bomb for marine low-speed machine

Abstract

The invention discloses a constant-volume combustion bomb flow heating system for a marine low-speed machine in the technical field of electromagnetic heating. The constant-volume combustion bomb flow heating system comprises a heating controller, a flow heating module and a peripheral component, the flowing heating module is a heating sleeve, is provided with an alternating current coil and is connected to a heating controller through a coil joint; a heating controller outputs current and frequency-adjustable alternating current to an alternating current coil, a flowing heating module guides a magnetic field to be spread in a heating sleeve, a heating body generates induction current, and air flowing in the heating sleeve is heated through the heat radiation effect; peripheral parts are arranged on the heating sleeve, sealing and heat insulation are achieved, and air is conveyed. The device has the advantages that the internal magnetic field of the alternating current coil can be fully utilized, the requirement that the air flow and the heated air temperature are within a certain range can be met through the heating controller, and the circuit arrangement is simplified.

Description

Technical Field

[0001] The invention relates to a heating system in the field of electromagnetic heating technology, and in particular to a constant-volume incendiary bomb flow heating system for marine low-speed engines where the internal magnetic field of an alternating current coil can be fully utilized. Background Technology

[0002] With global warming and the increasing depletion of fossil fuels, energy has become a global issue, leading to increasingly stringent requirements for engine combustion and emission characteristics. This makes research on fuel combustion processes, including combustion mechanisms and emission control, of paramount importance. Currently, research on combustion and emissions in marine low-speed engines is limited, necessitating further experimentation. During combustion, changes in cylinder volume interfere with the analysis of in-cylinder combustion gas temperature and pressure. Constant-volume combustion bombs eliminate the influence of volume changes on combustion, facilitating control of pressure, temperature, and component concentration during combustion and enabling real-time measurement. The experimental results directly reflect the essence of combustion phenomena, aiding in understanding reaction mechanisms and improving combustion technology; thus, they are an important research tool for combustion and emissions.

[0003] The combustion process in marine low-speed engines typically occurs near the top dead center of the compression stroke. To simulate the high-temperature and high-pressure environment of this process, the air supplied to the constant-volume combustion bomb needs to be heated to ensure that the air reaches the auto-ignition temperature of the fuel. This also allows the initial pressure and temperature of the constant-volume combustion bomb to be closer to the actual combustion process, making it an indispensable step in studying the combustion process using constant-volume combustion bombs.

[0004] To heat the supplied air, the common method is to directly heat it using internal heating elements after it enters the constant-volume incendiary bomb, and then use sensors to monitor the air temperature until it meets the requirements. However, since the heating elements are located on the bomb wall, it is difficult to ensure uniform heating of the internal air, which can easily cause stratification of air properties. In this case, the actual state of the air during the experiment deviates from the experimental requirements, introducing errors into the experimental results.

[0005] Flow heating refers to the direct heating of the supplied air in the inlet duct of a constant-volume incendiary bomb. This method arranges the heating system in the gas path. Compared with internal or external heating of the incendiary bomb, air flow heating is an effective way to enhance the consistency of gas pressure and temperature parameters entering the cylinder. Air flow heating methods are divided into: (a) Direct heating. This method allows the medium and air to come into direct contact. The heat exchange mainly comes from thermal radiation, and some of the heat exchange is also related to thermal convection. The heating medium is a metal material or conductive ceramic, which has electrical conductivity. The direct heating method can directly transfer electrical energy to the heating medium and convert it into the internal energy of the air. It has a simple structure and high thermal efficiency, but it is prone to uneven heating of the air, which affects the heat conduction to the air. The temperature of the heat source material is also high, and it needs to withstand additional thermal stress and heat load. It has high requirements for the high temperature resistance of the material: if a metal material medium is used, the temperature of the air in contact with the surface of the heating medium is high, which may cause a surface reaction with the heating element; if a ceramic medium is used, the impact and heat load resistance is weak, and the service life is short. (b) Indirect heating. This method first converts electrical energy into internal energy stored in an intermediate medium, which then heats the gas. The intermediate medium used for indirect heating has a very large surface area, enhancing the uniformity of the heating process, increasing the heating rate, and effectively suppressing direct interaction between the air and the heat source. However, the process of transferring heat to the air through the intermediate medium involves a certain thermal resistance, hindering heat conduction, and space is required for its arrangement. If the intermediate medium is a flowing medium, the flowing heating system requires additional piping for medium circulation; therefore, heat exchange structures with a solid intermediate medium are simpler. However, due to the large size of marine low-speed engines, and the large air intake of the constant-volume incendiary bomb for research purposes, using a solid as the intermediate heating medium also presents the drawback of high thermal inertia, making automatic control and regulation difficult.

[0006] Based on this, the present invention proposes a marine low-speed engine constant volume combustion bomb flow heating system with solid as intermediate medium that can significantly reduce thermal resistance and thermal inertia and improve heating rate, so as to overcome the defects of difficult heating temperature control and adjustment and slow heating rate. Summary of the Invention

[0007] To address the shortcomings of the aforementioned technologies, this invention proposes a constant-volume incendiary bomb flow heating system for marine low-speed engines. This system, using a solid as the intermediate medium, significantly reduces thermal resistance and thermal inertia while increasing the heating rate. This overcomes the difficulties in controlling and adjusting the heating temperature and the slow heating rate.

[0008] This invention includes a heating controller, a coil connector, a heating sleeve, an exhaust pipe, an inlet sealing cover, an inlet-side sealing gasket, an inlet-side buffer gasket, an exhaust-side buffer gasket, an exhaust-side sealing gasket, an exhaust sealing cover, connecting bolts, connecting nuts, fixing bolts, and a device bracket. The inlet sealing cover, inlet-side sealing gasket, and inlet-side buffer gasket are sequentially arranged at the inlet end of the heating sleeve and connected to the inlet end of the heating sleeve by connecting bolts and connecting nuts. The exhaust-side buffer gasket, exhaust-side sealing gasket, and exhaust sealing cover are sequentially arranged at the exhaust end of the heating sleeve and connected to the inlet end of the heating sleeve by connecting nuts and fixing bolts. The exhaust pipe is connected to the exhaust sealing cover by fixing bolts. The device bracket is arranged on the outer wall surface of the heating sleeve.

[0009] The heating sleeve includes a heating element, a heat insulation tube, an inner elastic heat insulation layer, an alternating current coil, an outer elastic heat insulation layer, a radial heat insulation layer, a sealing tube, a heating element positioning body, a telescopic spring, a heating element fixing body, an axial heat insulation layer, an air outlet fixing body, a cylindrical pin, an air inlet flange, an air outlet flange, and flange connection bolt threaded holes. Inside the heating sleeve, from the inside to the outside radially, the heating element, heat insulation tube, inner elastic heat insulation layer, alternating current coil, outer elastic heat insulation layer, radial heat insulation layer, and sealing tube are arranged in a ring shape in cross-section. The heating element is a mesh-like porous foam metal, cylindrical in shape, consisting of several stacked pieces along its axis, contacting the inner wall of the insulation tube. The heating element, insulation tube, inner elastic insulation layer, alternating current coil, and outer elastic insulation layer all have flush end faces, and are located within the end faces of the sealing tube. The outlet end face is flush with the outlet end face of the radial insulation layer; the inlet end face of the radial insulation layer is flush with the inlet end face of the sealing tube, and the sealing tube is located within the inlet end face. The heating element positioning body is aligned with the inlet end face of the sealing tube, and contacts the inlet end faces of the heating element, insulation tube, inner elastic insulation layer, alternating current coil, and outer elastic insulation layer. The heating element positioning body has a through hole along its axis, and a boss structure near the radial insulation layer, with a telescopic spring arranged inside.

[0010] The heating element, insulation tube, inner elastic insulation layer, alternating current coil, and outer elastic insulation layer are in close contact with the heating element fixing body on the outlet side. The heating element fixing body is in contact with the axial insulation layer. The outer edge of the axial insulation layer is in contact with the sealing tube and extends towards the air inlet to contact the radial insulation layer. The axial insulation layer is also in contact with the air outlet fixing body, which extends axially towards the outlet. The heating element fixing body, axial insulation layer, and air outlet fixing body have through holes along their axes, and each has cylindrical pin holes on its outer circumference. The heating element fixing body, axial insulation layer, and air outlet fixing body are connected together by cylindrical pins. The radial insulation layer is composed of several stacked insulation layers, some of which have grooves. The inlet-side flange and outlet-side flange are respectively located on the inlet and outlet side ends of the sealing tube. Both the inlet-side flange and outlet-side flange have threaded holes for flange connection bolts, which are through holes.

[0011] Furthermore, in this invention, an air inlet buffer gasket, an air inlet sealing gasket, and an air inlet sealing cover are sequentially provided on the outer side of the air inlet end face of the sealing tube; the air inlet sealing cover is provided with an air inlet cover connecting bolt thread hole, which is a through hole; the air inlet sealing gasket and the air inlet buffer gasket are also provided with through holes in the same position; the air inlet flange, the air inlet buffer gasket, the air inlet sealing gasket, and the air inlet sealing cover are connected by connecting bolts and fixed with connecting nuts; an air inlet hole is provided on the axis of the air inlet sealing cover, which is a through hole; an annular mounting boss is arranged along the air inlet sealing cover, extending in the direction of air flow to be inserted into the heating element positioning body; the air inlet sealing cover is also provided with two wire lead-out holes, which are through holes. The two ends of the alternating current coil are placed in the grooves arranged in the radial insulation layer, and then led out of the heating sleeve through the lead wire outlet hole and the air inlet sealing cover plate; the surface of the part where the lead wire of the alternating current coil contacts the air inlet sealing cover plate is protected by an insulating sleeve; the two ends of the alternating current coil are provided with coil connectors to connect to the heating controller.

[0012] Furthermore, in this invention, an outlet-side buffer gasket, an outlet-side sealing gasket, and an outlet-side sealing cover are sequentially provided on the outer side of the outlet end face of the sealing tube; the outlet-side sealing cover is provided with an outlet-side connecting bolt threaded hole, which is a through hole; the outlet-side sealing gasket and the outlet-side buffer gasket are also provided with holes at the same positions; the outlet-side flange, the outlet-side buffer gasket, the outlet-side sealing gasket, and the outlet-side sealing cover are connected by connecting bolts and fixed with connecting nuts; an outlet hole is provided on the axis of the outlet-side sealing cover, which is a through hole; a connecting boss is arranged on the outlet-side sealing cover, extending in the opposite direction of air flow to be inserted into the outlet fixing body and the outlet-side flange; a fixing bolt threaded hole is provided inside the connecting boss, which is a blind hole and extends from the outer end face of the outlet-side sealing cover in the opposite direction of air flow.

[0013] Furthermore, in this invention, an air outlet pipe is arranged outside the air outlet sealing cover; a sealing flange is arranged at the air inlet end of the air outlet pipe and several fixing bolt threaded holes are opened, and the fixing bolt threaded holes are through holes; the fixing bolts are screwed into the fixing bolt threaded holes provided in the connecting boss through the sealing flange, and there are washers to reduce wear; the air outlet channel is on the axis of the air outlet pipe.

[0014] This invention relates to an indirect heating flow heating system, which is a heating sleeve structure comprising an alternating current coil and an internal heating element. An insulating tube surrounds the heating element, and an air intake passage is formed inside the insulating tube. The alternating current coil is wound around the outside of the insulating tube and is powered by a heating controller.

[0015] The heating element has a spatial network structure. This structure results in a large specific surface area, high melting point, and low thermal deformation rate, making it less prone to deformation in high-temperature oxidizing atmospheres. By uniformly distributing the spatial network structure within the gas flow space, the heating rate of the flowing air is increased, and the interference of boundary layer effects on heating uniformity and heating rate is reduced.

[0016] The heating element is placed inside an insulating tube, which reduces heat loss caused by thermal radiation from the surface of the heating element. The heating element consists of several stacked heating blocks with a spatial mesh structure.

[0017] An alternating current coil is located outside the insulation tube. The alternating current coil is connected to an external heating controller, providing alternating current to generate a magnetic field within the foam metal space, thus providing a heat source for the flowing air. The alternating current coil has coil connectors at both ends for connection to the heating controller.

[0018] The alternating current coil is surrounded by a radial insulation layer, which is composed of several stacked layers. Outside the radial insulation layer is a sealed tube, with flanges on both the inlet and outlet sides, namely the inlet flange and the outlet flange, respectively. When the alternating current coil is energized and heats up, the radial insulation layer reduces heat radiation and conduction to the sealed tube, improving the efficiency of converting electrical energy into Joule heat in the heating element, thus ensuring that energy is concentrated for induction heating of the air. The radial insulation layer also improves the mechanical strength of the alternating current coil and provides chemical protection for the inner wall of the sealed tube and the alternating current coil.

[0019] A device support is provided outside the sealing tube, and the device support is welded to the side of the sealing tube to ensure that the heating sleeve can be placed on the ground.

[0020] The alternating current coil is equipped with elastic thermal insulation layers both inside and outside the space. The inner elastic thermal insulation layer covers the space between the alternating current coil and the insulation tube. When the alternating current coil generates Joule heat due to energization, the inner and outer elastic thermal insulation layers prevent the alternating current coil from contacting the insulation tube and the radial insulation layer, respectively, eliminating wear or localized ablation, and preventing excessive thermal deformation stress. This provides a buffer space for thermal deformation at different temperatures and enhances the system's adaptability.

[0021] The air inlet side of the sealing tube is equipped with a heating element positioning body. The axis of the heating element positioning body has a through hole for gas to pass through. Both end faces coincide with the end face of the air inlet side of the heating sleeve and are in contact with the heating element and the heat insulation tube, so as to limit the displacement of the heating element towards the air inlet side.

[0022] The heating element positioning body is provided with a boss with a through hole and a telescopic spring at the contact point with the air inlet flange. The telescopic spring can provide elastic force to the heating element positioning body, so that the heating element positioning body can always be in close contact with the heating element and the heat insulation pipe, which enhances the reliability of limiting the displacement of the heating element to the air inlet side and reserves space for thermal deformation.

[0023] The sealing tube has a heating element fixing body, an axial insulation layer, and an outlet fixing body arranged sequentially along the gas flow direction on the gas outlet side, and there is a through hole for gas to pass through on the axis.

[0024] The heating element fixing body contacts all annular components of the heating section, but not the sealing tube. A boss is provided on the outer surface to ensure contact between the axial and radial insulation layers, reducing heat loss from the heating element and alternating current coil through the outlet side of the heating sleeve. The outlet fixing body is in close contact with the axial insulation layer and the sealing tube, and a boss with a through hole is provided on its axis, forming an annular groove between the outlet fixing body and the sealing tube. The heating element fixing body, axial insulation layer, and outlet fixing body are connected by cylindrical pins.

[0025] The air inlet sealing cover is located on the outside of the air inlet side of the heating sleeve. It has several threaded holes and is fixed to the air inlet flange of the sealing tube with several connecting bolts, and then reinforced with connecting nuts. The air inlet sealing cover has two wire lead-out holes. The alternating current coil is straight at both ends inside the heating sleeve. The wires are led out of the heating sleeve through the two wire lead-out holes and then connected to the heating controller. The air inlet sealing cover also has an air inlet to allow air to flow in before heating.

[0026] The straight conductor segment of the alternating current coil leading out of the heating sleeve is covered by a coil sleeve at the point of contact with the sealing cover to ensure insulation of the straight conductor segment from other components. The radial insulation layer has grooves in certain areas to accommodate the straight conductor segment of the alternating current coil leading out of the heating sleeve.

[0027] The conductors of the alternating current coil have a hollow structure. The heating controller provides cooling water to the energized alternating current coil through the coil connector to prevent the alternating current coil itself or the inner and outer elastic insulation layers from being damaged by excessive temperature.

[0028] The vent sealing cover is located outside the vent side of the heating sleeve and contacts the fixed flange. The vent sealing cover has several threaded through holes and is fixed to the fixed flange with several connecting bolts, further secured with connecting nuts. The vent sealing cover also has several threaded blind holes. The vent pipe has a fixed flange with several threaded through holes. The vent sealing cover and the vent pipe are fixed in position using fixing bolts.

[0029] The vent sealing cover is also provided with an vent hole, and the vent pipe is also provided with an vent channel structure. The two are connected on the axis so that the high-temperature air heated by the heated body is output through the vent pipe.

[0030] The end face of the vent sealing cover that contacts the vent pipe fixing flange is provided with a boss, and the blind ends of the several threaded blind holes extend into the boss. After assembly, the boss of the vent sealing cover is inserted into the annular groove formed by the vent fixing body and the vent side flange of the sealing pipe to improve the stability of the assembly.

[0031] Sealing gaskets and buffer gaskets are also provided on the outer surfaces of both ends of the sealing tube, and holes are drilled according to the positions of the connecting bolts. The sealing gaskets restrict the pressing position of the inlet and outlet sealing covers inside the sealing tube, preventing excessive pressing that could damage the internal structure and ensuring the airtightness of the device. The buffer gaskets are located between the sealing gaskets and the inlet and outlet sealing covers to absorb vibrations of the sealing surface and compensate for any possible unevenness in the machining of the sealing surface, thereby reducing wear on the sealing surface.

[0032] Compared with existing technologies, this invention, employing the above technical solution, has the following advantages: The heating element used in this invention significantly increases the specific surface area of ​​the intermediate medium while reducing its weight and avoiding contact with the circuit, thus promoting heat transfer from the intermediate medium to the air. The heating controller used in this solution is connected to the power grid, and the heating coil surrounds the heating element, through which a high-frequency alternating current flows, resulting in a non-uniform current variation. According to Maxwell's electromagnetic field theory, the changing electric field generates a magnetic field in the surrounding space, thereby creating a changing magnetic field within the heating coil. Simultaneously, according to Maxwell's electromagnetic field theory, the changing magnetic field generates an electric field in the surrounding space, thus inducing an electromotive force and forming eddy currents within the heating element. According to Joule's law, Joule heat is generated inside the heating element, causing its temperature to rise rapidly. The heating element has a large contact area with the flowing air, and its temperature is higher than that of the air. Heat is primarily transferred to the air entering the incendiary bomb through radiation, achieving rapid heating of the air. According to the requirements of constant-volume incendiary bomb experiments, the heating controller can be used to control the frequency and intensity of the heating current to control the temperature of the high-temperature air entering the incendiary bomb. This design features a non-contact relationship between the power supply and the heating medium (intermediate medium), simplifying the circuit layout. Simultaneously, the heating element possesses resistance, facilitating the rapid conversion of electrical energy in the eddy currents for quick heating of the air. Since heat exchange between the heating element and the air occurs within the pores of the heating element, the heated air temperature is more uniform, reducing the stratification of air properties and eliminating the interference of non-uniform properties on the experimental results.

[0033] Meanwhile, the heating element space coincides with the airflow path, eliminating the need for additional space and simplifying the layout of the circuitry and heating element. Furthermore, the presence of heat insulation components significantly reduces heat dissipation from the alternating current coil and heating element, improving energy efficiency. Attached Figure Description

[0034] Figure 1 This is a three-dimensional structural diagram illustrating the air inflow side structure of the present invention;

[0035] Figure 2 This is a three-dimensional structural diagram illustrating the airflow side structure of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure of the present invention related to airflow and heating control;

[0037] Figure 4 This is a schematic longitudinal section of the structure of the present invention, which embodies the function of heating flowing air.

[0038] Figure 5 yes Figure 4 Schematic diagram of the structure of section AA in the middle;

[0039] Figure 6 This is a three-dimensional structural diagram of the air inflow side end cap of the present invention;

[0040] Figure 7 This is a three-dimensional structural schematic diagram of the air outlet side end cap of the present invention;

[0041] Figure 8 This is a schematic diagram of the cross-sectional structure of the air outlet pipe of the present invention;

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Heating controller; 2. Coil connector; 3. Inlet sealing cover; 31. Inlet cover connecting bolt threaded hole; 32. Assembly boss; 33. Inlet hole; 34. Wire lead-out hole; 4. Inlet side sealing gasket; 5. Inlet side buffer gasket; 6. Heating sleeve; 611. Heating element; 612. Insulation tube; 613. Inner elastic insulation layer; 614. Alternating current coil; 615. Outer elastic insulation layer; 616. Radial insulation layer; 617. Sealing tube; 621. Heating element positioning body; 622. Telescopic spring; 623. Heating element fixing body; 624. Axial insulation. Layer, 625, Outlet fixing body, 626, Cylindrical pin, 627, Inlet side flange, 628, Outlet side flange, 629, Flange connecting bolt threaded hole, 7, Outlet side buffer gasket, 8, Outlet side sealing gasket, 9, Outlet sealing cover plate, 91, Outlet cover plate connecting bolt threaded hole, 92, Fixing bolt threaded hole, 93, Outlet hole, 94, Connecting boss, 10, Outlet pipe, 1001, Fixing flange, 1002, Fixing bolt threaded hole, 1003, Outlet duct, 11, Connecting bolt, 12, Connecting nut, 13, Fixing bolt, 14, Device bracket. Detailed Implementation

[0044] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are based on the technical solutions of the present invention and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Any process scheme that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art is within the scope of protection defined by the claims of the present invention.

[0045] Example

[0046] Specific implementation examples Figures 1 to 8 As shown.

[0047] Figure 1 and Figure 2 The figure shown is a visual representation of the invention. The three-dimensional shape of the heating system matches the air inlet sealing cover 3, the air inlet side sealing gasket 4, the air inlet side buffer gasket 5, the heating sleeve 6, the air outlet side buffer gasket 7, the air outlet side sealing gasket 8, the air outlet sealing cover 9, and the air outlet pipe 10. This involves the arrangement and dimensional processing of the threaded channels.

[0048] Reference Figures 1 to 3 The energy conversion process of the present invention involves a heating controller 1, a heating element 611, and an alternating current coil 614. The heating controller 1 has the function of a power supply, used to provide alternating current to the alternating current coil 614.

[0049] Reference Figures 3 to 5 The heating sleeve 6 contains a heating element 611. The heating element 611 is a foamed metal with a spatial network structure, possessing a large specific surface area. Due to the presence of gas flow pores, it provides heat to the air and ensures airflow within it, while also ensuring uniform heating as the air flows through the pores. The heating element 611 is externally equipped with a heat-insulating structure, comprising an insulation tube 612 and an inner elastic insulation layer 613. The insulation tube 612 surrounds the heating element 611, and the inner elastic insulation layer 613 covers the outside of the insulation tube 612. The inner elastic insulation layer 613 is surrounded by an alternating current coil 614. The insulation tube 612 suppresses the dissipation of high-temperature radiant energy from the heating element 611, thereby increasing the heat exchange between the heating element 611 and the air. The inner elastic insulation layer 613 is positioned between the insulation tube 612 and the alternating current coil 614, suppressing heat conduction losses from the heating element 611 through the insulation tube 612. An outer elastic insulation layer 615 and a radial insulation layer 616 surround the alternating current coil 614 in sequence, which respectively suppress heat dissipation caused by heat conduction and radiation of the alternating current coil 614. The radial insulation layer 616 is covered by a sealing pipe 617, which is a steel pipe with flanges at both ends. The flanges at both ends are an inlet flange 627 and an outlet flange 628, each with X flange connection bolt thread holes 629.

[0050] Preferably, the insulating tube 612 is made of quartz, the inner elastic insulating layer 613 and the outer elastic insulating layer 615 are made of aerogel, and the radial insulating layer 616 is made of insulating ceramic, consisting of several 1 / n (n≥2) insulating ceramic rings stacked together. Glass prevents the penetration of heat radiation from high-temperature objects. The insulating ceramic has extremely low magnetic permeability, guiding the induced magnetic field generated by the alternating current coil 614 to propagate along itself, reducing magnetic energy leakage and preventing deformation of the alternating current coil 614. Aerogel has extremely low thermal conductivity, reducing heat dissipation caused by radial heat conduction of the heating element 611 and the alternating current coil 614, thereby improving the utilization rate of the electrical energy output by the heating controller. Furthermore, the elasticity of the aerogel reduces the thermal deformation stress of each layer, improving the safety of the heating sleeve 6.

[0051] like Figure 4As shown, the radial insulation layer 616 overlaps with the intake flange 627. A heating element positioning body 621 is placed inside the intake flange 627. The heating element positioning body 621 covers the end face of the insulation pipe 612, the inner elastic insulation layer 613, the alternating current coil 614, the outer elastic insulation layer 615, and the radial insulation layer 616 near the intake side, while also partially covering the heating element 621. A through hole is provided in the middle to allow air to flow into the heating element 611.

[0052] Preferably, the heating element positioning body 621 is provided with two through holes for leading the wires of the alternating current coil 614 out of the heating sleeve 6.

[0053] Preferably, the radial insulation layer 616 has grooves in some of its heat-insulating ceramic rings at certain positions, and the grooves as a whole can accommodate the lead wires of the alternating current coil 614 leading out of the heating sleeve 6, preventing the component materials from squeezing each other.

[0054] Reference Figures 1-3 , Figure 6 An intake-side buffer gasket 5, an intake-side sealing gasket 4, and an intake sealing cover plate 3 are sequentially arranged on the outer side of the intake-side flange 627. Each gasket has X threaded holes 31 for intake cover plate connecting bolts, which match the threaded holes 629 for flange connecting bolts on the end face of the intake-side flange 627. They are connected using connecting bolts 11 and connecting nuts 12. The intake sealing cover plate 3 has a mounting boss 32. After being connected to the sealing pipe 617, the mounting boss 32 is inserted into the heating element positioning body 621 to further limit the axial displacement of the heating element 621. An air inlet hole 33 is opened on the axis of the intake sealing cover plate 3 for direct air intake. The intake-side buffer gasket 5, the intake-side sealing gasket 4, and the intake sealing cover plate 3 each have two wire lead-out holes 34.

[0055] During assembly, the two ends of the alternating current coil 614 are stretched into straight lines, and the straight sections are inserted into the grooves provided in the radial insulation layer 616. The lead-out holes 34 lead out the air intake sealing cover 3, followed by the sequential insertion of the heating element positioning body 621, the air intake side buffer gasket 5, the air intake side sealing gasket 4, and the air intake sealing cover 3. The insulating coil sleeve is then inserted into the portion of the straight section that contacts the air intake sealing cover 3 to prevent the conductivity of the components themselves from interfering with the energy transfer to the alternating current coil 614. Finally, coil connectors 2 are installed at both ends of the alternating current coil 614 to connect to the heating controller 1.

[0056] The alternating current coil 614 has a hollow structure. Cooling water is introduced by the heating controller 1 to reduce the temperature of the alternating current coil 614 and prevent the material from deforming or melting due to excessive temperature.

[0057] Reference Figure 4Near the air outlet of the heating sleeve 6, the end faces of the heating element 611, the insulation tube 612, the inner elastic insulation layer 613, the alternating current coil 614, the outer elastic insulation layer 615, and the radial insulation layer 616 are flush. Each of these end faces contacts the heating element fixing body 623, which partially covers the heating element 611 and the radial insulation layer 616, but does not contact the sealing tube 617. The axial insulation layer 624 is made of insulating ceramic and has ring ribs, contacting the radial insulation layer 616 and the sealing tube 617, effectively reducing the leakage of magnetic field energy near the air outlet of the heating sleeve 6 and the radiative dissipation of internal energy in the heating element 611. Under the combined action of the radial insulation layer 616 and the axial insulation layer 624, the magnetic field generated by the coil is guided into the heating element 611. The outlet fixing body 625 contacts the inner wall of the sealing tube 617 and the axial insulation layer 624. It has annular ribs on its axis, forming an annular groove between the outlet fixing body 625 and the inner wall of the sealing tube 617. The heating element fixing body 623, the axial insulation layer 624, and the outlet fixing body 625 all have through holes on their axes and several cylindrical pin holes on their surfaces, connected by cylindrical pins 626.

[0058] Reference Figure 1 , Figure 2 , Figure 7 The outer side of the outlet flange 628 is sequentially provided with an outlet buffer gasket 7, an outlet sealing gasket 8, and an outlet sealing cover plate 9. Each gasket has X outlet cover plate connecting bolt threaded holes 91, which match the flange connecting bolt threaded holes 629 on the outlet flange 627 end face. They are connected using connecting bolts 11 and connecting nuts 12. The outlet sealing cover plate 9 has Y fixing bolt threaded holes 93 and a connecting boss 94. The fixing bolt threaded holes 93 are blind holes, with the blind end located inside the connecting boss 94. After assembly, the connecting boss 94 is inserted into the annular groove formed by the axis of the sealing tube 617 and the outlet fixing body 625. The outlet sealing cover plate 9 contacts the outlet flange 628 through the outlet sealing gasket 8 and the outlet buffer gasket 7.

[0059] Reference Figure 8 The vent sealing cover 9 is also connected to a vent pipe 10. The vent pipe 10 has a fixing flange 1001 with Y threaded holes 1002 for fixing bolts, which correspond to the vent sealing cover 9. The two parts are tightly fixed by fixing bolts 13. The vent pipe 10 is provided with a vent passage 1003 for outputting heated high-temperature air. Preferably, X > Y.

[0060] Connecting bolt 11 and fixing bolt 13 are used together with washers. The lead wire of the alternating current coil 614 leading out of the heating sleeve 6 is straight. At the contact point with the air inlet sealing cover 3, the surface is covered with a coil sleeve made of insulating material to prevent the conductivity of the air inlet sealing cover 3 and the heating element positioning body 621 from interfering with the power supply from the heating controller 1 to the alternating current coil 614. Several device supports 14 are provided on the sealing tube 617. The assembled heating sleeve 6 is placed on the ground or experimental table through the device supports 14.

[0061] The specific implementation instructions are as follows:

[0062] like Figures 1 to 5 As shown, the heating controller 1 is connected to 380V AC power, and the alternating current coil 614 is supplied with AC power through the coil connector 2. The alternating current coil 614 generates an alternating magnetic field in the surrounding space. Due to the extremely low magnetic resistance of the radial insulation layer 616 and the axial insulation layer 624, the magnetic field lines generally propagate along the radial insulation layer 616 and the axial insulation layer 624, thus ensuring that the magnetic field lines converge inside the heating sleeve 6, and there is no significant leakage of the magnetic field lines. The heating element 611 has a spatial mesh structure, which can be analyzed as a closed loop element. The magnetic flux through the closed loop element is in a changing state, thus generating an induced electromotive force inside the heating element 611, which in turn generates eddy currents. Due to the dissipation effect of the heating element 611's own resistance, the heating element 611 generates Joule heat, and the temperature rises rapidly. Because the heating element 611 has pores, when air enters the heating sleeve 6 through the air inlet 33, it flows through the heating element 611. Due to the large specific surface area of ​​the mesh structure, the temperature rises rapidly due to thermal radiation as the air flows through. The alternating current ensures that the heating element 611 continuously generates heat to heat the air flowing at a certain speed. The heating element 611 is wrapped with a heat-insulating tube 612 made of quartz, which has a high melting point and prevents the penetration of high-temperature thermal radiation. It can always maintain its tubular shape and suppress heat dissipation caused by thermal radiation. The heat-insulating tube 612 has a thermal conductivity, but the inner elastic heat insulation layer 613 is made of aerogel material with an extremely low thermal conductivity, suppressing conduction losses. With non-contact heating and the heat insulation effect of the heat-insulating tube 612 and the inner elastic heat insulation layer 613, the temperature of the heating element 611 can be higher than the temperature of the alternating current coil 614, thus increasing the output heated air temperature range. The alternating current coil 614 is surrounded by an external elastic heat insulation layer 615, which also suppresses the energy dissipation of the alternating current coil 614 to the outside. At the same time, the radial heat insulation layer 616 is made of ceramic material, which also has the function of insulating heat radiation. Under the combined effect of the two, there is no significant energy loss in the alternating current coil 614. In addition, the external elastic heat insulation layer 615 and the radial heat insulation layer 616 prevent wear on the alternating current coil 614 and maintain its fixed shape.

[0063] During the heating process, the heating element 611, the insulation tube 612, and the alternating current coil 614 undergo radial thermal deformation. The inner elastic insulation layer 613 and the outer elastic insulation layer 615 are elastic, providing a buffer space for thermal deformation and dispersing thermal stress to avoid structural damage.

[0064] A telescopic spring 622 is provided on the air inlet side of the heating sleeve 6. It is in a compressed state at room temperature and acts on the heating element positioning body 621. During the heating process, the heating element 611 undergoes axial thermal deformation. The telescopic spring 622 exerts a repulsive force on the heating element positioning body 621, which suppresses the change in the position of the end face of the heating element positioning body 621 in contact with the heating element 611, reduces the displacement of the end face of the heating element 611 on the air inlet side, and ensures the thermal stability of the overall structure of the assembly.

[0065] On the gas outlet side of the heating sleeve 6, there is a heating element fixing body 623, an axial insulation layer 624, and a gas outlet fixing body 625, connected by several cylindrical pins 626. A connecting pair exists between the heating element fixing body 623 and the insulation tube 612 to fix the axial boundary of the heating element 611 and suppress radiation dissipation at the fixing point. The outer surface of the axial insulation layer 624 has annular ribs, which contact the radial insulation layer 616 and enclose the heating element fixing body 623 within the annular ribs, providing mechanical protection. The axial insulation layer 624 guides the magnetic field in the radial insulation layer 616, allowing magnetic field lines to form a path in the insulation material and be directly guided to the heating element 611 for induction heating. The gas outlet end face of the axial insulation layer 624 is a smooth machined surface, contacting the gas outlet fixing body 625. The heating sleeve 6 has an outlet on its outlet side and an outlet flange 628 on the outside. An outlet sealing cover 9 and an outlet pipe 10 are connected in sequence. The outlet sealing cover 9 has an outlet hole 93 on its axis, and the outlet pipe 10 has an outlet channel 1002 on its axis for outputting heated air. Obviously, the temperature of the output air is slightly lower than that of the heating element 611.

[0066] In some embodiments, the output current and output frequency of the heating controller 1 can be adjusted within a certain range, thereby changing the output air temperature to meet the needs of different experimental conditions for high-temperature air.

[0067] In some embodiments, the alternating current coil 614 has a hollow structure. Cooling water is introduced at the same time as the heating controller 1 is energized to control the temperature of the alternating current coil from becoming too high. Under the insulation effect of the radial insulation layer 616 and the axial insulation layer 624 on heat radiation, the electrical energy of the alternating current coil 614 is not significantly dissipated.

[0068] The above description of the embodiments of the present invention is descriptive and not limiting. Therefore, it should be noted that any modifications, substitutions, and improvements that do not depart from the spirit and scope of the present invention and the appended claims are within the scope of the present invention and should not be construed as exceeding the limitations of the above description and claims.

Claims

1. A flow heating system for a marine low-speed engine constant-volume incendiary bomb, comprising a heating controller (1), a coil connector (2), a heating sleeve (6), and an exhaust pipe (10), characterized in that, It also includes an intake sealing cover (3), an intake side sealing gasket (4), an intake side buffer gasket (5), an exhaust side buffer gasket (7), an exhaust side sealing gasket (8), an exhaust sealing cover (9), a connecting bolt (11), a connecting nut (12), a fixing bolt (13), and a device bracket (14). The air inlet sealing cover (3), air inlet side sealing gasket (4), and air inlet side buffer gasket (5) are arranged sequentially at the air inlet end of the heating sleeve (6) and connected to the air inlet end of the heating sleeve (6) by connecting bolts (11) and connecting nuts (12). The air outlet buffer gasket (7), the air outlet sealing gasket (8), and the air outlet sealing cover plate (9) are arranged sequentially at the air outlet end of the heating sleeve (6) and connected to the air inlet end of the heating sleeve (6) by connecting nuts (12) and fixing bolts (13). The vent pipe (10) is connected to the vent sealing cover plate (9) by fixing bolts (13), and the device bracket (14) is arranged on the outer wall of the heating sleeve (6); The heating sleeve (6) includes a heating body (611), a heat insulation tube (612), an inner elastic heat insulation layer (613), an alternating current coil (614), an outer elastic heat insulation layer (615), a radial heat insulation layer (616), a sealing tube (617), a heating body positioning body (621), a telescopic spring (622), a heating body fixing body (623), an axial heat insulation layer (624), an air outlet fixing body (625), a cylindrical pin (626), an air inlet side flange (627), an air outlet side flange (628), and flange connection bolt threaded holes (629). Inside the heating sleeve (6), from the inside to the outside along the radial direction, are heating element (611), heat insulation tube (612), inner elastic heat insulation layer (613), alternating current coil (614), outer elastic heat insulation layer (615), radial heat insulation layer (616), and sealing tube (617), all arranged in a ring shape in cross-section. The heating element (611) is a mesh-like porous foam metal, cylindrical in shape, and consists of several stacked pieces along its axis, contacting the inner wall of the insulation tube (612). The heating element (611), insulation tube (612), inner elastic insulation layer (613), alternating current coil (614), and outer elastic insulation layer (615) all have flush end faces, and are located within the end faces of the sealing tube (6). The outlet end face is flush with the outlet end face of the radial insulation layer (616); the inlet end face of the radial insulation layer (616) is flush with the sealing tube (617). The intake side end face is flush, and the sealing tube (617) is inside the intake side end face; the heating element positioning body (621) is aligned with the intake side end face of the sealing tube (617), and the heating element positioning body (621) is in contact with the intake side end faces of the heating element (611), the heat insulation tube (612), the inner elastic heat insulation layer (613), the alternating current coil (614), and the outer elastic heat insulation layer (615); the axis of the heating element positioning body (621) has a through hole, and a boss structure is located near the radial heat insulation layer (616), with the telescopic spring (622) arranged inside; The outlet end faces of the heating element (611), the heat insulation tube (612), the inner elastic heat insulation layer (613), the alternating current coil (614), and the outer elastic heat insulation layer (615) are in close contact with the heating element fixing body (623), and the heating element fixing body (623) is in contact with the axial heat insulation layer (624); the outer edge of the axial heat insulation layer (624) is in contact with the sealing tube (617) and extends towards the air inlet to contact the radial heat insulation layer (616); axial The insulation layer (624) is also in contact with the air outlet fixing body (625), and the air outlet fixing body (625) extends backward in the axial direction of the air outlet; the heating body fixing body (623), the axial insulation layer (624), and the air outlet fixing body (625) have through holes on their axes, and all of them have cylindrical pin holes arranged on their outer circular sides; the heating body fixing body (623), the axial insulation layer (624), and the air outlet fixing body (625) are connected together by cylindrical pins (626); The radial insulation layer (616) is composed of several insulation layers stacked together, and some insulation layers have grooves arranged in them; The inlet flange (627) and outlet flange (628) are respectively arranged on the inlet and outlet end faces of the sealing tube (617). The inlet flange (627) and outlet flange (628) are respectively provided with flange connection bolt thread holes (629), which are through holes.

2. The marine low-speed engine constant-volume combustion bomb flow heating system according to claim 1, characterized in that... On the outside of the air inlet side end face of the sealing pipe (617), an air inlet side buffer gasket (5), an air inlet side sealing gasket (4), and an air inlet sealing cover plate (3) are arranged in sequence; the air inlet sealing cover plate (3) is provided with an air inlet cover plate connecting bolt thread hole (31), which is a through hole, and the air inlet side sealing gasket (4) and the air inlet side buffer gasket (5) are also provided with through holes in the same position; air inlet side flange (627), air inlet side buffer gasket (5), and air inlet side sealing gasket (4) are also provided. The air intake sealing cover (3) is connected by connecting bolts (11) and fixed with connecting nuts (12); the air intake sealing cover (3) has an air intake hole (33) on its axis, and the air intake hole (33) is a through hole; an annular mounting boss (32) is arranged on the air intake sealing cover (3) and extends in the direction of air flow to be inserted into the heating element positioning body (621); the air intake sealing cover (3) is also provided with two wire lead-out holes (34), and the wire lead-out holes (34) are through holes; The alternating current coil (614) is placed in the grooves of the radial insulation layer (616) at both ends, and then led out of the heating sleeve (6) through the lead wire hole (34) and the air inlet sealing cover (3); the part where the lead wire of the alternating current coil (614) contacts the air inlet sealing cover (3) is protected by an insulating sleeve; the alternating current coil (614) is provided with coil connectors (2) at both ends to connect to the heating controller (1).

3. The marine low-speed engine constant-volume combustion bomb flow heating system according to claim 1, characterized in that... The outer side of the outlet end face of the sealing tube (617) is provided with an outlet buffer gasket (7), an outlet sealing gasket (8), and an outlet sealing cover plate (9) in sequence; the outlet sealing cover plate (9) is provided with an outlet cover plate connecting bolt thread hole (91), the outlet cover plate connecting bolt thread hole (91) is a through hole, and the outlet sealing gasket (8) and the outlet buffer gasket (7) are also provided with holes in the same position; the outlet flange (629), the outlet buffer gasket (7), the outlet sealing gasket (8), and the outlet sealing cover plate (9) are connected by a connecting bolt (1 1) A threaded connection is formed and fixed with a connecting nut (12); an air outlet hole (93) is provided on the axis of the air outlet sealing cover (9), and the air outlet hole (93) is a through hole; a connecting boss (94) is arranged on the air outlet sealing cover (9), which extends in the opposite direction of air flow to be inserted into the air outlet fixing body (625) and the air outlet side flange (628); a fixing bolt thread hole (92) is provided inside the connecting boss (94), and the fixing bolt thread hole (92) is a blind hole, which extends from the outer end of the air outlet sealing cover (9) in the opposite direction of air flow.

4. The marine low-speed engine constant-volume combustion bomb flow heating system according to claim 1, characterized in that... An air outlet pipe (10) is arranged outside the air outlet sealing cover (9); a sealing flange (1001) is arranged at the air inlet end of the air outlet pipe (10) and several fixing bolt thread holes (1002) are opened, and the fixing bolt thread holes (1002) are through holes; the fixing bolts (13) are screwed into the fixing bolt thread holes (92) provided in the connecting boss (94) through the sealing flange (1001), and there are washers to reduce wear; the air outlet pipe (1003) is an air outlet channel on the axis of the air outlet pipe (10).

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