Constant volume apparatus and method for simulating turbulent direct injection combustion

Abstract

The present application relates to the technical field of engine test, in particular to a constant volume device and method for simulating turbulent direct injection combustion, which comprises a combustion tank, four sound wave excitation devices and a support fixed on the top of the combustion tank, wherein a reciprocating mechanism is arranged on the support, a reciprocating frame capable of moving up and down is connected to the reciprocating mechanism, the reciprocating stroke of the reciprocating frame is adjustable, a driving gear ring and a revolute frame are coaxially arranged on the reciprocating frame, four nozzle modules are arranged on the revolute frame, each nozzle module comprises a jet nozzle, two toothed tracks and a rotating seat rotatably connected to the revolute frame, two hinged shafts are fixed on the jet nozzle, and the two hinged shafts are hingedly connected to the rotating seat.The present application has the beneficial effect of solving the problem that the single turbulent flow generation method in the prior art cannot simulate the extremely complex, transient and multi-physical field coupled turbulent flow environment in the real engine cylinder with high fidelity.

Description

Technical Field

[0001] This invention relates to the field of engine testing technology, specifically to a constant-volume device and method for simulating turbulent direct injection combustion. Background Technology

[0002] In order to conduct controllable and repeatable basic research on combustion in a laboratory environment, constant volume combustion devices have become the core experimental platform for simulating the flow and combustion process in an engine cylinder. Among them, generating a turbulent field with controllable intensity, isotropic properties, and capable of simulating the complex structure inside a real engine cylinder within a constant volume bomb is the core objective pursued by such devices. Existing technologies can be mainly divided into two categories: one is to directly generate turbulence by mechanical or pneumatic means. For example, patent document CN113702051B discloses a constant volume device for simulating turbulent direct injection combustion. It uses a dual-output shaft motor to drive two sets of symmetrical piston-type air pumping devices, and generates opposing jets through a balanced flow divider, which collide at the center of the burner to form an isotropic turbulent field. Another type of technology attempts to introduce new physical fields to regulate the flow. For example, prior art document 2CN120194940A discloses a constant volume combustion device that simulates eddy and tumble motion. It innovatively adopts an electromagnetic drive mechanism to generate circumferential eddies or vertical tumbles non-contactly by applying a rotating magnetic field or gradient magnetic field to the magnetohydrodynamic particles. In summary, existing technologies suffer from a fundamental technical problem: Single turbulence generation and control methods cannot integrate and achieve coordinated and coupled control of multiple physical fields and multi-scale parameters such as mechanical kinetic energy drive, acoustic spectrum modulation, electromagnetic field intervention, and dynamic changes in combustion chamber geometry on a single experimental platform. Therefore, they cannot reconstruct and simulate the extremely complex transient and multi-physical field coupled turbulence environment faced by real engine direct injection combustion with high fidelity. Based on this, the present invention provides a constant volume apparatus and method for simulating turbulent direct injection combustion to solve the problems mentioned in the background art. Summary of the Invention

[0003] This invention addresses the technical problems existing in the prior art by providing a constant-volume device and method for simulating turbulent direct injection combustion. This solves the problem that existing devices cannot reconstruct and simulate the extremely complex transient, multi-physics coupled turbulent environment faced by real engine direct injection combustion with high fidelity.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a constant volume device for simulating turbulent direct injection combustion, comprising a combustion tank; It also includes four acoustic excitation devices; The bracket is fixed on the top of the combustion tank and has a reciprocating mechanism. The reciprocating mechanism is connected to a reciprocating frame that can move up and down. The reciprocating stroke of the reciprocating frame is adjustable. The reciprocating frame has a coaxially rotating active gear ring and a revolution frame. The revolution frame has four nozzle modules. The nozzle module includes a jet nozzle, two gear rails, and a rotating seat rotatably connected to a revolution frame. Two hinge shafts are fixedly mounted on the jet nozzle, and both hinge shafts are hinged to the rotating seat. A torsion spring is provided at the hinge point between one hinge shaft and the rotating seat, and a reciprocating bevel gear is fixedly mounted on the other hinge shaft. Both gear rails are fixedly connected to the revolution frame, and the two gear rails are respectively located on the upper and lower sides of the reciprocating bevel gear. Each gear rail has an alternating array of bevel tooth sections and toothless sections. The bevel tooth sections mesh with the reciprocating bevel gear. A driven gear that meshes with the driving gear ring is fixedly mounted on the rotating seat. A multi-channel gas supply mechanism connected to the jet nozzle; A magnetic tube is fixedly mounted on a combustion tank, and an array of magnetic field generating devices are arranged on the magnetic tube. Four deformable wall units are arrayed and installed inside the combustion tank. Deformation drive mechanism, which drives the deformation of deformable wall unit; Monitoring unit for monitoring the interior cavity of the combustion tank; The fan shaft is rotatably connected to the bracket, and the fan shaft is equipped with an array of flow-equalizing fan blades.

[0005] As a preferred technical solution of the present invention, the combustion tank has a spherical combustion chamber inside, and a fuel injection device and an ignition device are fixedly installed at the bottom of the spherical combustion chamber. The spherical combustion chamber is connected to four flange connection ports, and the four acoustic excitation devices are respectively mounted on the four flange connection ports.

[0006] As a preferred technical solution of the present invention, the monitoring unit includes a high-speed camera, a temperature probe, and an anemometer fixed on the combustion tank. The monitoring ends of the high-speed camera, the temperature probe, and the anemometer all extend to the spherical combustion chamber. A main controller is fixed on the bracket, and the data ends of the high-speed camera, the temperature probe, and the anemometer are all connected to the main controller.

[0007] As a preferred technical solution of the present invention, two variable frequency motors are fixedly installed on the bracket, and a hollow sleeve shaft is rotatably connected to the bracket. Two synchronous belts are driven to the output shaft of the variable frequency motors. One synchronous belt is driven to the hollow sleeve shaft, and the other synchronous belt is driven to the fan shaft. A driven shaft is fixedly installed on the revolving frame. The driven shaft is provided with a square transmission section. A transmission groove with open ends and slidably connected to the square transmission section is opened on the hollow sleeve shaft. A transmission gear shaft is rotatably sleeved on the driven shaft. The driving gear ring is fixedly installed on the transmission gear shaft. A first bevel gear is fixedly installed on both the transmission gear shaft and the driven shaft. A synchronous shaft is rotatably connected to the reciprocating frame. A synchronous bevel gear is installed on the synchronous shaft. Both first bevel gears are meshed with the synchronous bevel gear. The cross-section of the transmission groove and the square transmission section is a regular hexagon. The two first bevel gears are symmetrically arranged about the horizontal plane where the axis of the synchronous bevel gear is located. Encoders are integrated in both variable frequency motors. The data terminals of both encoders are connected to the main controller.

[0008] As a preferred embodiment of the present invention, the reciprocating mechanism includes a horizontal shaft rotatably connected to a support and a linear transmission module fixedly mounted on the support. A reciprocating adjustment frame is drivenly connected to the linear transmission module. The reciprocating adjustment frame is slidably connected to the support. A second bevel gear is installed on both the horizontal shaft and the hollow sleeve shaft. The two second bevel gears mesh orthogonally. A through shaft that is linked to the horizontal shaft is rotatably connected to the reciprocating adjustment frame. Four reciprocating toothed gears arranged in an array are fixedly installed on the through shaft. A rack plate is fixedly installed on the reciprocating frame. The driving strokes of the four reciprocating toothed gears on the rack plate are different. Two elastic reset members are installed between the reciprocating frame and the support. A limit spring is fixedly installed on the bottom surface of the reciprocating frame. The other end of the limit spring is fixedly connected to the combustion tank.

[0009] As a preferred technical solution of the present invention, the through shaft is provided with a through groove that is open at both ends and slidably connected to the horizontal shaft. The cross-section of the through groove and the through shaft is a regular hexagon. Each of the four reciprocating toothed gears is provided with a sector tooth segment. The starting point of the teeth of the four sector tooth segments is the same, and the number of teeth of the four sector tooth segments is different.

[0010] As a preferred technical solution of the present invention, the multi-channel gas supply mechanism is fixedly mounted on the combustion tank with an airflow equalizer. The airflow equalizer is connected to an air inlet connector. A gas distribution ring pipe is fixedly mounted on the top of the combustion tank. Three air inlet manifolds are connected between the airflow equalizer and the gas distribution ring pipe. Each air inlet manifold is equipped with an airflow regulating valve. A driven valve ring is rotatably connected to the inner wall of the gas distribution ring pipe. Four metal corrugated hoses are fixedly mounted on the driven valve ring. The four metal corrugated hoses are respectively connected to four jet nozzles.

[0011] As a preferred technical solution of the present invention, the deformable wall unit comprises layers stacked sequentially from the outside to the inside: Active deformation layer, which is an elastic metal sheet; The fluid-driven layer has a microchannel network inside; A rigid backplate is fixed to the combustion tank.

[0012] As a preferred technical solution of the present invention, the deformation driving mechanism includes a fluid distribution pipe, a fluid connector is fixedly connected to the fluid distribution pipe, and four distribution connectors are connected to the fluid distribution pipe. The four distribution connectors are respectively connected to the fluid driving layer in the four deformable wall units, and a distribution valve is installed in each of the four distribution connectors.

[0013] As a preferred technical solution of the present invention, the simulated turbulent direct injection combustion method includes the following steps: S1. Construct the initial turbulent field, start the multi-channel gas supply mechanism, distribute the gas to multiple jet nozzles through the airflow equalizer and the independently adjustable intake manifold, and start at least two independently controlled drive devices to drive all jet nozzles to revolve synchronously, and drive the flow equalization fan blades to rotate downstream of the jet nozzle outlet. S2. Dynamic modulation of the flow field controls the jet nozzles to oscillate periodically around their own axis while they are revolving, so that the jet direction changes continuously. The acoustic excitation device is activated to emit acoustic waves of a specific frequency and phase into the spherical combustion chamber; Start the magnetic field generator to apply a controllable magnetic field inside the spherical combustion chamber; The deformation drive mechanism is activated to inject drive fluid into the deformable wall unit of the spherical combustion chamber wall, causing the wall to deform in a controllable manner, dynamically changing the volume of the spherical combustion chamber and inducing secondary flow; S3. Fuel injection and ignition: When the monitoring unit confirms that the flow field in the spherical combustion chamber has reached the preset conditions, the fuel injection device is controlled to inject fuel into the flow field, and the ignition device is started at the preset time or under the flow field conditions to ignite the fuel. S4. Data Acquisition and Analysis: The monitoring unit synchronously acquires flame images, temperature field, and velocity field data during the combustion process and feeds the data back to the main controller for analysis in real time.

[0014] The beneficial effects of this invention are:

[0015] 1. This invention achieves deep integration and coordinated control of mechanical kinetic energy drive, acoustic spectrum modulation, electromagnetic field intervention, and dynamic geometric changes in the combustion chamber on an experimental platform. It solves the problem that existing single turbulence generation methods cannot accurately simulate the extremely complex, transient multi-physics coupled turbulent environment inside a real engine cylinder. By integrating a jet nozzle composite motion mechanism, an acoustic excitation device, an array magnetic field generator, and deformable wall units, this device can simultaneously apply multiple physical actions such as mechanical shearing, acoustic excitation, electromagnetic guidance, and volume disturbance. This allows for the reconstruction of a realistic turbulent structure with highly spatiotemporal dynamic characteristics and anisotropic adjustability within a constant-volume combustion chamber, significantly improving the fidelity of the simulation and the controllability of the experiment.

[0016] 2. This invention achieves multi-scale, cross-dimensional synergistic modulation of the turbulent field from macroscopic to microscopic levels through the linkage and coordination among multiple subsystems. Specifically, the jet nozzle completes periodic self-oscillation motion while revolving, forming an unsteady shear jet. The acoustic module intervenes with specific frequencies and phases to selectively excite or suppress turbulent vortices. The magnetic field generator applies Lorentz force to the ionized medium, guiding the evolution of the flow structure. The deformable wall unit dynamically changes the wall morphology and combustion chamber volume by injecting high-temperature fluid, inducing secondary flow. These methods are not simply superimposed, but are coupled and reinforced under unified control, producing a synergistic effect of "1+1>2". Thus, in experiments, multiple parameters such as turbulence intensity, energy spectrum distribution, and flow field structure are independently or jointly adjustable, providing an unprecedented experimental platform for studying multi-physics coupling mechanisms.

[0017] 3. By integrating monitoring units such as high-speed cameras, temperature probes, and wind speed and direction meters, and linking them with the main controller in real time, the system can dynamically sense the flow field state and adaptively adjust various physical field parameters, forming a closed-loop experimental mode for the entire process of monitoring, control, combustion, and feedback. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the constant volume device for simulating turbulent direct injection combustion according to the present invention. Figure 2 For the present invention Figure 1 A magnified schematic diagram of the partial structure at point A in the middle; Figure 3 For the present invention Figure 1 A structural diagram from another perspective; Figure 4 For the present invention Figure 3 A magnified schematic diagram of the local structure at point B; Figure 5 For the present invention Figure 4 A schematic diagram of the cross-sectional structure; Figure 6 For the present invention Figure 5A magnified schematic diagram of the local structure at point C; Figure 7 For the present invention Figure 5 A magnified schematic diagram of the local structure at point D; Figure 8 This is a schematic diagram of the fan shaft and flow equalization fan blades of the present invention; Figure 9 This is a schematic diagram of the toothed track and the orbiter of the present invention; Figure 10 This is a schematic diagram of the jet nozzle structure of the present invention.

[0019] The attached diagram lists the components represented by each number as follows: 1. Combustion tank; 2. Acoustic excitation device; 3. Support frame; 4. Reciprocating frame; 5. Driving gear ring; 6. Revolution frame; 7. Jet nozzle; 8. Gear rail; 9. Rotary seat; 10. Hinge shaft; 11. Torsion spring; 12. Bevel gear section; 13. Driven gear; 14. Magnetic guide cylinder; 15. Magnetic field generator; 16. Deformable wall unit; 17. Fan shaft; 18. Flow equalization fan blade; 19. Spherical combustion chamber; 20. Fuel injection device; 21. Ignition device; 22. Flange connection port; 23. High-speed camera; 24. Temperature... 25. Probe; 26. Anemometer; 27. Main controller; 28. Variable frequency motor; 29. ​​Hollow sleeve shaft; 30. Driven rotating shaft; 31. Transmission gear shaft; 32. Horizontal shaft; 33. Linear transmission module; 34. Reciprocating adjustment frame; 35. Through shaft; 36. Reciprocating toothed gear; 37. Rack plate; 38. Elastic reset component; 39. Limit spring; 40. Air distribution ring pipe; 41. Intake manifold; 42. Driven valve ring; 43. Metal corrugated hose; 44. Fluid distribution pipe; 45. Synchronous shaft. Detailed Implementation

[0020] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] The present invention provides the following preferred embodiments: like Figures 1-10 As shown, the constant volume device for simulating turbulent direct injection combustion includes a combustion tank 1; The combustion tank 1 has a spherical combustion chamber 19 inside. A fuel injection device 20 and an ignition device 21 are fixedly installed at the bottom of the spherical combustion chamber 19. Four flange connection ports 22 are connected to the spherical combustion chamber 19. It also includes four acoustic excitation devices 2, which are respectively mounted on four flange connection ports 22; The axes of the four flange connection ports 22 all intersect with the center of the spherical combustion chamber 19, and the sound-emitting end of the acoustic excitation device 2 extends into the interior of the spherical combustion chamber 19, with a distance of not less than 10mm from the wall of the spherical combustion chamber 19. Four acoustic excitation devices 2 are installed around the spherical combustion chamber 19, which can emit acoustic waves of specific frequencies and phases; These sound waves are coupled with the airflow field inside the spherical combustion chamber 19, which can excite or suppress oscillations at specific frequencies, and can be used to study combustion instability, knocking tendency, or to achieve ultra-uniform mixing through active acoustic control. The introduction of sound waves makes the frequency characteristics of the turbulent field tunable, enhances the spatiotemporal controllability of the flow, and provides experimental means for studying the coupling mechanism between acoustic flow and combustion. The acoustic excitation device 2 can emit acoustic waves at a specific frequency and phase without contacting the flow field. This non-contact excitation method avoids the flow field disturbance and energy loss caused by structural intervention in traditional mechanical or pneumatic turbulence generators. By adjusting the frequency, amplitude and phase of the acoustic waves, it is possible to selectively excite or suppress specific vortex scales, thereby controlling the turbulence energy spectrum distribution. At the same time, this excitation method achieves the synergistic effect of acoustic resonance and flow shear layer, promoting the micro-mixing of fuel and oxidant, and achieving an ultra-uniform mixing state that is difficult to achieve with traditional mechanical mixing.

[0022] The bracket 3 is fixed on the top of the combustion tank 1 and is equipped with a reciprocating mechanism. The reciprocating mechanism is connected to a reciprocating frame 4 that can move up and down. The reciprocating stroke of the reciprocating frame 4 is adjustable. The reciprocating frame 4 is equipped with a coaxially rotating active gear ring 5 and a revolution frame 6. A monitoring unit is used for monitoring the interior cavity of combustion tank 1; The monitoring unit includes a high-speed camera 23, a temperature probe 24, and an anemometer 25 fixed on the combustion tank 1. The monitoring ends of the high-speed camera 23, the temperature probe 24, and the anemometer 25 all extend to the spherical combustion chamber 19. The main controller 26 is fixed on the bracket 3. The data ends of the high-speed camera 23, the temperature probe 24, and the anemometer 25 are all connected to the main controller 26.

[0023] The high-speed camera 23 can capture dynamic images of flame propagation and flow field structure; The temperature probe monitors the combustion temperature distribution in real time. The anemometer and wind direction meter measure local flow velocity and direction. The three work together to achieve synchronous measurement of multiple physical quantities in the entire field of transient combustion process, overcoming the defects of time asynchrony and spatial mismatch in traditional single-point or sequential measurement. By combining image processing and sensor data fusion, the spatiotemporal evolution of three-dimensional temperature field, velocity field and flame surface morphology can be reconstructed, providing high-confidence experimental data for mechanism modeling of turbulent combustion. Through real-time feedback from the main controller 26, the experimental conditions can be adaptively adjusted, forming a closed-loop experimental process of monitoring, control, and optimization, which significantly improves the intelligence level and data reliability of the experiment.

[0024] Two variable frequency motors 27 are fixedly installed on bracket 3. Each variable frequency motor 27 has an integrated encoder. The data terminals of the two encoders are connected to the main controller 26. A hollow sleeve shaft 28 is rotatably connected to the bracket 3. Two synchronous belts are driven to the output shaft of the variable frequency motor 27, and one synchronous belt is driven to the hollow sleeve shaft 28. A driven shaft 29 is fixedly mounted on the orbital frame 6. A square transmission section is provided on the driven shaft 29. A transmission groove with open ends and slidably connected to the square transmission section is provided on the hollow sleeve shaft 28. The cross-sections of the transmission groove and the square transmission section are both regular hexagonal. A transmission gear shaft 30 is rotatably mounted on the driven shaft 29. The driving gear ring 5 is fixedly mounted on the transmission gear shaft 30. First bevel gears are fixedly mounted on both the transmission gear shaft 30 and the driven shaft 29. A synchronous shaft 45 is rotatably connected to the reciprocating frame 4. A synchronous bevel gear is mounted on the synchronous shaft 45. Both first bevel gears are meshed with the synchronous bevel gears. The two first bevel gears are symmetrically arranged about the horizontal plane where the axis of the synchronous bevel gear is located.

[0025] The reciprocating mechanism includes a horizontal shaft 31 rotatably connected to the support 3 and a linear transmission module 32 fixedly mounted on the support 3. A reciprocating adjustment frame 33 is connected to the linear transmission module 32 and is slidably connected to the support 3. A second bevel gear is installed on both the horizontal shaft 31 and the hollow sleeve shaft 28. The two second bevel gears mesh orthogonally. A through shaft 34 that is linked to the horizontal shaft 31 is rotatably connected to the reciprocating adjustment frame 33. Four reciprocating toothed gears 35 arranged in an array are fixedly installed on the through shaft 34. A rack plate 36 is fixedly installed on the reciprocating frame 4. The driving strokes of the four reciprocating toothed gears 35 on the rack plate 36 are different. Two elastic reset members 37 are installed between the reciprocating frame 4 and the support 3. A limit spring 38 is fixedly installed on the bottom surface of the reciprocating frame 4. The other end of the limit spring 38 is fixedly connected to the combustion tank 1.

[0026] The through shaft 34 has a through groove with openings at both ends and sliding connection with the horizontal shaft 31. The cross-section of the through groove and the through shaft 34 is a regular hexagon. Each of the four reciprocating toothed gears 35 is provided with a sector tooth segment. The starting point of the teeth of the four sector tooth segments is the same, and the number of teeth of the four sector tooth segments is different.

[0027] In a preferred embodiment, the number of teeth corresponding to the four sector segments are 2 teeth, 4 teeth, 6 teeth and 8 teeth respectively, and the arc angle corresponding to the 8 teeth is 130°; Two variable frequency motors 27 drive the hollow sleeve shaft 28 and the fan shaft 17 respectively, realizing the revolution of the jet nozzle 7 system and the independent speed regulation of the flow equalization fan blade 18.

[0028] The transmission system adopts a bevel driven gear 13 and a synchronous shaft 45 to ensure the controllable synchronous and reverse motion of the driving gear ring 5 and the revolving frame 6. The reciprocating mechanism achieves multi-stroke adjustable reciprocating motion of the reciprocating frame 4 through the cooperation of the toothed driven gear 13 and the rack plate 36. This design enables the jet nozzle 7 to achieve complex trajectory motion in three-dimensional space. Combined with the flow equalization fan blade 18, it can form an unsteady, multi-scale turbulent structure in the spherical combustion chamber 19, which greatly enhances the spatial complexity and temporal dynamics of the turbulence. The orbiter 6 is equipped with four nozzle modules; The nozzle module includes a jet nozzle 7, two toothed rails 8, and a rotating seat 9 rotatably connected to the orbital frame 6. Two hinge shafts 10 are fixedly mounted on the jet nozzle 7, and both hinge shafts 10 are hinged to the rotating seat 9. A torsion spring 11 is provided at the hinge point between one hinge shaft 10 and the rotating seat 9, and a reciprocating bevel gear is fixedly mounted on the other hinge shaft 10. Both toothed rails 8 are fixedly connected to the orbital frame 6. The two toothed rails 8 are respectively located on the upper and lower sides of the reciprocating bevel gear. Each toothed rail 8 is alternately arrayed with a bevel tooth section 12 and a toothless section. The bevel tooth section 12 meshes with the reciprocating bevel gear. A driven gear 13 that meshes with the driving gear ring 5 is fixedly mounted on the rotating seat 9. Each bevel tooth segment 12 corresponds to a central angle of 30°. There are four bevel tooth segments 12 installed on the toothed rail 8, and the number of toothless segments is also four. In a preferred embodiment, the bevel tooth segments 12 on the two toothed rails 8 are offset by 45°. The bevel tooth section 12 on the upper toothed rail 8 is used to drive the jet nozzle 7 to swing forward 15°. The bevel tooth section 12 on the lower toothed rail 8 is used to drive the jet nozzle 7 to swing in the opposite direction by 15°, and the torsion spring 11 is used to drive the jet nozzle 7 to automatically reset. The nozzle module meshes with the reciprocating bevel gear through the bevel tooth section 12 on the upper and lower toothed rails 8, driving the jet nozzle 7 to swing forward and backward 15° under the action of the torsion spring 11. The toothed section 12 and the toothless section are arranged alternately on the toothed rail 8, and the two toothed rails 8 are misaligned by 45°, so that the jet nozzle 7 can oscillate periodically while revolving. This combined motion of revolution and oscillation causes the airflow jet direction to change continuously, forming strong shear and vortex, which significantly improves turbulence intensity and spatial coverage, simulating the interaction process of unsteady jet and turbulence in the cylinder of a real engine. A multi-channel gas supply mechanism is connected to the jet nozzle 7; A multi-channel gas supply mechanism is fixedly mounted on the combustion tank 1 by an airflow equalizer 39. An airflow equalizer 39 is connected to an air inlet connector. A gas distribution ring pipe 40 is fixedly mounted on the top of the combustion tank 1. Three air inlet manifolds 41 are connected between the airflow equalizer 39 and the gas distribution ring pipe 40. Each air inlet manifold 41 is equipped with an airflow regulating valve. A driven valve ring 42 is rotatably connected to the inner wall of the gas distribution ring pipe 40. Four metal corrugated hoses 43 are fixedly mounted on the driven valve ring 42. The four metal corrugated hoses 43 are respectively connected to four jet nozzles 7.

[0029] The multi-channel gas supply mechanism supplies gas to the gas distribution ring pipe 40 through the airflow equalizer 39 and three intake manifolds 41 with regulating valves, and then delivers it to the four jet nozzles 7 through the metal corrugated hose 43. The airflow equalizer 39 can evenly distribute the airflow and reduce pressure pulsation; The regulating valve enables independent flow control in each branch; This structure ensures the synchronization and adjustability of the airflow in the multi-jet nozzle 7, supports the construction of symmetrical or asymmetrical jet modes, and provides flexible aerodynamic conditions for studying multi-jet interference, collision and fusion. The fan shaft 17 is rotatably connected to the bracket 3, and another synchronous belt is connected to the fan shaft 17 for transmission. The fan shaft 17 is provided with an array of flow equalization fan blades 18.

[0030] The flow equalization fan blade 18 is located below the air outlet of the jet nozzle 7; The fan shaft 17 is located below the outlet of the jet nozzle 7, and its flow equalizing fan blades 18 are driven by an independent motor, which can generate an auxiliary flow field; The rotation of the flow equalization fan blade 18 can shear and guide the jet of the jet nozzle 7, enhance flow mixing, suppress local dead zones, and can work together with the oscillation of the jet nozzle 7 and the acoustic field to construct a composite turbulent structure. This design improves the uniformity and controllability of the flow field, and is especially suitable for simulating combustion processes under high eddy ratio or strong tumble conditions. A magnetic tube 14 is fixedly mounted on a combustion tank 1, and a magnetic field generating device 15 is arranged in an array on the magnetic tube 14. The magnetic cylinder 14 is arranged around the combustion tank 1, and the array magnetic field generator 15 on it can generate a magnetic field with controllable intensity and direction. When ionized gas or magnetic particles are present in the spherical combustion chamber 19, the magnetic field can exert a Lorentz force on them, affecting the flow structure and turbulence evolution. The multi-field coupling of magnetic field with mechanical flow and acoustic field can simulate the turbulent combustion environment under electromagnetic-assisted combustion or magnetohydrodynamic control, thus expanding the research dimensions of combustion control. Four deformable wall units 16 are arrayed and installed in the inner cavity of the combustion tank 1; The deformable wall unit 16 includes the following components stacked sequentially from the outside to the inside: Active deformation layer, which is an elastic metal sheet; The fluid-driven layer has a microchannel network inside; A rigid backplate is fixed to the combustion tank 1.

[0031] The deformation drive mechanism includes a fluid distribution pipe 44, on which a fluid connector is fixedly connected. Four distribution connectors are connected to the fluid distribution pipe 44, and the four distribution connectors are respectively connected to the fluid drive layer in the four deformable wall unit 16. Each of the four distribution connectors is equipped with a distribution valve.

[0032] Fluid connectors are used to access high-temperature liquid metal; The deformable wall unit 16 consists of an elastic metal sheet, a fluid drive layer with an embedded microchannel network, and a rigid backplate. By injecting high-temperature liquid metal into the fluid-driven layer, the deformation plate can be controlled to undergo local or overall deformation, thereby dynamically changing the shape and volume of the spherical combustion chamber 19 wall. Wall deformation can induce boundary layer separation, generate secondary flow, or change the turbulence scale, enabling real-time coupled control of the geometry and flow characteristics of the spherical combustion chamber 19.

[0033] The simulated turbulent direct injection combustion method includes the following steps: S1. Construct an initial turbulent field, start the multi-channel gas supply mechanism, distribute the gas to multiple jet nozzles 7 through the airflow equalizer 39 and the independently adjustable intake manifold 41, and simultaneously start at least two independently controlled drive devices to drive all jet nozzles 7 to revolve synchronously, and drive the flow equalization fan blades 18 to rotate downstream of the jet nozzle 7 outlet. S2. Dynamic modulation of the flow field controls the jet nozzle 7 to oscillate periodically around its own axis while it is revolving, so that the jet direction changes continuously. The acoustic excitation device 2 is activated to emit acoustic waves of a specific frequency and phase into the spherical combustion chamber 19; Start the magnetic field generator 15 to apply a controllable magnetic field inside the spherical combustion chamber 19; The deformation drive mechanism is activated to inject drive fluid into the deformable wall unit 16 of the spherical combustion chamber 19, causing the wall to deform in a controllable manner, dynamically changing the volume of the spherical combustion chamber 19 and inducing secondary flow. S3. Fuel injection and ignition: When the monitoring unit confirms that the flow field in the spherical combustion chamber 19 has reached the preset conditions, the fuel injection device 20 is controlled to inject fuel into the flow field, and the ignition device 21 is started to ignite at a preset time or under the flow field conditions. S4. Data Acquisition and Analysis: The monitoring unit synchronously acquires flame images, temperature field and velocity field data during the combustion process, and feeds the data back to the main controller 26 for analysis in real time.

[0034] The specific steps for using this invention are as follows: At the start of the experiment, the multi-channel gas supply mechanism delivers gas to the four jet nozzles 7 via the metal corrugated hose 43 through the airflow equalizer 39 and the adjustable intake manifold 41. Meanwhile, the two variable frequency motors 27 drive the orbiter 6 to rotate the nozzle module through the synchronous belt and bevel driven gear 13 transmission system, and drive the fan shaft 17 to rotate the flow equalization fan blade 18, thereby establishing a basic turbulent field in the spherical combustion chamber 19 composed of the superposition of rotating jet and auxiliary shear flow. Based on this, the nozzle module itself achieves periodic forward and reverse oscillation through the meshing of the upper and lower staggered toothed rails 8 and the reciprocating bevel gear, under the reset action of the torsion spring 11, so that the jet direction changes continuously, further enhancing the shear and vortex intensity of the flow field. Subsequently, the acoustic excitation device 2 emits acoustic waves of a specific frequency and phase from around the cavity, which are coupled with the flow field to modulate the turbulence spectrum. The array-type magnetic field generator 15 on the magnetic tube 14 can apply a controllable magnetic field to generate Lorentz force on ionized components or magnetic particles, guiding the flow structure. The deformation drive mechanism injects high-temperature liquid metal into the microchannel network of the deformable wall unit 16, driving the elastic thin plate of the wall to undergo controllable deformation, dynamically changing the geometry and volume of the spherical combustion chamber 19, inducing secondary flow and changing the turbulence scale. When the preset flow field conditions are met, the fuel injection device 20 and the ignition device 21 operate under the command of the timing controller to achieve direct injection and ignition. Throughout the combustion process, the high-speed camera 23, temperature probe 24, and anemometer 25 of the monitoring unit simultaneously collect data on flame morphology, temperature field, and velocity field, and feed this data back to the main controller 26 in real time. This forms a closed-loop control system that integrates flow field construction, multi-field intervention, combustion triggering, and data acquisition, thereby simulating the complex turbulent direct injection combustion environment of a real engine cylinder with high fidelity, characterized by unsteady conditions, multi-scale, and multi-physical field coupling.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A constant-volume device for simulating turbulent direct injection combustion, comprising a combustion tank (1), characterized in that: It also includes four acoustic excitation devices (2); The bracket (3) is fixed on the top of the combustion tank (1) and is provided with a reciprocating mechanism. The reciprocating mechanism is connected with a reciprocating frame (4) that can move up and down. The reciprocating stroke of the reciprocating frame (4) is adjustable. The reciprocating frame (4) is provided with a coaxially rotating active gear ring (5) and a revolution frame (6). The revolution frame (6) is provided with four nozzle modules. The nozzle module includes a jet nozzle (7), two toothed rails (8), and a rotating seat (9) rotatably connected to a revolution frame (6). Two hinge shafts (10) are fixedly mounted on the jet nozzle (7). Both hinge shafts (10) are hinged to the rotating seat (9). A torsion spring (11) is provided at the hinge point between one hinge shaft (10) and the rotating seat (9). A reciprocating bevel gear is fixedly mounted on the other hinge shaft (10). Both toothed rails (8) are fixedly connected to the revolution frame (6). The two toothed rails (8) are respectively set on the upper and lower sides of the reciprocating bevel gear. Each toothed rail (8) is alternately arrayed with a bevel tooth section (12) and a toothless section. The bevel tooth section (12) meshes with the reciprocating bevel gear. A driven gear (13) that meshes with the driving gear ring (5) is fixedly mounted on the rotating seat (9). A multi-channel gas supply mechanism is connected to the jet nozzle (7); A magnetic tube (14) is fixed on a combustion tank (1), and a magnetic field generating device (15) is arranged in an array on the magnetic tube (14). Four deformable wall units (16) are arrayed and installed in the inner cavity of the combustion tank (1); Deformation drive mechanism drives the deformable wall unit (16) to deform; A monitoring unit is used for monitoring the interior cavity of the combustion tank (1); The fan shaft (17) is rotatably connected to the bracket (3), and the fan shaft (17) is provided with an array of flow equalization fan blades (18).

2. The constant-volume device for simulating turbulent direct injection combustion according to claim 1, characterized in that, The combustion tank (1) has a spherical combustion chamber (19) inside. A fuel injection device (20) and an ignition device (21) are fixedly installed at the bottom of the spherical combustion chamber (19). Four flange connection ports (22) are connected to the spherical combustion chamber (19). The four acoustic excitation devices (2) are respectively mounted on the four flange connection ports (22).

3. The constant-volume device for simulating turbulent direct injection combustion according to claim 1, characterized in that, The monitoring unit includes a high-speed camera (23), a temperature probe (24), and an anemometer (25) fixed on the combustion tank (1). The monitoring ends of the high-speed camera (23), the temperature probe (24), and the anemometer (25) all extend to the spherical combustion chamber (19). A main controller (26) is fixed on the bracket (3). The data ends of the high-speed camera (23), the temperature probe (24), and the anemometer (25) are all connected to the main controller (26).

4. The constant-volume device for simulating turbulent direct injection combustion according to claim 1, characterized in that, Two variable frequency motors (27) are fixedly installed on the bracket (3). A hollow sleeve shaft (28) is rotatably connected to the bracket (3). Two synchronous belts are driven to the output shaft of the variable frequency motor (27). One synchronous belt is driven to the hollow sleeve shaft (28), and the other synchronous belt is driven to the fan shaft (17). A driven shaft (29) is fixedly installed on the revolution frame (6). A square transmission section is provided on the driven shaft (29). A transmission square groove with open ends and slidably connected to the square transmission section is opened on the hollow sleeve shaft (28). A transmission gear shaft (30) is rotatably sleeved on the driven shaft (29). The active gear ring (5) is fixed on the transmission gear shaft (30). The first bevel gear is fixedly installed on both the transmission gear shaft (30) and the driven shaft (29). The reciprocating frame (4) is rotatably connected to the synchronous shaft (45). The synchronous shaft (45) is equipped with a synchronous bevel gear. Both first bevel gears are meshed with the synchronous bevel gear. The cross-sections of the transmission square groove and the square transmission section are both regular hexagons. The two first bevel gears are symmetrically arranged with the horizontal plane where the axis of the synchronous bevel gear is located as the axis. Both variable frequency motors (27) have integrated encoders. The data terminals of both encoders are connected to the main controller (26).

5. The constant-volume device for simulating turbulent direct injection combustion according to claim 4, characterized in that, The reciprocating mechanism includes a horizontal shaft (31) rotatably connected to a bracket (3) and a linear transmission module (32) fixedly mounted on the bracket (3). A reciprocating adjustment frame (33) is drivenly connected to the linear transmission module (32). The reciprocating adjustment frame (33) is slidably connected to the bracket (3). A second bevel gear is installed on both the horizontal shaft (31) and the hollow sleeve shaft (28). The two second bevel gears mesh orthogonally. A through shaft (28) that is linked to the horizontal shaft (31) is rotatably connected to the reciprocating adjustment frame (33). 34), four reciprocating toothed gears (35) arranged in an array are fixedly installed on the through shaft (34), and a rack plate (36) is fixedly installed on the reciprocating frame (4). The driving stroke of the four reciprocating toothed gears (35) on the rack plate (36) is different. Two elastic reset members (37) are installed between the reciprocating frame (4) and the bracket (3). A limit spring (38) is fixedly installed on the bottom surface of the reciprocating frame (4), and the other end of the limit spring (38) is fixedly connected to the combustion tank (1).

6. The constant-volume device for simulating turbulent direct injection combustion according to claim 5, characterized in that, The through shaft (34) has a through groove with openings at both ends and sliding connection with the horizontal shaft (31). The cross-section of the through groove and the through shaft (34) is a regular hexagon. Each of the four reciprocating toothed gears (35) is provided with a sector tooth segment. The starting point of the teeth of the four sector tooth segments is the same, and the number of teeth of the four sector tooth segments is different.

7. The constant-volume device for simulating turbulent direct injection combustion according to claim 1, characterized in that, The multi-channel gas supply mechanism is fixedly mounted on the airflow equalizer (39) of the combustion tank (1). The airflow equalizer (39) is connected to an air inlet connector. The top of the combustion tank (1) is fixedly mounted with a gas distribution ring pipe (40). Three air inlet manifolds (41) are connected between the airflow equalizer (39) and the gas distribution ring pipe (40). Each air inlet manifold (41) is equipped with an airflow regulating valve. The inner wall of the gas distribution ring pipe (40) is rotatably connected to a driven valve ring (42). Four metal corrugated hoses (43) are fixedly mounted on the driven valve ring (42). The four metal corrugated hoses (43) are respectively connected to four jet nozzles (7).

8. The constant-volume device for simulating turbulent direct injection combustion according to claim 1, characterized in that, The deformable wall unit (16) comprises layers stacked sequentially from the outside to the inside: Active deformation layer, which is an elastic metal sheet; The fluid-driven layer has a microchannel network inside; A rigid back plate is fixed to the combustion tank (1).

9. The constant-volume device for simulating turbulent direct injection combustion according to claim 8, characterized in that, The deformation driving mechanism includes a fluid distribution pipe (44), on which a fluid connector is fixedly connected. Four distribution connectors are connected to the fluid distribution pipe (44), and the four distribution connectors are respectively connected to the fluid driving layer in the four deformable wall units (16). Each of the four distribution connectors is equipped with a distribution valve.

10. A combustion method for a constant-volume combustion device simulating turbulent direct injection combustion as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Construct an initial turbulent field, start the multi-channel gas supply mechanism, distribute the gas to multiple jet nozzles (7) through the airflow equalizer (39) and the independently adjustable intake manifold (41), and start at least two independently controlled drive devices to drive all jet nozzles (7) to revolve synchronously, and drive the flow equalization fan blades (18) to rotate downstream of the jet nozzle (7) outlet. S2. Dynamic modulation of the flow field controls the jet nozzle (7) to oscillate periodically around its own axis while it is revolving, so that the jet direction changes continuously. Start the acoustic excitation device (2) to emit acoustic waves of a specific frequency and phase into the spherical combustion chamber (19); Start the magnetic field generator (15) and apply a controllable magnetic field in the spherical combustion chamber (19); The deformation drive mechanism is activated to inject drive fluid into the deformable wall unit (16) of the spherical combustion chamber (19) wall, so that the wall undergoes controllable deformation, dynamically changing the volume of the spherical combustion chamber (19) and inducing secondary flow; S3. Fuel injection and ignition: When the flow field in the spherical combustion chamber (19) is confirmed by the monitoring unit to meet the preset conditions, the fuel injection device (20) is controlled to inject fuel into the flow field, and the ignition device (21) is started at the preset time or under the flow field conditions to ignite. S4. Data acquisition and analysis: The monitoring unit synchronously acquires flame images, temperature field and velocity field data during the combustion process, and feeds the data back to the main controller (26) for analysis in real time.

Images