Experimental method and device for piston push-powder compression characteristics based on parallel light projection

Abstract

The application discloses a kind of experimental method and device based on parallel light projection of piston push powder compression characteristics, experimental method includes the following contents: optical assembly, piston push powder device and projection screen are arranged side by side;Piston push powder device has the shell and piston push rod assembly of high light transmittance, which is loaded with powder fuel;Parallel light is sent by optical assembly, parallel light passes through piston push powder device, and the powder fuel in piston push powder device and piston push rod assembly form projection on projection screen;Push piston rod assembly compresses powder fuel, according to the height change of projection, obtain the volume change and packing density change of powder fuel;Combined with the thrust data of piston rod assembly, obtain the compression characteristics of powder fuel in the process of piston pushing. It is used to study the response characteristics of powder fuel packing density under the action of piston pushing.

Description

Technical Field

[0001] This invention belongs to the field of powder engine technology, specifically relating to an experimental method and apparatus for analyzing the compression characteristics of piston-propelled powder based on parallel light projection. Background Technology

[0002] For powder fuel engine supply systems, existing research generally employs a piston-driven method to quantitatively supply powder fuel. This method also fills the space left by the output powder, ensuring a constant powder fuel density in the storage tank. However, in reality, to ensure good supply and fluidized transport performance of the powder fuel in the storage tank, it is typically stored in a relatively loose state. Therefore, when the piston drives the supply of powder fuel, the loose powder fuel in the tank will inevitably gradually compact under the piston's compression, deviating from its initial packing state. Since the powder fuel flow rate is usually designed based on the initial packing density, this process will cause the powder fuel flow rate to deviate from the design value during actual engine operation, which is detrimental to the precise control of engine thrust.

[0003] Research on the compressibility of powders mainly focuses on powder metallurgy and pharmaceutical preparation. There is no unified standard for determining powder compression curves; generally, the molding method is used. The molding method typically involves first loading the powder into a precision-sized mold, then slowly applying pressure to the powder within the mold using a punch on a materials testing machine. The pressure is directly measured using a pressure gauge. The density of the compressed powder briquettes is usually determined using a combination of in-mold and out-of-mold methods. The in-mold method utilizes a stress-strain curve plotting device on the materials testing machine, while the out-of-mold method involves measuring the density after the powder briquettes have been demolded using a drainage method. These methods use mechanical devices to apply pressure to the powder to obtain the compression curve, but this differs significantly from the force exerted by a piston on the powder fuel in a powder supply system. Firstly, in powder supply systems, the piston applies force only to one side of the powdered fuel, while in molding, it applies to both sides. Secondly, molding typically compresses the powder into a block-like solid, but in powder engines, it's necessary to avoid the piston compacting the powder. Thirdly, existing experimental setups lack visualization capabilities and cannot obtain the piston's influence on powder loading density or the changes in powder packing profile during delivery without interference. Therefore, existing experimental methods cannot meet the requirements.

[0004] Currently, there are no experimental methods or apparatus in the field of powder fuel engines to study the effects of piston pushing on changes in powder packing density and packing profile. However, the piston pushing process has a significant impact on the packing state of powder fuel in the powder fuel supply system, leading to unpredictable powder packing density in the tank and hindering precise control of the powder fuel engine's thrust. Therefore, there is an urgent need to establish an experimental method and apparatus to study the impact of piston pushing on the compression characteristics of powder fuel. Summary of the Invention

[0005] The purpose of this invention is to provide an experimental method and apparatus for studying the compression characteristics of powder fuel pushed by a piston based on parallel light projection, so as to study the density response characteristics of powder fuel under piston pushing action.

[0006] This invention employs the following technical solution: an experimental method for the compression characteristics of piston-driven powder based on parallel light projection, the experimental method including the following:

[0007] The optical components, piston-driven powder pusher, and projection screen are arranged side by side; the piston-driven powder pusher has a high-transmittance housing and piston pusher assembly, which contains powdered fuel.

[0008] Parallel light is emitted through optical components, and the parallel light passes through the piston-powder pushing device. The powdered fuel and piston pusher assembly inside the piston-powder pushing device form a projection on the projection screen.

[0009] The piston rod assembly is driven to compress powdered fuel. The volume change and packing density change of the powdered fuel are obtained based on the change in projection height. Combined with the thrust data of the piston rod assembly, the compression characteristics of the powdered fuel during piston pushing are obtained.

[0010] Furthermore, it includes optical components, a piston-driven powder-pushing device, and a projection screen arranged in parallel;

[0011] The piston-powder pushing device has a high-transmittance housing and a piston push rod assembly. The piston push rod assembly includes a piston, which together with the housing forms a chamber for placing powdered fuel. The side of the piston away from the chamber is connected to a motor guide rod that is connected to a motor through a thrust detection element. The motor is used to provide power for the piston to move and compress the fuel powder.

[0012] Furthermore, the thrust detection element includes a connecting block connected to the piston, which is connected to one end of the motor guide rod via a thrust sensor.

[0013] Furthermore, the housing includes removable upper and lower tubes.

[0014] Furthermore, the receiving screen is equipped with grid coordinate paper.

[0015] Furthermore, the optical components include a convex lens.

[0016] The beneficial effects of this invention are as follows: By utilizing parallel light projection, this invention enables non-contact measurement of changes in the powdered fuel loading height during piston pushing, avoiding interference with the piston pushing process and also preventing the influence of light refraction on reading the powdered fuel accumulation height. This invention can also study the influence of piston speed on powdered fuel loading density by adjusting the motor speed, can pre-compact the powdered fuel to study the influence of the degree of pre-compaction on the piston pushing process, and can perform layered loading of various powdered fuels to study the influence of the layered loading method on the piston pushing process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the experimental apparatus for the piston-pushed powder compression characteristics based on parallel light projection according to the present invention.

[0018] Figure 2 This is a graph showing the motor thrust data at different piston speeds in the embodiment;

[0019] Figure 3 The diagram shows the powder fuel compression ratio at different piston speeds in the embodiment.

[0020] Among them, 1. point light source, 2. convex lens, 3. connecting rod, 4. upper tube, 5. receiving screen, 6. grid coordinate paper, 7. high-definition camera, 8. powdered fuel and piston projection, 9. powdered fuel, 10. lower tube, 11. piston, 12. connecting block, 13. thrust sensor, 14. motor, 15. motor guide rod, 16. measurement and control system. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] This invention provides an experimental method for analyzing the compression characteristics of piston-propelled powder based on parallel light projection. The experimental method includes the following:

[0023] The optical components, piston-propelled powder device, and projection screen 5 are arranged side by side; the piston-propelled powder device has a high-transmittance housing and piston rod assembly, which contains powdered fuel.

[0024] Parallel light is emitted through the optical component, and the parallel light passes through the piston-powder pushing device, where the powdered fuel and piston pusher assembly inside the piston-powder pushing device form a projection on the projection screen 5.

[0025] The piston rod assembly is driven to compress the powdered fuel. The volume change and packing density change of the powdered fuel are obtained based on the height change of the projection. Combined with the thrust data of the piston rod assembly, the compression characteristics of the powdered fuel during piston pushing are obtained.

[0026] The relative volumetric compressibility is used to describe the density response characteristics of powdered fuel, and the relationship between the two is as follows:

[0027]

[0028]

[0029] In the formula: C represents the relative volumetric compressibility of the powdered fuel, H0, V0 and ρ0 represent the initial projected height, packing volume and packing density of the powdered fuel, respectively, and H, V and ρ represent the projected height, packing volume and packing density of the powdered fuel during the compression process, respectively.

[0030] This invention also provides an experimental apparatus for the piston-driven powder compression characteristics based on parallel light projection, such as... Figure 1 As shown, it includes optical components, a piston powder pushing device, and a projection screen 5 arranged in parallel.

[0031] The piston-powder pushing device features a high-transmittance outer shell and a piston pusher assembly, which holds powdered fuel. The piston pusher assembly includes a piston 11, which, together with the outer shell, forms a chamber for holding the powdered fuel. The side of the piston 11 furthest from the chamber is connected to a motor guide rod 15, which is connected to a motor 14 via a thrust detection element. The motor 14 provides the power for the piston 11 to move and compress the fuel powder. Before the experiment, the piston 11 is not directly connected to the connecting block 12, thrust sensor 13, motor 14, or motor guide rod 15 in the motor assembly. This ensures that the initial measurement value of the thrust detection element 13 is 0 under different experimental conditions, facilitating comparison of experimental results.

[0032] In some embodiments, the thrust detection element includes a connecting block 12 connected to the piston 11, and the connecting block 12 is connected to one end of the motor guide rod 15 via a thrust sensor 13. The thrust sensor 13 can acquire changes in thrust, and data from both the thrust sensor 13 and the motor 13 are connected to the measurement and control system 16 to send the thrust data of the piston rod assembly to the measurement and control system. The connecting block 12 increases the force-bearing area of ​​the piston 11, resulting in more uniform force distribution and preventing damage to the thrust sensor 13 due to excessive force.

[0033] In some embodiments, the housing includes a detachable upper tube 4 and a lower tube 10, connected on both sides by a connecting rod 3. The upper and lower tubes can be made of acrylic cylindrical tubes, and the detachable design facilitates the placement of fuel powder 9. This structural design allows the powdered fuel to be filled only in the lower acrylic glass tube during initial powder loading, and the upper layer of powdered fuel is leveled to be parallel to the cross-section of the cylindrical tube, resulting in more accurate and reliable experimental results.

[0034] In some embodiments, a grid coordinate paper 6 is provided on the receiving screen 5. The height change of the projection can be easily measured by the projection on the coordinate paper, and a high-definition camera 7 can be placed away from the receiving screen 5. The side of the piston powder pushing device allows the high-definition camera 7 to accurately record the projection size parameters on the grid paper from any angle.

[0035] In some embodiments, the optical component includes a convex lens 2. The convex lens can convert a point light source into parallel light to pass through the piston-powder pushing device for experiments. Parallel light can accurately reflect changes in the height of the powdered fuel buildup, unaffected by changes in the relative position of the light source and the powdered fuel.

[0036] Example

[0037] To verify the experimental effectiveness of this invention in studying the dynamic response characteristics of powdered fuel loading density under piston pushing action, a piston-pushing experiment was conducted. The force conditions of the thrust sensor during piston-pushing are as follows: Figure 2 As shown. During the start-up phase, the piston needs to overcome static friction, which is greater than kinetic friction, resulting in a thrust peak in the motor thrust. Once the friction between the piston and the wall transforms into kinetic friction, the motor thrust decreases rapidly. The volumetric compressibility of powdered fuel at different piston velocities is shown in the figure. Figure 3 As shown, under the condition of the same piston travel distance, the faster the piston speed, the faster the volumetric compressibility of powdered fuel changes, but the maximum compressibility remains almost the same.

[0038] This invention relates to an experimental method and apparatus for studying the compression characteristics of piston-push fuel powder based on parallel light projection. When investigating the influence of the piston-push process on the powder packing density, a control system controls a motor to move the motor guide rod, thrust sensor, and connecting block upwards to push the piston, thereby achieving the pushing of the powdered fuel. During the experiment, light emitted from a point light source is parallelized by a convex lens and illuminates the high-transmittance upper and lower tubes. Due to the obstruction of the powdered fuel and piston components, projections of these components are left on the grid coordinate paper of the receiving screen. By recording the height changes of the projections on the grid coordinate paper using a high-definition camera, the volume change and packing density change of the powdered fuel can be calculated. Simultaneously, combined with the thrust data collected by the thrust sensor, the compression characteristics of the powdered fuel during piston-push can be obtained.

[0039] This invention studies the influence of piston speed on the packing density of powdered fuel by adjusting the speed of the motor. It can also pre-compact powdered fuel and study the influence of the degree of pre-compaction on the piston pushing process. Furthermore, it can perform layered packing of various powdered fuels and study the influence of the layered packing method on the piston pushing process, etc.

[0040] This invention utilizes parallel light projection to achieve non-contact measurement of the change in powdered fuel loading height during piston pushing, avoiding interference with the piston pushing process and preventing the influence of light refraction on the reading of the powdered fuel accumulation height. To ensure the powdered fuel accumulation surface is horizontal during the experiment, the design consists of an upper and lower tube. During powdered fuel loading, excess powdered fuel is loaded into the lower tube and gently smoothed with a scraper before the upper tube is installed. The two tubes are connected by a long connecting rod. To obtain the thrust of the motor during piston pushing, a miniature thrust sensor is mounted on the motor guide rod. To ensure uniform force on the piston, a connecting block is installed on the other side of the thrust sensor, increasing the piston's force-bearing area. Before the experiment, the connecting block maintains a certain gap with the piston to ensure that the initial thrust of the motor is zero in each experiment.

Claims

1. An experimental method for the compression characteristics of piston-propelled powder based on parallel light projection, characterized in that, The experimental method Includes the following: The optical components, piston-powder-pushing device and projection screen (5) are arranged side by side; the piston-powder-pushing device has a high-transmittance shell and piston rod assembly, which contains powdered fuel. Parallel light is emitted through the optical components, and the parallel light passes through the piston-powder pushing device. The powdered fuel and piston pusher assembly in the piston-powder pushing device form a projection on the projection screen (5). The piston rod assembly is pushed to compress the powdered fuel. The volume change and packing density change of the powdered fuel are obtained based on the height change of the projection. Combined with the thrust data of the piston rod assembly, the compression characteristics of the powdered fuel during piston pushing are obtained. The piston-powder pushing device has a high-transmittance outer shell and a piston push rod assembly; the piston push rod assembly includes a piston (11), which together with the outer shell forms a chamber for placing the powdered fuel; the side of the piston (11) away from the chamber is connected to a motor guide rod (15) connected to a motor (14) via a thrust detection element; the motor (14) is used to provide power for the piston (11) to move and compress the powdered fuel.

2. The experimental method for piston-pushed powder compression characteristics based on parallel light projection as described in claim 1, characterized in that, The thrust detection element includes a connecting block (12) connected to the piston (11), and the connecting block (12) is connected to one end of the motor guide rod (15) via a thrust sensor (13).

3. The experimental method for piston-pushed powder compression characteristics based on parallel light projection as described in claim 2, characterized in that, The housing includes a detachable upper tube (4) and a lower tube (10).

4. The experimental method for piston-pushed powder compression characteristics based on parallel light projection as described in claim 2, characterized in that, The projection screen (5) is provided with grid coordinate paper (6).

5. The experimental method for piston-pushed powder compression characteristics based on parallel light projection as described in claim 2, characterized in that, The optical component includes a convex lens (2).

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