A carbon soot thermophoresis sampling device suitable for use under pressurized conditions

Abstract

The present invention relates to the technical field of soot particles, and provides a soot thermophoresis sampling device suitable for use under pressurized conditions, comprising: a guide member provided on the outside of a combustion chamber, the guide member having a cavity, the cavity being connected to the combustion chamber, the combustion chamber being used to generate a turbulent flame; a ball valve provided on the guide member, for controlling the opening and closing of the cavity; a probe and a drive assembly, the probe being connected to the drive assembly, and under the action of the drive assembly, the probe being able to reciprocate along its own axial direction, and when the ball valve is in an open state, the probe being able to penetrate the cavity and extend into the combustion chamber for sampling. The soot thermophoresis sampling device suitable for use under pressurized conditions provided by the present invention, by providing a guide member, a probe and a drive assembly, under the action of the drive assembly, the probe can be extended into the combustion chamber to collect soot particles, and the soot particles are attached to the probe by utilizing the thermophoresis force generated by the temperature gradient between the flame and the probe, resulting in a fast sampling speed, thereby improving the measurement accuracy of the sample.

Description

Technical Field

[0001] The present invention relates to the technical field of soot particles, and in particular to a soot thermophoresis sampling device suitable for use under pressurized conditions. Background Art

[0002] During the combustion of hydrocarbon fuels, it is known that fuel molecules will continuously crack and merge with small molecular hydrocarbon substances to form soot precursors, which will then grow rapidly through condensation and gas-particle phase transition, and finally develop into tightly connected chain polymers, namely soot particles, through dehydrogenation and carbonization.

[0003] Most soot particles emitted by aircraft engines are PM2.5, with some even smaller than PM0.1. These tiny soot particles can directly enter the lungs and circulatory system, causing serious harm to the human body. Airborne soot particles can absorb solar radiation and contribute to the greenhouse effect. Furthermore, soot particles can damage the engine's blade structure and reduce its lifespan. Currently, research into soot generation mechanisms and control of soot emissions have become pressing challenges for both academia and industry.

[0004] Therefore, it is necessary to sample soot particles in the combustion exhaust of aircraft engines, monitor their number concentration, and study parameters such as the size distribution, morphological characteristics, and component composition of soot particles in different combustion areas, so as to intuitively grasp and understand the laws of soot generation and evolution characteristics, and thus propose ideas and methods for controlling soot emissions.

[0005] Sampling soot particles typically involves filter adsorption. This involves the accumulation of solid particles on a filter element as combustion exhaust passes through it. The weight change before and after the smoke is passed through the filter element is then used to calculate the amount of soot generated. Existing filter adsorption methods can only collect soot particles from combustion chamber exhaust. The measurement results are often subject to significant error due to the influence of exhaust temperature, and morphological observation and analysis of the collected samples are also impossible. Summary of the Invention

[0006] The present invention provides a soot thermophoresis sampling device suitable for use under pressurized conditions, which is used to solve the defect in the prior art of large measurement error when sampling soot particles using a filter element adsorption method.

[0007] The present invention provides a carbon soot thermophoresis sampling device suitable for use under pressurized conditions, comprising: a combustion chamber, a guide member is provided on the outside of the combustion chamber, the guide member has a cavity, the cavity is connected to the combustion chamber, and the combustion chamber is used to generate a turbulent flame; a ball valve is provided on the guide member, and is used to control the on and off of the cavity; a probe and a drive assembly, the probe is connected to the drive assembly, and under the action of the drive assembly, the probe can reciprocate along its own axial direction, and when the ball valve is in an open state, the probe can pass through the cavity and extend to the interior of the combustion chamber for sampling.

[0008] According to a soot thermophoresis sampling device suitable for use under pressurized conditions provided by the present invention, the probe includes: a clamping portion, which is used to connect to the driving assembly; a sampling portion, which is clamped by the clamping portion, and the sampling portion is provided with at least one sampling membrane along its length direction.

[0009] According to the present invention, a soot thermophoresis sampling device suitable for use under pressurized conditions is provided, wherein the sampling portion comprises: a pair of sheets, the pair of sheets being clamped by the clamping portion, the sampling membrane being clamped between the pair of sheets, and a through hole being provided at a position opposite to the sampling membrane of each sheet, wherein the diameter of the through hole is smaller than the diameter of the sampling membrane.

[0010] According to the present invention, a soot thermophoresis sampling device suitable for use under pressurized conditions is provided, wherein the sampling membrane comprises: a metal mesh; and a carbon layer, wherein the carbon layer covers the metal mesh.

[0011] According to a carbon soot thermophoresis sampling device suitable for pressurized conditions provided by the present invention, the combustion chamber also includes: a combustion chamber casing; a moving plate, the moving plate is movably connected to the combustion chamber casing, the moving plate and the combustion chamber casing are configured to form the combustion chamber, and the guide is arranged on the moving plate.

[0012] According to a soot thermophoresis sampling device suitable for pressurized conditions provided by the present invention, the combustion chamber also includes: a connecting plate, which is detachably connected to the combustion chamber casing, and the moving plate is clamped between the connecting plate and the combustion chamber casing.

[0013] According to a soot thermophoresis sampling device suitable for pressurized conditions provided by the present invention, the driving assembly includes: a cylinder, the piston rod of the cylinder is connected to the probe; an electromagnetic switching valve, the electromagnetic switching valve is connected to the rod chamber and the rodless chamber of the cylinder through a pipeline; and a power-off relay, the power-off relay is electrically connected to the electromagnetic switching valve to control the extension and retraction of the piston rod through the electromagnetic switching valve.

[0014] According to the present invention, a soot thermophoresis sampling device suitable for use under pressurized conditions further includes: an adapter, wherein the adapter is a hollow structure, and one end of the adapter is connected to the guide.

[0015] According to the present invention, a carbon soot thermophoresis sampling device suitable for pressurized conditions also includes: an adjusting part, the end face of the adjusting part is connected to the end face of the cylinder, the adjusting part is sleeved on the outside of the adapter, and when the adjusting part rotates, it can drive the adapter closer to or away from the end face of the cylinder.

[0016] According to the present invention, a soot thermophoresis sampling device suitable for use under pressurized conditions is provided, wherein the sampling time of the soot thermophoresis sampling device is greater than or equal to 50 milliseconds.

[0017] The carbon soot thermophoresis sampling device provided by the present invention is suitable for use under pressurized conditions. By providing a guide, a probe and a drive assembly, the probe can be extended into the combustion chamber under the action of the drive assembly to collect carbon soot particles. The thermophoretic force generated by the temperature gradient between the flame and the probe is used to make the carbon soot particles adhere to the probe. The sampling speed is fast, thereby improving the measurement accuracy of the sample. At the same time, the carbon soot particles can also be microscopically observed to obtain the microstructural information of the carbon soot particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 Schematic diagram of the structure of the soot thermophoresis sampling device suitable for use under pressurized conditions provided by the present invention;

[0020] Figure 2 It is a cross-sectional view of the cylinder, adjustment part, adapter and probe;

[0021] Figure 3 is a schematic diagram of the probe structure;

[0022] Figure 4 It is a structural diagram of the drive component;

[0023] Reference numerals:

[0024] 11: Moving plate; 12: Connecting plate; 13: Guide; 20: Ball valve; 30: Adapter; 40: Adjusting part; 51: Cylinder; 52: Solenoid switching valve; 53: Power-off relay; 54: Air source; 55: Power supply; 60: Probe; 61: Clamping part; 62: Sampling part; 511: Piston rod. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0026] The features of the terms "first" and "second" in the description and claims of the present invention may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0027] The following combination Figure 1-Figure 4 The present invention describes a soot thermophoresis sampling device suitable for use under pressurized conditions.

[0028] like Figure 1 As shown, in one embodiment of the present invention, a soot thermophoresis sampling device suitable for use under pressurized conditions includes: a combustion chamber, a ball valve 20, a probe 60, and a drive assembly. A guide 13 is provided on the outside of the combustion chamber. The guide 13 has a cavity that is connected to the combustion chamber, and the combustion chamber is used to generate a turbulent flame. The ball valve 20 is provided on the guide 13 to control the connection of the cavity. The probe 60 is connected to the drive assembly. Under the action of the drive assembly, the probe 60 can reciprocate along its own axial direction. When the ball valve 20 is in the open state, the probe 60 can extend through the cavity to the interior of the combustion chamber for sampling.

[0029] Specifically, the guide member 13 is a hollow structure that communicates with the combustion chamber. A ball valve 20 is mounted on the guide member 13. When the probe 60 is not sampling, the ball valve 20 is closed, isolating the probe 60 from the flame within the combustion chamber. When sampling is required, the ball valve 20 is opened, and the drive assembly moves the probe 60 along the cavity of the guide member 13, extending into the combustion chamber to collect a sample of soot particles. After sampling, the drive assembly drives the probe 60 in the opposite direction, exiting the guide member 13, and the ball valve 20 closes.

[0030] Furthermore, in this embodiment, the sampling principle of probe 60 is based on the thermophoresis phenomenon. This phenomenon refers to the phenomenon that, in a non-isothermal field, because gas molecules in the high-temperature portion have higher kinetic energy than those in the low-temperature portion, solid particles suspended in the gaseous medium are subjected to a thermophoretic force acting in the opposite direction of the temperature gradient, causing them to migrate toward the low-temperature portion. Based on this principle, soot particles in the flame are attracted to the cooler probe 60.

[0031] The embodiment of the present invention provides a soot thermophoresis sampling device suitable for pressurized conditions. By setting a guide, a probe and a drive assembly, under the action of the drive assembly, the probe can be extended into the interior of the combustion chamber to collect soot particles. The thermophoretic force generated by the temperature gradient between the flame and the probe is used to make the soot particles adhere to the probe. The sampling speed is fast, thereby improving the measurement accuracy of the sample. At the same time, the collected soot particle samples can be photographed and analyzed using a transmission electron microscope. The average diameter, size distribution and morphological characteristics of the soot particles can be obtained by processing the images with ImageJ software.

[0032] like Figure 3 As shown, in one embodiment of the present invention, the probe 60 includes a clamping portion 61 and a sampling portion 62. The clamping portion 61 is used to connect to the driving assembly, and the sampling portion 62 is clamped by the clamping portion 61. The sampling portion 62 is provided with at least one sampling membrane along its length.

[0033] Specifically, in this embodiment, the sampling portion 62 comprises a pair of sheets, with the sampling membrane sandwiched between the two sheets. The sheets are clamped by the clamping portion 61, thereby securing the sampling membrane between the two sheets. Furthermore, each sheet is provided with a through hole at a position opposite the sampling membrane to allow soot particles to adhere to the sampling membrane.

[0034] Furthermore, in an embodiment of the present invention, the sampling membrane comprises a metal mesh and a carbon layer. The carbon layer covers the metal mesh. Specifically, the metal mesh is a copper mesh having a diameter of 3 mm, and one side of the copper mesh is covered with the carbon layer. The diameter of the through-hole in the sheet is smaller than that of the sampling membrane to prevent the sampling membrane from falling through the through-hole. Optionally, the diameter of the through-hole is 2 mm.

[0035] Furthermore, multiple through-holes can be provided along the length of the pair of sheets, with a sampling membrane sandwiched between each through-hole. When the probe 60 is inserted into the combustion chamber, the multiple sampling membranes can simultaneously sample, enabling simultaneous sampling at multiple radial positions. Furthermore, to prevent interference from other elements on the soot particulate matter sampling effect, the sheets can be made of titanium alloy.

[0036] like Figure 1As shown, in one embodiment of the present invention, the combustion chamber further comprises: a combustion chamber casing and a moving plate 11. The moving plate 11 is movably connected to the combustion chamber casing, and the moving plate 11 and the combustion chamber casing form a combustion chamber. The guide 13 is provided on the moving plate 11.

[0037] Specifically, in this embodiment, the combustion chamber housing and the movable plate 11 form a combustion chamber, which is used to generate a turbulent flame. The movable plate 11 can move along the combustion chamber housing, thereby changing the position of the guide member 13 relative to the combustion chamber housing. When the probe 60 is extended into the combustion chamber, soot particles can be measured at different locations within the combustion chamber. Optionally, in this embodiment, the probe 60 can sample within a 21 cm radius centered on the guide member 13.

[0038] Furthermore, the combustion chamber further comprises a connecting plate 12. The connecting plate 12 is detachably connected to the combustion chamber casing, and the moving plate 11 is sandwiched between the connecting plate 12 and the combustion chamber casing.

[0039] Specifically, to ensure stable combustion chamber operation, good sealing between the various combustion chamber components is essential. A rubber ring seals the movable plate 11 and connecting plate 12, while a graphite gasket provides a static seal between the connecting plate 12 and the combustion chamber casing. Furthermore, the movable plate 11 is sandwiched between the connecting plate 12 and the combustion chamber casing. By moving the movable plate 11, the relative position of the guide 13 and the combustion chamber interior can be adjusted, thereby adjusting the sampling position of the probe 60 within the combustion chamber.

[0040] like Figure 4 As shown, in one embodiment of the present invention, the drive assembly includes: a cylinder 51, an electromagnetic switching valve 52, and a power-off relay 53. The piston rod 511 of the cylinder 51 is connected to the probe 60, and the electromagnetic switching valve 52 is connected to the rod chamber and the rodless chamber of the cylinder 51 via a pipeline. The power-off relay 53 is electrically connected to the electromagnetic switching valve 52 to control the extension and retraction of the piston rod 511 through the electromagnetic switching valve 52.

[0041] Specifically, the electromagnetic switching valve 52 is connected to the gas source 54, and the power supply 55 supplies power to the electromagnetic switching valve 52 and the power-off relay 53. Initially, the piston rod 511 in the cylinder 51 is in a retracted position. During sampling, the power supply 55 energizes the power-off relay 53 and the electromagnetic switching valve 52. Gas from the gas source 54 passes through the electromagnetic switching valve 52 and enters the rodless chamber of the cylinder 51, causing the pressure in the rodless chamber to be higher than that in the rod chamber. The piston rod 511 extends, driving the probe 60 toward the combustion chamber. The ball valve 20 opens, and the probe 60 extends through the cavity of the guide 13 into the combustion chamber. The thermophoretic force generated by the temperature gradient between the flame and the probe 60 causes soot particles to adhere to the sampling membrane of the probe 60, thereby achieving soot particle sampling.

[0042] After sampling, the power-off relay 53 can be set to a power-off time. When the power-off time is reached, the electromagnetic switching valve 52 switches the flow direction of the gas. After passing through the electromagnetic switching valve 52, the gas enters the rod chamber of the cylinder 51. At this time, the pressure in the rod chamber is greater than that in the rodless chamber, and the piston rod 511 contracts, driving the probe 60 to reset. During the sampling process, in order to obtain a reasonable carbon soot particle sample while preventing the probe 60 from staying in the flame for too long, resulting in carbon soot particle deposition and inability to distinguish, it is necessary to adjust the carbon soot particle sampling time according to the flame field, that is, adjust the power-off time of the power-off relay 53. The sampling time commonly used in combustion chambers is 100ms. By using the carbon soot thermophoresis sampling device provided in the embodiment of the present invention, the shortest sampling time can be shortened to 50ms.

[0043] If probe 60 spends too much time in the combustion chamber during its movement, the sampling membrane may collect soot particles along its path, leading to sampling errors. Therefore, a high-speed camera is required to calibrate the probe's operating characteristics during the sampling process. Table 1 shows the statistical results of probe 60's operating characteristics using the high-speed camera.

[0044] In the table below, the setting time of the power-off relay 53 is not less than 0.35s, and the proportion of the time that the probe 60 moves in the combustion chamber is less than 20%. That is, the carbon soot particles on the path that may be collected by the probe 60 during its movement in the combustion chamber are relatively small compared with the amount collected at the set sampling position (probe stop position), and will not have a significant impact on the final result.

[0045] Table 1 Statistics of probe movement time and residence time in the combustion chamber

[0046]

[0047] Optionally, in an embodiment of the present invention, the gas source 54 is nitrogen.

[0048] like Figure 1 and Figure 2 As shown, in one embodiment of the present invention, a soot thermophoresis sampling device suitable for use under pressurized conditions further includes an adapter 30 and an adjustment member 40. The adapter 30 is hollow, one end of which is connected to the guide member 13. The end face of the adjustment member 40 is connected to the end face of the cylinder 51. The adjustment member 40 is sleeved onto the exterior of the adapter 30. Rotation of the adjustment member 40 can move the adapter 30 closer to or further from the end face of the cylinder 51.

[0049] Specifically, as the probe 60 extends under the influence of the cylinder 51, it first passes through the adapter 30 and then through the guide 13 into the combustion chamber. The adjustment member 40 is threadedly connected to the adapter 30. Rotating the adjustment member 40 adjusts the distance between the cylinder 51 and the adapter 30, thereby changing the position of the cylinder 51. This allows for fine-tuning of the radial sampling position during sampling, facilitating radial positioning.

[0050] The carbon soot thermophoresis sampling device suitable for pressurized conditions provided by the embodiment of the present invention can accurately control the sampling time and improve the reliability of the sampling results. At the same time, the sampling device can simultaneously complete the carbon soot collection at multiple radial positions at a certain axial position. By adjusting the position of the moving plate, the axial sampling position can be flexibly changed. The operation is simple and the sampling efficiency is greatly improved. The sealing design in the carbon soot thermophoresis sampling device suitable for pressurized conditions provided by the embodiment of the present invention can enable the device to complete the carbon soot collection in the pressurized combustion chamber, effectively reduce the pressure loss in the combustion chamber caused by sampling, play a role in stabilizing sampling, and fill the current domestic technical gap in the invasive sampling of carbon soot particles in the turbulent flame of the actual combustion chamber.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A soot thermophoresis sampling device suitable for use under pressurized conditions, characterized in that: include: a combustion chamber, wherein a guide member is provided on the outside of the combustion chamber, the guide member having a cavity, the cavity being in communication with the combustion chamber, and the combustion chamber is used to generate a turbulent flame; a ball valve, provided on the guide member, for controlling the opening and closing of the cavity; A probe and a drive assembly, wherein the probe is connected to the drive assembly. Under the action of the drive assembly, the probe can reciprocate along its own axial direction. When the ball valve is open, the probe can extend through the cavity to the interior of the combustion chamber for sampling. The probe includes: a clamping portion, which is used to connect to the drive assembly; a sampling portion, which is clamped by the clamping portion and is provided with at least one sampling membrane along its length; the drive assembly includes a cylinder, and the piston rod of the cylinder is connected to the probe; An adapter, wherein the adapter is a hollow structure, and one end of the adapter is connected to the guide member; An adjusting member, the end face of which is connected to the end face of the cylinder, and the adjusting member is sleeved on the outside of the adapter. When the adjusting member rotates, it can drive the adapter to move closer to or farther away from the end face of the cylinder.

2. The soot thermophoresis sampling device suitable for pressurized conditions according to claim 1, characterized in that: The sampling unit includes: A pair of sheets, the pair of sheets are clamped by the clamping part, the sampling membrane is clamped between the pair of sheets, and a through hole is provided at a position opposite to the sampling membrane of each sheet, and the diameter of the through hole is smaller than the diameter of the sampling membrane.

3. The soot thermophoresis sampling device suitable for use under pressurized conditions according to claim 1, characterized in that: The sampling membrane comprises: Metal mesh; A carbon layer covers the metal mesh.

4. The soot thermophoresis sampling device suitable for use under pressurized conditions according to claim 1, characterized in that: The combustion chamber further comprises: combustion chamber casing; A moving plate is movably connected to the combustion chamber casing, the moving plate and the combustion chamber casing form the combustion chamber, and the guide is arranged on the moving plate.

5. The soot thermophoresis sampling device suitable for pressurized conditions according to claim 4, characterized in that: The combustion chamber further comprises: A connecting plate is detachably connected to the combustion chamber casing, and the moving plate is clamped between the connecting plate and the combustion chamber casing.

6. The soot thermophoresis sampling device suitable for pressurized conditions according to claim 1, characterized in that: The drive assembly further includes: an electromagnetic switching valve connected to the rod chamber and the rodless chamber of the cylinder through a pipeline; A power-off relay is electrically connected to the electromagnetic switching valve to control the extension and retraction of the piston rod through the electromagnetic switching valve.

7. The soot thermophoresis sampling device suitable for use under pressurized conditions according to claim 1, characterized in that: The sampling time of the soot thermophoresis sampling device is greater than or equal to 50 milliseconds.

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