A device for inhibiting capillary gas-liquid two-phase flow

Abstract

A device for suppressing capillary gas-liquid two-phase flow includes: a flange, a frame, a front chamber, a capillary, a phase change heat-absorbing metal sheet, and a ceramic heat insulation pad. Propellant enters the catalytic bed through the capillary and undergoes catalytic combustion, releasing heat. The ceramic heat insulation pad in the front chamber first prevents some heat transfer to the capillary, and then the phase change heat-absorbing metal sheet further reduces the capillary outlet temperature through phase change heat absorption. This invention effectively suppresses the generation of gas-liquid two-phase flow in the capillary, thereby solving the thrust reduction fault of a single-component engine and extending the engine working chamber pressure from 1.8MPa-1.2MPa to 1.8MPa-0.3MPa. Simultaneously, it eliminates the safety hazard caused by propellant deflagration within the capillary, thereby improving the reliability of the single-component engine.

Description

Technical Field

[0001] This invention relates to a device for suppressing capillary gas-liquid two-phase flow, belonging to the field of thruster technology. Background Technology

[0002] A single-component thruster consists of a solenoid valve, injector, catalytic bed, and thermal control components. Different injector capillary tubes are used to achieve varying thrust levels. During engine operation, propellant enters the catalytic bed through the capillary tube and undergoes catalytic combustion. The resulting high temperature is transferred to the capillary tube via radiation and conduction. The capillary tube outlet temperature reaches 400-600℃ during thruster operation, inevitably leading to propellant vaporization within the capillary. This transforms the flow within the capillary into a two-phase flow problem involving cold flow, evaporation, and thermal decomposition phase changes. When the propellant flow rate is high, cold flow dominates, and evaporation and thermal decomposition are relatively limited, thus having little impact on the normal operation of the thruster. As the propellant flow rate gradually decreases, the proportion of evaporation and thermal decomposition gradually increases, leading to a continuous increase in the gas phase component within the capillary. This results in significant gas resistance, which can severely affect the normal flow of the propellant, altering the combustion balance of the thruster and ultimately impacting its thrust performance. Generally, for low-thrust thrusters, a thrust reduction fault will occur when the thruster inlet pressure is around 1.2 MPa (corresponding to a propellant flow rate of approximately 80 mg / s). Furthermore, excessively high temperatures may even cause propellant combustion and decomposition within the capillary tube, leading to capillary rupture and unpredictable safety risks to the entire satellite. The most effective and direct way to eliminate these faults and safety hazards is to reduce the capillary tube temperature, especially the temperature at the capillary root. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of existing technologies and propose a device for suppressing capillary gas-liquid two-phase flow. Through the design of phase-change heat-absorbing metal sheets and heat-insulating ceramic sheets, the temperature of the capillary tube in the injector of a single-component engine is effectively reduced, thereby suppressing the gas-liquid two-phase flow in the capillary. This invention effectively solves the thrust reduction fault caused by gas-liquid two-phase flow in single-component thrusters, and also eliminates safety hazards such as deflagration caused by excessive temperature, thereby improving the reliability of single-component thrusters and expanding the application conditions of the product.

[0004] The technical solution of this invention is:

[0005] A device for suppressing capillary gas-liquid two-phase flow includes: a flange, a frame, a front chamber, a capillary, a phase change heat-absorbing metal sheet, and a ceramic heat insulation pad;

[0006] The flange and the forecourt are connected by a frame, and the two ends of the capillary tube are fixedly connected to the flange and the forecourt, respectively.

[0007] The anterior chamber includes: ductal structures and a cavity;

[0008] A phase change heat-absorbing metal sheet is fitted onto the outer wall of the anterior ventricular duct structure; a ceramic heat insulation pad is placed inside the cavity of the anterior chamber; a capillary tube passes through the interior of the anterior ventricular duct structure and is inserted into the ceramic heat insulation pad;

[0009] The ceramic heat insulation pad is machined with through holes, and the end of the capillary passes through the through holes on the ceramic heat insulation pad, so that the propellant flows into the catalytic bed through the capillary.

[0010] Preferably, the capillary is located inside the frame, and the distance between the flange and the anterior chamber is less than the length of the capillary, causing the capillary portion between the flange and the anterior chamber to bend.

[0011] Preferably, the phase change heat-absorbing metal sheet is fixed to the outer wall of the duct structure at the top of the anterior chamber by brazing;

[0012] The flange and frame, the forecourt and frame, and the forecourt and capillary tube are all fixed by brazing.

[0013] Preferably, both the cavity of the anterior chamber and the ceramic heat insulation pad have an axisymmetric structure.

[0014] Preferably, the cross-section of the anterior chamber is circular;

[0015] Clearance fit between the capillary tube and the ceramic heat insulation pad;

[0016] The sidewall of the ceramic heat insulation pad is fitted with the inner wall of the front room with a clearance.

[0017] Preferably, the ratio of the outer diameter of the capillary to the outer diameter of the contact surface A is 1:2.3 to 2.5;

[0018] Among them, contact surface A is the annular contact surface between the phase change heat-absorbing metal sheet and the front chamber.

[0019] Preferably, the axial length of the phase change heat-absorbing metal sheet is consistent with the axial length of the anterior ventricular duct structure;

[0020] The total axial length of the phase change heat-absorbing metal sheet ranges from 6 to 8 mm.

[0021] Preferably, the internal material of the phase change heat-absorbing metal sheet is Zn4Al alloy, and the outer shell is formed by copper plating, with the shell material being oxygen-free copper.

[0022] Preferably, the phase change heat-absorbing metal sheet comprises: a cylindrical section and a conical section;

[0023] The rounded corners of the conical section create a curve in the generatrix, which facilitates heat conduction.

[0024] The ratio of the axial length of the conical segment to the axial length of the cylindrical segment is 0.5 to 0.8:1.

[0025] The outer diameter of the cylindrical section shall not be less than 20 mm.

[0026] Preferably, the ceramic heat insulation pad material is silicon dioxide ceramic.

[0027] The beneficial effects of this invention compared to the prior art are:

[0028] 1) This invention uses a heat insulation pad placed in the forecourt to effectively prevent the heat generated by propellant combustion from spreading to the capillary, thus solving the problem of excessively high capillary temperature from the source. Compared with ceramic combustion chambers, it avoids the problem of welding ceramic and metal.

[0029] 2) This invention utilizes the heat absorption of metal phase change and the material's own heat capacity to reduce the temperature at the root of the capillary tube. While suppressing the gas-liquid two-phase flow phenomenon generated during the operation of the single-component engine, it avoids the drawback of needing to provide an external heat interface for heat dissipation such as copper wire. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the device structure of the present invention.

[0031] Figure 2 This is a flowchart of the method of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings.

[0033] A device for suppressing capillary gas-liquid two-phase flow, such as Figure 1 The components shown include: flange 1, frame 2, front chamber 3, capillary tube 4, phase change heat-absorbing metal sheet 5, and ceramic heat insulation pad 6.

[0034] Flange 1 and the anterior chamber 3 are connected by frame 2, and both ends of capillary tube 4 are fixedly connected to flange 1 and anterior chamber 3, respectively. Figure 1 As shown, the propellant flows into the catalyst bed from top to bottom through capillary 4.

[0035] The capillary tube 4 is located inside the frame 2. The distance between the flange 1 and the anterior chamber 3 is less than the length of the capillary tube 4, causing the portion of the capillary tube 4 between the flange 1 and the anterior chamber 3 to bend.

[0036] A duct structure is provided on the upper end face of the anterior chamber 3;

[0037] Phase change heat-absorbing metal sheet 5 is fitted onto the outer wall of the anterior chamber 3 conduit structure; capillary tube 4 passes through the interior of the anterior chamber 3 conduit structure;

[0038] The top conduit structure of the anterior chamber 3 is used to prevent contact between the phase change heat-absorbing metal sheet 5 and the capillary tube 4.

[0039] The phase change heat-absorbing metal sheet 5 is fixed to the outer wall of the top conduit structure of the anterior chamber 3 by brazing.

[0040] The flange 1 and frame 2, the anterior chamber 3 and frame 2, and the anterior chamber 3 and capillary tube 4 are all fixed by brazing.

[0041] A ceramic heat insulation pad 6 is placed inside the cavity of the front chamber 3; the ceramic heat insulation pad 6 is machined with through holes, and the end of the capillary 4 passes through the through holes on the ceramic heat insulation pad 6, so that the propellant flows into the catalyst bed through the capillary 4.

[0042] The cavity within the anterior chamber 3 is an axisymmetric space.

[0043] The cross-section of the anterior chamber 3 is circular. In this embodiment of the invention, the axial length of the ceramic heat insulation pad 6 is 1-2 mm. There is a clearance fit between the capillary tube 4 and the ceramic heat insulation pad 6; there is also a clearance fit between the sidewall of the ceramic heat insulation pad 6 and the inner wall of the anterior chamber 3.

[0044] In this embodiment of the invention, flange 1 has a mechanical interface for mounting a solenoid valve, frame 2 supports capillary tube 4, capillary tube 4 has a C-shaped bend, downstream of pre-chamber 3 is connected to catalytic bed, and the lower end face of phase change heat-absorbing metal sheet 5 contacts the upper end face of pre-chamber 3. While ensuring mechanical strength, the planar contact between phase change heat-absorbing metal sheet 5 and the upper end face of pre-chamber 3 should be minimized. Ceramic heat insulation pad 6 has a small circular hole in the middle.

[0045] The conduit structure on the anterior chamber 3 is used to thicken the outer wall of the capillary tube 4 to avoid the corrosion of the capillary tube 4 by the brazing material during long-term use.

[0046] Since the upper end of the front chamber 3 is for heat transfer to the capillary tube 4, it would be better if the front chamber 3 and the phase change heat-absorbing metal sheet 5 did not come into contact. However, considering practical engineering considerations, in this embodiment of the invention, the front chamber 3 and the phase change heat-absorbing metal sheet 5 are in contact. The lower end face of the phase change heat-absorbing metal sheet 5 and the upper end face of the front chamber 3 can be welded or not.

[0047] The ratio of the outer diameter of the capillary tube 4 to the outer diameter of the contact surface A is 1:2.3 to 2.5, where the contact surface A is the annular contact surface between the phase change heat-absorbing metal sheet 5 and the front chamber 3.

[0048] The axial length of the phase change heat-absorbing metal sheet 5 is consistent with the axial length of the conduit structure. The total axial length of the phase change heat-absorbing metal sheet 5 ranges from 6 to 8 mm.

[0049] like Figure 1As shown, the phase change heat-absorbing metal sheet 5 includes a cylindrical section and a conical section. The conical section has rounded corners, forming a curve in its generatrix, which facilitates heat conduction. The ratio of the axial length of the conical section to the axial length of the cylindrical section is 0.5 to 0.8:1. The cylindrical and conical sections are machined with interconnecting through holes. The outer diameter of the cylindrical section of the phase change heat-absorbing metal sheet 5 is not less than 20 mm.

[0050] Flange 1, frame 2, anterior chamber 3, and capillary tube 4 are all made of high-temperature alloys.

[0051] The phase change heat-absorbing metal sheet 5 has a sandwich structure, with the inner material being Zn4Al alloy and the outer material being copper-plated to form a shell. The shell material is oxygen-free copper, and in this embodiment of the invention, the copper plating thickness is 0.5 mm.

[0052] The heat capacity of Zn4Al alloy is approximately 0.52 J / g·K. The melting point of Zn4Al alloy is 381℃.

[0053] The ceramic heat insulation pad 6 is made of silicon dioxide ceramic, and its thermal conductivity is 0.27 W / cm·K.

[0054] Example

[0055] like Figure 2 As shown, the method for suppressing capillary gas-liquid two-phase flow using the device for suppressing capillary gas-liquid two-phase flow of the present invention includes the following specific steps:

[0056] 1) The propellant enters capillary 4 and is throttled, with a flow rate in the range of 50 mg / s to 200 mg / s;

[0057] 2) The throttled propellant enters the catalytic bed through the ceramic heat insulation pad 6 and undergoes catalytic combustion, releasing heat;

[0058] 3) The low thermal conductivity of the ceramic heat insulation pad 6 is used to prevent some of the heat from being transferred to the wall of the front chamber 3;

[0059] 4) The phase change heat-absorbing metal sheet 5 further absorbs the heat transferred from the front chamber 3 to the capillary tube 4 through the phase change process, effectively suppressing the generation of gas-liquid two-phase flow.

[0060] In this embodiment of the invention, the ceramic heat insulation pad 6 has a thickness of 2 mm and a thermal conductivity of 0.27 W / cm·K. Through the ceramic heat insulation pad 6, the wall temperature of the anterior chamber 3 can be reduced by approximately 300°C. The phase change heat-absorbing metal sheet 5, fixed to the protrusion of the anterior chamber 3, absorbs the heat transferred from the anterior chamber 3 to the capillary 4 through a phase change process, further reducing the temperature at the root of the capillary 4. The phase change heat-absorbing metal sheet 5 has a thickness of 6 mm, an outer diameter of 20 mm, and an outer layer of oxygen-free copper with a thickness of 1 mm.

[0061] This invention utilizes a temperature control design with a ceramic heat insulation pad 6 and a phase change heat-absorbing metal sheet 5 to maintain the temperature at the root of the capillary tube 4 at approximately 300°C. When the propellant flow rate is 100 mg / s, the pressure drop across the capillary tube 4 is within the range of 0.35 MPa to 0.45 MPa.

[0062] The device for suppressing capillary gas-liquid two-phase flow described in this invention is applied to a 0.2N thruster and verified by high-altitude simulated hot test. It can extend the reliable operating conditions of the 0.2N thruster from 1.2MPa-2.0MPa to 0.3MPa-2.0MPa.

[0063] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make possible variations and modifications to the technical solutions of the present invention using the disclosed methods and techniques without departing from the spirit and scope of the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall fall within the protection scope of the present invention. Where there is no conflict, the embodiments of this application and the technical features thereof can be combined with each other.

[0064] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A device for suppressing capillary gas-liquid two-phase flow, characterized in that, include: Flange (1), frame (2), anterior chamber (3), capillary tube (4), phase change heat-absorbing metal sheet (5) and ceramic heat insulation pad (6); The flange (1) and the anterior chamber (3) are connected by the frame (2), and the two ends of the capillary tube (4) are fixedly connected to the flange (1) and the anterior chamber (3) respectively. The anterior chamber (3) includes: ductal structures and lumen; A phase change heat-absorbing metal sheet (5) is fitted onto the outer wall of the conduit structure of the anterior chamber (3); a ceramic heat insulation pad (6) is placed inside the cavity of the anterior chamber (3); a capillary tube (4) passes through the inside of the conduit structure of the anterior chamber (3) and inserts the ceramic heat insulation pad (6). The ceramic heat insulation pad (6) is processed with through holes, and the end of the capillary (4) passes through the through holes on the ceramic heat insulation pad (6), so that the propellant flows into the catalyst bed through the capillary (4); The phase change heat-absorbing metal sheet (5) includes: a cylindrical section and a conical section; The rounded corners of the conical section create a curve in the generatrix, which facilitates heat conduction. The ratio of the axial length of the conical segment to the axial length of the cylindrical segment is 0.5~0.8:

1. The outer diameter of the cylindrical section shall not be less than 20mm.

2. The device for suppressing capillary gas-liquid two-phase flow according to claim 1, characterized in that, The capillary tube (4) is located inside the frame (2), and the distance between the flange (1) and the anterior chamber (3) is less than the length of the capillary tube (4), causing the capillary tube (4) between the flange (1) and the anterior chamber (3) to bend.

3. The device for suppressing capillary gas-liquid two-phase flow according to claim 1, characterized in that, The phase change heat-absorbing metal sheet (5) is fixed to the outer wall of the top conduit structure of the anterior chamber (3) by brazing; The flange (1) and frame (2), the anterior chamber (3) and frame (2), and the anterior chamber (3) and capillary (4) are all fixed by brazing.

4. The device for suppressing capillary gas-liquid two-phase flow according to claim 1, characterized in that, The cavity of the anterior chamber (3) and the ceramic heat insulation pad (6) are both axisymmetric structures.

5. The device for suppressing capillary gas-liquid two-phase flow according to claim 4, characterized in that, The cross-section of the anterior chamber (3) is circular; The capillary tube (4) and the ceramic heat insulation pad (6) are fitted with a clearance. The sidewall of the ceramic heat insulation pad (6) is fitted with the inner wall of the anterior chamber (3) with a clearance.

6. The device for suppressing capillary gas-liquid two-phase flow according to claim 1, characterized in that, The ratio of the outer diameter of the capillary tube (4) to the outer diameter of the contact surface A is 1:2.3~2.5; Among them, the contact surface A is the annular contact surface between the phase change heat-absorbing metal sheet (5) and the front chamber (3).

7. The device for suppressing capillary gas-liquid two-phase flow according to claim 1, characterized in that, The axial length of the phase change heat-absorbing metal sheet (5) is consistent with the axial length of the conduit structure of the anterior chamber (3); The total axial length of the phase change heat-absorbing metal sheet (5) ranges from 6 to 8 mm.

8. A device for suppressing capillary gas-liquid two-phase flow according to any one of claims 1 to 7, characterized in that, The internal material of the phase change heat-absorbing metal sheet (5) is Zn4Al alloy, and the outer shell is formed by copper plating. The shell material is oxygen-free copper.

9. A device for suppressing capillary gas-liquid two-phase flow according to any one of claims 1 to 7, characterized in that, The ceramic heat insulation pad (6) is made of silicon dioxide ceramic.

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