Ultralow-temperature pipeline visualization device for liquid rocket engine test

Abstract

The invention provides an ultralow-temperature pipeline visualization device for a liquid rocket engine test. The ultralow-temperature pipeline visualization device comprises an inlet flange, an outer sealing gasket, a vacuum sealing ring, an inner sealing gasket, an outer observation pipe, an inner observation pipe, an outlet flange and a vacuum quick-release connector. The inner side sealing structures of the inlet flange and the outlet flange are the same, each of the inlet flange and the outlet flange comprises an annular sealing groove, and an outer sealing gasket is additionally arranged in each annular sealing groove and used for being sealed with the outer observation pipe and keeping the vacuum degree between the outer observation pipe and the inner observation pipe; a protruding sealing ring is arranged in the center of the inner side of the outer observation pipe and comprises a sealing ring groove and a wedge-shaped end face sealing groove, a vacuum sealing ring is installed in the sealing ring groove, and the vacuum degree between the outer observation pipe and the inner observation pipe is kept. An inner sealing gasket is installed in the wedge-shaped end face sealing groove and used for preventing a medium in the inner observation pipe from leaking out.

Description

Technical Field

[0001] The invention belongs to the field of cryogenic technology, and in particular relates to a medium observation and precooling state confirmation method for a cryogenic test system. Background Art

[0002] With the rapid development of aerospace, petrochemical and other fields, the demand for reliability verification of components used in low-temperature working environments is increasing, and the amount of low-temperature tests is increasing year by year. However, the existing low-temperature test pre-cooling or workpiece movement flexibility inspection relies on experience judgment or time accumulation, and cannot visually confirm the pre-cooling of the tested product and the test system or the low-temperature movement of the tested product. The assessment of the actual low-temperature working conditions is insufficient, especially for the incomplete test coverage of key low-temperature components in aerospace, LNG and other systems. The test accuracy and test efficiency of the existing test system can no longer meet the current large number of test requirements. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the problems existing in the relevant testing technology. The present application provides a device for visually observing the flow state of a low-temperature medium, and provides an assembly method and a method of use for the device.

[0004] The technical solution of the present invention is: a cryogenic pipeline visualization device for liquid rocket engine testing, comprising: an inlet flange, an outer sealing gasket, a vacuum sealing ring, an inner sealing gasket, an outer observation tube, an inner observation tube, an outlet flange, and a vacuum quick-release connector;

[0005] The inlet flange and the outlet flange have the same inner sealing structure, both of which include an annular sealing groove, and an outer sealing gasket is installed in the annular sealing groove to seal with the outer observation tube and maintain the vacuum between the outer observation tube and the inner observation tube; a raised sealing ring is arranged at the inner center, and the raised sealing ring includes a sealing ring groove and a wedge-shaped end face sealing groove, wherein a vacuum sealing ring is installed in the sealing ring groove to maintain the vacuum between the outer observation tube and the inner observation tube; an inner sealing gasket is installed in the wedge-shaped end face sealing groove to prevent the medium in the inner observation tube from leaking out;

[0006] The inlet flange has a radial hole on the side and an axial hole on the inside, and the radial hole is connected to the axial hole; the radial hole is welded with a vacuum quick-release connector, and the axial hole is located between the annular sealing groove and the raised sealing ring to provide a vacuum between the outer observation tube and the inner observation tube;

[0007] The inlet flange and the outlet flange are fastened by a structural member so that the inlet flange and the outlet flange clamp the inner and outer sealing gaskets and the inner and outer observation tubes.

[0008] Preferably, the inlet flange and the outlet flange are provided with threaded pipe joints on the outside, the inlet flange is connected to the downstream system of the product, and the outlet flange is threadedly connected to the system exhaust pipeline or is directly emptied.

[0009] Preferably, a limiting step is designed at the port of the external observation tube to prevent excessive compression of the sealing gasket during tightening, which causes uneven force on the inner and outer observation tubes and reduces the stiffness of the material.

[0010] Preferably, sealing grooves and limiting steps are designed at both ends of the inner observation tube from the outside to the inside, the sealing grooves are used to prevent the vacuum sealing ring from being cut during the assembly of the inner observation tube; the limiting steps are used to perform wedge-shaped end face sealing with the inner sealing gasket.

[0011] Preferably, the inlet flange and the outlet flange have a plurality of axial through holes for inserting screws and then symmetrically fastening them on both sides of the inlet and outlet flanges with bolts, so that the inlet flange and the outlet flange clamp the inner and outer sealing gaskets and the inner and outer observation tubes, ensuring the vacuum between the outer observation tube and the inner observation tube and the medium flowing in the inner observation tube will not leak out.

[0012] Preferably, the volume of the vacuum chamber formed between the inner observation tube and the outer observation tube is no more than 0.5 L, and the effective wall thickness of the outer observation tube and the inner observation tube are both 5 to 8 mm.

[0013] Preferably, the vacuum sealing ring is an O-shaped rubber ring that can withstand low environmental temperatures; the inner sealing pad and the outer sealing pad are made of a compressible low-temperature resistant sealing gasket material, and the material includes F4, copper or soft aluminum.

[0014] Preferably, the outer observation tube and the inner observation tube are made of PMMA or quartz.

[0015] An assembly method of a cryogenic pipeline visualization device for a liquid rocket engine test comprises:

[0016] Install the outer sealing gasket in the annular sealing groove of the inlet flange, install the vacuum sealing ring in the sealing ring groove, install the inner sealing gasket in the wedge-shaped end face sealing groove of the raised sealing ring, and apply vacuum sealing mud that is resistant to low temperature environment around the vacuum sealing ring;

[0017] Assemble the inner observation tube and the inlet flange, confirm that the vacuum sealing ring enters the straight pipe section through the inner observation tube sealing groove, and after the inner observation tube limit step contacts the inner sealing gasket, put the outer observation tube into the outer sealing gasket, place the inner sealing gasket on the free end of the inner observation tube, and put the outer sealing gasket into the free end of the outer observation tube;

[0018] Place the vacuum sealing ring into the sealing ring groove of the raised sealing ring of the outlet flange, and evenly apply low-temperature resistant vacuum mud; install the outlet flange in place, confirm that the inner observation tube and the outer observation tube are perpendicular to the inlet flange and the outlet flange, and use bolts and nuts to symmetrically tighten the inlet flange and the outlet flange, and finally make both ends of the inner observation tube contact with the inner sealing gasket, and both ends of the outer observation tube contact with the outer sealing gasket, and the vacuum sealing rings all stay in the sealing ring groove of the raised sealing ring;

[0019] Shake and observe to check, and the assembly is completed after confirmation.

[0020] A method for using a cryogenic pipeline visualization device for liquid rocket engine testing, comprising:

[0021] Connect the inlet flange of the equipped ultra-low temperature pipeline visualization device to the downstream system of the product, and connect the outlet flange to the system exhaust pipeline threadedly or directly exhaust it;

[0022] Connect the vacuum pump to the vacuum quick-release connector welded on the side of the inlet flange, turn on the vacuum pump, and when the vacuum degree is better than 4.0×10 -3 After pa, ultra-low temperature medium was introduced into the inner observation tube, and the medium was observed to flow in the inner observation tube.

[0023] The beneficial effects of the present invention compared with the prior art are:

[0024] The ultra-low temperature pipeline visualization device of the present invention has been installed at the outlet of the ultra-low temperature test system for many times to conduct verification tests, and the flow of ultra-low temperature medium can be successfully observed. It can be seen from the above specific technical solution that it has at least the following beneficial effects:

[0025] (1) The present application adopts a combination of a radial low-temperature resistant O-ring seal and an axial wedge-shaped end face seal, wherein the O-ring is used to ensure the vacuum degree and the wedge-shaped end face seal is used for medium sealing.

[0026] (2) The present invention uses bolts and nuts (the bolts and nuts of the present invention achieve the effect of uniform force during the compression process) to compress the observation tube with the inlet flange and the outlet flange, and the installation is symmetrical, with good sealing effect. The device has a simple structure, is easy to disassemble and inspect, and has the advantages of low installation and maintenance costs.

[0027] (3) The present invention uses a wedge-shaped sealing gasket, which has a sealing property and a guiding function at the same time, so as to facilitate the assembly process to ensure that the inlet flange, the outlet and the inner observation tube are perpendicular to each other, thereby reducing the difficulty of assembling the device.

[0028] (4) The limiting steps designed for the outer observation tube and the inner observation tube of the present invention have a self-limiting design to prevent damage to the observation tube during the tightening process and reduce the assembly success rate due to over-positioning.

[0029] (5) The present invention has a 360° observation window, which can freely define the installation position according to the direction of the system pipeline, observe the medium flow in all directions, and observe the flow state of ultra-low temperature fluids of different densities. It is suitable for observing various ultra-low temperature media such as liquid nitrogen.

[0030] (6) The present invention adopts a vacuum jacket structure, and after confirming that the vacuum degree of the outer observation tube and the inner observation tube reaches better than 4.0×10 -3 After pa, the total heat leakage can be maintained at a low level, thus preventing the alternating stress generated by heat exchange from causing deformation and rupture of the observation tube. The device is installed downstream of the test system to observe the flow of low-temperature media. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 An overall structural diagram of a visualization device for ultra-low temperature piping for a liquid rocket engine test system provided in an embodiment of the present application.

[0032] Figure 2 Schematic diagram of the inlet flange provided for this application.

[0033] Figure 3 Schematic diagram of the external observation tube provided for this application.

[0034] Figure 4 Schematic diagram of the internal observation tube provided for this application.

[0035] Figure 5 Schematic diagram of the outlet flange provided for this application.

[0036] Description of reference numerals:

[0037] 1. Inlet flange; 11. Axial hole; 12. Radial hole; 13. Raised sealing ring; 14. Annular sealing groove; 15. Sealing ring groove; 16. Wedge-shaped end face sealing groove

[0038] 2. Nut; 3. Vacuum quick-release connector; 4. Stud;

[0039] 5. External observation tube; 51. External observation tube limit step;

[0040] 6. Internal observation tube; 61. Internal observation tube limit step; 62. Internal observation tube sealing groove

[0041] 7. Inner sealing gasket; 8. Vacuum sealing ring; 9. Outer sealing gasket;

[0042] 10. Outlet flange; 101. Raised sealing ring; 102. Annular sealing groove; 103. Sealing ring groove; 104. Wedge-shaped end face sealing groove DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention more clearly understood, the spirit of the contents disclosed by the present invention will be clearly explained with the accompanying drawings and detailed descriptions below. After understanding the embodiments of the contents of the present invention, any technician in the relevant technical field can change and modify the techniques taught by the contents of the present invention without departing from the spirit and scope of the contents of the present invention.

[0044] The exemplary embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention. In addition, elements / components with the same or similar reference numerals used in the drawings and embodiments are used to represent the same or similar parts.

[0045] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0046] As used herein, "and / or" includes any or all combinations of the items described.

[0047] The terms "aligned", "vertical", "around", "uniform", "in place", "normal", etc. used herein are used to modify any quantity or error that can vary slightly, but these slight changes or errors do not change their essence. Generally speaking, the range of slight changes or errors modified by such terms can be 5% or other values ​​in the embodiment. Those skilled in the art should understand that the aforementioned values ​​can be adjusted according to actual needs and are not limited thereto.

[0048] Certain terms that are used to describe the invention are discussed below or elsewhere in the specification to provide additional guidance to those skilled in the art regarding the description of the invention.

[0049] The inlet flange 1 should first be equipped with the outer sealing gasket 9 in the annular sealing groove 14, the vacuum sealing ring 8 in the sealing ring groove 15, the inner sealing gasket 7 in the wedge-shaped end face sealing groove 16 of the raised sealing ring 13, and low-temperature resistant vacuum sealing mud is applied around the vacuum sealing ring 8, the inner observation tube 6 is assembled with the inlet flange 1, and after confirming that the vacuum sealing ring 8 enters the straight pipe section (the straight pipe section is the part between 61 and 62) through the inner observation tube sealing groove 62, and the inner observation tube limit step 61 contacts the inner sealing gasket 7, the outer observation tube 5 is placed in the outer sealing gasket 9, the inner sealing gasket 7 is placed on the free end of the inner observation tube 6, and the outer sealing gasket 9 is placed in the free end of the outer observation tube 5 (from right to left). Install on the left, the installation process is 1, 5, 6, 7, 8, 9, 10), put the vacuum sealing ring 8 into the sealing ring groove 103 of the raised sealing ring 101, and evenly apply low-temperature resistant vacuum mud (each reassembly requires evenly applying vacuum mud around the vacuum sealing ring); install the outlet flange 10 in place, confirm that the inner observation tube 6 and the outer observation tube 5 are perpendicular to the inlet flange 1 and the outlet flange 10, and use bolts and nuts to symmetrically tighten the visualization device of the ultra-low temperature pipeline, and finally make both ends of the inner observation tube 6 contact with the inner sealing gasket 7, and both ends of the outer observation tube 5 contact with the outer sealing gasket 9, and the vacuum sealing ring 8 all stay in the sealing ring grooves 15 and 103 of the raised sealing rings 13 and 101. There is no abnormal sound when shaking the device, and there is no relative movement between the outer observation tube 5 and the inlet flange 1 and the outlet flange 10. The inlet flange 1 and the outlet flange 10 are visually horizontal, which can be regarded as assembly completion. After completion, the assembly state is as follows Figure 1 shown.

[0050] Connect the inlet flange of the visualization device of the ultra-low temperature pipeline to the downstream system of the product, and thread the outlet flange to the system exhaust pipeline or directly exhaust it. The thickness of the inlet flange used in this example is 20mm, the thickness of the outlet flange is 16mm, the effective wall thickness of the external observation tube and the internal observation tube are both 5mm, and the volume of the vacuum cavity formed between the internal observation tube and the external observation tube is not more than 0.5L. Connect the vacuum pump to the 3 vacuum quick-release connectors welded on the side of the inlet flange, turn on the vacuum pump, and observe that the vacuum degree can drop normally. When the vacuum degree is better than 4.0×10 -3 After pa, ultra-low temperature medium (temperature range under liquid oxygen and liquid nitrogen environment) is allowed to be introduced for use. After the device is cooled, it can be observed (with the naked eye or the collection system) that the medium is flowing in the inner observation tube.

[0051] The visualization device of ultra-low temperature pipelines described in this application has been successfully applied to ultra-low temperature test systems many times. When the flow of liquid refrigerant is observed through the device, it can be regarded that the system has reached heat transfer equilibrium with the refrigerant. The above is only an illustrative specific implementation method of this application. The device described in this application can also be used to verify the heat transfer efficiency of the vaporizer and other example applications. Without departing from the concept and principle of this application, any equivalent changes and modifications made by any technician in this field should fall within the scope of protection of this application.

[0052] Parts not described in detail in the present invention belong to common knowledge of those skilled in the art.

Claims

1. A cryogenic pipeline visualization device for liquid rocket engine testing, characterized in that include: Inlet flange, outer gasket, vacuum seal ring, inner gasket, outer observation tube, inner observation tube, outlet flange, vacuum quick-release connector; The inlet flange and the outlet flange have the same inner sealing structure, both of which include an annular sealing groove, and an outer sealing gasket is installed in the annular sealing groove to seal with the outer observation tube to maintain the vacuum between the outer observation tube and the inner observation tube; a raised sealing ring is arranged at the inner center, and the raised sealing ring includes a sealing ring groove and a wedge-shaped end face sealing groove, wherein a vacuum sealing ring is installed in the sealing ring groove to maintain the vacuum between the outer observation tube and the inner observation tube; an inner sealing gasket is installed in the wedge-shaped end face sealing groove to prevent the medium in the inner observation tube from leaking out; The inlet flange has a radial hole on the side and an axial hole on the inside, and the radial hole is connected to the axial hole; the radial hole is welded with a vacuum quick-release connector, and the axial hole is located between the annular sealing groove and the raised sealing ring to provide a vacuum between the outer observation tube and the inner observation tube; The inlet flange and the outlet flange are fastened by a structural member so that the inlet flange and the outlet flange clamp the inner and outer sealing gaskets and the inner and outer observation tubes.

2. The device according to claim 1, characterized in that: The inlet flange and the outlet flange are provided with threaded pipe joints on the outside, the inlet flange is connected to the downstream system of the product, and the outlet flange is threadedly connected to the system exhaust pipe or is directly exhausted.

3. The device according to claim 1, characterized in that: The outer observation tube is designed with a limiting step at the port to prevent the sealing gasket from being compressed too much during tightening, resulting in uneven force on the inner and outer observation tubes and reducing the material stiffness.

4. The device according to claim 1, characterized in that: Sealing grooves and limiting steps are designed at both ends of the inner observation tube from outside to inside in sequence. The sealing grooves are used to prevent the vacuum sealing ring from being cut when the inner observation tube is assembled; the limiting steps are used to perform wedge-shaped end face sealing with the inner sealing gasket.

5. The device according to claim 1, characterized in that: The inlet flange and the outlet flange are provided with a plurality of axial through holes for inserting screws and then symmetrically fastening them with bolts on both sides of the inlet and outlet flanges, so that the inlet flange and the outlet flange clamp the inner and outer sealing gaskets and the inner and outer observation tubes, ensuring the vacuum between the outer observation tube and the inner observation tube and the medium flowing in the inner observation tube will not leak out.

6. The device according to claim 1, characterized in that: The volume of the vacuum cavity formed between the inner observation tube and the outer observation tube is no more than 0.5L, and the effective wall thickness of the outer observation tube and the inner observation tube are both 5 to 8mm.

7. The device according to claim 1, characterized in that: The vacuum sealing ring adopts an O-shaped rubber ring that can withstand low environmental temperatures; the inner sealing pad and the outer sealing pad are made of compressible low-temperature resistant sealing gasket material, and the material includes F4, copper or soft aluminum.

8. The device according to claim 1, characterized in that: The outer observation tube and the inner observation tube are made of PMMA or quartz.

9. A method for assembling a cryogenic pipeline visualization device for liquid rocket engine testing, characterized in that include: Install the outer sealing gasket in the annular sealing groove of the inlet flange, install the vacuum sealing ring in the sealing ring groove, install the inner sealing gasket in the wedge-shaped end face sealing groove of the raised sealing ring, and apply vacuum sealing mud that is resistant to low temperature environment around the vacuum sealing ring; Assemble the inner observation tube and the inlet flange, confirm that the vacuum sealing ring enters the straight pipe section through the inner observation tube sealing groove, and after the inner observation tube limit step contacts the inner sealing gasket, put the outer observation tube into the outer sealing gasket, place the inner sealing gasket on the free end of the inner observation tube, and put the outer sealing gasket into the free end of the outer observation tube; Place the vacuum sealing ring into the sealing ring groove of the raised sealing ring of the outlet flange, and evenly apply low-temperature resistant vacuum mud; install the outlet flange in place, confirm that the inner observation tube and the outer observation tube are perpendicular to the inlet flange and the outlet flange, and use bolts and nuts to symmetrically tighten the inlet flange and the outlet flange, and finally make both ends of the inner observation tube contact with the inner sealing gasket, and both ends of the outer observation tube contact with the outer sealing gasket, and the vacuum sealing rings all stay in the sealing ring groove of the raised sealing ring; Shake and observe to check, and the assembly is completed after confirmation.

10. A method for using a cryogenic pipeline visualization device for liquid rocket engine testing, characterized in that include: Connect the inlet flange of the equipped ultra-low temperature pipeline visualization device to the downstream system of the product, and connect the outlet flange to the system exhaust pipeline threadedly or directly exhaust it; Connect the vacuum pump to the vacuum quick-release connector welded on the side of the inlet flange, turn on the vacuum pump, and when the vacuum degree is better than 4.0×10 -3 After pa, ultra-low temperature medium was introduced into the inner observation tube, and the medium was observed to flow in the inner observation tube.

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