Variable-mach-number variable-area convergent-divergent nozzle and method of use

Abstract

The present application belongs to the technical field of aerodynamic heat protection ground test equipment of space vehicles, and discloses a variable Mach number telescopic conical nozzle and a using method thereof. The variable Mach number telescopic conical nozzle comprises a nozzle throat section, a first-stage nozzle expansion section, a second-stage nozzle expansion section and a nozzle exit section which are connected in turn from front to back, a sealing element is arranged on the contact surface of each section, and each section is installed with a matched electric hydraulic push rod to realize the pushing and pulling and positioning of the corresponding section. The variable Mach number telescopic conical nozzle and the using method thereof utilize the sleeve type sandwich water-cooled nozzle, combine with the movable heater base, realize the change of the nozzle exit diameter during the operation of the arc wind tunnel, and thus change the pressure, heat flow and other parameters of the nozzle exit flow field in a large range in the ground heat protection test of the hypersonic vehicle heat protection system, realize the simulation in a wide parameter range, widen the test capacity of the arc wind tunnel, and have the engineering practical value.

Description

Technical Field

[0001] This invention belongs to the technical field of aerodynamic heat protection ground test equipment for spacecraft, specifically relating to a variable Mach number telescopic cone nozzle and its usage method. Background Technology

[0002] Currently, with the rapid development of hypersonic flight technology, ground-based thermal protection testing of hypersonic vehicle thermal protection systems places increasingly higher demands on the operational capabilities of arc wind tunnels. In particular, the wide-range pressure changes and severe force / thermal coupling encountered by hypersonic vehicles during wide-airspace flight require arc wind tunnels to provide a large range of pressure and heat flux variations during thermal protection testing. For arc wind tunnels, a nozzle with fixed throat and exit dimensions has a fixed nominal Mach number. If it is necessary to change parameters such as pressure and heat flux at the nozzle exit flow field, this can only be achieved by adjusting the operating parameters of the arc heater. However, pressure changes in the conventional high-temperature, high-speed test flow field are achieved by matching the start-up parameters of the arc heater, such as airflow and current, to the nozzle. Due to the limited adjustment range of these parameters, some thermal protection testing tests with large pressure variations during hypersonic flight cannot be conducted continuously and must be carried out in stages using different nozzles, significantly reducing the effectiveness of the testing.

[0003] Currently, there is an urgent need to develop a variable Mach number telescopic conical nozzle and its application method for use in electric arc wind tunnels to improve the parameter variation range of the high-temperature and high-speed test flow field. Summary of the Invention

[0004] One technical problem to be solved by the present invention is to provide a variable Mach number telescopic conical nozzle, and another technical problem to be solved by the present invention is to provide a method of using the variable Mach number telescopic conical nozzle, so as to overcome the defects of the prior art.

[0005] The variable Mach number telescopic conical nozzle of the present invention includes a nozzle throat section, a first-stage nozzle expansion section, a second-stage nozzle expansion section and a nozzle outlet section that are stacked and connected from front to back. Each section has a sealing element on its contact surface and an electric hydraulic push rod installed in each section to realize the pushing, pulling and positioning of the corresponding section. The nozzle throat section, the first-stage nozzle expansion section, and the second-stage nozzle expansion section are equipped with segment connection flanges; the nozzle outlet section is equipped with a test section connection flange. Cooling water pipes are installed inside the connecting flanges of each section and the connecting flange of the test section, with inlet and outlet ports on the surface.

[0006] Furthermore, the telescopic dimension of the variable Mach number telescopic cone nozzle is matched with the moving distance of the arc heater.

[0007] Furthermore, the inner surfaces of the nozzle throat section, the first-stage nozzle expansion section, the second-stage nozzle expansion section, and the nozzle exit section are all conical rotating surfaces with a half-cone angle ranging from 5° to 10°. The inner surface joints between the sections have no reverse steps, and the difference between the forward joints is less than or equal to 1 mm.

[0008] Furthermore, the first-stage and second-stage nozzle expansion sections are expanded into several stages of nozzle expansion sections.

[0009] Furthermore, the nozzle throat section, the first-stage nozzle expansion section, the second-stage nozzle expansion section, and the nozzle outlet section are all single-end flange water inlet and outlet, and sandwich water-cooled welded structures.

[0010] Furthermore, sliding support frames are installed at the connecting flanges of each section and the connecting flange of the test section, and each sliding support frame moves with the corresponding section.

[0011] Furthermore, the sealing element is made of silicone rubber.

[0012] Furthermore, the electro-hydraulic push rods corresponding to the nozzle throat section, the first-stage nozzle expansion section, the second-stage nozzle expansion section, and the nozzle exit section are evenly distributed circumferentially, and the combined force of the electro-hydraulic push rods corresponding to each section is greater than the maximum vacuum suction force of the corresponding section; the cylinder of the electro-hydraulic push rod is fixedly connected to the connecting flange of the corresponding section, and the head of the electro-hydraulic push rod is fixedly connected to the connecting flange of the next section by a threaded connection, and the extension length of the electro-hydraulic push rod is not less than the inner surface length of the next section.

[0013] Furthermore, the cooling water pipeline includes several sets of inlet and outlet cooling pipes connected by a ring-shaped pipeline.

[0014] The method of using the variable Mach number telescopic cone nozzle of the present invention includes the following steps: S10. Install a variable Mach number telescopic cone nozzle; Install a movable heater base on the arc heater of the arc wind tunnel; connect the section connecting flange of the nozzle throat section to the arc heater; connect the test section connecting flange to the test section of the arc wind tunnel, with the outlet located inside the test section; S20. Determine the test conditions for the variable Mach number telescopic cone nozzle; Based on the pressure and heat flow parameter variation ranges required for the ground thermal protection test of the hypersonic vehicle thermal protection system, the length variation range of the variable Mach number telescopic conical nozzle is determined, and the test conditions for the variable Mach number telescopic conical nozzle are selected. S30. Conduct ground-based thermal protection assessment tests on the thermal protection system of hypersonic aircraft; The variable Mach number telescopic conical nozzle is fully extended to its longest position. The arc wind tunnel is then activated to complete the first stage of the hypersonic vehicle thermal protection system ground-based thermal protection assessment. Simultaneously, the electro-hydraulic push rod corresponding to the nozzle exit section is retracted, and the position of the arc heater is adjusted via the movable heater base to complete the second stage of the hypersonic vehicle thermal protection system ground-based thermal protection assessment. The electro-hydraulic push rod corresponding to the second-stage nozzle expansion section is retracted, and the position of the arc heater is adjusted via the movable heater base to complete the third stage of the hypersonic vehicle thermal protection system ground-based thermal protection assessment. Finally, the electro-hydraulic push rod corresponding to the first-stage nozzle expansion section is retracted, and the position of the arc heater is adjusted via the movable heater base to complete the fourth stage of the hypersonic vehicle thermal protection system ground-based thermal protection assessment. Conversely, according to the test plan, the variable Mach number telescopic conical nozzle is fully retracted and gradually extended to conduct a ground-based thermal protection test of the hypersonic vehicle's thermal protection system. S40. Shut down the electric arc wind tunnel and complete the ground-based thermal protection test of the hypersonic vehicle's thermal protection system.

[0015] The variable Mach number telescopic conical nozzle and its application method of the present invention utilize a sleeve-type jacketed water-cooled nozzle combined with a movable heater base to realize the change of nozzle outlet diameter during the operation of the electric arc wind tunnel. This allows for a wide range of changes in parameters such as pressure and heat flux of the nozzle outlet flow field in ground thermal protection system test of hypersonic aircraft, enabling simulation of a wide parameter range, expanding the testing capabilities of the electric arc wind tunnel, and possessing practical engineering value. Attached Figure Description

[0016] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0017] Figure 1 This is a schematic diagram of the variable Mach number telescopic conical nozzle of the present invention; Figure 2 This is a schematic diagram showing the changing position of the expansion section of the first-stage nozzle of the variable Mach number telescopic conical nozzle of the present invention. Figure 3 This is a schematic diagram showing the changing position of the expansion section of the second-stage nozzle in the variable Mach number telescopic conical nozzle of the present invention. Figure 4 This is a schematic diagram showing the contraction of each nozzle expansion section into its final position in the variable Mach number telescopic conical nozzle of the present invention.

[0018] In the diagram, 1. Nozzle throat section; 2. Electro-hydraulic push rod; 3. First-stage nozzle expansion section; 4. Seal; 5. Second-stage nozzle expansion section; 6. Nozzle outlet section; 7. Section connecting flange; 8. Test section connecting flange; 9. Cooling water pipe; 10. Inlet; 11. Outlet. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] Example: Figure 1 As shown, the variable Mach number telescopic conical nozzle of this embodiment includes a nozzle throat section 1, a first-stage nozzle expansion section 3, a second-stage nozzle expansion section 5, and a nozzle outlet section 6 that are stacked and connected from front to back. Each section has a sealing element 4 on its contact surface and an electric hydraulic push rod 2 installed on each section to realize the pushing, pulling, and positioning of the corresponding section. A section connecting flange 7 is installed at the front end of nozzle throat section 1, first-stage nozzle expansion section 3 and second-stage nozzle expansion section 5; a test section connecting flange 8 is installed at the front end of nozzle outlet section 6. Cooling water pipes 9 are installed inside the connecting flanges 7 of each section and the connecting flange 8 of the test section, with inlet 10 and outlet 11 on the surface.

[0021] Furthermore, the telescopic dimension of the variable Mach number telescopic cone nozzle is matched with the moving distance of the arc heater.

[0022] Furthermore, the inner surfaces of the nozzle throat section 1, the first-stage nozzle expansion section 3, the second-stage nozzle expansion section 5, and the nozzle outlet section 6 are all conical rotating surfaces with a half-cone angle ranging from 5° to 10°. The inner surface joints between the sections have no reverse steps, and the difference between the forward joints is less than or equal to 1 mm.

[0023] Furthermore, the first-stage nozzle expansion section 3 and the second-stage nozzle expansion section 5 are expanded into several stages of nozzle expansion sections.

[0024] Furthermore, the nozzle throat section 1, the first-stage nozzle expansion section 3, the second-stage nozzle expansion section 5, and the nozzle outlet section 6 are all single-end flange water inlet and outlet, and sandwich water-cooled welded structures.

[0025] Furthermore, sliding support frames are installed at the connecting flanges 7 of each section and the connecting flange 8 of the test section, and each sliding support frame moves with the corresponding section.

[0026] Furthermore, the sealing element 4 is made of silicone rubber.

[0027] Furthermore, the electro-hydraulic push rods 2 corresponding to the nozzle throat section 1, the first-stage nozzle expansion section 3, the second-stage nozzle expansion section 5, and the nozzle outlet section 6 are evenly distributed circumferentially, and the combined force of the electro-hydraulic push rods 2 corresponding to each section is greater than the maximum vacuum suction force of the corresponding section; the cylinder of the electro-hydraulic push rod 2 is fixedly connected to the connecting flange of the corresponding section, and the head of the electro-hydraulic push rod 2 is fixedly connected to the connecting flange of the next section by a threaded connection, and the extension length of the electro-hydraulic push rod 2 is not less than the inner surface length of the next section.

[0028] Furthermore, the cooling water pipe 9 includes several sets of inlet and outlet cooling pipes connected by a ring pipe.

[0029] The method of using the variable Mach number telescopic cone nozzle in this embodiment includes the following steps: S10. Install a variable Mach number telescopic cone nozzle; Install a movable heater base on the arc heater of the arc wind tunnel; connect the section connecting flange 7 of the nozzle throat section 1 to the arc heater; connect the test section connecting flange 8 to the test section of the arc wind tunnel, with the outlet located inside the test section. S20. Determine the test conditions for the variable Mach number telescopic cone nozzle; Based on the pressure and heat flow parameter variation ranges required for the ground thermal protection test of the hypersonic vehicle thermal protection system, the length variation range of the variable Mach number telescopic conical nozzle is determined, and the test conditions for the variable Mach number telescopic conical nozzle are selected. S30. Conduct ground-based thermal protection assessment tests on the thermal protection system of hypersonic aircraft; like Figure 1 As shown, the variable Mach number telescopic conical nozzle is fully extended, so that it is at its longest point. The arc wind tunnel is then activated to complete the first phase of the ground-based thermal protection test of the hypersonic vehicle's thermal protection system. Figure 2 As shown, the electro-hydraulic push rod 2 corresponding to the synchronous contraction nozzle exit section 6 is used, and the position of the arc heater is adjusted accordingly through the movable heater base of the arc heater to complete the ground heat protection test of the hypersonic vehicle thermal protection system in the second stage; as shown Figure 3 As shown, the electro-hydraulic push rod 2 corresponding to the synchronous contraction of the second-stage nozzle expansion section 5 is adjusted, and the position of the arc heater is adjusted accordingly via the movable heater base of the arc heater, completing the ground heat protection test of the hypersonic vehicle thermal protection system in the third stage; as shown Figure 4 As shown, the electro-hydraulic push rod 2 corresponding to the expansion section 3 of the first-stage nozzle is synchronously contracted, and the position of the arc heater is adjusted accordingly through the movable heater base of the arc heater to complete the ground heat protection test of the hypersonic vehicle thermal protection system in the fourth stage. Conversely, according to the test plan, the variable Mach number telescopic cone nozzle is fully retracted, following the direction from... Figures 4 to 1 In sequence, the variable Mach number telescopic cone nozzle is gradually opened to conduct ground heat protection test of the hypersonic vehicle's thermal protection system. S40. Shut down the electric arc wind tunnel and complete the ground-based thermal protection test of the hypersonic vehicle's thermal protection system.

[0030] In this embodiment, the outlet inner diameter of nozzle throat section 1 is ΦD4, and the corresponding length of electro-hydraulic push rod 2 is L6; the outlet inner diameter of first-stage nozzle expansion section 3 is ΦD3, the corresponding length of the conical rotating surface is L5, and the corresponding length of electro-hydraulic push rod 2 is L4; the outlet inner diameter of second-stage nozzle expansion section 5 is ΦD2, the corresponding length of the conical rotating surface is L3, and the corresponding length of electro-hydraulic push rod 2 is L2; ​​the outlet inner diameter of nozzle outlet section 6 is ΦD1, and the corresponding length of the conical rotating surface is L1. Wherein, L6≥L5, L4≥L3, and L2≥L1.

[0031] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. For those skilled in the art, all features disclosed in the present invention, or all steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A variable Mach number telescopic conical nozzle, characterized in that, The variable Mach number telescopic conical nozzle includes a nozzle throat section (1), a first-stage nozzle expansion section (3), a second-stage nozzle expansion section (5), and a nozzle outlet section (6) that are stacked and connected from front to back. Each section has a sealing element (4) on its contact surface and an electric hydraulic push rod (2) installed on each section to realize the pushing, pulling, and positioning of the corresponding section. The nozzle throat section (1), the first-stage nozzle expansion section (3) and the second-stage nozzle expansion section (5) are equipped with section connecting flanges (7); the nozzle outlet section (6) is equipped with test section connecting flanges (8). Cooling water pipes (9) are installed inside the connecting flanges (7) of each section and the connecting flanges (8) of the test section, with inlet (10) and outlet (11) on the surface.

2. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, The telescopic dimension of the variable Mach number telescopic cone nozzle is matched with the moving distance of the arc heater.

3. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, The inner surfaces of the nozzle throat section (1), the first-stage nozzle expansion section (3), the second-stage nozzle expansion section (5) and the nozzle outlet section (6) are all conical rotating surfaces with a half-cone angle range of 5° to 10°. There are no reverse steps at the inner surface joints between the sections, and the difference between the forward joints is less than or equal to 1 mm.

4. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, The first-stage nozzle expansion section (3) and the second-stage nozzle expansion section (5) are expanded into several stages of nozzle expansion sections.

5. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, The nozzle throat section (1), the first-stage nozzle expansion section (3), the second-stage nozzle expansion section (5) and the nozzle outlet section (6) are all single-end flange water inlet and outlet, and sandwich water-cooled welded structures.

6. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, Sliding support frames are installed at the connecting flanges (7) of each section and the connecting flanges (8) of the test section, and each sliding support frame moves with the corresponding section.

7. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, The sealing element (4) is made of silicone rubber.

8. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, The electro-hydraulic push rods (2) corresponding to the nozzle throat section (1), the first-stage nozzle expansion section (3), the second-stage nozzle expansion section (5), and the nozzle outlet section (6) are evenly distributed circumferentially. The combined force of the electro-hydraulic push rods (2) corresponding to each section is greater than the maximum vacuum suction force of the corresponding section. The cylinder of the electro-hydraulic push rod (2) is fixedly connected to the connecting flange of the corresponding section. The head of the electro-hydraulic push rod (2) is fixedly connected to the connecting flange of the next section by a threaded connection. The extension length of the electro-hydraulic push rod (2) is not less than the inner surface length of the next section.

9. The variable Mach number telescopic conical nozzle according to claim 1, characterized in that, The cooling water pipe (9) includes several sets of inlet and outlet cooling pipes connected by a ring pipe.

10. A method of using a variable Mach number telescopic conical nozzle, which is used in any one of the variable Mach number telescopic conical nozzles according to claims 1 to 9, characterized in that, The method of use includes the following steps: S10. Install a variable Mach number telescopic cone nozzle; Install a movable heater base on the electric arc heater of the electric arc wind tunnel; connect the section connecting flange (7) of the nozzle throat section (1) to the electric arc heater; connect the test section connecting flange (8) to the test section of the electric arc wind tunnel, with the outlet located inside the test section; S20. Determine the test conditions for the variable Mach number telescopic cone nozzle; Based on the pressure and heat flow parameter variation ranges required for the ground thermal protection test of the hypersonic vehicle thermal protection system, the length variation range of the variable Mach number telescopic conical nozzle is determined, and the test conditions for the variable Mach number telescopic conical nozzle are selected. S30. Conduct ground-based thermal protection assessment tests on the thermal protection system of hypersonic aircraft; The variable Mach number telescopic conical nozzle is fully extended, so that the variable Mach number telescopic conical nozzle is at its longest point. The electric arc wind tunnel is activated to complete the first stage of the hypersonic vehicle thermal protection system ground thermal protection test. The electric hydraulic push rod (2) corresponding to the nozzle exit section (6) is simultaneously contracted, and the position of the electric arc heater is adjusted accordingly through the movable heater base of the electric arc heater to complete the second stage of the hypersonic vehicle thermal protection system ground thermal protection test. The electric hydraulic push rod (2) corresponding to the second stage nozzle expansion section (5) is simultaneously contracted, and the position of the electric arc heater is adjusted accordingly through the movable heater base of the electric arc heater to complete the third stage of the hypersonic vehicle thermal protection system ground thermal protection test. The electric hydraulic push rod (2) corresponding to the first stage nozzle expansion section (3) is simultaneously contracted, and the position of the electric arc heater is adjusted accordingly through the movable heater base of the electric arc heater to complete the fourth stage of the hypersonic vehicle thermal protection system ground thermal protection test. Conversely, according to the test plan, the variable Mach number telescopic conical nozzle is fully retracted and gradually extended to conduct a ground-based thermal protection test of the hypersonic vehicle's thermal protection system. S40. Shut down the electric arc wind tunnel and complete the ground-based thermal protection test of the hypersonic vehicle's thermal protection system.

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