Antenna window material ablation wave transmission test device

Abstract

An antenna window material ablation wave-transparent test device is used for test research of microwave antenna window material ablation wave-transparent performance in plasma jet, and is based on alternating current arc heater ground test equipment and combined with special requirements of antenna window ablation tests, the test device at the downstream of an arc heater is designed, and a microwave test system is utilized to test the ablation wave-transparent performance of the microwave antenna window material. Detection of microwave transmission performance change conditions before, during and after ablation of the antenna window test piece is completed, and support is provided for research and screening of wave-transparent materials of model departments.

Description

Technical Field

[0001] The present invention belongs to the research field of wave-transparent materials for aircraft antenna windows. Background Art

[0002] To improve the hit accuracy and enhance the electronic countermeasure capability, advanced tactical aircraft will adopt various new terminal guidance radar systems, such as millimeter-wave radar, frequency-agile radar, variable-frequency radar, etc. At the same time, dual-mode or multi-mode compound guidance is also adopted, such as passive radar / active radar, passive radar / infrared imaging, passive radar / TV imaging, etc., and image matching technology is applied to achieve map / terrain matching guidance. The radar seeker is located at the head of the aircraft. In order to protect the seeker antenna to work properly during flight, an antenna window that meets the usage requirements must be adopted. The antenna window is an important structural component of the seeker. It not only needs to ensure the necessary aerodynamic shape, withstand the aerodynamic heating and various loads during flight, and reduce the influence of the flight environment on the electronic equipment inside the cover, but also is the channel for transmitting and receiving electromagnetic waves. Therefore, it is required not only to have excellent environmental resistance and mechanical properties, but also to have excellent electromagnetic transmission characteristics and excellent high-temperature resistance. Thus, a multi-functional structure - heat-resistant - wave-transparent composite material must be used. In recent years, with the development of technology, the research field of aircraft antenna window materials has been continuously iterated and innovated. During the development and improvement of new materials, the wave-transmission effect needs to be identified through ground simulation tests; before the model is finalized, the selection of wave-transmission window materials also needs to be screened through ground simulation tests. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to develop a test device for simulating the ablation of wave-transparent materials for radar antenna windows.

[0004] The technical solution of the present invention: An ablation wave-transmission test device for antenna window materials, comprising an arc heater, a transition section, a mixing and stabilizing chamber, a diffuser section, a microwave experimental section, an inlet pipe, a microwave test system, a material for matching ablation, and an antenna window material;

[0005] The upstream of the transition section is connected to the arc chamber flange of the arc heater, and the downstream is connected to the inlet flange of the mixing and stabilizing chamber; the inlet pipe is located at the inlet of the mixing and stabilizing chamber and leads directly to the inner cavity of the mixing and stabilizing chamber; the inlet diameter of the mixing and stabilizing chamber is the same as the outlet diameter of the transition section, and the inlet size of the diffuser section is the same as the outlet of the mixing and stabilizing chamber; the microwave experimental section is the installation and bearing component for the material for matching ablation and the antenna window material. The material for matching ablation and the antenna window material are symmetrically installed on two side walls of the microwave experimental section. After installation, a rectangular flow channel sealed on all sides is formed. The material for matching ablation is used as the observation window for the antenna window material and the ablation matching part;

[0006] The gas flow heated by the arc heater enters the mixing and stabilizing chamber, mixes with a certain proportion of cold gas flow radially injected from the intake pipe to adjust the enthalpy value of the gas flow, and then is rectified into a rectangular flow field at the outlet and flows into the expansion section. It expands in the expansion section, reaches the predetermined Mach number and then flows into the microwave test section, ablates the antenna window material with the cooperation of the matching combustion material, and the microwave test system real-time collects the change of the wave-transmitting performance during the ablation process of the antenna window material.

[0007] Preferably, the microwave test system includes a microwave source, a transmitting antenna, a receiving antenna, and a receiving device;

[0008] During the test process, the transmitting antenna is placed outside the antenna window material, and the transmitting antenna is connected to the microwave source; the receiving antenna is placed outside the matching combustion material, and the receiving antenna connected to the receiving device real-time collects the change of the wave-transmitting performance during the ablation process of the antenna window material.

[0009] Preferably, the arc heater adopts an AC arc heater, and the current is reduced to less than 1000 A by multi-arm current equalization.

[0010] Preferably, the inlet diameter of the mixing and stabilizing chamber is the same as the outlet diameter of the transition section, expands to a straight section with a semi-cone angle of 70° - 80°, the length-diameter ratio of the straight section ≥ 1, and contracts from a circle to a rectangle at the downstream outlet end, and the two semi-cone angles of the contraction are 70° - 75° and 20° - 30° respectively.

[0011] Preferably, the inlet size of the expansion section is the same as the outlet of the mixing and stabilizing chamber, both are rectangles, the narrow side of the rectangle remains unchanged, and the wide side expands to the effective ablation side length of the wave-transmitting material carried by the microwave test section with a semi-cone angle of 15 - 20°.

[0012] Preferably, the inlet of the mixing and stabilizing chamber is circular, expands to Φ100 mm with a semi-cone angle of 75°, the length-diameter ratio of the Φ100 mm section ≥ 1, contracts from a circle of Φ100 mm to a rectangle of 30 mm × 12 mm at the downstream outlet end, and the two semi-cone angles are 72° and 24° respectively; the 12 mm narrow side at the inlet of the expansion section remains unchanged, and the 30 mm wide side expands to 90 mm with a semi-cone angle of 18° to form an outlet of 90 mm × 12 mm; after the matching combustion material and the antenna window material are installed in the microwave test section, a rectangular flow channel sealed on all sides is formed, and the effective ablation area is 90 mm × 90 mm.

[0013] Preferably, the matching combustion material is selected as quartz glass.

[0014] Preferably, the transition section, the mixing and stabilizing chamber, the expansion section, and the microwave test section are all inner and outer jacket sandwich water-cooled structures, the inner jacket material is selected as copper, and the outer jacket material is carbon steel.

[0015] Preferably, during the test, the transition section, the mixing and stabilizing chamber, the expansion section, and the microwave test section are all cooled with high-pressure water at 3-4 MPa. The high-pressure water is introduced from the bottom and discharged from the top to improve the cooling effect.

[0016] Advantages of the present invention: The present invention closely combines the research and development of radar antenna window materials and the requirements for screening model antenna window materials. Relying on an alternating current arc heater, a test device suitable for the ablation of wave-transparent materials is developed. During the test process, the change in the wave-transmission performance of the material is measured, which is of positive significance for the development of models and the screening of radar antenna windows with excellent ablation and wave-transmission performance. Brief Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the ablation and wave-transmission test device for the antenna window material of the alternating current arc heater.

[0018] Figure 2 It is the curve of the change in the wave-transmission performance of a certain antenna window material before, during, and after ablation. Detailed Embodiments

[0019] During the reentry flight of the aircraft, due to the effect of aerodynamic heating, the windward surface of the seeker antenna window will undergo high-temperature ablation, which affects the wave-transmission performance of the antenna window. In order to screen out the antenna window materials with better wave-transmission performance after ablation, this method uses an arc heater to carry out the ablation test of the antenna window material, and uses microwave testing technology to measure the change in the wave-transmission performance of the antenna window material during the ablation process, and directly gives the quantitative change in the wave-transmission performance of the antenna window material after ablation, serving the research and development and screening of wave-transparent materials for the antenna window.

[0020] The present invention consists of a test device and a microwave testing system. The test device includes an arc heater 1, a transition section 2, a mixing and stabilizing chamber 3, an expansion section 4, a microwave test section 5, an air inlet pipe 6, a matching ablation material 11, and an antenna window material 12. The test preferably uses a microwave testing system composed of a microwave source 7, a transmitting antenna 8, a receiving antenna 9, and a receiving device 10. The arc heater test device is used to simulate the aerodynamic heating environment of the antenna window, carry out the ablation test on the wave-transparent material, and monitor the change in the wave-transmission performance of the wave-transparent material of the antenna window during the ablation process in real time, and screen out the material with the most excellent ablation and wave-transmission performance.

[0021] The arc heater 1 selects an AC arc heater. The A, B, and C phase electrodes of this heater are arranged in a "star" pattern in space and are connected by a mixing chamber in the middle to form a heater with a three-phase symmetric "star" arc load. Its greatest feature is that the power supply is directly taken from the three-phase 10 kV industrial power grid, without the need for a complex and expensive rectifier power supply system. And because of the six-arm sharing, each arm can reach a relatively high total power when the current is ≤1000 A, providing a high-enthalpy flow field to effectively ablate the antenna window material. Under such current conditions, the heater electrodes basically do not generate thermal burn-out, thus providing a guarantee for the wave-transmitting flow field with high purity requirements.

[0022] The upstream of the described adapter section 2 is connected to the arc chamber flange of the arc heater 1, and the downstream is connected to the inlet flange of the mixing and stabilizing chamber 3; the inlet pipe 6 is located at the inlet of the mixing and stabilizing chamber 3, with an inner diameter of Φ6, symmetrically arranged in 2 paths, directly leading to the inner cavity of the mixing and stabilizing chamber 3, and is used to radially inject a certain proportion of cold air to adjust the enthalpy value of the total air flow; the inlet diameter of the mixing and stabilizing chamber 3 is the same as the outlet diameter of the adapter section 1, and expands to Φ100 mm at a semi-cone angle of 75°. The length-to-diameter ratio of the Φ100 mm section is ≥1, and the larger the length-to-diameter ratio, the more conducive to uniform air flow mixing; at the downstream outlet end, it shrinks from a Φ100 mm circle to a 30 mm×12 mm rectangle, with two semi-cone angles of 72° and 24° respectively; the inlet size of the expansion section 4 is the same as the outlet of the mixing and stabilizing chamber, which is 30 mm×12 mm. Among them, the 12 mm narrow side remains unchanged, and the 30 mm wide side expands to 90 mm at a semi-cone angle of 18° to form an outlet of 90 mm×12 mm; the microwave test section 5 is the installation and bearing component for the matching ablation material 11 and the antenna window material 12. The matching ablation material 11 is used as the observation window of the antenna window material 12 and the matching ablation part, with the same size as the antenna window material 12, which is 95 mm×90 mm. The two are symmetrically installed on the microwave test section 5 as two side walls. 95 mm is in the height direction, and there are 2.5 mm at the top and bottom for clamping. After installation, a rectangular flow-through channel sealed on all sides is formed, and the effective ablation area is 90 mm×90 mm;

[0023] In a preferred example given by the present invention, the matching ablation material 11 selects quartz glass with a melting point as high as 1713°C and a low coefficient of thermal expansion, which has stable performance. Its functions include not only closing the flow field but also serving as a window for observing the ablation process of the antenna window material 12;

[0024] The adapter section 2, the mixing and stabilizing chamber 3, the expansion section, and the microwave test section 5 are all of an inner and outer sleeve sandwich water-cooled structure. The inner sleeve material is selected as copper with good thermal conductivity, and the outer sleeve material is made of high-quality carbon steel. During the test, high-pressure water at 3.5 MPa is passed through each section for cooling, and the high-pressure water adopts a water flow direction of entering from the bottom and exiting from the top to improve the cooling effect;

[0025] During the test, the high-temperature and high-pressure gas heated by the arc heater 1 flows into the mixing and stabilizing chamber 2, mixes with a certain proportion of cold gas radially injected from the intake pipe 6 to adjust the enthalpy value of the gas flow, and then is rectified into a rectangular flow field at the outlet and flows into the expansion section 4. It expands in the expansion section 4, reaches a certain Mach number and then flows into the microwave test section 5, where the antenna window material 12 is ablated with the cooperation of the burning material 11. The transmitting antenna 8 and the receiving antenna 9 of the microwave test system are respectively placed on both sides of the antenna window material 12 and the burning material 11 to dynamically measure the transmission curve in real time during the test process. As Figure 2 shown, the change in the transmission rate of the antenna window material during the entire test process before and after ablation is obtained, providing support for the development and screening of the antenna window transmission material by the model department.

[0026] The unpublicized technology of the present invention belongs to the common general knowledge of those skilled in the art.

Claims

1. An ablation and wave - transmitting test device for antenna window materials, characterized in that: It includes an arc heater, a transition section, a mixing and stabilizing chamber, a diffuser section, a microwave test section, an intake pipe, a microwave test system, a material for matching combustion, and an antenna window material; The upstream of the transition section is connected to the arc chamber flange of the arc heater, and the downstream is connected to the inlet flange of the mixing and stabilizing chamber; the intake pipe is located at the inlet of the mixing and stabilizing chamber and directly leads to the inner cavity of the mixing and stabilizing chamber; the inlet diameter of the mixing and stabilizing chamber is the same as the outlet diameter of the transition section, and the inlet size of the diffuser section is the same as the outlet of the mixing and stabilizing chamber; the microwave test section is an installation and bearing component for the material for matching combustion and the antenna window material. The material for matching combustion and the antenna window material are symmetrically installed on the two side walls of the microwave test section. After installation, a rectangular flow passage sealed on all sides is formed. The material for matching combustion is used as the observation window of the antenna window material and for cooperating with the ablation part; The gas heated by the arc heater flows into the mixing and stabilizing chamber, mixes with a certain proportion of cold air flow radially injected from the intake pipe to adjust the enthalpy value of the air flow, and then is rectified into a rectangular flow field at the outlet and flows into the diffuser section. It expands in the diffuser section, reaches a predetermined Mach number and then flows into the microwave test section, and ablates the antenna window material with the cooperation of the material for matching combustion. The microwave test system real-time collects the change in the wave transmission performance during the ablation process of the antenna window material.

2. The ablation and wave - transmitting test device for an antenna window material according to claim 1, wherein: The microwave test system includes a microwave source, a transmitting antenna, a receiving antenna, and a receiving device; During the test process, the transmitting antenna is placed outside the antenna window material, and the transmitting antenna is connected to the microwave source; the receiving antenna is placed outside the material for matching combustion, and the receiving antenna connected to the receiving device real-time collects the change in the wave transmission performance during the ablation process of the antenna window material.

3. An ablation and wave - transmitting test device for an antenna window material according to claim 1, characterized in that: The arc heater adopts an AC arc heater, and the current is reduced to below 1000 A through multi-arm equal current sharing.

4. An ablation and wave-transparent test device for an antenna window material according to claim 1, characterized in that: The inlet diameter of the mixing and stabilizing chamber is the same as the outlet diameter of the transition section, expands to a straight section with a half-cone angle of 70° - 80°, and the length-diameter ratio of the straight section ≥ 1. At the downstream outlet end, it shrinks from a circle to a rectangle, and the two half-cone angles of the shrinkage are 70° - 75° and 20° - 30° respectively.

5. An ablation and wave-transparent test device for an antenna window material according to claim 1, characterized in that: The inlet size of the diffuser section is the same as the outlet of the mixing and stabilizing chamber, both are rectangular. The narrow side of the rectangle remains unchanged, and the wide side expands to the effective ablation side length of the wave-transmitting material carried by the microwave test section with a half-cone angle of 15 - 20°.

6. The ablation and wave-transmitting test device for an antenna window material according to claim 1, characterized in that: The inlet of the mixing and stabilizing chamber is circular, expands to Φ100 mm with a half-cone angle of 75°, and the length-diameter ratio of the Φ100 mm section ≥ 1. At the downstream outlet end, it shrinks from a Φ100 mm circle to a 30 mm × 12 mm rectangle, and the two half-cone angles are 72° and 24° respectively; the 12 mm narrow side at the inlet of the diffuser section remains unchanged, and the 30 mm wide side expands to 90 mm with a half-cone angle of 18° to form a 90 mm × 12 mm outlet; after the material for matching combustion and the antenna window material are installed in the microwave test section, a rectangular flow passage sealed on all sides is formed, and the effective ablation area is 90 mm × 90 mm.

7. An ablation and wave-transparent test device for an antenna window material according to claim 1, characterized in that: The material for matching combustion selects quartz glass.

8. An ablation and wave - transmitting test device for an antenna window material according to claim 1, characterized in that: The transition section, the mixing and stabilizing chamber, the diffuser section, and the microwave test section are all inner and outer jacket sandwich water-cooled structures. The inner jacket material is selected as copper, and the outer jacket material is carbon steel.

9. An ablation and wave - transmitting test device for an antenna window material according to claim 8, characterized in that: During the experiment, the transition section, the mixing and stabilizing chamber, the expansion section, and the microwave experimental section are all cooled with high-pressure water at 3-4 MPa. The high-pressure water flows in from the bottom and out from the top to enhance the cooling effect.

Images