A low compensation spray structure

Abstract

The present invention relates to a low-compensation spray structure, comprising a high-thermal-conductivity front edge, a spray pipe, a semi-enclosed cavity, a porous core, a vaporized fluid, a liquid supply pipe, a storage tank, a liquefied fluid, a heat pipe, a temperature control switch, and a thermal insulation sleeve. The high-thermal-conductivity front edge, the spray pipe, and the semi-enclosed cavity form an integrated structure, with one end of the spray pipe passing through a stagnation point of the high-thermal-conductivity front edge to communicate with the external environment, and the other end extending into the semi-enclosed cavity. The porous core is placed in the semi-enclosed cavity, and the vaporized fluid is adsorbed on the porous core. One end of the liquid supply pipe is connected to the spray pipe, and the other end passes through the storage tank to be inserted into the liquefied fluid. The heat pipe sequentially passes through the high-thermal-conductivity front edge, the semi-enclosed cavity, the storage tank, the liquefied fluid, and is connected to the temperature control switch. The thermal insulation sleeve covers the exposed liquid supply pipe and heat pipe. The spray structure of the present invention reduces the use compensation of active heat protection, thereby improving the safety and reliability of the heat protection structure.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal protection of high-speed aircraft and relates to a low-compensation spray structure. Background Art

[0002] With the emergence and development of high-speed aircraft, the operating temperature of the leading edge structure of aircraft is getting higher and higher, reaching or even exceeding the upper temperature limit of the existing thermal protection material system.

[0003] There are three main methods for thermal protection of aircraft leading edges: passive thermal protection based on materials; semi-passive thermal protection based on heat pipe radiation; and active thermal protection based on working fluid dissipation. Active thermal protection offers the best thermal protection performance, but its structure is complex and difficult to implement. In particular, active cooling structures generally require a power source to drive the working fluid transmission and dissipation to achieve thermal protection. This not only increases the cost of active thermal protection but also reduces the safety and reliability of the thermal protection structure. Summary of the Invention

[0004] The technical problem solved by the present invention is to overcome the deficiencies of the prior art, propose a low-compensation spray structure, reduce the use compensation of active heat protection, and improve the safety and reliability of the heat protection structure.

[0005] The solution to the technical problem of the present invention is: a low compensation spray structure, including a high heat conductive leading edge, a spray pipe, a semi-enclosed cavity, a porous core, a vaporized medium, a liquid supply pipe, a storage tank, a liquefied medium, a heat conductive pipe, a temperature control switch and a heat insulating sleeve;

[0006] Among them, the high thermal conductivity front edge, spray tube, and semi-enclosed cavity are an integrated structure. One end of the spray tube passes through the high thermal conductivity front edge stagnation point and is connected to the external environment, and the other end extends into the semi-enclosed cavity; the porous core is placed in the semi-enclosed cavity, and the vaporized medium is adsorbed on the porous core; one end of the liquid supply pipe is connected to the spray tube, and the other end passes through the storage tank and is inserted into the liquefied medium; the heat conduction pipe passes through the high thermal conductivity front edge, the semi-enclosed cavity, the storage tank, the liquefied medium and is connected to the temperature control switch in sequence; the thermal insulation sleeve covers the exposed liquid supply pipe and heat conduction pipe.

[0007] Furthermore, the high thermal conductivity leading edge is a leading edge type niobium-based high temperature heat pipe or a tantalum-based high temperature heat pipe, the high temperature heat pipe wall thickness is 1.5-3mm, and the equivalent density is not more than 4400kg / m 3 , length 200-400mm;

[0008] The material of the spray pipe, the semi-enclosed cavity, the porous core, the liquid supply pipe and the heat conduction pipe is the same as that of the high heat conduction leading edge.

[0009] Furthermore, the spray tube is a variable diameter through tube, the inner diameter of the end connected to the high thermal conductivity leading edge is 4-10mm, the inner diameter of the end extending into the semi-enclosed cavity is 1-1.5mm, and the wall thickness of the variable diameter through tube is 1.2-3mm.

[0010] Furthermore, the semi-enclosed cavity is connected to the high thermal conductivity front edge through a common wall surface, and the thickness of the common wall surface is 2-5 mm.

[0011] Furthermore, the porous core has a pore diameter of 35-200 μm and a porosity greater than 30%.

[0012] Furthermore, the vaporized medium is metallic zinc, and the purity of the metallic zinc is greater than 99%;

[0013] The liquefaction medium is a lead-bismuth alloy, and the melting point of the lead-bismuth alloy is lower than 150°C.

[0014] Furthermore, the inner diameter of the liquid supply tube is 1-3 mm and the wall thickness is 1-1.5 mm;

[0015] The inner diameter of the heat conducting pipe is 4-18 mm, and the wall thickness is 1.2-2.5 mm; the outer wall of the portion of the heat conducting pipe extending into the storage tank is spirally distributed, thereby increasing the heat exchange area.

[0016] Furthermore, the storage tank is made of 316L stainless steel and has a capacity of 3-10L;

[0017] The liquefied medium is placed in a storage tank, and its volume accounts for 30-75% of the volume of the storage tank.

[0018] Furthermore, the temperature control switch is controlled by the temperature of the liquefied medium. When the temperature of the liquefied medium is lower than 150°C, the temperature control switch is in the open state; when the temperature of the liquefied medium is higher than 200°C, the temperature control switch is in the closed state.

[0019] Furthermore, the thermal insulation sleeve is made of alumina felt, the thickness of the alumina felt is 6-25 mm, and the thermal conductivity is less than 0.1 W / (m·K).

[0020] The beneficial effects of the present invention compared with the prior art are:

[0021] (1) The spray structure of the present invention has low cost and uses aerodynamic heating to drive the spray process, without the need for additional power devices.

[0022] (2) The spray structure of the present invention has good cooling effect, adaptive control of the spray process, high working fluid utilization rate and good temperature control effect.

[0023] (3) The spray structure of the present invention has high safety, good spray medium stability, and is easy to store and transport. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a low-compensation spray structure of the present invention;

[0025] Figure 2(a) shows the heat flux distribution on a leading edge surface before spraying in an embodiment of the present invention;

[0026] Figure 2(b) shows the heat flux distribution on a leading edge surface after spraying in an embodiment of the present invention;

[0027] Figure 3 This is the temperature change curve of the leading edge stagnation point before and after the spray in the embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention proposes a low-compensation spray structure, which uses a high-temperature heat pipe as a high-thermal conductivity leading edge to quickly transfer the heat from aerodynamic heating to a low-boiling-point working fluid. After the low-boiling-point working fluid is heated, it vaporizes and expands to act on the liquid working fluid in the storage tank to realize the spray cooling function.

[0029] like Figure 1 As shown, the spray structure includes a high thermal conductivity front edge 1, a spray tube 2, a semi-enclosed chamber 3, a porous core 4, a vaporized fluid 5, a liquid supply tube 6, a storage tank 7, a liquefied fluid 8, a heat pipe 9, a temperature control switch 10, and a thermal insulation sleeve 11. The high thermal conductivity front edge 1, spray tube 2, and semi-enclosed chamber 3 form an integrated structure. One end of the spray tube 2 passes through the stagnation point of the high thermal conductivity front edge 1 to communicate with the external environment, and the other end extends into the semi-enclosed chamber 3. The porous core 4 is placed in the semi-enclosed chamber 3, and the vaporized fluid 5 is adsorbed by the porous core 4. One end of the liquid supply tube 6 communicates with the spray tube 2, and the other end passes through the storage tank 7 and is inserted into the liquefied fluid 8. The heat pipe 9 passes through the high thermal conductivity front edge 1, the semi-enclosed chamber 3, the storage tank 7, and the liquefied fluid 8 in sequence and is connected to the temperature control switch 10. The thermal insulation sleeve 11 covers the exposed liquid supply tube 6 and heat pipe 9.

[0030] The low-compensation spray structure of the present invention operates as follows: Under low aerodynamic heating conditions, the temperature of the high-thermal-conductivity leading edge 1 (high-temperature heat pipe) rises, increasing its thermal conductivity. Heat entering the leading edge is rapidly transferred over long distances in the front-to-back direction, gradually reaching a uniform temperature. At this point, the heat entering the leading edge is radiated into the surrounding environment through its upper and lower surfaces. Meanwhile, the lead-bismuth alloy (liquefied medium 8) has a relatively low initial temperature, and the temperature control switch 10 is in the open state. Air entering the heat pipe 9 passes through the uniform temperature leading edge and enters the storage tank 7, heating the lead-bismuth alloy and melting it into a liquid. Under high aerodynamic heating conditions, the temperature of the high-thermal-conductivity leading edge 1 further increases, transferring heat from the leading edge into the semi-enclosed chamber 3, causing the metallic zinc (vaporizing medium 5) to melt and vaporize. This vaporization increases the pressure within the semi-enclosed chamber 3. Under the influence of the pressure differential, zinc vapor escapes from the leading edge stagnation point along the spray tube 2. The escape of zinc vapor creates a negative pressure environment within the liquid supply pipe 6. Under negative pressure, the lead-bismuth working medium enters the spray pipe 2 along the liquid supply pipe 6 and is then ejected into the environment, forming spray cooling. At this time, the leading edge simultaneously realizes thermal protection function through spray cooling and surface radiation.

[0031] Furthermore, the high thermal conductivity front edge 1 is a front edge type niobium-based high temperature heat pipe or a tantalum-based high temperature heat pipe. The high temperature heat pipe has a wall thickness of 1.5-3 mm and an equivalent density of no more than 4400 kg / m 3, length 200-400mm.

[0032] The material of the spray tube 2 , the semi-enclosed cavity 3 , the porous core 4 , the liquid supply tube 6 and the heat conduction tube 9 is the same as that of the high thermal conductivity leading edge 1 .

[0033] The spray tube 2 is a variable diameter through tube, with an inner diameter of 4-10 mm at the end connected to the high thermal conductivity leading edge and an inner diameter of 1-1.5 mm at the end extending into the semi-enclosed cavity. The wall thickness of the variable diameter through tube is 1.2-3 mm.

[0034] The semi-enclosed cavity 3 is connected to the high thermal conductivity front edge 1 via a common wall surface. The thickness of the common wall surface is 2-5 mm.

[0035] The porous core 4 has a pore diameter of 35-200 μm and a porosity greater than 30%.

[0036] The vaporized medium 5 is metallic zinc, and the purity of the metallic zinc is greater than 99%.

[0037] The inner diameter of the liquid supply pipe 6 is 1-3 mm, and the wall thickness is 1-1.5 mm.

[0038] The storage tank 7 is made of 316L stainless steel and has a capacity of 3-10L.

[0039] The liquefied medium 8 is placed in the storage tank 7, and its volume accounts for 30-75% of the volume of the storage tank.

[0040] The liquefaction medium 8 is a lead-bismuth alloy, and the melting point of the lead-bismuth alloy is lower than 150°C.

[0041] The inner diameter of the heat pipe 9 is 4-18 mm, and the wall thickness is 1.2-2.5 mm. The outer wall of the portion of the heat pipe 9 extending into the storage tank 7 is spirally distributed to increase the heat exchange area.

[0042] The temperature control switch 10 is controlled by the temperature of the liquefied medium. When the temperature of the liquefied medium is lower than 150°C, the temperature control switch is in an open state; when the temperature of the liquefied medium is higher than 200°C, the temperature control switch 10 is in a closed state.

[0043] The heat-insulating sleeve 11 is made of alumina felt, which has a thickness of 6-25 mm and a thermal conductivity of less than 0.1 W / (m·K).

[0044] The present invention will be further described below in conjunction with the embodiments.

[0045] Example 1

[0046] In order to demonstrate the feasibility of this method, a low compensation spray structure was designed with a leading edge niobium-based high-temperature heat pipe as the high thermal conductivity leading edge. The specific parameters of the low compensation spray structure are as follows: the leading edge niobium-based high-temperature heat pipe wall thickness is 2mm, the equivalent density is 3000kg / m 3, length 260mm. The spray tube is a variable diameter through tube, with an inner diameter of 4mm at the end connecting to the high thermal conductivity front edge and a 1mm inner diameter at the end extending into the closed cavity. The wall thickness of the variable diameter through tube is 1.5mm. The total wall thickness between the semi-enclosed cavity and the high thermal conductivity front edge is 2.5mm. The porous core has a pore diameter of 50μm and a porosity of 40%. The vaporized medium is metallic zinc with a purity of 99.5%. The inner diameter of the liquid supply pipe is 1mm and the wall thickness is 1.5mm. The volume of the 316L stainless steel storage tank is 3L. The volume of the liquefied medium accounts for 35% of the volume of the storage tank. The liquefied medium is a lead-bismuth eutectic alloy with a melting point of 125°C. The inner diameter of the heat conduction pipe is 4mm and the wall thickness is 1.2mm. The thickness of the alumina felt of the insulation sleeve is 10mm and the thermal conductivity is 0.08W / (m·K).

[0047] This embodiment theoretically calculates the heat protection performance of the designed spray structure. Figure 2(a) shows the heat flux distribution of a certain leading edge surface before spraying, and Figure 2(b) shows the heat flux distribution of a certain leading edge surface after spraying. It can be seen that after adopting the low compensation spray structure, the maximum heat flux of the leading edge surface is reduced from 5000kW / m 2 Down to 3200kW / m 2 , a decrease of about 40%.

[0048] Figure 3 A stagnation point temperature curve for a certain aircraft's leading edge is presented. Using low-compensation spray cooling, the maximum stagnation point temperature at the leading edge of the aircraft dropped from 1600°C to 900°C. This temperature reduction allows the use of nickel-based superalloys instead of refractory metals for thermal protection, significantly improving the aircraft's reliability and safety.

[0049] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications 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 scope of protection of the technical solutions of the present invention.

[0050] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A low compensation spray structure, characterized in that: It comprises a high thermal conductivity leading edge (1), a spray pipe (2), a semi-enclosed cavity (3), a porous core (4), a vaporized medium (5), a liquid supply pipe (6), a storage tank (7), a liquefied medium (8), a heat conducting pipe (9), a temperature control switch (10) and a heat insulating sleeve (11); The high thermal conductivity front edge (1), the spray pipe (2), and the semi-enclosed cavity (3) are in an integrated structure. One end of the spray pipe (2) passes through the stationary point of the high thermal conductivity front edge (1) to communicate with the external environment, and the other end extends into the semi-enclosed cavity (3); the porous core (4) is placed in the semi-enclosed cavity (3), and the vaporized medium (5) is adsorbed on the porous core (4); one end of the liquid supply pipe (6) is in communication with the spray pipe (2), and the other end passes through the storage tank (7) and is inserted into the liquefied medium (8); the heat conduction pipe (9) passes through the high thermal conductivity front edge (1), the semi-enclosed cavity (3), the storage tank (7), the liquefied medium (8), and is connected to the temperature control switch (10) in sequence; and the heat insulation sleeve (11) covers the exposed liquid supply pipe (6) and the heat conduction pipe (9).

2. A low compensation spray structure according to claim 1, characterized in that: The high thermal conductivity front edge (1) is a front edge type niobium-based high temperature heat pipe or a tantalum-based high temperature heat pipe, the high temperature heat pipe wall thickness is 1.5-3mm, and the equivalent density is not more than 4400kg / m 3 , length 200-400mm; The material of the spray pipe (2), the semi-enclosed cavity (3), the porous core (4), the liquid supply pipe (6) and the heat conduction pipe (9) is the same as that of the high heat conduction leading edge (1).

3. A low compensation spray structure according to claim 1, characterized in that: The spray pipe (2) is a variable diameter through pipe, the inner diameter of the end connected to the high heat conductive front edge is 4-10 mm, the inner diameter of the end extending into the semi-enclosed cavity is 1-1.5 mm, and the wall thickness of the variable diameter through pipe is 1.2-3 mm.

4. A low compensation spray structure according to claim 1, characterized in that: The semi-enclosed cavity (3) is connected to the high thermal conductivity front edge (1) via a common wall surface, and the thickness of the common wall surface is 2-5 mm.

5. The low compensation spray structure according to claim 1, characterized in that: The porous core (4) has a pore diameter of 35-200 μm and a porosity greater than 30%.

6. A low compensation spray structure according to claim 1, characterized in that: The vaporized medium (5) is metallic zinc, and the purity of the metallic zinc is greater than 99%; The liquefaction medium (8) is a lead-bismuth alloy, and the melting point of the lead-bismuth alloy is lower than 150°C.

7. The low compensation spray structure according to claim 1, characterized in that: The liquid supply pipe (6) has an inner diameter of 1-3 mm and a wall thickness of 1-1.5 mm; The inner diameter of the heat conducting pipe (9) is 4-18 mm, and the wall thickness is 1.2-2.5 mm; the outer wall of the portion of the heat conducting pipe (9) extending into the storage tank (7) is spirally distributed, thereby increasing the heat exchange area.

8. The low compensation spray structure according to claim 1, characterized in that: The storage tank (7) is made of 316L stainless steel and has a capacity of 3-10L; The liquefied medium (8) is placed in the storage tank (7), and its volume accounts for 30-75% of the volume of the storage tank.

9. The low compensation spray structure according to claim 1, characterized in that: The temperature control switch (10) is controlled by the temperature of the liquefied medium. When the temperature of the liquefied medium is lower than 150° C., the temperature control switch is in an open state; when the temperature of the liquefied medium is higher than 200° C., the temperature control switch (10) is in a closed state.

10. The low compensation spray structure according to claim 1, characterized in that: The heat-insulating sleeve (11) is made of alumina felt, the thickness of the alumina felt is 6-25 mm, and the thermal conductivity is less than 0.1 W / (m·K).

Images