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CN-121973925-A - Composite phase change thermal protection device

CN121973925ACN 121973925 ACN121973925 ACN 121973925ACN-121973925-A

Abstract

The invention discloses a composite phase change heat protection device which is of a multi-layer structure, wherein a small-channel heat-driven phase change heat conduction assembly, a self-adaptive heat insulation layer and a radiation coating are respectively arranged from inside to outside, an ultrahigh-temperature phase change heat buffer head cone is arranged on a windward side, the small-channel heat-driven phase change heat conduction assembly comprises a liquid filling pipe, a plate body, smooth inclined ribs and saw-tooth vertical ribs, the smooth inclined ribs and the saw-tooth vertical ribs are arranged in the plate body in a staggered manner to form a continuous gradual-change section snake-shaped closed loop, the continuous gradual-change section snake-shaped closed loop comprises a series of continuous gradual-change section small channels and U-shaped units, the self-adaptive heat insulation layer is formed by staggered assembly of a high-temperature low-expansion-coefficient inner layer and a high-expansion-coefficient outer layer, the phase change heat buffer head cone comprises a packaging layer and an ultrahigh-temperature solid-liquid phase change material packaged in the self-adaptive heat insulation device is provided with the performance of starting speed and high-efficiency heat conduction and instantaneous thermal shock prevention, and is an effective scheme for heat protection of a hypersonic aircraft.

Inventors

  • CHEN YONGPING
  • FAN CHENGCHENG

Assignees

  • 苏州科技大学

Dates

Publication Date
20260505
Application Date
20260213

Claims (10)

  1. 1. The composite phase-change heat protection device comprises a heat protection main body and is characterized in that the heat protection main body is of a multi-layer structure, and a small-channel heat-driven phase-change heat conduction assembly, a self-adaptive heat insulation layer and a radiation coating are arranged on the heat protection main body from inside to outside; The small-channel heat-driven phase change heat dispersion component comprises a plate body, a continuous gradual-change serpentine closed loop arranged in the plate body and a phase change working medium injected into the continuous gradual-change serpentine closed loop, wherein the continuous gradual-change cross-section serpentine closed loop consists of continuous gradual-change cross-section small channels and U-shaped units, two adjacent continuous gradual-change cross-section small channels are connected through one U-shaped unit, the cross section of one continuous gradual-change cross-section small channel in the two continuous gradual-change cross-section small channels connected with one U-shaped unit is unidirectionally increased, and the cross section of the other continuous gradual-change cross-section small channel is unidirectionally decreased; The self-adaptive heat insulation layer is composed of an inner layer structure and an outer layer structure, wherein the inner layer structure comprises an inner layer substrate and protrusions arranged on the surface of the inner layer substrate, the outer layer structure comprises an outer layer substrate and grooves arranged on the surface of the outer layer substrate, the protrusions of the inner layer structure are located in the grooves of the outer layer structure, the inner layer structure is integrally made of high-temperature low-linear expansion coefficient materials, and the outer layer structure is integrally made of high-temperature Gao Xian expansion coefficient materials, so that the inner layer structure and the outer layer structure generate different degrees of thermal deformation in the temperature rising process.
  2. 2. The composite phase change thermal protection device according to claim 1, wherein smooth diagonal ribs and saw tooth vertical ribs are provided in the plate body, the smooth diagonal ribs and the saw tooth vertical ribs being alternately arranged so that two continuous gradual cross-section small passages with opposite cross-section change directions are formed between the two saw tooth vertical ribs by one smooth diagonal rib.
  3. 3. The composite phase change thermal protection device according to claim 1, wherein a bionic grading groove is arranged in the small continuous gradual-change section channel, the bionic grading groove is of a second grade, and at least two secondary grooves are arranged in the first-grade groove.
  4. 4. The composite phase change thermal protection device according to claim 3, wherein the depth of the secondary groove in the bionic grading groove is 1/10-1/2 of the depth of the primary groove.
  5. 5. The composite phase change thermal protection device of claim 1, wherein the hydraulic diameter maximum value D max of the continuous graded-section small channel in the continuous graded-section serpentine closed loop is: wherein sigma represents the surface tension of the injected phase change working medium, ρ l 、ρ v is the bubble point density and dew point density of the injected phase change working medium respectively, and g represents the gravitational acceleration.
  6. 6. The composite phase change thermal protection device of claim 1, wherein the cross-sectional shape of the continuous graded-section small channel in the continuous graded-section serpentine closed loop is any one of rectangular, square, triangular, trapezoidal.
  7. 7. The composite phase change thermal protection device of claim 1, wherein the number of continuous graded-section small channels in the continuous graded-section serpentine closed loop is at least 6.
  8. 8. The composite phase change thermal protection device according to any one of claims 1-7, wherein a phase change thermal buffer head cone is arranged at the front end of the thermal protection main body and is arranged on the windward side of the composite phase change thermal protection device, the phase change thermal buffer head cone comprises a packaging layer and an ultra-high temperature solid-liquid phase change material inside the packaging layer, and the ultra-high temperature solid-liquid phase change material can instantly absorb a large amount of heat and avoid instant thermal shock.
  9. 9. The composite phase change thermal protection device according to claim 1, wherein the phase change working medium is alkali metal, and the filling amount of the phase change working medium is 20% -80%.
  10. 10. The composite phase change thermal protection device of claim 1, wherein the small channel thermally driven phase change thermal grooming assembly is fabricated by: Step one, integrally processing and forming a plate body provided with a continuous gradual-change section serpentine closed loop; welding the liquid filling pipe on the plate body; Step three, cleaning the whole welded plate body of the liquid filling pipe; Step four, vacuum leak detection is carried out on the cleaned plate body; Fifthly, placing the plate body subjected to leak detection in a high-temperature vacuum furnace for high-temperature degassing treatment, and then carrying out vacuum leak detection again; step six, filling high-purity liquid alkali metal into a continuous gradual change section serpentine closed loop through a liquid filling pipe in a vacuum environment; and seventhly, sealing the liquid filling pipe, and welding and reinforcing the seal in a vacuum environment.

Description

Composite phase change thermal protection device Technical Field The invention relates to the field of hypersonic thermal protection, in particular to a composite phase-change thermal protection device. Background In recent years, the technology of hypersonic aircrafts rapidly develops, and the aerodynamic heating intensity born by windward parts such as control surfaces, wing leading edges, nose cones and the like in the flying process is remarkably increased, and the aerodynamic heating intensity is accompanied by remarkable transient thermal load fluctuation and thermal shock effect. Such extreme thermal environments not only place stringent demands on the aircraft structural materials, but also pose serious challenges to the performance and reliability of the thermal protection system that is responsible for the heat conduction and transfer tasks. Existing thermal protection systems can be generally divided into three categories, passive, semi-active and active. The passive heat protection system mainly depends on the low heat conduction property and heat capacity effect of the heat insulation material to delay the structural temperature rise, has limited heat conduction capacity, is difficult to effectively control the structural temperature under the conditions of high heat flux density and long-time action, and realizes forced heat dissipation by introducing a cooling medium circulation or a complex control system, and has the advantages of complex system structure and high quality cost although the heat conduction capacity is strong, so that the comprehensive requirements of the hypersonic aircraft on light weight and high reliability are difficult to meet. In contrast, semi-active thermal protection systems have a better balance between system complexity and heat channeling capacity, and are becoming an important development direction for hypersonic aircraft thermal protection technologies. In semi-active thermal protection systems, the high temperature phase change heat diverting assembly takes on the important task of rapidly transferring and distributing localized high intensity aerodynamic heat to a larger structural area. Typical high-temperature heat-conducting components are generally based on heat pipes or similar phase-change heat transfer principles, realize efficient heat transport by means of the evaporation-condensation process of an internal alkali metal working medium, and have the advantages of high heat transfer capacity, no need of external energy driving and the like. However, the existing high-temperature heat-dissipating component still faces a plurality of problems to be solved in engineering application under extreme heat environment. On one hand, the traditional heat dredging component is mainly dependent on a capillary structure to provide a working medium backflow driving force, and the heat transfer performance of the traditional heat dredging component is obviously constrained by capillary limit, sonic velocity limit, dry limit and the like. Under the complex working conditions of high heat flux density, transient thermal shock or aircraft load change, overload and the like, the thermal dispersion assembly is easy to enter a heat transfer limit state too early, so that dispersion capacity is reduced and even local failure is caused. On the other hand, the heat dredging component is highly sensitive to the distribution, flow structure and heat boundary conditions of working media in the starting stage, and the problems of starting lag, temperature overshoot, unstable working media circulation direction and the like are easy to occur, so that stable and efficient heat dredging performance is difficult to maintain in a complex heat environment. In addition, the existing heat-conducting assembly generally lacks an effective transient heat buffering and heat limiting mechanism when facing sudden or periodical high-strength pneumatic heat shock, and is difficult to simultaneously realize quick response, stable operation and limit protection. Therefore, it is highly desirable to provide a high performance thermal protection device capable of adapting to extreme aerodynamic thermal environments, which has excellent heat dissipating capability under high heat flow conditions, and is capable of realizing stable working medium circulation during the start-up phase, performing adaptive regulation and control on heat entering the dissipating system when the thermal load is continuously increased or suddenly changed, and simultaneously providing effective thermal buffering and structural protection for critical parts under transient extreme conditions, so as to meet urgent requirements of hypersonic aircrafts on high reliability, strong environmental adaptability and long-life operation of the heat dissipating assembly. Disclosure of Invention The invention aims to solve the technical problem of providing a composite phase change heat protection device which realizes efficient dredgin