38results about How to "Improve infrared stealth performance" patented technology

The invention discloses an optical transparent ultra-wideband radar and infrared double-stealth structure, and relates to the technical field of multi-spectrum stealth, and the stealth structure mainly comprises a low-emissivity infrared stealth layer and an ultra-wideband radar wave-absorbing layer. In order to realize high transmittance of visible light, an optical transparent material transparent conductive film and a transparent dielectric are selected in the overall structural design; the radar wave-absorbing layer adopts a conductive film-medium-conductive film sandwich type wave-absorbing structure; the transparent conductive film is etched into a frequency selective surface by adopting a laser etching process to finish the preparation of the radar and infrared compatible stealth material; the optical transparent ultra-wideband radar and infrared compatible stealth material has high designability, the contradictory problem of optical transparency, radar stealth and infrared stealth can be well solved from the perspective of structural design by adopting a metamaterial technology, and the optical transparent ultra-wideband radar and infrared compatible stealth material has good ultra-wideband radar wave absorption performance, low infrared emissivity and optical transparency.

The invention discloses a throat offset type pneumatic vector spraying pipe with a parallelogram section. A spraying pipe inner runner comprises a spraying pipe inlet, an equal straight segment, a first-throat front convergent section, a first throat, a second-throat front expanding segment, a second-throat front convergent section and a second throat which communicate in sequence; an inclined side wall face begins to be arranged on a certain position in the inner runner, the circulation section from the inner runner to the second throat is in a parallelogram shape, through the shape design ofthe parallelogram circulation section, the good airflow mixing effect is obtained, the spraying pipe infrared hidden property is effectively improved, meanwhile, the large thrust vector angle is provided for an aircraft still, the inclined side wall face has the offset effect on the airflow, under the vector and non-vector state, the initial pitching and yaw vector angles exist, the requirement of pneumatic-hidden integrated layout of the future aircraft can be met, and the purpose is wide.

The invention provides an aerogel composite material with a heat insulation and stealth function and a preparation method of the aerogel composite material, and belongs to the technical field of aerogel composite materials. The aerogel composite material comprises a nano-fiber aerogel matrix layer, a nano-fiber aerogel conductive layer and a nano-fiber aerogel heat insulation layer. According to the invention, under the condition of not using an adhesive, the effective fixation of aerogel particles and the tight combination between the base material and each functional layer can be realized by utilizing the unique hydrophilicity and pore structure of the nanofibers, and the heat insulation performance of the base material layer and the heat insulation layer is utilized; the electromagnetic shielding and controllable heat transmission performance of the conducting layer can achieve the heat insulation and electromagnetic infrared double-shielding synergistic function, and the invention has application prospects in the fields of national defense military industry and functional textiles.

The invention discloses a design method of an elliptic throat offset type pneumatic thrust vectoring nozzle. An inner flow channel of the elliptic throat offset type pneumatic thrust vectoring nozzle comprises a nozzle inlet, an equal straight section, a first throat front convergence section, a first throat, a second throat front expansion section, a second throat front convergence section and a second throat which communicate in sequence. According to the design method, the flow field structure of the inner flow channel is changed by designing the shape of each section of flow section into an elliptic shape, then a good inner and outer flow mixing effect can be achieved under the conditions of providing an omnidirectional vector angle and ensuring efficient vector thrust performance, and the infrared stealth performance of the spray pipe is effectively improved, so that the urgent requirements of modern aircrafts on strong stealth performance and high maneuvering performance are met; and in addition, the unique flat appearance of the elliptic throat offset type pneumatic thrust vectoring nozzle is more suitable for the aircrafts with special appearances such as flying wing layout, the requirement for the pneumatic-stealth integrated layout of the aircrafts in the future can be met, and the application range is wide.

The invention discloses a segmented convergence type double-S-curve binary mixed exhaust system which is used for infrared stealth of a turbofan engine. The contour of the segmented convergence type double-S-curve binary mixed exhaust system converges in an axial symmetry shape firstly and then converges in a double-S-curve shape. The segmented convergence type double-S-curve binary mixed exhaust system is composed of a pointed conical central cone, an outer culvert axial symmetry convergence section, an outer culvert double-S-curve binary convergence section, an inner culvert axial symmetry convergence section and an inner culvert S-curve convergence section. The pointed conical central cone and the inner culvert axial symmetry convergence section are connected to form an inner culvert wall surface, in this way, local expansion of an inner culvert channel can be prevented, and flow separation on the wall surface of the central cone is restrained. The outer culvert axial symmetry convergence section and the outer culvert double-S-curve binary convergence section are connected to form an outer culvert wall surface, and accordingly blockage on typical high-temperature components such as the central cone and the inner culvert inlet section can be formed more effectively. By the adoption of the segmented convergence type double-S-curve binary mixed exhaust system, compared with an existing double-S-curve binary mixed exhaust system, the infrared emanation characteristic of the exhaust system can be further restrained while the aerodynamic performance of the exhaust system is further improved.

The invention relates to the design technique of aero-engine nozzles, in particular to a convergent-divergent nozzle with a stealth function, and aims to at least solve the problem of large occupation of a conventional convergent-divergent nozzle. The convergent-divergent nozzle with the stealth function comprises a convergent segment, a divergent segment and a straight tubular transition throat segment, wherein the end surface of a first inlet end of the convergent segment is circular, the end surface of a first outlet end, parallel to the end surface of the first inlet end, is semi-circular, and the centers of the two end surfaces are on the same plane; the end surface of a second inlet end of the divergent segment is semi-circular, the end surface of a second outlet end, parallel to the end surface of the second inlet end, is circular, and the centers of the two end surfaces are on the same plane; and the straight tubular transition throat segment is connected with the first outlet end in a sealing manner through a third inlet end and connected with the second inlet end in a sealing manner through a third outlet end. The convergent-divergent nozzle with the stealth function is simple in structure, light in weight, high in reliability and convenient to mount, manufacture and lose weight, and can enhance the infrared stealth effect and the radar stealth effect without changing the structure of a plane.

The invention provides a double-oil-way jet integrated afterburner. A double-oil-way jet mode is adopted in the integrated afterburner. Jet positions for fuel oil jetting are the central position of the tail of a fairing spoke flameholder and the central position of a thrust augmentation inner cone. Compared with the prior art, the fuel oil jetting mode is changed, and as for an outer oil way, the jetted fuel oil is mixed with high-temperature mixed gas, and the atomizing effect is improved under the effect of the shear force of the high-temperature mixed gas; and as for a central oil way, since the thrust augmentation inner cone enables a wide low-speed backflow area to be formed behind the afterburner, the jetted fuel oil of the part is fully mixed with high-temperature mixed gas in the low-speed area, and the premixing effect is enhanced. Combustion is jointly conducted through the two oil ways in the afterburner, so that the combustion efficiency of the afterburner is improved, and the combustion stability is good. Meanwhile, the fuel oil can effectively decrease the temperature of the thrust augmentation inner cone to improve the infrared stealth performance of an engine.

The invention belongs to the technical field of functional materials, and provides an invisible tire decorative cover. The invisible tire decorative cover comprises a hub cover (1) and camouflage grass (2); a fixed support is arranged on the inner side of the hub cover (1); the hub cover is fixedly connected on a vehicle hub through the fixed support; the hub cover (1) is of a multi-layer structure and sequentially comprises a base material (16), an infrared camouflage coating, a radar absorbing coating (13), a metal reflection layer (12) and a protective layer (11); when the hub cover (1) isfixedly connected with the vehicle hub, the protective layer (11) is positioned on the side close to the vehicle hub; the camouflage grass is pasted on the surface of the side, away from the infraredcamouflage coating, of the base material (16) of the hub cover (1); and the infrared camouflage coating comprises a cooling coating and a heat insulation coating, wherein phase change capsules are dispersed in the cooling coating, and the heat insulation coating is low in heat conductivity coefficient. The invisible tire decorative cover can solve the problem of invisibility of a tire part of a vehicle, and the infrared camouflage effect is remarkably improved.

The invention discloses an electromagnetic wave broadband selective absorption micro-nano structure and a preparation method thereof. The micro-nano structure comprises a substrate, a reflector and an absorber which are continuously connected, the base material is a dielectric medium or metal; the reflector is a metal layer and covers the substrate; the absorber is located above the reflector and is of an inverted cone periodic structure or an arrangement type multi-scale coplanar unit periodic structure formed by overlapping a metal layer and a dielectric layer; wherein the inverted cone periodic structure is a structure formed by periodically arranging a plurality of inverted cone monomers in a matrix, each inverted cone monomer is formed by overlapping at least two groups of metal layers and dielectric layers, and the top layer is a metal layer; the arrangement type multi-scale coplanar unit periodic structure is an arrangement type multi-scale coplanar unit periodic structure of a continuous dielectric layer or an arrangement type multi-scale coplanar unit periodic structure of a discontinuous dielectric layer. The plasma broadband selective absorption micro-nano structure disclosed by the invention can be used for compatible design of infrared stealth and radiation cooling.

The invention discloses a compact ship broadside exhaust system. The compact ship broadside exhaust system sequentially comprises a main engine outlet reducer pipe, an omega-shaped exhaust expansion joint, an exhaust bent pipe, a broadside exhaust square silencer, an exhaust bent pipe, an exhaust baffle valve, a broadside connecting pipe, a broadside flow guide cap, a drainer and the like, a heatinsulation layer is arranged in the broadside exhaust square silencer, heat insulation layers are laid outside an exhaust pipe and pipeline accessories, and the exhaust system is fixed to a ship bodystructure through an elastic hanging bracket. The system adopts various measures to ensure that seawater does not enter the main engine when the ship sails, and vibration and heat of the main engine can be effectively prevented from being transferred to the ship body structure.

The invention belongs to the technical field of engine design, and particularly relates to a spray pipe and an aircraft afterbody slit exhaust cooling device. The device comprises a gas collecting cavity communicated with an engine outer culvert, the gas collecting cavity is located between the side wall of a spray pipe and the inner wall face and the outer wall face of a throat adjusting piece, the gas collecting cavity is provided with a side wall exhaust slit (1) at the rear end of the side wall of the spray pipe, the side wall exhaust slit (1) is formed in the front side of an aircraft afterbody or a tail cone (3), and exhaust of the side wall exhaust slit (1) is roughly parallel to the jet flow direction of the spray pipe; the air collecting cavity is provided with an expansion section exhaust slit (5) on the inner wall surface of the expansion section of the throat adjusting sheet of the spray pipe, and the exhaust direction of the expansion section exhaust slit (5) is approximately parallel to the airflow flowing direction of the near wall surface of the expansion section adjusting sheet of the spray pipe. The overall strength of the cooling mechanism is improved, the machining difficulty and the machining cost are reduced, the cooling range of the spray pipe and the aircraft afterbody is larger, the cooling effect is better, and meanwhile the backward radar stealth and infrared stealth effects of an aircraft can be better improved.

The invention relates to the field of high-temperature stealth materials, and particularly discloses a resin-based heat-proof composite material with the surface coated with a high-temperature infrared stealth coating and a preparation method thereof. The resin-based heat-proof composite material takes high silica fiber, Shi Ying fiber, aluminosilicate fiber or basalt oxide fiber as reinforcements, the resin matrix is one or a mixture of phenolic aldehyde and silicon resin, and the hollow microspheres are additives in the resin matrix; according to the high-temperature infrared stealth coating, precious metal serves as low-emissivity filler, lead-free glass serves as a binder, and the glass softening point temperature is 400-1100 DEG C. The composite material has good thermal insulation and infrared stealth properties, and a glass phase in the high-temperature infrared stealth coating on the surface of the composite material can be quickly melted in a medium-low heat flow high-temperature environment, so that the surface of the decomposed composite material is effectively sealed and filled; and the glass melt and oxide fibers in the composite material are sintered to be firmly attached to the surface of the material so that falling and stripping of the coating caused by decomposition of the composite material are avoided.

The invention discloses a throat offset type pneumatic vectoring exhaust nozzle with saw-tooth-shaped solid tabs at an outlet. The throat offset type pneumatic vectoring exhaust nozzle comprises an exhaust nozzle body, wherein a flow channel in the exhaust nozzle sequentially comprises an exhaust nozzle inlet, an isometric section, a first throat front part convergent section, a first throat, a second throat front part expanding section, a second throat front part convergent section and a second throat; and the saw-tooth-shaped solid tabs are arranged on upper and lower wall surfaces at the downstream of the second throat front part convergent section and a projection area of the outlet of the exhaust nozzle is not changed. According to the throat offset type pneumatic vectoring exhaust nozzle disclosed by the invention, the saw-tooth-shaped solid tabs which are inclined toward are arranged at upper and lower sides of the outlet; and an infrared stealth function of the exhaust nozzle is improved under the condition that the projection area of the outlet is equal to an original projection area. Compared with a standard throat offset type pneumatic vectoring exhaust nozzle with a rectangular outlet section, the exhaust nozzle provided by the invention can be used for effectively reducing the speed of a flow spraying central line and reducing the length of a core region and noisesthrough reinforcing flow spraying and blending of the outlet; and meanwhile, the exhausting temperature is reduced and the infrared stealth function is improved.

The invention relates to an infrared stealth film for a radar antenna and a preparation method of the infrared stealth film; the film is of a multi-layer film structure, the multi-layer film structurecomprises a substrate, and high-refractive-index material layers and low-refractive-index material layers which are sequentially and alternately stacked on the substrate from inside to outside, and the specific arrangement is SUB|(H1L1)m(H2L2)n|AIR, wherein SUB is a substrate, AIR represents air, H1 and H2 represent high-refractive-index materials with two thicknesses, L1 and L2 represent low-refractive-index materials with two thicknesses, and each layer has a specific physical thickness, and m and n represent the number of layers. According to the invention, low emission is realized on a common infrared detection waveband, high emission is realized on other wavebands, and the material and the substrate have high-transmittance characteristics on radar waves, so that the radar antenna canwork normally, and effective invisibility and timely dissipation of a heat source target can be realized.

The invention discloses an encircling-type double-duct variable-cycle engine and a control method. The engine comprises an inner duct and an outer duct; the outer duct and the inner duct adopt a common air intake and exhaust device, and the common air intake and exhaust device comprises an adjustable air intake center cone, an adjustable exhaust tail cone, an adjusting channel and an adjusting flow; the device also comprises an outer duct support plate and an inner duct support plate which are used for rectifying and supporting to ensure that the air outlet direction of the air flow is backward in the axial direction without the speed perpendicular to the radial direction; a high-pressure contra-rotating turbine which forms a high-pressure rotor, a low-pressure contra-rotating gas compressor and a high-pressure barrel shaft keep the same rotating speed; and a low-pressure contra-rotating turbine which forms a low-pressure rotor, a low-pressure contra-rotating compressor, a fan and a low-pressure barrel shaft keep the same rotating speed. The two ducts share the air inlet and exhaust device, the adjustable air inlet center cone and the adjustable exhaust tail cone are used for adjusting the channels and adjusting the flow of the inner channel and the flow of the outer channel, then the working modes are changed and switched, and the requirements of high-speed flight and efficient flight are met.