CN114572387B - Forward-jet flow resistance-reducing heat-proof method for hypersonic-velocity pointed cone aircraft - Google Patents

Forward-jet flow resistance-reducing heat-proof method for hypersonic-velocity pointed cone aircraft Download PDF

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CN114572387B
CN114572387B CN202210483128.2A CN202210483128A CN114572387B CN 114572387 B CN114572387 B CN 114572387B CN 202210483128 A CN202210483128 A CN 202210483128A CN 114572387 B CN114572387 B CN 114572387B
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jet flow
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CN114572387A (en
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蒋崇文
韩天依星
胡姝瑶
高振勋
李椿萱
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Beihang University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C21/00—Influencing air flow over aircraft surfaces by affecting boundary layer flow
    • B64C21/02—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like
    • B64C21/04—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like for blowing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C30/00—Supersonic type aircraft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B10/00—Means for influencing, e.g. improving, the aerodynamic properties of projectiles or missiles; Arrangements on projectiles or missiles for stabilising, steering, range-reducing, range-increasing or fall-retarding
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/10—Drag reduction

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Abstract

The invention discloses a forward jet flow resistance-reducing and heat-preventing method for a hypersonic pointed cone aircraft, wherein a jet flow resistance-reducing and heat-preventing system is arranged on the wall surface of the windward side of the aircraft, and comprises a plurality of jet pipes, and the jet pipes jet in the forward direction along the incoming flow direction of the wall surface of the windward side of the aircraft; the spray pipes are sonic or supersonic spray pipes, and a plurality of spray pipes are uniformly distributed along the circumferential direction or the spanwise direction of the pointed cone to form an array covering circumferential or spanwise range, and the shape, the size and the working parameters of the spray pipes are optimally set. The method aims at the hypersonic pointed cone aircraft, a jet flow resistance-reducing and heat-preventing system of the hypersonic pointed cone aircraft can be arranged on most of the windward side of the aircraft, the pressure resistance and the friction resistance can be respectively reduced by different mechanisms, the jet flow resistance-reducing and heat-preventing effects are achieved, the downstream of jet flow has a heat flow reducing effect under different jet flow conditions, and the heat flow reducing area covers the cone section and extends to the column section.

Description

Forward-jet flow resistance-reducing heat-proof method for hypersonic-velocity pointed cone aircraft
Technical Field
The invention belongs to the field of aircraft design, and relates to a forward jet flow resistance-reducing and heat-preventing method for a hypersonic nose cone aircraft.
Background
Hypersonic flight technology is one of the key technologies affecting future international relationship patterns, but hypersonic flight causes aerodynamic drag and aerodynamic heating problems. The pneumatic resistance is dominant, the total resistance can reach 2/3, and the total resistance is obviously increased along with the increase of the flight Mach number, so that the pneumatic performance of the aircraft is seriously influenced; aerodynamic heating corresponds to thermal protection requirements and therefore imposes severe constraints on the overall design of the aircraft, which often also impose additional limitations on the aerodynamic performance of the aircraft. Therefore, the resistance-reducing and heat-preventing technology is one of the key supporting technologies of the hypersonic aircraft technology.
A hypersonic publishing engineering series monograph 'a new method for reducing and preventing heat of a space mission aircraft and application thereof' indicates that the existing methods for reducing and preventing heat are divided into an active method and a passive method. The passive method mainly adopts special surface materials, seriously depends on a new material technology, and is greatly influenced by an ablation environment. The active methods are divided into a windward concave cavity, a reverse jet flow, a drag reduction rod, energy delivery and a combined configuration thereof, wherein the reverse jet flow and the drag reduction rod are two main methods in the existing research. The resistance-reducing rod limits the aircraft head detached shock waves to a far position at the upstream through geometric constraint, a separation area is formed between the resistance-reducing rod and the aircraft head, weak separation shock waves are generated, the wall surface pressure and heat flow of the aircraft head are reduced, a high-heat-flow environment is borne by the head of the resistance-reducing rod, and the resistance-reducing rod is applied to American trident missiles. The reverse jet flow realizes the function similar to a resistance-reducing rod through jet flow, the shock wave of the detached body is limited at the upstream of the reverse jet flow, a backflow area is formed at the head of the aircraft, the shock wave of the head is weakened, and the purposes of resistance reduction and heat prevention are achieved. However, the active method mainly aims at the wave resistance generated by the passivation of the head of the blunt body aircraft, and the resistance reduction purpose is achieved by weakening the strong falling body shock wave into the oblique shock wave through a flow control method. For the pointed cone aircraft with small head bluntness, the head wave drag ratio is small, and the drag reduction effect of the method is not obvious.
Disclosure of Invention
Aiming at the problems, the invention provides a forward jet flow resistance-reducing and heat-preventing method for a hypersonic pointed cone aircraft, aiming at the hypersonic pointed cone aircraft, a jet pipe is arranged on the wall surface of the windward side of the aircraft to jet flow in a forward direction, so that the pressure resistance and the friction resistance can be effectively reduced, the jet flow resistance-reducing effect is realized, the heat-preventing effect is realized at the downstream of the jet flow under different jet flow conditions, and the heat flow reducing area covers a cone section and extends to a column section.
The invention adopts the following technical scheme:
a forward jet flow resistance-reducing and heat-preventing method for a hypersonic pointed cone aircraft is characterized in that a jet flow resistance-reducing and heat-preventing system is arranged on the windward side wall surface of the aircraft and comprises a plurality of jet pipes, and the jet pipes jet in the forward direction along the incoming flow direction of the windward side wall surface of the aircraft.
Further, the spray pipe is a sonic or supersonic spray pipe.
Furthermore, the spray pipes are uniformly distributed along the circumferential direction of the pointed cone to form an array coverage circumferential range, the coverage angle range accounts for 50-100% of the angle range of the windward side, and the axes of the spray pipes form acute angles with the wall tangent plane and the local incoming flow direction of the spray pipes.
Furthermore, the spray pipes are arranged along the extension direction of the airplane body or the wings to form an array coverage span, the coverage angle range accounts for 50% -100% of the angle range of the windward side, and the axes of the spray pipes form acute angles with the wall tangent plane and the local incoming flow direction of the spray pipes.
Further, the minimum outlet static pressure of the spray pipe is larger than the wall surface pressure of the aircraft bypass flow at the arrangement position of the spray pipe when no jet flow exists, and the maximum outlet static pressure of the spray pipe is required to ensure that the shock wave generated by interference does not fall off, so that upstream flow separation caused by the jet flow is avoided.
Furthermore, the Mach number of the jet flow outlet is 1-2, and the static pressure ratio of the jet flow is 10-40.
Further, determining the static pressure at the outlet and the total area of the outlet of the spray pipe comprises the following steps:
(1) determining the resistance reduction value to be achieved by the jet flow resistance reduction and heat protection system in each flight section design point of the aircraftDGiving estimated jet flow drag reduction amplification factorK，K>1, obtaining the required jet vacuum net thrustF= D/K；
(2) Determining the quality consumption of working medium of jet flow anti-drag heat protection system in the whole flight profile processmAnd working time of jet flow anti-drag heat-proof systemtTo obtain the flow rate of the jet flowQ=m/t；
(3) Vacuum net thrust based on jet flowFAnd jet flow rateQDetermining outlet static pressure of a nozzlepAnd total area of the outlet of the nozzleA；
(4) According to the total area of the outlet of the nozzleADetermining the arrangement number of the spray pipes, the outlet area of each spray pipe, the arrangement position of the spray pipes and the axial direction of the spray pipes, wherein the spray pipes are arranged along the circumferential direction or the spreading direction, and the outlet static pressures of the spray pipes are allp；
(5) After the initial design of the jet flow anti-drag heat protection system is obtained according to the steps (1) to (4), in order to meet the overall design requirement of the aircraft, iterative optimization is carried out on the design parameters of the jet flow anti-drag heat protection system on the basis of numerical calculation or experiment, and the final scheme of the jet flow anti-drag heat protection system is determined.
Further, the step (3) is specifically:
Figure 33456DEST_PATH_IMAGE001
（1）
wherein the content of the first and second substances,Fin order to jet the vacuum net thrust,pis the static pressure at the outlet of the spray pipe,Ais the total area of the outlet of the spray pipe, gamma is the specific heat ratio of a given working medium,Mfor a given design jet exit mach number,M≥1；
Figure 208085DEST_PATH_IMAGE002
（2）
wherein the content of the first and second substances,Qin order to jet the flow rate of the liquid,p 0 the total pressure of the inlet of the spray pipe is,Ais the total area of the outlets of the spray pipes,q(M) In order to be the flow coefficient,Ris the gas constant of the jet flow working medium, gamma is the specific heat ratio of the given working medium,T 0 total temperature for a given jet operation;
Figure 339989DEST_PATH_IMAGE003
（3）
Figure 600069DEST_PATH_IMAGE004
（4）
simultaneous equations (1) - (4) for determining the static pressure at the outlet of a nozzlepAnd total area of the outlet of the nozzleA。
Compared with the prior art, the invention has the beneficial effects that:
(1) the arrangement position of the existing active method is limited to the head of the aircraft, and the application range of the invention is expanded to most areas of the windward side of the aircraft.
(2) The existing active method is suitable for a pointed cone aircraft with a small blunt head, and sets the shape, the size and the working parameters of a jet flow resistance-reducing heat-proof system according to the appearance characteristics.
(3) The piezoresistive to friction ratios are different for different aircraft. The existing active method drag reduction mechanism is to reduce the pressure resistance caused by strong shock waves. The invention can respectively reduce the pressure resistance and the friction resistance by different mechanisms, can be formed by designing and adjusting different resistance reductions, and has wider application range.
(4) The invention can play a role in heat protection while realizing jet flow resistance reduction, the downstream of jet flow has heat flow reducing effect under different jet flow conditions, and the heat flow reducing area covers the conical section and extends to the column section.
Drawings
FIG. 1 is a schematic view of an aircraft reference profile, where 1 is the aircraft reference profile;
FIG. 2 is an enlarged schematic view of the nose of an aircraft nozzle-carrying profile, where 2 is the aircraft nozzle-carrying profile;
FIG. 3 is a wall pressure distribution diagram of the aircraft under different jet flow conditions, calculated from the CFD values in example 1, with the abscissa being the geometric coordinate with the apex of the head of the reference profile as the origin, in m, and the ordinate being the ratio of the wall pressure to the incoming static pressure;
FIG. 4 is a distribution diagram of coefficient of friction of aircraft wall surfaces under different jet flow conditions obtained by CFD numerical calculation in example 1, and the abscissa is a geometric coordinate with the vertex of the head of the reference profile as the origin;
FIG. 5 is a wall heat flow distribution diagram of an aircraft under different jet flow conditions obtained by CFD numerical calculation in example 1, and the abscissa is a geometric coordinate with the vertex of the head of the reference profile as the origin;
FIG. 6 is a schematic view showing the arrangement of the nozzles in example 2.
Detailed Description
The invention is further described below with reference to the accompanying drawings and examples, it being understood that the examples described below are intended to facilitate the understanding of the invention, and are not intended to limit it in any way.
The invention relates to a forward jet flow resistance-reducing and heat-preventing method for a hypersonic pointed cone aircraft, in particular to a jet flow resistance-reducing and heat-preventing system arranged on the windward side wall surface of the aircraft, wherein the jet flow resistance-reducing and heat-preventing system comprises a plurality of jet pipes, and the jet pipes jet in the forward direction along the incoming flow direction of the windward side wall surface of the aircraft.
Preferably, the nozzle is a sonic or supersonic nozzle.
The jet pipes are arranged on the wall surface of the windward side of the aircraft, the jet pipes are uniformly distributed along the circumferential direction of the pointed cone to form an array coverage circumferential range, the coverage angle range accounts for 50% -100% of the angle range of the windward side, and the axis of each jet pipe forms an acute angle with the tangent plane of the wall surface and the local incoming flow direction of each jet pipe.
Aiming at the fuselage or the wing of an aircraft with flat appearance such as a belt wing or a wing body fusion or a wave carrier, spray pipes are arranged along the extension direction of the fuselage or the wing to form an array covering span-wise range, the covering angle range accounts for 50% -100% of the angle range of the windward side, and the axes of the spray pipes form acute angles with the wall tangent plane and the local incoming flow direction of the spray pipes.
Preferably, for the jet flow of the nozzle, the minimum outlet static pressure of the nozzle is controlled according to the flight environment pressure, so that the jet flow is in an underexpansion working state, namely the minimum outlet static pressure of the nozzle is greater than the wall surface pressure of the aircraft bypass flow at the position where the nozzle is arranged when the jet flow does not exist; and controlling the static pressure ratio (outlet static pressure/incoming static pressure of the spray pipe) of the jet flow within a certain range, wherein the maximum outlet static pressure of the spray pipe is ensured to prevent the shock wave generated by interference from falling off, and the upstream flow separation caused by the jet flow is avoided to generate adverse interference.
The jet flow is in an under-expansion state, and the pressure resistance of the downstream wall surface of the outlet of the spray pipe is reduced through free expansion. The jet flow interferes with the incoming flow, a low-pressure interference area is generated at the downstream of the jet flow, and the wall surface pressure resistance is further reduced. In addition, the jet flow forms an air film on the wall surface, and the wall surface velocity gradient is reduced by changing the velocity profile of the boundary layer, so that the wall surface friction resistance is reduced; the gas film changes the composition of gas components in the boundary layer, and the wall friction can be further reduced by adopting a jet flow working medium with lower dynamic viscosity.
Preferably, the design of the jet pipe of the jet flow resistance-reducing and heat-preventing system needs to determine all parameters of the jet pipe, including five parameters of jet flow outlet total temperature, jet flow outlet Mach number, working medium specific heat ratio, outlet static pressure and outlet area of the jet pipe. Considering that the overall design requirement of the aircraft directly gives two constraints of jet flow and jet flow, the remaining two parameters are determined after three parameters are given, and the adjustment spaces of temperature, Mach number and specific heat ratio among the five parameters are relatively small, so that the required outlet static pressure and outlet area of the spray pipe are given through calculation, and the method has better engineering application significance.
Specifically, the method for determining the static pressure and the total area of the outlet of the spray pipe comprises the following steps of:
(1) determining the resistance reduction value to be achieved by the jet flow resistance reduction and heat protection system in each flight section design point of the aircraftDGiving estimated jet flow drag reduction amplification factorK，K>1，KThe value is (1.0, 3.0)]The time is optimal, and the required jet vacuum net thrust is obtainedF = D/K；
(2) Determining the working medium quality consumption of a jet flow resistance-reducing and heat-proof system in the whole process of flight profilemAnd working time of jet flow anti-drag heat-proof systemtTo obtain the flow rate of the jet flowQ=m/t；
(3) Vacuum net thrust based on jet flowFAnd jet flow rateQDetermining outlet static pressure of nozzlepAnd total area of the outlet of the nozzleAThe method specifically comprises the following steps:
according to the overall design requirement of the aircraft, the total working temperature of the jet flow is givenT 0 When the air source is compressed air, the temperature of the room can be taken out, and when the air source is engine bleed air, the total working temperature of the engine can be taken out; specific heat ratio of given working mediumγFor bimolecular gases, it is usualγ= 1.4; mach number of jet outlet of given designM，M≥1，MOptimally =1.
Jet vacuum net thrustFCan be expressed as:
Figure 210042DEST_PATH_IMAGE001
（1）
in the formulaFIn order to jet the vacuum net thrust,pis the outlet of a nozzleThe static pressure at the mouth is,Ais the total area of the outlets of the spray pipes,γfor a given specific heat ratio of the working medium,Mjet exit mach number for a given design;
flow rate of jetQCan be expressed as:
Figure 239178DEST_PATH_IMAGE002
（2）
in the formula (I), the compound is shown in the specification,Qis the jet flow rate;p 0 the total pressure of the inlet of the spray pipe is used;Athe total area of the outlets of the spray pipes;q(M) The flow coefficient is equal to the ratio of the critical area to the outlet area of a single spray pipe, wherein the critical area is the cross-sectional area of the position where the flow velocity is the sound velocity in the flow of the spray pipe and is approximately the cross-sectional area of a throat;Ris the gas constant of the jet flow working medium;γthe specific heat ratio of the working medium is given;T 0 the total temperature for a given jet operation.
Figure 745246DEST_PATH_IMAGE003
（3）
Figure 227043DEST_PATH_IMAGE004
（4）
Simultaneous equations (1) - (4) for determining outlet static pressure of nozzlepAnd total area of the outlet of the nozzleA。
(4) According to the total area of the outlet of the nozzleADetermining the arrangement number of the spray pipes, the outlet area of each spray pipe, the arrangement position of the spray pipes and the axial direction of the spray pipes, wherein the spray pipes are arranged along the circumferential direction or the spreading direction, and the outlet static pressures of the spray pipes are allp；
(5) After the initial design of the jet flow anti-drag heat protection system is obtained according to the steps (1) - (4), in order to meet the overall design requirements of the aircraft, iterative optimization is carried out on the design parameters of the jet flow anti-drag heat protection system on the basis of numerical calculation or experiment, and the final scheme of the jet flow anti-drag heat protection system is determined.
As further illustrated by examples 1 and 2, the selected aircraft datum profile is shown in FIG. 1, and the aircraft has a total length of 7m, a cone length of 3.6m, a column length of 3.4m, a column diameter of 750mm, and a blunting radius of 30 mm.
Example 1:
the position and size of the nozzle arrangement on the aircraft are determined. Aiming at the hypersonic pointed cone aircraft with small head bluntness, a sound velocity/supersonic velocity spray pipe is arranged on the wall surface of the windward side to form an array covering 360-degree range in the circumferential direction, and the axis of the spray pipe forms a small acute angle with the tangent plane of the wall surface and the local incoming flow direction of the spray pipe. As shown in figure 2, the included angle between the axis of the spray pipe and the tangent plane of the wall surface is 10 degrees, the spray pipes are uniformly arranged in the circumferential direction of the column section of the aircraft, the width of the outlet of each spray pipe is 5mm, and the axial distance between the center of the outlet of each spray pipe and the head of the aircraft is 233 mm.
The incoming flow is air, the incoming flow Mach number is 6, the incoming flow pressure is 101325Pa, and the incoming flow static temperature is 300K; the jet flow working medium is hydrogen, the Mach number of the jet flow outlet is 1 and 2, the jet flow static pressure ratio (outlet static pressure/incoming flow static pressure of a spray pipe) is 10, 20 and 40, the total temperature of the jet flow outlet is 300K, the aircraft is set to be an isothermal wall surface, and the wall temperature is 300K.
The wall surface pressure distribution of the aircraft under different jet flow conditions obtained by CFD numerical calculation is shown in FIG. 3, and the wall surface friction coefficient distribution of the aircraft under different jet flow conditions obtained by CFD numerical calculation is shown in FIG. 4. The results of fig. 3 show that the downstream of the jet flow has local low-pressure interference areas under different jet flow conditions, the results of fig. 4 show that the downstream of the jet flow has reduced friction under different jet flow conditions, the drag reduction area covers the conical section and extends to the cylindrical section, the results of fig. 5 show that the downstream of the jet flow has reduced heat flow under different jet flow conditions, and the heat flow reduction area covers the conical section and extends to the cylindrical section.
Jet flow drag reduction amplification factorKIs the ratio of the aircraft resistance reduction to the jet vacuum net thrust, is used for evaluating the jet flow resistance reduction effect,K =1 indicates that the jet drag reduction scheme is the same as jet direct as the thrust effect,K >1 shows that jet drag reduction schemes can achieve additional beneficial disturbances compared to jet direct as thrust. Specifically, the formula is shown as follows:
Figure 640707DEST_PATH_IMAGE005
（5）
in the formulaF on In order to apply force to the aircraft in the direction of resistance when jet flow is used,F off in order to apply force in the direction of aircraft resistance when jet flow is not used,F j is jet vacuum net thrust.
Table 1 shows the aircraft drag reduction and amplification factors obtained by numerical integration. Drag reduction is more pronounced as jet exit mach number and jet static pressure ratio increase, but the amplification factor decreases. The result shows that the drag reduction effect of the forward jet drag reduction scheme in the embodiment is remarkable, under the conditions that the jet outlet Mach number is 1 and the jet static pressure ratio is 40, the drag reduction can reach 16.49 percent of the total drag, the higher amplification factor (1.7947) is realized, and the output of the jet drag reduction scheme is considered to be greater than the input.
TABLE 1
Figure 524349DEST_PATH_IMAGE006
Example 2:
the nozzle position, outlet width and jet direction were the same as in example 1. The spray pipes are arranged in a mode of being shown in figure 6, the spray pipes with the angle of 22.5 degrees are arranged at intervals of 45 degrees, the total number of the spray pipes is 8, the array covers the range of 180 degrees in the circumferential direction, and the total area of outlets of the spray pipes is half of that of the spray pipes in the embodiment 1. The inflow conditions, the jet flow working medium, the total temperature of the jet flow outlet and the wall temperature in the calculation conditions are the same as those in the embodiment 1, the Mach number of the jet flow outlet is 1, and the jet flow static pressure ratio is 40, so that the results show that the piezoresistance is reduced by 4.51%, the total resistance is reduced by 10.31%, the piezoresistance is reduced by 43.69%, and the amplification factor is 2.1064.
The result of the nozzle arrangement mode is similar to the result of the jet flow outlet Mach number of 1 and the jet flow static pressure ratio of 20 in the embodiment 1, which shows that different nozzle arrangement modes can achieve equivalent resistance reduction effect under the condition of the same jet flow and vacuum net thrust, namely the forward jet flow resistance reduction and heat prevention method provided by the invention can adjust the nozzle arrangement mode to adapt to the actual application requirement on the premise of ensuring the resistance reduction effect.
It will be apparent to those skilled in the art that various modifications and improvements can be made to the embodiments of the present invention without departing from the inventive concept thereof, and these modifications and improvements are intended to be within the scope of the invention.

Claims (5)

1. A forward jet flow resistance-reducing and heat-preventing method for a hypersonic pointed cone aircraft is characterized in that a jet flow resistance-reducing and heat-preventing system is arranged on the wall surface of the windward side of the aircraft, the jet flow resistance-reducing and heat-preventing system comprises a plurality of jet pipes, the jet pipes jet in a forward direction along the incoming flow direction of the wall surface of the windward side of the aircraft, the pressure resistance and the friction resistance can be effectively reduced, the jet flow resistance-reducing effect is achieved, the downstream of the jet flow has a heat flow reducing effect under different jet flow conditions, and a heat flow reducing area covers a cone section and extends to a column section;
the spray pipe is a sonic or supersonic spray pipe;
the spray pipes are uniformly distributed along the circumferential direction of the conical section of the pointed cone to form an array coverage circumferential range, the coverage angle range accounts for 50% -100% of the angle range of the windward side, and the axis of each spray pipe forms an acute angle with the wall tangent plane and the local incoming flow direction of each spray pipe.
2. The forward jet flow resistance-reducing and heat-preventing method for the hypersonic pointed cone aircraft as claimed in claim 1, wherein the minimum outlet static pressure of the jet pipe is greater than the wall pressure of the aircraft bypass flow at the position where the jet pipe is arranged when no jet flow exists, and the maximum outlet static pressure of the jet pipe ensures that the shock wave generated by interference does not fall off and the upstream flow separation caused by the jet flow is avoided.
3. The method of forward jet flow drag reduction and heat protection for hypersonic nose cone vehicles according to claim 1, wherein jet exit mach number is in the range of mach 1-2 and jet static pressure ratio is in the range of 10-40.
4. The forward jet drag reduction and thermal protection method for hypersonic nose cone vehicles according to claim 1, wherein determining the static exit pressure and the total exit area of said nozzle comprises the steps of:
(1) determining the resistance reduction value to be achieved by the jet flow resistance reduction and heat protection system in each flight section design point of the aircraftDGiving estimated jet flow drag reduction amplification factorK，K>1, obtaining the required jet vacuum net thrustF= D/K；
(2) Determining the working medium quality consumption of a jet flow resistance-reducing and heat-proof system in the whole process of flight profilemAnd working time of jet flow anti-drag heat-proof systemtTo obtain the flow rate of the jet flowQ=m/t；
(3) Vacuum net thrust based on jet flowFAnd jet flow rateQDetermining outlet static pressure of nozzlepAnd total area of the outlet of the nozzleA；
(4) According to the total area of the outlet of the nozzleADetermining the arrangement number of the spray pipes, the outlet area of each spray pipe, the arrangement position of the spray pipes and the axial direction of the spray pipes, wherein the spray pipes are arranged along the circumferential direction, and the outlet static pressures of the spray pipes are allp；
(5) After the initial design of the jet flow anti-drag heat protection system is obtained according to the steps (1) to (4), in order to meet the overall design requirement of the aircraft, iterative optimization is carried out on the design parameters of the jet flow anti-drag heat protection system on the basis of numerical calculation or experiment, and the final scheme of the jet flow anti-drag heat protection system is determined.
5. The forward jet flow resistance-reducing and heat-preventing method for the hypersonic pointed cone aircraft according to claim 4, wherein the step (3) is specifically as follows:
Figure 303212DEST_PATH_IMAGE001
（1）
wherein the content of the first and second substances,Fin order to jet the vacuum net thrust,pis the static pressure at the outlet of the spray pipe,Ais the total area of the outlet of the spray pipe, gamma is the specific heat ratio of a given working medium,Mfor a given design jet exit mach number,M≥1；
Figure 354214DEST_PATH_IMAGE002
（2）
wherein the content of the first and second substances,Qin order to jet the flow rate of the liquid,p 0 the total pressure of the inlet of the spray pipe is,Ais the total area of the outlets of the spray pipes,q(M) In order to be the flow coefficient,Ris the gas constant of the jet flow working medium, gamma is the specific heat ratio of the given working medium,T 0 total temperature for a given jet operation;
Figure 699745DEST_PATH_IMAGE003
（3）
Figure 928732DEST_PATH_IMAGE004
（4）
simultaneous equations (1) - (4) for determining outlet static pressure of nozzlepAnd total area of the outlet of the nozzleA。
CN202210483128.2A 2022-05-06 2022-05-06 Forward-jet flow resistance-reducing heat-proof method for hypersonic-velocity pointed cone aircraft Active CN114572387B (en)

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