Hypersonic aircraft and head heat and resistance reducing structure thereof
By setting the main and auxiliary holes of the reverse jet on the blunt-head base of the hypersonic aircraft, a porous reverse jet is formed, which solves the problems of excessive pressure of the single-hole reverse jet and poor robustness, and reduces the jet pressure and improves robustness. , suitable for engineering applications of hypersonic aircraft.
Patent Information
- Application Number
- CN202420433853.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-06
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-03-06
AI Technical Summary
Hypersonic aircraft have problems with aerodynamic resistance and aerodynamic heating caused by arch shock waves on the head during long flights in the atmosphere. Traditional methods such as single-hole reverse jets require high-pressure jets and are poorly robust, which cannot meet engineering application requirements.
Design a heat-reducing and drag-reducing structure for the head, including the main and auxiliary holes of the counter jet on the blunt-head body base. The main hole is located at the stagnation point and the auxiliary hole is located on the downstream side of the main hole. It supplies gas independently to form a porous reverse jet. Reduce jet pressure and improve robustness.
It has achieved the reduction of the pressure required for jet flow, improved robustness, avoided the demand for high-pressure gas generation devices, maintained the original pneumatic shape and material strength, and has great engineering application prospects.
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Figure CN222137014U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to but is not limited to the field of aerospace, and in particular to a hypersonic aircraft and a head heat reduction and drag reduction structure thereof. Background Art
[0002] At present, for hypersonic aircraft flying for a long time in the atmosphere, the bow shock wave generated at the head will compress the incoming flow, which will cause the aircraft head to face great aerodynamic resistance and aerodynamic heating problems. The traditional sharp or blunt aerodynamic shape of the aircraft head cannot achieve aerodynamic drag reduction and heat protection at the same time. Reverse jet technology is a mainstream flow control method (such as the attached Figure 1 As shown in Figure 2, the bow shock wave can be pushed away from the head of the aircraft to achieve aerodynamic drag reduction and heat reduction at the same time. However, the commonly used reverse jet method mainly relies on a single hole reverse jet located at the stagnation point. In order to achieve the desired heat reduction and drag reduction effect, a single hole is often required to jet at a higher pressure.
[0003] In order to achieve a more efficient heat reduction and drag reduction effect, researchers have proposed some improvement methods for the reverse jet technology. For example: Patent CN114148504B and Patent CN110641727A both propose to combine the two flow control methods of drag reduction rod and reverse jet to achieve more efficient heat reduction and drag reduction. Patent CN107719630A proposes to use the layer sweating method to further achieve efficient heat reduction and drag reduction effects on the basis of single-hole reverse jet. It can be seen that the current improvement methods for reverse jet are mostly focused on combining with other flow control methods or cooling methods to achieve efficient heat reduction and drag reduction effects.
[0004] For the single-hole reverse jet technology that is currently being studied, in order to achieve the desired heat reduction and drag reduction effects, a single hole is often required to jet at a higher pressure, which means that the hypersonic aircraft needs to carry a high-pressure gas generation device, which is not conducive to the safe operation of the aircraft. In addition, since the single-hole jet only relies on a single hole located at the stagnation point to achieve drag reduction and heat protection, it faces the problem of poor robustness and cannot meet the requirements of engineering applications. For the combined configuration of the drag reduction rod and the reverse jet proposed by predecessors, since the drag reduction rod itself only has a drag reduction effect, the heat protection effect is mainly achieved by the reverse jet, so this combined configuration still has the technical defects of the single-hole reverse jet. As for the configuration combining the reverse jet with the sweating of the laminate, since the blunt head is replaced by the laminate structure, it is also necessary to consider the material strength and reliability of the laminate configuration compared with the original structure. Utility Model Content
[0005] The present application provides a hypersonic aircraft and a heat reduction and drag reduction structure at its head, which can reduce the pressure required for the jet without changing the original aerodynamic shape and material strength of the blunt head base, and has great engineering application prospects in hypersonic aircraft.
[0006] The present application provides a head heat reduction and drag reduction structure for a hypersonic aircraft, the head heat reduction and drag reduction structure comprising: a blunt body base, the blunt body base being provided with a reverse jet main hole and a reverse jet auxiliary hole, the reverse jet main hole and the reverse jet auxiliary hole being arranged to supply air independently respectively; the reverse jet main hole being located at a stagnation point of the blunt body base; along the incoming flow direction, the reverse jet auxiliary hole being located at the downstream side of the reverse jet main hole.
[0007] The head heat reduction and drag reduction mechanism provided in the embodiment of the present application has an additional reverse jet auxiliary hole on the downstream side of the reverse jet main hole, and the reverse jet main hole and the reverse jet auxiliary hole can be used to jointly spray the reverse jet, thereby realizing multi-porous reverse jet heat reduction and drag reduction. Compared with the single-hole reverse jet technology, the multi-porous reverse jet can avoid the problem of excessive pressure of the single-hole jet and can reduce the pressure required for the reverse jet, which means that the hypersonic aircraft does not need to carry a high-pressure gas generating device, which is conducive to the safe operation of the aircraft; and the robustness of the multi-porous reverse jet is also better than that of the single-hole reverse jet, and the reverse jet main hole and the reverse jet auxiliary hole can be independently controlled, which has great engineering application prospects in hypersonic aircraft. Compared with the configuration combining reverse jet and layer sweating, this solution does not need to change the original aerodynamic shape and material strength of the blunt body base.
[0008] In an exemplary embodiment, the number of the reverse jet auxiliary holes is multiple; the multiple reverse jet auxiliary holes are arranged at intervals along the circumference of the blunt body base, and are arranged inside the backflow vortex generated by the jet of the reverse jet main hole.
[0009] In an exemplary embodiment, the reverse jet main hole is a cylindrical hole, and the central axis of the reverse jet main hole extends axially along the blunt body base; the reverse jet auxiliary hole is a cylindrical hole, and the central axis of the reverse jet auxiliary hole is perpendicular to the central axis of the reverse jet main hole.
[0010] In an exemplary embodiment, the ratio of the diameter of the reverse jet main hole to the diameter of the blunt body base is 0.08, and the ratio of the diameter of the reverse jet auxiliary hole to the diameter of the reverse jet main hole is 0.25.
[0011] In an exemplary embodiment, the plurality of reverse jet auxiliary holes are divided into a plurality of rows along the axial direction of the blunt body base, and any two adjacent rows of reverse jet auxiliary holes are staggered along the circumferential direction of the blunt body base.
[0012] In an exemplary embodiment, the plurality of reverse jet auxiliary holes are divided into two rows along the axial direction of the blunt body base, and each row includes 16 reverse jet auxiliary holes.
[0013] In an exemplary embodiment, along the incoming flow direction, the distance between the median vertical plane of a row of the reverse jet auxiliary holes on the upstream side and the upstream end face of the reverse jet main hole is recorded as a, and the distance between the median vertical plane of a row of the reverse jet auxiliary holes on the downstream side and the median vertical plane of a row of the reverse jet auxiliary holes on the upstream side is recorded as b; the ratio of a to the diameter of the reverse jet main hole is in the range of 0.472 to 0.855; the ratio of b to the diameter of the reverse jet main hole is in the range of 0.125 to 0.375.
[0014] In an exemplary embodiment, the ratio of a to the diameter of the main hole of the reverse jet is 0.472, and the ratio of b to the diameter of the main hole of the reverse jet is 0.25.
[0015] In an exemplary embodiment, the ratio of the jet static pressure to the incoming flow stagnation pressure is recorded as the stagnation pressure ratio PsR; the reverse jet main hole is configured to eject a sonic jet in the opposite direction of the incoming flow at a pressure of PsR=2, and the reverse jet auxiliary hole is configured to eject a sonic jet along the axial direction of the reverse jet auxiliary hole at a pressure of PsR<2.
[0016] In an exemplary embodiment, the blunt body base is provided with a main hole air supply channel and an auxiliary hole air supply channel which are independent of each other, the reverse jet main hole is connected to the main hole air supply channel, and the reverse jet auxiliary hole is connected to the auxiliary hole air supply channel.
[0017] An embodiment of the present application also provides a hypersonic aircraft with a hemispherical blunt-head configuration, comprising a head heat reduction and drag reduction structure as described in any one of the above embodiments.
[0018] The hypersonic aircraft provided in the embodiment of the present application has the following advantages because it includes the head heat reduction and drag reduction structure in the above embodiment: the aerodynamic resistance and aerodynamic thermal flow peak problems downstream of the main hole in the case of a single-hole reverse jet are improved by adding staggered auxiliary holes, and the heat reduction and drag reduction effect can be adjusted by changing the auxiliary hole jet pressure. The overall required jet pressure is low, no high-pressure gas generating device is required, and the original aerodynamic shape and material strength of the blunt head base are not changed. It has great engineering application prospects in hypersonic aircraft.
[0019] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is the flow schlieren diagram of the single-hole reverse jet;
[0021] Figure 2a A schematic diagram of the front view of a heat reduction and drag reduction structure for a head provided in some embodiments of the present application;
[0022] Figure 2b for Figure 2a The schematic diagram of the right side structure of the head heat reduction and drag reduction structure shown;
[0023] Figure 2c for Figure 2a A schematic diagram of the top view of the heat reduction and drag reduction structure of the head is shown;
[0024] Figure 3 for Figure 2a Schematic diagram of the cross-sectional structure along the AA direction;
[0025] Figure 4 for Figure 2a A schematic diagram of the three-dimensional structure of the head heat reduction and drag reduction structure is shown;
[0026] Figure 5a The heat reduction and drag reduction cloud diagrams of Example 1, Comparative Example 1 and Comparative Example 2 are shown;
[0027] Figure 5b The circumferential average heat reduction and drag reduction curves of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 are shown;
[0028] Figure 6 The flow field schlieren diagram and the wall pressure coefficient Cp cloud diagram as well as the flow field temperature cloud diagram and the wall Stanton number St cloud diagram of comparative example 1 are shown;
[0029] Figure 7 The flow field schlieren diagram and the wall pressure coefficient Cp cloud diagram as well as the flow field temperature cloud diagram and the wall Stanton number St cloud diagram of the first embodiment are illustrated.
[0030] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0031] 1. Blunt body base, 2. Reverse jet main hole, 3. Reverse jet auxiliary hole, 4. Main hole air supply channel, 5. Auxiliary hole air supply channel. DETAILED DESCRIPTION
[0032] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.
[0033] The present application embodiment provides a head heat reduction and drag reduction mechanism for a hypersonic aircraft. Figure 2a , Figure 2b , Figure 2c , Figure 3 and Figure 4As shown, the head heat reduction and drag reduction structure includes: a blunt body base 1. The blunt body base 1 can be a hemispherical, semi-ellipsoidal or other rotating body shape.
[0034] The blunt body base 1 is provided with a reverse jet main hole 2 and a reverse jet auxiliary hole 3. Both the reverse jet main hole 2 and the reverse jet auxiliary hole 3 are used to eject the reverse jet. The reverse jet main hole 2 is located at the stagnation point of the blunt body base; along the incoming flow direction, the reverse jet auxiliary hole 3 is located on the downstream side of the reverse jet main hole 2. The reverse jet main hole 2 and the reverse jet auxiliary hole 3 are arranged to be connected to the gas supply device respectively, and to supply gas independently respectively, and the jet pressure of the reverse jet main hole 2 is greater than the jet pressure of the reverse jet auxiliary hole 3.
[0035] by Figure 4 The three-dimensional coordinate system established in is taken as the reference, the direction of the incoming flow is the x direction, and the direction of the airflow ejected from the reverse jet main hole 2 is the -x direction.
[0036] The head heat reduction and drag reduction mechanism provided in the embodiment of the present application has an additional reverse jet auxiliary hole 3 on the downstream side of the reverse jet main hole 2, and the reverse jet main hole 2 and the reverse jet auxiliary hole 3 can be used to jointly spray the reverse jet, thereby realizing multi-porous reverse jet heat reduction and drag reduction. Compared with the single-hole reverse jet technology, the multi-porous reverse jet can avoid the problem of excessive pressure of the single-hole jet and can reduce the pressure required for the reverse jet, which means that the hypersonic aircraft does not need to carry a high-pressure gas generating device, which is conducive to the safe operation of the aircraft; and the multi-porous reverse jet can independently control the reverse jet main hole 2 and the reverse jet auxiliary hole 3 respectively, so the robustness is also better than the single-hole reverse jet, and it has great engineering application prospects in hypersonic aircraft. Compared with the configuration of combining reverse jet with layer sweating, this solution does not need to change the original aerodynamic shape and material strength of the blunt body base 1.
[0037] In some exemplary embodiments, Figure 2a , Figure 2b , Figure 2c , Figure 3 and Figure 4 As shown, the reverse jet main hole 2 is arranged at the stagnation point of the blunt body base 1. The stagnation point (also called stationary point) is usually the upstream end area of the blunt body base 1 along the incoming flow direction, that is, the vertex area of the blunt body base 1 facing the incoming flow, which is not limited to a point-shaped area, but can also be a surface-shaped area.
[0038] There are multiple reverse jet auxiliary holes 3. The multiple reverse jet auxiliary holes 3 are arranged at intervals along the circumference of the blunt body base 1 and are arranged within the range of the backflow vortex generated by the reverse jet main hole 2.
[0039] exist Figure 1In the embodiment, the free incoming flow flows toward the aircraft head in the x direction, and the reverse jet hole ejects the reverse jet in the -x direction. The reverse jet can push the bow shock wave away from the aircraft head, and achieve aerodynamic drag reduction and heat reduction at the same time. The reverse jet forms a recirculation vortex under the action of the incoming flow, and the recirculation vortex is attached to the area on the surface of the aircraft head, that is, the recirculation area. In this solution, the reverse jet auxiliary hole 3 is arranged on the downstream side of the reverse jet main hole 2, and is located in the recirculation area.
[0040] The study found that the single-hole reverse jet causes the pressure coefficient peak and the Stanton number peak due to the reattachment of the recirculation vortex of the main hole. By opening an auxiliary hole in the recirculation area, the reattachment of the recirculation vortex can be effectively suppressed, thereby reducing the single-hole pressure coefficient peak and the Stanton number peak, achieving better heat reduction and drag reduction effects.
[0041] In some exemplary embodiments, Figure 3 As shown, the reverse jet main hole 2 is a cylindrical hole, and the jet of the reverse jet main hole 2 is supplied by the main hole air supply channel 4, the central axis of the channel extends along the axial direction of the blunt body base 1 and is colinear with the central axis of the blunt body base 1.
[0042] like Figure 3 As shown, the reverse jet auxiliary hole 3 is a cylindrical hole, the jet of the reverse jet auxiliary hole 3 is supplied by the annular auxiliary hole air supply channel 5, and the central axis of the reverse jet auxiliary hole 3 is perpendicular to the central axis of the reverse jet main hole 2.
[0043] The main hole air supply channel 4 and the auxiliary hole air supply channel 5 can be arranged on the blunt body base 1 and are independent of each other. For example, the main hole air supply channel 4 and the auxiliary hole air supply channel 5 can form a nested channel structure, the main hole air supply channel 4 is located on the inner side, and the auxiliary hole air supply channel 5 is an annular channel, which is sleeved on the outer side of the main hole air supply channel 4, but is not connected to the main hole air supply channel 4. Figure 3 shown.
[0044] Since the outer surface of the blunt body base 1 is a smooth curved surface, not a straight surface, the port shape of the reverse jet auxiliary hole 3 on the outer surface of the blunt body base 1 is not a regular circle, but a circle with an area larger than the diameter of the reverse jet auxiliary hole 3. In this way, the opening area of the reverse jet auxiliary hole 3 on the outer surface of the blunt body base 1 is larger (larger than the solution of the reverse jet auxiliary hole 3 being set obliquely), which is conducive to improving the airflow sprayed by the reverse jet auxiliary hole 3 to form an air film, thereby improving the cooling effect. In addition, the reverse jet auxiliary hole 3 adopts a cylindrical hole. Compared with the special-shaped hole, the jet speed of the cylindrical hole is larger, which is conducive to pushing the shock wave farther, thereby helping to improve the drag reduction effect of the reverse jet, and compared with the special-shaped hole, it is simple to process and easier to implement, and has a greater prospect for engineering application.
[0045] Moreover, the reverse jet main hole 2 and the reverse jet auxiliary hole 3 are both cylindrical in shape, which is relatively regular in shape, so that the blunt body base 1 can be easily processed and formed, and can also be easily connected to components such as pipes and valves, so that the reverse jet main hole 2 and the reverse jet auxiliary hole 3 can be independently supplied with gas, which is convenient for connecting and assembling the blunt body base 1 and the gas generating device. As for the specific connection and assembly method between the blunt body base 1 and the gas generating device, it is not limited here, as long as the required pressure of sonic airflow can be provided to the reverse jet main hole 2 and the reverse jet auxiliary hole 3 respectively.
[0046] In some embodiments, the diameter of the reverse jet main hole 2 is greater than the diameter of the reverse jet auxiliary hole 3. The ratio of the diameter of the reverse jet main hole 2 to the diameter of the blunt body base 1 is 0.08, and the ratio of the diameter of the reverse jet auxiliary hole 3 to the diameter of the reverse jet main hole 2 is 0.25. The diameter of the blunt body base 1 refers to the diameter of the downstream end of the blunt body base 1 (along the incoming flow direction).
[0047] The simulation experiment results verify that when the diameters of the reverse jet main hole 2 and the reverse jet auxiliary hole 3 meet the above requirements, a better heat reduction and drag reduction effect can be achieved.
[0048] In some exemplary embodiments, Figure 2a , Figure 2b , Figure 2c , Figure 3 and Figure 4 As shown, the plurality of reverse jet auxiliary holes 3 are divided into a plurality of rows along the axial direction of the blunt body base 1 , and any two adjacent rows of reverse jet auxiliary holes 3 are staggered along the circumferential direction of the blunt body base 1 .
[0049] In other words, the reverse jet auxiliary holes 3 are arranged in a staggered manner, which enables the jets of multiple reverse jet auxiliary holes 3 to interact with each other and effectively cover the downstream wall surface, thereby achieving a good heat reduction and drag reduction effect downstream.
[0050] In some embodiments, Figure 2a , Figure 2b , Figure 2c , Figure 3 and Figure 4 As shown, the plurality of reverse jet auxiliary holes 3 are divided into two rows along the axial direction of the blunt body base 1 , and each row includes 16 reverse jet auxiliary holes 3 .
[0051] like Figure 2b As shown, along the incoming flow direction, the distance between the mid-vertical plane P1 of the row of reverse jet auxiliary holes 3 on the upstream side and the upstream end surface P0 of the reverse jet main hole 2 is recorded as a. The distance between the mid-vertical plane P2 of the row of reverse jet auxiliary holes 3 on the downstream side and the mid-vertical plane P1 of the row of reverse jet auxiliary holes 3 on the upstream side is recorded as b. P0, P1, and P2 are all perpendicular to the axial direction of the blunt body base 1.
[0052] Wherein, the ratio of a to the diameter of the reverse jet main hole 2 is in the range of 0.472 to 0.855, such as 0.472, 0.485, 0.5, 0.525, 0.55, 0.575, 0.6, 0.625, 0.65, 0.675, 0.7, 0.725, 0.75, 0.775, 0.8, 0.825, 0.855, etc. The ratio of b to the diameter of the reverse jet main hole 2 is in the range of 0.125 to 0.375, such as 0.125, 0.15, 0.175, 0.2, 0.225, 0.25, 0.275, 0.3, 0.325, 0.35, 0.375, etc.
[0053] In one embodiment, the ratio of a to the diameter of the reverse jet main hole 2 is 0.472, and the ratio of b to the diameter of the reverse jet main hole 2 is 0.25.
[0054] The simulation experiment results verify that when a and b meet the above requirements, a better heat reduction and drag reduction effect can be achieved.
[0055] In some exemplary embodiments, the ratio of the jet static pressure to the incoming flow stagnation pressure is recorded as the stagnation pressure ratio PsR. The reverse jet main hole 2 is configured to eject a sonic jet in the reverse direction of the incoming flow at a pressure of PsR=2, and the reverse jet auxiliary hole 3 is configured to eject a sonic jet in the axial direction of the reverse jet auxiliary hole 3 at a pressure of PsR<2.
[0056] In other words, both the reverse jet main hole 2 and the reverse jet auxiliary hole 3 eject sonic jets, the reverse jet main hole 2 ejects airflow at a pressure of PsR=2, and the reverse jet auxiliary hole 3 ejects airflow at a pressure of PsR<2.
[0057] For a single-hole reverse jet, in order to achieve the desired heat reduction and drag reduction effect, the PsR needs to reach 3 to 5, or even higher, so it is necessary to carry a high-pressure gas generator. In the embodiment of the present application, the reverse jet main hole 2 only requires a pressure of PsR = 2, and the reverse jet auxiliary hole 3 requires a lower jet pressure. Therefore, the head heat reduction and drag reduction structure of the embodiment of the present application can effectively reduce the jet pressure, so that the hypersonic aircraft does not need a high-pressure gas generator. In addition, by adjusting the jet pressure of the reverse jet auxiliary hole 3, the heat reduction and drag reduction effect can also be adjusted to meet the different needs of different products.
[0058] An embodiment and three comparative examples are introduced below to illustrate the principle and effect of the head heat reduction and drag reduction structure provided in the embodiment of the present application.
[0059] Embodiment 1 (Multi-hole reverse jet)
[0060] like Figure 2a , Figure 2b , Figure 2c , Figure 3 and Figure 4 As shown, the head heat reduction and drag reduction structure includes a blunt body base 1. The blunt body base 1 is provided with a reverse jet main hole 2 (referred to as the main hole) and a reverse jet auxiliary hole 3 (referred to as the auxiliary hole). The blunt body base 1 is hemispherical.
[0061] The reverse jet main hole 2 is arranged at the stagnation point of the blunt body base 1, and the ratio of the diameter of the reverse jet main hole 2 to the diameter of the blunt body base 1 is 0.08.
[0062] The reverse jet auxiliary holes 3 are arranged on the downstream side of the reverse jet main hole 2. The reverse jet auxiliary holes 3 have 2 rows and 32 cylindrical holes. Each row of reverse jet auxiliary holes 3 has 16 holes, and they are evenly distributed along the circumference of the blunt body base 1, and the two rows of auxiliary holes are arranged in a staggered manner. The ratio of the diameter of the reverse jet auxiliary holes 3 to the diameter of the reverse jet main hole 2 is 0.25.
[0063] Along the incoming flow direction, the distance between the mid-vertical plane of the row of reverse jet auxiliary holes 3 located on the upstream side and the upstream end face of the reverse jet main hole 2 is recorded as a, and the distance between the mid-vertical plane of the row of reverse jet auxiliary holes 3 located on the downstream side and the mid-vertical plane of the row of reverse jet auxiliary holes 3 located on the upstream side is recorded as b. The ratio of a to the diameter of the reverse jet main hole 2 is 0.472, and the ratio of b to the diameter of the reverse jet main hole 2 is 0.25.
[0064] The ratio of the jet static pressure to the incoming flow stagnation pressure is recorded as the stagnation pressure ratio PsR. The reverse jet main hole 2 is set to eject the sonic jet in the opposite direction of the incoming flow at a pressure of PsR=2, and the reverse jet auxiliary hole 3 is set to eject the sonic jet in the axial direction of the reverse jet auxiliary hole 3 at a pressure of PsR=0.5.
[0065] Comparative Example 1 (Single-hole reverse jet)
[0066] The difference from the first embodiment is that the blunt body base 1 is only provided with the reverse jet main hole 2, and no reverse jet auxiliary hole 3 is provided.
[0067] Comparative Example 2 (Single-hole reverse jet)
[0068] The difference from the comparative example 1 is that the reverse jet main hole 2 is arranged to eject a sonic jet in the reverse direction of the incoming flow direction at a pressure of PsR=3.
[0069] Comparative Example 3 (No reverse jet)
[0070] The difference from the comparative example 1 is that the blunt body base 1 does not have the reverse jet main hole 2 and there is no reverse jet.
[0071] Figure 5a and Figure 5b The figure shows the comparison of the heat reduction and drag reduction effects of the reverse jet obtained by numerical calculation. Figure 5aThe heat reduction and drag reduction cloud diagrams of Example 1, Comparative Example 1 and Comparative Example 2 are shown. Figure 5b The circumferential average heat reduction and drag reduction curves of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are shown. The calculated working condition inflow Mach number is 4, the total pressure is 1.37 MPa, the total temperature is 397 K, the ratio of the main hole jet static pressure to the inflow stagnation pressure of the porous reverse jet is PsR=2.0, the ratio of the auxiliary hole jet static pressure to the inflow stagnation pressure is PsR=0.5, and the blunt surface pressure coefficient Cp and the Stanton number St are used to reflect the dimensionless aerodynamic drag and the dimensionless heat flux density respectively.
[0072] In addition, the blunt head surface pressure coefficient and Stanton number of the single-hole reverse jet under the conditions of the ratio of the jet static pressure to the incoming flow stagnation pressure PsR = 2.0 (i.e., comparative example 1), the single-hole reverse jet under the conditions of the ratio of the jet static pressure to the incoming flow stagnation pressure PsR = 3.0 (i.e., comparative example 2), and the condition of no reverse jet (i.e., comparative example 3) were calculated and compared with the multi-hole reverse jet (i.e., embodiment 1).
[0073] pass Figure 5a It can be seen that for the case of single-hole jet PsR = 2.0 (i.e. comparative example 1), the introduction of staggered auxiliary holes downstream can effectively reduce the peak pressure coefficient and the peak Stanton number of the single-hole downstream. Figure 5b From the circumferential average heat reduction and drag reduction curve, it can be seen that when the auxiliary hole jet pressure ratio PsR=0.5, the peak value of the pressure coefficient and the peak value of the Stanton number in the single hole can be reduced by 6.65% and 34.84% respectively, which has a good heat reduction and drag reduction effect compared with the non-jet condition (i.e., comparative example 4).
[0074] The heat reduction and drag reduction mechanism of porous reverse jet is Figure 6 It can be seen that the single-hole reverse jet generates the peak value of the pressure coefficient and the peak value of the Stanton number due to the reattachment of the return vortex of the main hole. Figure 7 It can be seen that by opening auxiliary holes in the recirculation area corresponding to the recirculation vortex, the re-attachment of the recirculation vortex can be effectively suppressed, thereby reducing the peak value of the single-hole pressure coefficient and the peak value of the Stanton number. In addition, the staggered arrangement of the auxiliary holes can make the auxiliary hole jets interact with each other and effectively cover the downstream wall, thereby achieving a good heat reduction and drag reduction effect downstream.
[0075] When PsR=3.0 for single-hole reverse jet (i.e. comparative example 2), the jet flow rate is the same as the total mass flow rate for multi-hole reverse jet (i.e. embodiment 1). Figure 5a and Figure 5b As shown in the figure, the multi-hole reverse jet is better than the single-hole reverse jet at the same mass flow rate in terms of heat reduction, but the drag reduction effect is slightly lower than that of the single-hole reverse jet at the same mass flow rate.
[0076] In general, the two rows of staggered auxiliary holes set downstream of the main hole can reduce the aerodynamic resistance and aerodynamic thermal peak downstream of the single hole, and the heat reduction and drag reduction effect can be adjusted by changing the jet pressure of the auxiliary holes, thereby avoiding the problem of excessive pressure of the single-hole jet. At the same time, the robustness of the multi-porous reverse jet is also better than that of the single-hole reverse jet, and it has higher potential for engineering application.
[0077] The embodiment of the present application also provides a hypersonic aircraft, including a head heat reduction and deceleration structure as in any one of the above embodiments, and thus has all the above-mentioned beneficial effects, which will not be repeated here.
[0078] In summary, the hypersonic aircraft and the head heat reduction and deceleration structure provided in the embodiment of the present application, based on the single-hole reverse jet, introduces the auxiliary hole jet downstream of the main hole to obtain a multi-hole reverse jet layout method, which can achieve efficient heat reduction and drag reduction. This multi-hole layout form does not require the use of high-pressure main hole jets, and can adjust the heat reduction and drag reduction effect by changing the low-pressure jet pressure of the auxiliary hole under a certain jet pressure of the main hole, without changing the original blunt head configuration and material strength. It has the characteristics of reliability and efficiency, and helps to solve the aerodynamic drag and aerodynamic heat challenges faced by hypersonic aircraft during long-duration flight in the atmosphere.
[0079] In the description of the embodiments of the present application, it should be noted that the orientations or positional relationships indicated by the terms “upper”, “lower”, “one side”, “the other side”, “one end”, “the other end”, “side”, “relative”, “four corners”, “periphery”, “mouth-shaped structure”, etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the structure referred to has a specific orientation, is constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application.
[0080] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "connection", "direct connection", "indirect connection", "fixed connection", "installation", and "assembly" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; the terms "installation", "connection", and "fixed connection" can be a direct connection, or an indirect connection through an intermediate medium, or can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.
[0081] Although the embodiments disclosed in the present application are as above, the described contents are only embodiments adopted for facilitating understanding of the present application, and are not intended to limit the present application. It should be noted that the above embodiments or embodiments are merely exemplary, and not restrictive. Therefore, the present application is not limited to the contents specifically shown and described herein. Various modifications, substitutions or omissions may be made to the forms and details of implementation without departing from the scope of the present application.
Claims
1. A head heat reduction and drag reduction structure for a hypersonic aircraft, characterized in that: The head heat reduction and drag reduction structure comprises: A blunt body base, wherein the blunt body base is provided with a reverse jet main hole and a reverse jet auxiliary hole, wherein the reverse jet main hole and the reverse jet auxiliary hole are configured to supply air independently respectively; the reverse jet main hole is located at a stagnation point of the blunt body base; and along the incoming flow direction, the reverse jet auxiliary hole is located on the downstream side of the reverse jet main hole.
2. The head heat reduction and drag reduction structure according to claim 1, characterized in that: The number of the reverse jet auxiliary holes is multiple; the multiple reverse jet auxiliary holes are arranged at intervals along the circumference of the blunt body base, and are arranged inside the backflow vortex generated by the jet of the reverse jet main hole.
3. The head heat reduction and drag reduction structure according to claim 2, characterized in that: The reverse jet main hole is a cylindrical hole, and the central axis of the reverse jet main hole extends along the axial direction of the blunt body base; The reverse jet auxiliary hole is a cylindrical hole, and the central axis of the reverse jet auxiliary hole is perpendicular to the central axis of the reverse jet main hole.
4. The head heat reduction and drag reduction structure according to claim 3, characterized in that: The ratio of the diameter of the reverse jet main hole to the diameter of the blunt body base is 0.08, and the ratio of the diameter of the reverse jet auxiliary hole to the diameter of the reverse jet main hole is 0.
25.
5. The head heat reduction and drag reduction structure according to any one of claims 2 to 4, characterized in that: The plurality of reverse jet auxiliary holes are divided into a plurality of rows along the axial direction of the blunt body base, and any two adjacent rows of reverse jet auxiliary holes are staggered along the circumferential direction of the blunt body base.
6. The head heat reduction and drag reduction structure according to claim 5, characterized in that: The plurality of reverse jet auxiliary holes are divided into two rows along the axial direction of the blunt body base, and each row includes 16 reverse jet auxiliary holes.
7. The head heat reduction and drag reduction structure according to claim 6, characterized in that: Along the incoming flow direction, the distance between the mid-vertical plane of the reverse jet auxiliary holes in a row on the upstream side and the upstream end surface of the reverse jet main hole is recorded as a, and the distance between the mid-vertical plane of the reverse jet auxiliary holes in a row on the downstream side and the mid-vertical plane of the reverse jet auxiliary holes in a row on the upstream side is recorded as b; The ratio of a to the diameter of the reverse jet main hole is in the range of 0.472 to 0.855; The ratio of b to the diameter of the reverse jet main hole is in the range of 0.125 to 0.
375.
8. The head heat reduction and drag reduction structure according to claim 7, characterized in that: The ratio of a to the diameter of the main hole of the reverse jet is 0.472, and the ratio of b to the diameter of the main hole of the reverse jet is 0.
25.
9. The head heat reduction and drag reduction structure according to any one of claims 1 to 4, characterized in that: The ratio of the jet static pressure to the incoming flow stagnation pressure is recorded as the stagnation pressure ratio PsR; the reverse jet main hole is configured to eject a sonic jet in the reverse direction of the incoming flow at a pressure of PsR=2, and the reverse jet auxiliary hole is configured to eject a sonic jet in the axial direction of the reverse jet auxiliary hole at a pressure of PsR<2; and / or The blunt body base is provided with a main hole air supply channel and an auxiliary hole air supply channel which are independent of each other, the reverse jet main hole is communicated with the main hole air supply channel, and the reverse jet auxiliary hole is communicated with the auxiliary hole air supply channel.
10. A hypersonic aircraft, characterized in that: The invention comprises a head heat reduction and drag reduction structure as claimed in any one of claims 1 to 9.