CN107016199B - Design method of shock-wave-free boundary layer displacement bulge - Google Patents
Design method of shock-wave-free boundary layer displacement bulge Download PDFInfo
- Publication number
- CN107016199B CN107016199B CN201710238758.2A CN201710238758A CN107016199B CN 107016199 B CN107016199 B CN 107016199B CN 201710238758 A CN201710238758 A CN 201710238758A CN 107016199 B CN107016199 B CN 107016199B
- Authority
- CN
- China
- Prior art keywords
- point
- bulge
- revolving body
- edge line
- curve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/17—Mechanical parametric or variational design
Abstract
The invention provides a design method of a shock-wave-free boundary layer displacement bulge. Because complete Mach compression is adopted in the solution of the reference flow field, no shock wave is generated on the designed bump at the design point, and the loss caused by the shock wave is avoided; and finally, based on the given trailing edge molded line, generating bulges by adjusting the relative position of each streamline, and achieving the purpose of profile optimization. The design of the reference flow field based on pressure distribution is more targeted, and the design efficiency is higher; only Mach wave compression is carried out on incoming flow, so that loss of shock waves to the incoming flow is avoided; the displacement effect of the bulge on the boundary layer is improved through the control of the trailing edge molded line.
Description
Technical Field
The invention relates to a hypersonic/hypersonic aircraft, in particular to a boundary layer displacement bump design method based on symmetrical surface pressure distribution driving and trailing edge profile control for a hypersonic air inlet channel.
Background
The development of ultra/hypersonic aircraft involves national security and peace of space utilization. In weaponry development, the super/hypersonic aircraft defeats the normal interception mode by flying at high speed, and the large amount of kinetic energy carried can cause huge destructive power. Therefore, the research and development of the hypersonic/hypersonic aircraft have great significance for strengthening national defense strength, and the field is one of the high technology fronts of international competition at present.
The air inlet channel of the hypersonic/hypersonic aircraft mainly has the functions of capturing incoming flow and boosting pressure so as to meet the combustion requirement. However, the generation and reflection of the port shock wave may lose the energy of the incoming flow, and the higher the flight speed, the greater the loss. Meanwhile, due to the existence of the fuselage precursor, a boundary layer with a certain thickness is formed at the inlet of the air inlet channel by incoming flow, and if a large amount of low-energy air flow enters the air inlet channel, shock wave/boundary layer interference is intensified, and the anti-back pressure capability of the isolation section is also reduced. In order to solve these problems, it is conventional to reserve a gap between the engine body and the air inlet channel, the height of which is equal to the thickness of the local boundary layer, so as to achieve the function of displacing the boundary layer. However, the boundary layer suction system and the bypass system of the air inlet channel increase the weight of the aircraft, reduce the reliability and simultaneously reduce the stealth performance of the aircraft.
Bump-type air inlets were proposed by Rockschid Martin in the nineties of the last century. The bulge air inlet channel is characterized in that a three-dimensional bulge structure is used for replacing an original partition channel between a machine body and the air inlet channel in front of the air inlet channel. The bulge generates a transverse pressure gradient through the special design of the molded surface, so that the low-energy flow of the boundary layer at the inlet of the air inlet channel automatically flows out from the two sides of the inlet of the air inlet channel, and the purpose of displacing the boundary layer is achieved. Long-term model simulation, flight test and practical application prove that the design has advantages in maneuverability, stealth, reliability, manufacturing cost and weight of the aircraft.
At present, the design methods of the bulge configuration mainly comprise two methods: one is a profile design method based on a cone-guide waverider. The method is described in detail in the document "owlong aircraft Bump air duct design [ J ], yangkai, nanjing university of aerospace proceedings 2007", and is applied to owlong aircraft. The method introduces a cone-guided wave multiplication method adopted by the design of the supersonic speed lifting body into the design of the bulge. Specifically, for a given conical object plane, a flow field of the object plane under a given inflow condition is obtained by solving a Taylor-Maccoll formula or by adopting a characteristic line method, and the flow field is called as a reference flow field. And obtaining the upper surface profile of the bulge in the reference flow field through a given leading edge line or an upper surface trailing edge line based on a streamline tracing technology. And the lower surface of the bulge is the body profile of the body where the bulge is located. An improvement of this method is to design the bulge by using a osculating cone method, which introduces new variables for the bulge design and enables the design of bulges of more various sizes. Another method is to solve the wall by inverse eigen-curve method based on the pressure distribution to the bump. The document "utility model lateral pressure gradient controlled bulge inlet design [ P ], zheng xianggang, liyiqing, youlingcheng, 201620095001.3, 2016.06.15" realizes this approach. The method applies the method of solving the air inlet profile by the inverse characteristic line method in the air inlet design to the bump design. The method is characterized in that a reverse characteristic line method is used, and the reverse characteristic line method is a method for reversely solving the wall shape and the reference flow field by giving a certain aerodynamic parameter.
However, the bulge configuration design variable by adopting the cone-guided wave-multiplication method is too small to meet the requirements of different machine types on the bulge size. Meanwhile, the design of the reference flow field in the method is blindness and low in design efficiency. And with the increase of flight Mach number, the shock wave generated by the conical guided wave bulge causes great energy loss.
The method for reversely solving the bulge profile through the pressure distribution on the given bulge theoretically solves the design of the bulge, and the designed bulge profile can generate specific pressure distribution. In practice, however, a good pressure distribution on the bulge is difficult to give. In addition, the existing design of the bulge basically generates shock waves, so that certain loss is caused to the total pressure of incoming flow, and meanwhile, the resistance is increased.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a design method of a shock-wave-free boundary layer displacement bulge. A bump is a device that achieves compression of the incoming flow and boundary layer displacement by creating a transverse pressure gradient. The present invention relates generally to the design of the compression profile of a bulge. The length and width of the bump and the profile of the trailing edge are predetermined in the design, and the height of the bump can be adjusted by the pressure profile. The profile of the bulge is a smooth curved surface and is tangent to the bottom surface. The bulge compresses incoming flow through Mach waves, no shock waves are generated, and therefore shock wave loss is avoided.
The technical scheme of the invention is as follows:
a design method of a shock-wave-free boundary layer displacement bulge comprises the following steps:
(1) designing a pressure distribution curve of a revolving body bus;
giving a free incoming flow condition; defining the rotating shaft of the revolving body as an X axis, and giving the projection length L of the revolving body generatrix on the X axis, the starting point of the revolving body generatrix and the corresponding pressure value P thereof1The point with the maximum pressure value on the revolving body generatrix and the corresponding maximum pressure value P2Revolution body bus tail end point and corresponding pressure value P3. The initial point of the revolving body generatrix is also the initial point of the bulge, and the terminal point of the revolving body generatrix is also the terminal point of the bulge. The given parameters satisfy the constraints: abscissa x of starting point of revolving body generatrix10, the abscissa x of the terminal point of the generatrix of the rotator3L; pressure value P of initial point of revolving body generatrix1And pressure value P of tail end point of revolving body generatrix3Equal to the pressure P of the incoming flow∞I.e. P1＝P3＝P∞。
Taking the point with the maximum pressure value on the revolving body bus as a boundary, and calling a pressure curve between the starting point of the revolving body bus and the point with the maximum pressure value on the revolving body bus as a pressure rising curve; the pressure curve between the point on the revolving body generatrix where the pressure value is maximum and the tail end point of the revolving body generatrix is called a pressure drop curve.
In the design of the pressure rising curve, a sine fitting method is adopted, the initial point of a revolving body bus is taken as a central symmetrical point of the sine curve at the rising section, the point with the maximum pressure value on the revolving body bus is taken as the highest point of the sine curve, and the abscissa x of the initial point of the revolving body bus and the point with the maximum pressure value on the revolving body bus is taken as the abscissa x of the point1、x2And the pressure value P of the initial point of the revolving body bus and the point with the maximum pressure value on the revolving body bus1、P2Substituting into a sine function formula. To obtain formula (1):
the pressure rise curve can be obtained by solving the formula (1).
In the pressure drop curve solving process, the point with the maximum pressure value on the revolving body generatrix is taken as the highest point of the sine curve, and the tail end point of the revolving body generatrix is taken as the sine curveThe curve is positioned at the central symmetrical point of the descending section, and the coordinate (x) of the point with the maximum pressure value on the revolving body generatrix is also determined2,P2) And coordinates (x) of a terminal point of a revolving body generatrix3,P3) And (4) substituting the formula (1) to calculate a pressure drop curve.
(2) And solving the axisymmetric outward turning compression reference flow field by using a reverse characteristic line method.
(3) And determining the radius of the central body of the reference flow field according to the width and the height of the bulge.
Given the width W of the bump, the length of the bump is equal to the projection length L of the generatrix of the revolution body. And solving a central body in the axisymmetric outward turning compression reference flow field, wherein the central body is cylindrical and takes the X axis as a rotating shaft. The center body radius r is calculated from equation (9).
And according to the cylindrical central body obtained by the solution, making a tangent plane of the cylindrical central body, wherein the tangent plane is called the lower surface of the conical guided wave bump, the tangent plane and the cylindrical central body are intersected in a straight line, the straight line is called the symmetry axis of the lower surface of the conical guided wave bump, and the length of the straight line is equal to L. The intersection line of the lower surface of the conical guided wave-rider bulge and the axisymmetric outward turning compression reference flow field is a leading edge line. And (3) making a straight line perpendicular to the symmetry axis of the lower surface of the cone-guided wave-multiplying bulge by passing the tail end point of the symmetry axis of the lower surface of the cone-guided wave-multiplying bulge, and making the symmetry axis of the lower surface of the cone-guided wave-multiplying bulge be a perpendicular bisector of the straight line, namely the straight line is a rear edge line of the lower surface of the cone-guided wave-multiplying bulge, wherein the length of the straight line is equal to the width W of the given bulge. And the cone-guide wave-rider bulge lower surface back edge line is axisymmetric and externally rotated to compress the reference flow field at two points which are also a front edge line starting point and a front edge line end point respectively. Point 17 is the orthographic projection of the revolution solid generatrix end point 3 on the lower surface of the bulge. The point 18 is the starting point of the axis of symmetry 15 of the lower surface of the pyramidal waverider drum and is also the central point of symmetry of the leading edge line 14.
(4) The front edge line is equidistantly dispersed according to the spreading direction of the bump, and the distance magnitude of adjacent discrete points after dispersion is decimeter (namely the distance between the adjacent discrete points is integral multiple of 1 decimeter), so that the precision requirement can be basically met. By means of a streamline tracing technology known in the art, in the axisymmetric outward turning compression reference flow field, a series of streamlines are obtained by tracing the streamlines by taking discrete points obtained by dispersing on the front edge line as starting points. Wherein, the streamline obtained by tracing the streamline by taking the central symmetrical point of the leading edge line as the tracing starting point is the streamline of the symmetrical plane. The curve which is fitted by the terminal point of each streamline and is tangent to the lower surface of the drum is called the back edge line of the upper surface of the conical guided wave drum. The fitting of the top surface trailing edge line of the pyramidal guided wave drum package can be obtained by setting the above constraints in the commercial software Solidworks.
(5) And (4) according to the given trailing edge profile, re-integrating the streamline to obtain the final configuration.
Firstly, giving a bulge upper surface back edge line curve, wherein the bulge upper surface back edge line curve meets the following constraint: and (4) the two parts are bilaterally symmetrical, the symmetrical point is the highest point and is as high as the highest point of the rear edge line of the upper surface of the conical guided wave drum obtained in the step (4), and the symmetrical point is tangent to the lower surface of the drum. And then replacing the cone-guided wave drum upper surface back edge line with the drum upper surface back edge line curve. And (4) keeping the positions of the rear edge line curve of the upper surface of the bump and the flow line of the symmetric surface unchanged, and changing the transverse distance between other flow lines obtained by tracking the flow lines in the step (4) and the flow line of the symmetric surface to enable the tail end point of each flow line to be positioned at the position of a point with the same height as the position on the rear edge line of the upper surface of the cone-guided wave. And obtaining a bulge molded surface which is half of the symmetric surface through a Solidworks curved surface lofting function of commercial software according to the relative position of the newly obtained flow line. And finally, obtaining the profile of the other half of the bulge through symmetry to finally form a complete bulge profile.
The invention has the beneficial technical effects that:
setting the maximum value and the minimum value of the pressure on the symmetrical plane, and fitting a pressure curve of the symmetrical plane; complete Mach compression is adopted in the solution of the reference flow field, so that no shock wave is generated on a designed bump at a design point, and the loss caused by the shock wave is avoided; based on the given trailing edge molded line, the bulge is generated by adjusting the relative position of each streamline, and the purpose of profile optimization is achieved.
The design of the reference flow field based on pressure distribution is more targeted, and the design efficiency is higher; only Mach wave compression is carried out on incoming flow, so that loss of shock waves to the incoming flow is avoided; the displacement effect of the bulge on the boundary layer is improved through the control of the trailing edge molded line.
Drawings
FIG. 1 is a graph of the pressure distribution of a rotor generatrix;
FIG. 2 is a schematic diagram of a solution process for the eigen-line method.
FIG. 3 is a schematic diagram of the cone-guided wave-multiplication principle and the solution of the leading edge line.
FIG. 4 is a schematic view of a streamline tracing from a leading edge line.
FIG. 5 is a view showing the streamline distribution obtained by the initial design of the cone-guided wave-rider method and the streamline tracing method.
FIG. 6 is a rear view of a given bump upper surface trailing edge line after re-integrating the streamlines.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
A design method of a shock-wave-free boundary layer displacement bulge comprises the following steps:
(1) designing a pressure distribution curve of a revolving body bus;
as shown in fig. 1, given a free-stream condition; defining the rotating shaft of the revolving body as an X axis, and giving the projection length L of the revolving body generatrix on the X axis, the starting point 1 of the revolving body generatrix and the corresponding pressure value P thereof1Point 2 with maximum pressure value on revolving body generatrix and corresponding maximum pressure value P2Revolution body generatrix terminal point 3 and corresponding pressure value P3(ii) a The initial point 1 of the revolving body generatrix is also the initial point of the bulge, and the terminal point 3 of the revolving body generatrix is also the terminal point of the bulge. The given parameters satisfy the constraints: abscissa x of initial point 1 of revolving body generatrix10, the abscissa x of the rotor generatrix end point 33L; pressure value P of initial point 1 of revolving body generatrix1And pressure value P of revolution body generatrix terminal point 33Equal to the pressure P of the incoming flow∞I.e. P1＝P3＝P∞。
Taking a point 2 with the maximum pressure value on a revolving body bus as a boundary, and calling a pressure curve between a revolving body bus starting point 1 and the point 2 with the maximum pressure value on the revolving body bus as a pressure rising curve; the pressure curve between the point 2 with the maximum pressure value on the revolving body generatrix and the tail end point 3 of the revolving body generatrix is called a pressure drop curve.
In the design of the pressure rising curve, a sine fitting method is adopted, the initial point 1 of a revolving body bus is taken as a central symmetrical point of the sine curve at the rising section, the point 2 with the maximum pressure value on the revolving body bus is taken as the highest point of the sine curve, and the abscissa x of the initial point 1 of the revolving body bus and the abscissa x of the point 2 with the maximum pressure value on the revolving body bus is taken as the maximum point of the sine curve1、x2And the pressure value P of the initial point 1 of the revolving body bus and the point 2 with the maximum pressure value on the revolving body bus1、P2Substituting into a sine function formula. Equation set (1) is obtained:
the pressure rise curve can be obtained by solving the formula (1).
In the pressure drop curve solving process, a point 2 with the maximum pressure value on a revolving body generatrix is taken as the highest point of a sine curve, a tail end point 3 of the revolving body generatrix is taken as the central symmetry point of the sine curve in a descending section, and the coordinate (x) of the point with the maximum pressure value on the revolving body generatrix is also taken as the central symmetry point of the sine curve in the descending section2,P2) And coordinates (x) of a terminal point of a revolving body generatrix3,P3) And substituting the sine function formula, and calculating to obtain a pressure drop curve.
(2) And solving the axisymmetric outward turning compression reference flow field by using a reverse characteristic line method. The method is described in detail in the prior literature, and can be seen in research on a streamline tracking inward turning air inlet design method based on a characteristic line theory [ D ], national defense science and technology university 2012.11, p20-24 ]. The solving process of the method is described as follows:
given the free-flowing flow parameters, the flow parameters include local static pressure P, local density ρ, local velocity V, local static temperature T, and local flow direction angle θ. As shown in fig. 2, a mach wave line 5 generated when a free incoming flow passes through a starting point 1 of a revolving body generatrix is solved. The slope k of the mach wave line 5 is given by equation (2) where c is the local sound velocity, obtained by substituting the local velocity V, the local temperature T in the flow condition. μ is the mach angle and is also equal to the slope of the mach wave line 5. Meanwhile, the Mach wave line 5 passes through the initial point 1 of the revolving body generatrix, thereby determining the position parameter of the Mach wave line 5. The flow parameters on the mach wave line 5 are the same as the free-coming flow.
The Mach wave line 5 is equidistantly dispersed, the dispersion precision is determined according to the calculation capacity and the calculation requirement, the length magnitude of the bulge is generally designed to be meter (m), and the precision requirement can be better met when the magnitude of the distance between adjacent discrete points after dispersion is centimeter (cm).
As shown in fig. 2, the position coordinates of each discrete point on the mach wave line 5, the flow parameters, and the pressure distribution of the revolving body generatrix are used as input conditions, and the position coordinates of the characteristic line grid nodes on the revolving body generatrix and the position coordinates and the flow parameters on the characteristic line grid nodes in the axisymmetric outward-turning compression reference flow field are solved by a non-rotation characteristic line method (the non-rotation characteristic line method is a known technique in the art, and specifically, the non-rotation characteristic line method can be referred to in the "gas dynamics", children's order of culture, auspicious boring, deng nationality, higher education press, 2012, p227-269 "). The position coordinates are coordinate values of the characteristic line grid nodes on an axial coordinate axis X and a radial coordinate axis Y in a cylindrical coordinate system, and the flow parameters comprise local static pressure P, local density rho, local static temperature T, local speed V and local flow direction angle theta. According to different solving methods, the axisymmetric outward turning compression reference flow field and the points to be solved on the boundary thereof are divided into two types: points on the revolving body generatrix and points on the non-revolving body generatrix are called wall surface points, and points on the non-revolving body generatrix are called internal points. The initial point 1 of the revolving body generatrix is on the revolving body generatrix and on the Mach wave line 5, so the initial point 1 of the revolving body generatrix is an inner point and a wall surface point.
The dotted lines in fig. 2 represent characteristic lines, and the open nodes represent characteristic line mesh nodes. And solving the position coordinates and the flow parameters of the grid nodes of the characteristic lines by utilizing the position coordinates and the flow parameters of each discrete point on the Mach wave line 5 and the pressure distribution of the revolving body bus 11 and adopting a pre-estimation-correction method in the characteristic line method.
Further, the solving of the interior points comprises two conditions of solving the position coordinates and the flow parameters of the downstream interior points according to two upstream adjacent interior points and solving the position coordinates and the flow parameters of the downstream interior points according to the upstream wall surface point and the interior points of the upstream adjacent wall surface. The solving process of the interior points is a well-known technique in the art, and can be specifically seen in "gas dynamics, child's order, auspicious foramina, Deng Hua, higher education Press, 2012, p 240-241".
The solving process is described herein by taking as an example that any two upstream adjacent points 7 and 9 solve for their downstream point 10. The dashed lines 7-10 are referred to as the right row feature lines of point 7 and the dashed lines 9-10 are referred to as the left row feature lines of point 9.
Firstly, the estimation step is carried out: firstly, the coordinate position of the solution point 10 is obtained by the formula (3)
yb-ya＝tan(θa±μa)(xb-xa)(3)
The upper right corner of the parameter represents iteration times, the lower right corner of the parameter represents a space position, b is a node 10 on a feature line solved downstream, a represents an upstream adjacent feature point 7 and a point 9, a plus sign in an equation (3) is taken for a feature line 7-10 in the right row, a minus sign in an equation (3) is taken for a feature line 9-10 in the left row, and coordinates of the positions of the point 7 and the point 9 are respectively taken into an equation (3) for joint solving.
The flow parameter at point 10 is then obtained from equation (4)
Obtained by solving the formula (2)
And then, carrying out a correction step: by using
In place of tan (theta) in the formula (3)a±μa)(xb-xa) Term, to free
Then, in the formula (4), the amount other than the difference factor is substituted by the average value to obtain the formula (5), and the formula (5) is solved to obtain
And is obtained by solving the formula (2)
Finally, iterating the correction step until
ε10For a given value, the value range is generally set to 10-3-10-1。
The position coordinates and flow parameters of the point 10 are thus obtained, while the position coordinates and flow parameters of other internal points in the axisymmetric outward turning reference flow field can also be obtained in this way.
Further, the solution of the position coordinates of the characteristic line grid nodes on the revolving body generatrix can be obtained by a smoothing processing method of wall surface points. The process of solving the wall points in a sequential manner is well known in the art, and can be seen in particular in "gas dynamics",
kindergarten, auspicious Korea, Deng Hua, higher education Press, 2012, p242 "and literature" Weifeng ", research on design method of inward turning air inlet based on streamline tracking of characteristic line theory [ D ], national defense science and technology university, 2012.11, p 23-24". The design is specifically illustrated by the known example of an upstream wall surface point 1 and an interior point 6 adjacent to point 1 to solve for a downstream wall surface point 8.
The smooth processing process of the wall surface points is that a right-going characteristic line 6-8 is issued from the point 6 in a downstream mode and is intersected with the wall surface points 8. The position coordinates of the point 8 are obtained by solving equations (3) and (7) in series with the pressure distribution curve 4. The flow parameters at point 8 can be solved from equations (5) and (8). And similarly, iteration solution is carried out by adopting a prediction-correction method, and the termination condition of iteration is the same as the termination condition of iteration of the internal point. Similarly, in equations (3) and (5), subscript a represents the upstream wall point 1 and the inner point 6 adjacent to the point 1, and subscript b represents the downstream wall point 8, and in equation (7), subscript a represents the upstream wall point 1 and subscript b represents the downstream wall point 8. ,
ρaVa(Vb-Va)+(pb-pa)＝0(7)
the remaining points on the revolving body generatrix 11 can be calculated in this way, thereby forming the revolving body generatrix 11. The flow field area formed by the revolving body generatrix 11 and the Mach wave line 5 rotating for one circle around the X axis is the axisymmetric outward turning compression reference flow field.
(3) And determining the radius of the central body of the reference flow field according to the width and the height of the bulge.
Given the width W of the bump, the length of the bump is equal to the projection length L of the generatrix of the revolution body. And solving a central body in the axisymmetric outward turning compression reference flow field, wherein the central body is cylindrical and takes the X axis as a rotating shaft. The center body radius r is calculated from equation (9).
(4) As shown in fig. 3, a tangent plane of the cylindrical central body is determined according to the solved cylindrical central body, the tangent plane is called as the lower surface of the conical guided wave bump, the tangent plane intersects with the cylindrical central body at a straight line, the straight line is called as the symmetry axis 15 of the lower surface of the conical guided wave bump, and the length of the straight line is equal to L. The intersection line of the lower surface of the guided wave bulge and the axisymmetric outward turning compression reference flow field is a leading edge line 14. And (3) making a straight line perpendicular to the cone guide wave-multiplying bump lower surface symmetry axis 15 through a tail end point of the cone guide wave-multiplying bump lower surface symmetry axis 15, and making the cone guide wave-multiplying bump lower surface symmetry axis 15 be a perpendicular bisector of the straight line, and calling the straight line 16 as a cone guide wave-multiplying bump lower surface rear edge line 16, wherein the length of the straight line is equal to the width W of the given bump. The cone-guide wave-rider bulge lower surface back edge line 16 is axisymmetric and externally rotated to compress the reference flow field at two points which are respectively a front edge line starting point 12 and a front edge line end point 13. Point 17 is the orthographic projection of the revolution solid generatrix end point 3 on the lower surface of the bulge. The point 18 is the starting point of the symmetry axis 15 of the lower surface of the conical guided wave bulge and is also the central symmetry point of the leading edge line 14.
As shown in fig. 4, the bulge is symmetrical left and right about the symmetry plane, so that a half of the curved surface of the bulge about the symmetry plane can be designed, and then the other half of the curved surface can be obtained by a symmetrical method. The front edge line 14 is about half of the symmetry plane, namely a curve 18-12, the curve 18-12 is equidistantly dispersed according to the bulge extending direction, the discrete starting point is a point 18, the end point is a point 12, and generally, the distance between adjacent discrete points is decimeter (dm), so that the precision requirement can be basically met. In the axisymmetric outward turning compression reference flow field, a series of flow lines 19, 20, 21, 22, 23, 24, 25, 26 are obtained by performing flow line tracing by taking discrete points on a leading edge line as tracing starting points through a flow line tracing technology known in the art. Since the streamline 19 is traced by the central symmetry point 18 of the leading edge line 14, the streamline 19 is called a plane of symmetry streamline. And obtaining a curve which is fitted by the tail end points of the flow lines and tangent to the lower surface of the bulge, namely a half of the upper surface rear edge line of the cone guided wave bulge, and obtaining the upper surface rear edge line of the other half of the cone guided wave bulge through symmetry to finally obtain the complete upper surface rear edge line 27 of the cone guided wave bulge. The fitting of the top surface trailing edge line 27 of the pyramidal waverider drum package can be obtained by setting the above constraints in the commercial software Solidworks.
(5) And (4) according to the given trailing edge profile, re-integrating the streamline to obtain the final configuration.
Fig. 5 is a view showing a streamline distribution obtained by preliminary design using the cone-guided wave-rider method and the streamline tracing method, and fig. 6 is a view showing a bump obtained by re-integrating the streamline according to a given bump upper surface rear edge line. First, given the bulge upper surface trailing edge line curve 28, the bulge upper surface trailing edge line curve 28 satisfies the following constraint: and (4) the two parts are bilaterally symmetrical, the symmetrical point is the highest point and is as high as the highest point of the rear edge line 27 of the upper surface of the conical guided wave drum, which is obtained in the step (4), and the symmetrical point is tangent to the lower surface of the drum. The cone guided multiply drum upper surface trailing edge line 27 is then replaced with a drum upper surface trailing edge line curve 28. Keeping the positions of the bump upper surface back edge line curve 28 and the symmetry plane streamline 19 unchanged, changing the transverse distance of the other streamlines 20, 21, 22, 23, 24, 25 and 26 traced by the streamlines in the step (4) from the symmetry plane streamline 19, and enabling the tail end points of the streamlines 20, 21, 22, 23, 24, 25 and 26 to be positioned at the positions of points with the same height on the cone-guided wave upper surface back edge line 28, and the result is shown in fig. 6. And obtaining a bulge molded surface which is half of the symmetric surface through a Solidworks curved surface lofting function of commercial software according to the relative position of the newly obtained flow line. And finally, obtaining the profile of the other half of the bulge through symmetry to finally form a complete bulge profile.
The foregoing description of the preferred embodiments of the present invention has been included to describe the features of the invention in detail, and is not intended to limit the inventive concepts to the particular forms of the embodiments described, as other modifications and variations within the spirit of the inventive concepts will be protected by this patent. The subject matter of the present disclosure is defined by the claims, not by the detailed description of the embodiments.
Claims (4)
1. A design method of a shock-wave-free boundary layer displacement bulge is characterized by comprising the following steps:
(1) designing a pressure distribution curve of a revolving body bus;
giving a free incoming flow condition; defining the rotating shaft of the revolving body as an X axis, and giving the projection length L of the revolving body generatrix on the X axis, the starting point of the revolving body generatrix and the corresponding pressure value P thereof1The point with the maximum pressure value on the revolving body generatrix and the corresponding maximum pressure value P2Revolution body bus tail end point and corresponding pressure value P3(ii) a The initial point of the revolving body bus is also the initial point of the bulge, and the tail end point of the revolving body bus is also the tail end point of the bulge; the given parameters satisfy the constraints: abscissa x of starting point of revolving body generatrix10, the abscissa x of the terminal point of the generatrix of the rotator3L; pressure value P of initial point of revolving body generatrix1And pressure value P of tail end point of revolving body generatrix3Equal to the pressure P of the incoming flow∞I.e. P1＝P3＝P∞；
Taking the point with the maximum pressure value on the revolving body bus as a boundary, and calling a pressure curve between the starting point of the revolving body bus and the point with the maximum pressure value on the revolving body bus as a pressure rising curve; a pressure curve between a point with the maximum pressure value on a revolving body generatrix and a tail end point of the revolving body generatrix is called a pressure drop curve;
in the design of the pressure rising curve, a sine fitting method is adopted, the initial point of a revolving body bus is taken as a central symmetrical point of the sine curve at the rising section, the point with the maximum pressure value on the revolving body bus is taken as the highest point of the sine curve, and the abscissa x of the initial point of the revolving body bus and the point with the maximum pressure value on the revolving body bus is taken as the abscissa x of the point1、x2And the pressure value P of the initial point of the revolving body bus and the point with the maximum pressure value on the revolving body bus1、P2Substituting the sine function formula to obtain the following equation system:
the pressure rise curve can be obtained by solving the formula;
in the pressure drop curve solving process, the point with the maximum pressure value on the revolving body generatrix is taken as the highest point of the sine curve, and the tail end point of the revolving body generatrix is taken as the center of the sine curve at the descending sectionSymmetrical point, coordinate (x) of point with maximum pressure value on revolving body generatrix2,P2) And coordinates (x) of a terminal point of a revolving body generatrix3,P3) Substituting a sine function formula, and calculating to obtain a pressure drop curve;
(2) solving an axisymmetric outward turning compression reference flow field by using a reverse characteristic line method;
(3) determining the radius of the central body of the reference flow field according to the width and the height of the bulge;
giving the width W of the bulge, wherein the length of the bulge is equal to the projection length L of a revolving body bus; solving a central body in the axisymmetric outward turning compression reference flow field, wherein the central body is cylindrical, an X axis is taken as a rotating shaft, and the radius r of the central body is calculated by the following formula:
(4) according to the cylindrical central body obtained by the solution in the step (3), a tangent plane of the cylindrical central body is made, the tangent plane is called as the lower surface of the conical guided wave bump, the tangent plane and the cylindrical central body are intersected in a straight line, the straight line is called as the symmetry axis of the lower surface of the conical guided wave bump, and the length of the straight line is equal to L; the intersection line of the lower surface of the conical guided wave-rider bulge and the axisymmetric outward turning compression reference flow field is a front edge line; the starting point of the symmetry axis of the lower surface of the conical guided wave bump is also the central symmetry point of the front edge line; making a straight line perpendicular to the symmetry axis of the lower surface of the cone-guided wave-rider bulge by crossing the tail end point of the symmetry axis of the lower surface of the cone-guided wave-rider bulge, and making the symmetry axis of the lower surface of the cone-guided wave-rider bulge be a perpendicular bisector of the straight line, namely the straight line be a rear edge line of the lower surface of the cone-guided wave-rider bulge, wherein the length of the straight line is equal to the width W of the given bulge; the cone guided wave-rider bulge lower surface back edge line is axisymmetric outward turning compression reference flow field at two points which are a front edge line starting point and a front edge line end point respectively;
dispersing the leading edge line in an equidistant manner according to the expansion direction of the bulge, and respectively carrying out streamline tracing in an axisymmetric outward turning compression reference flow field by taking each discrete point obtained after dispersion on the leading edge line as a starting point to obtain a series of streamlines, wherein the streamline obtained by carrying out streamline tracing by taking the central symmetric point of the leading edge line as a tracing starting point is a symmetrical plane streamline; a curve which is fitted by the tail end point of each streamline and is tangent to the lower surface of the bulge is called a cone-guided wave-multiplying bulge upper surface rear edge line;
(5) according to the given trailing edge molded line, the streamline is reintegrated to obtain the final configuration;
firstly, giving a bulge upper surface back edge line curve, and replacing a cone-guided wave-multiplying bulge upper surface back edge line with the bulge upper surface back edge line curve; keeping the positions of the bulge upper surface rear edge line curve and the symmetrical plane streamline unchanged, and changing the transverse distance between other streamlines obtained by tracing the streamlines in the step (4) and the symmetrical plane streamline to enable the tail end point of each streamline to be positioned at the position of a point with the same height as the position on the conical guided wave upper surface rear edge line; according to the relative position of the newly obtained flow line, obtaining a bulge molded surface which is half of the symmetric surface through a Solidworks curved surface lofting function of software; and finally, obtaining the profile of the other half of the bulge through symmetry to finally form a complete bulge profile.
2. The method for designing a shock-free boundary layer displacement bulge as claimed in claim 1, wherein: in the step (4), since the bulge is symmetrical left and right about the symmetrical plane, a half of the curved surface of the bulge about the symmetrical plane can be designed, and then the other half of the curved surface can be obtained by a symmetrical method; equidistantly dispersing a curve from the central symmetrical point of the leading edge line to the starting point of the leading edge line according to the bulge extension direction to obtain a plurality of discrete points, wherein the discrete starting point is the central symmetrical point of the leading edge line, the end point is the starting point of the leading edge line, and the streamline tracing is carried out in the axisymmetric outer-turning compression reference flow field by respectively taking each discrete point obtained after the dispersion on the leading edge line as the starting point to obtain a series of streamline; wherein, the streamline obtained by tracing the streamline by taking the central symmetrical point of the leading edge line as a tracing starting point is a symmetrical plane streamline; and fitting the tail end points of the flow lines, wherein a curve tangent to the lower surface of the bulge is a half of the upper surface rear edge line of the cone guided wave bulge, and obtaining the upper surface rear edge line of the other half of the cone guided wave bulge through symmetry to finally obtain the complete upper surface rear edge line of the cone guided wave bulge.
3. The design method of shock-free boundary layer displacement bulge according to claim 1 or 2, characterized in that: and (4) when the leading edge line is equidistantly dispersed according to the spreading direction of the bulge, the distance magnitude of the adjacent discrete points after dispersion is decimeter.
4. The method for designing a shock-free boundary layer displacement bulge as claimed in claim 1, wherein: the bump upper surface trailing edge line curve given in step (5) satisfies the following constraint: and (4) the two parts are bilaterally symmetrical, the symmetrical point is the highest point and is as high as the highest point of the rear edge line of the upper surface of the conical guided wave drum obtained in the step (4), and the symmetrical point is tangent to the lower surface of the drum.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710238758.2A CN107016199B (en) | 2017-04-13 | 2017-04-13 | Design method of shock-wave-free boundary layer displacement bulge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710238758.2A CN107016199B (en) | 2017-04-13 | 2017-04-13 | Design method of shock-wave-free boundary layer displacement bulge |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107016199A CN107016199A (en) | 2017-08-04 |
| CN107016199B true CN107016199B (en) | 2020-05-05 |
Family
ID=59446555
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710238758.2A Active CN107016199B (en) | 2017-04-13 | 2017-04-13 | Design method of shock-wave-free boundary layer displacement bulge |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107016199B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107590330B (en) * | 2017-09-04 | 2020-08-11 | 中国人民解放军国防科技大学 | Design method of two-dimensional pre-compressed precursor with boundary layer displacement |
| CN108198240B (en) * | 2017-12-29 | 2021-03-26 | 厦门大学 | Three-dimensional bump reverse design method based on complex shock wave curved surface |
| CN111159899B (en) * | 2019-12-31 | 2022-05-24 | 西南科技大学 | Fundamental flow field with controllable double flow field parameters after reflection of shock wave and design method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5779189A (en) * | 1996-03-19 | 1998-07-14 | Lockheed Martin Corporation | System and method for diverting boundary layer air |
| CN103662087B (en) * | 2013-12-11 | 2015-07-15 | 厦门大学 | Hypersonic aerocraft and air inlet internal and external waverider integrated design method |
| CN104192302B (en) * | 2014-07-18 | 2015-08-12 | 中国人民解放军国防科学技术大学 | Based on the Waverider method of designing around tip Feng karman curve gyro-rotor benchmark flow field |
| CN105329462B (en) * | 2015-11-16 | 2016-08-24 | 中国人民解放军国防科学技术大学 | Osculating flow field based on variable wall surface pressure regularity of distribution waverider forebody derived method for designing |
| CN105667812B (en) * | 2016-01-29 | 2016-11-02 | 中国人民解放军国防科学技术大学 | Hypersonic aircraft precursor, air intake duct and wing rider integrated design method |
-
2017
- 2017-04-13 CN CN201710238758.2A patent/CN107016199B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN107016199A (en) | 2017-08-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107742011B (en) | Design method of impeller blade drag reduction micro-texture | |
| CN107016199B (en) | Design method of shock-wave-free boundary layer displacement bulge | |
| CN109279044B (en) | Aerodynamic shape design method of variable mach number osculating flow field waverider | |
| CN112340014B (en) | Inner-outer flow decoupling double-waverider high-speed air suction type aircraft and generation method thereof | |
| CN105667812A (en) | Waverider integration design method for hypersonic aircraft forebody, air inlet and wing | |
| CN109573092B (en) | Method for designing osculating axisymmetric Von Karman waverider | |
| CN104108470B (en) | Based on flush type every the planar hexagonal crystal of road layout and method of designing | |
| CN105134383B (en) | Hypersonic interior rotatable air intake duct lip cover method for designing based on streamline deviation | |
| CN110450963B (en) | Hypersonic aircraft body and inward turning type air inlet channel integrated design method and system | |
| CN110304267B (en) | Hypersonic aircraft design method and system | |
| CN103790639A (en) | Method for edge strip shape modifying of front edge of end area blade of turbine | |
| CN104912667A (en) | Design method of hypersonic speed internal-contraction air inlet channel carried out in steps | |
| CN105329462A (en) | Changeable wall surface pressure distribution rule-based osculating flow field ride precursor design method | |
| KR102616901B1 (en) | Aerodynamic layout design method and system for wide-speed-range hypersonic aircraft | |
| CN111767613A (en) | Design method of fixed-geometry high-speed air inlet channel inlet section with offset compression surface | |
| CN111003196B (en) | Full-wave-rider aircraft and design method and system thereof | |
| CN110104164B (en) | Front loading-air suction combined flow control method for transonic airfoil | |
| CN105539863B (en) | Hypersonic aircraft precursor, air intake duct and support plate integrated pneumatic layout method | |
| CN103982462B (en) | A kind of waveform jetting method of blade trailing edge | |
| Zhang | Research progress of hypersonic inlet inverse design based on curved shock compression system | |
| CN115659705B (en) | Fully-parameterized high-stealth air inlet channel design method and high-stealth air inlet channel | |
| CN115221639B (en) | Backpack semi-embedded inlet lip parametric design method suitable for flying wing layout | |
| Shi et al. | Serpentine inlet design and analysis | |
| Maruyama et al. | Aerodynamic characteristics of a two-dimensional supersonic biplane, covering its take-off to cruise conditions | |
| CN107628266B (en) | Design method of axisymmetric pre-compression precursor with boundary layer displacement |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |