Background
The large bypass ratio turbofan engine is a main flow power device of the current civil airliner, and the index requirements of the fuel consumption rate and noise of the civil aviation engine are improved year by year along with the pursuit of the airworthiness requirements on the economy and environmental protection of the engine. For large bypass ratio turbofan engines, the outer culvert efficiency affects the fuel consumption. The rotational-static interference noise of the fan and the outer culvert outlet guide vanes is an important component of engine noise.
FIG. 1 is a schematic view of a split outer culvert guide vane and a support plate. FIG. 2 is a schematic diagram of a fused outer culvert guide vane and fulcrum.
As shown in fig. 1 and 2, the conventional large-bypass-ratio turbofan engine has three blade structures including outlet guide vanes, support plates and partition walls. In order to further reduce the rotation and static interference noise of the engine fan, improve the culvert efficiency, reduce the fuel consumption rate and lighten the weight of the engine, the advanced civil large-bypass-ratio turbofan engine adopts the design technology of the integration of the culvert wall-dividing support plates and the guide vanes.
Compared with the traditional split guide vane, the integrated guide vane support plate has the advantages that the guide vane is farther away from the fan blade, and the noise of the engine fan from outer culvert to static interference is lower. The blade profile is integrally designed, the supporting plate and the partition wall blade profile are considered to be blocked by the design of an Outlet Guide Vane (OGV), the flow loss of the outlet guide vane supporting plate and the partition wall is smaller, and the external culvert efficiency of the engine is higher. The support plate also has a flow guiding function, has a more compact structure, is beneficial to reducing the number of blades of the outer culvert guide vanes and lightens the weight of the engine.
However, due to the fusion design, the blade has complex modeling, various optimization parameters, complex three-dimensional flow, huge numerical simulation calculation amount and complex optimization design. The guide vane scheme of the fused split wall support plate has poor circumferential periodicity, reduces calculation difficulty, generally adopts full-channel three-dimensional numerical simulation as a design simulation and checking means, and has huge number of full-channel calculation grids and long calculation time. In addition, for the design scheme of the guide vane of the fusion split wall support plate, the number of types of blades is large, the geometry of the fusion blade profile is special, the optimization parameters are large, and the optimization design difficulty is huge. The traditional method for developing the optimal design by utilizing the three-dimensional calculation result needs to develop a large amount of full-channel three-dimensional numerical simulation work, takes a large amount of calculation resources due to overlong calculation time and overlarge data volume, and is unfavorable for design iteration and analysis of the design result.
Therefore, in order to facilitate the designer to quickly iterate the design and obtain the design experience, a design analysis tool for quickly evaluating the design scheme needs to be developed, the three-dimensional calculation amount of the fusion guide vane design whole channel is reduced, and the design is quickly converged.
In view of this, a method for designing the fusion of the guide vanes of the partition support plate is designed by those skilled in the art to overcome the above technical problems.
Disclosure of Invention
The application aims to overcome the defects that in the prior art, the fusion design of guide vanes needs to carry out a large amount of full-channel three-dimensional numerical simulation work, overlong calculation time and overlarge data volume, occupies a large amount of calculation resources, is unfavorable for design iteration and analysis of design results and the like, and provides a split wall support vane fusion design method.
The application solves the technical problems by the following technical proposal:
the design method for fusing the guide vanes of the wall dividing support plates is characterized by comprising the following steps of:
S1 inputting three-dimensional blade modeling of all fusion blades and outer culvert guide vanes of the complete ring;
S2 aiming at a plurality of typical height-expanding sections, expanding the sections into a plane blade profile;
S3 solving inscribed circle radius and central streamline of channels formed by each adjacent blade aiming at the unfolded plane blade profile to obtain channel expansion ratio change on the central streamline of each channel and channel expansion ratio change of an inlet and an outlet of the adjacent channel;
S4 developing circumferential distribution analysis of expansion ratio;
S5 developing analysis of the expansion ratio in the channel;
S6 developing full-circle three-dimensional calculation;
S7 combining the three-dimensional calculation result and the expansion ratio change of the inlet and the outlet of each channel to optimize the attack angle of the inlet of each blade;
S8 and combining the three-dimensional calculation result and expansion ratio change in each channel to optimize isentropic Mach number distribution on the surface of each blade.
According to one embodiment of the application, the step S2 The method specifically comprises the following steps: the typical spanwise cross-sections include three-dimensional leaf profiles of 0% spanwise, 20% spanwise, 50% spanwise, 80% spanwise and 100% spanwise.
According to one embodiment of the application, the step S4 The method further comprises the following steps: judging whether the attack angle distribution of the blade is reasonable according to the circumferential distribution of the expansion ratio, if so, entering a step S5 The method comprises the steps of carrying out a first treatment on the surface of the If not, optimizing the inlet attack angle and expansion ratio distribution, and returning to the step S1 。
According to one embodiment of the application, the step S4 In the process, ,if the ratio AR of the expansion ratio of adjacent channels of the blade is greater than 1, the actual working attack angle of the blade is deviated; if the ratio AR of the expansion ratios of adjacent channels of the blade is smaller than 1, the actual working attack angle of the blade is biased negative.
According to one embodiment of the application, the ratio AR of the expansion ratio of the adjacent channels of the blade ranges from 0.85 to 1.15,
according to one embodiment of the application, the step S5 The method further comprises the following steps: judging whether the load distribution of the blade is reasonable, if so, entering the step S6 The method comprises the steps of carrying out a first treatment on the surface of the If not, optimizing the expansion ratio of the inside of the blade channel, and returning to the step S1 。
According to one embodiment of the application, the larger the gradient of the internal expansion ratio change of the channel is, the larger the characterization load is, and the blade modeling scheme is adjusted to uniformly change the internal expansion ratio of the blade channel.
According to one embodiment of the application, the step S6 And performing full-loop three-dimensional calculation to obtain isentropic Mach number distribution of all blade surfaces.
According to one embodiment of the application, the step S8 The method further comprises the following steps: judging whether optimization is finished, and ending if the optimization is finished; if not, returning to the step S1 。
According to one embodiment of the application, the fusion blade comprises at least one split-wall guide vane fusion blade and a plurality of support plate guide vane fusion blades; the outer culvert guide vane comprises a plurality of outer culvert guide vanes with a plurality of types of blade profiles.
The application has the positive progress effects that:
the method for designing the fusion of the guide vanes of the partition support plates has the following advantages:
1. the application provides a dimension reduction analysis means aiming at the complex design of the guide vane of the fusion split wall support plate, which is beneficial to reducing the complexity of designers and rapidly summarizing the design experience.
2. The application provides a parameter for describing circumferential geometric uniformity of a non-periodic blade, and after the full-ring modeling of the blade is completed, the modeling result can be analyzed and optimized through a channel expansion ratio.
3. According to the application, the three-dimensional modeling result is used as input, and before the full-circle three-dimensional calculation is carried out, the load and attack angle optimization of the full-circle blade can be carried out, so that the three-dimensional full-circle numerical simulation calculation in the process of optimizing the design is greatly reduced, the design efficiency is obviously improved, and the rapid convergence of the design is facilitated.
Detailed Description
In order to make the above objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below.
Embodiments of the present application will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to the preferred embodiments of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Furthermore, although terms used in the present application are selected from publicly known and commonly used terms, some terms mentioned in the present specification may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein.
Furthermore, it is required that the present application is understood, not simply by the actual terms used but by the meaning of each term lying within.
FIG. 3 is a schematic view of a 0% spanned section profile in the method of the present application. FIG. 4 is a schematic diagram of the channel expansion ratio in the method for designing the fusion of the split-wall support plates and guide vanes. FIG. 5 is a graph showing the variation of the expansion ratio of the channel in the method for designing the fusion of the guide vanes of the partition support plates. FIG. 6 is a schematic view of a 0% span-wise channel in a method of designing a split-wall support vane fusion. FIG. 7 shows the expansion ratio distribution of 0% of the span channels in the design method of the split wall support vane fusion. FIG. 8 is a flow chart of a method of the present application for designing a split-wall stay vane fusion.
As shown in fig. 3, in engineering application, the outer culvert and sub-wall support vane fusion scheme is generally composed of 1-2 sub-wall vane fusion vanes 10, a plurality of support vane fusion vanes 20, and a plurality of outer culvert vanes 30 with a plurality of types of vane patterns.
The design of the wall-dividing guide vane fusion blade 10 needs to consider the structural constraint of internal installation components, the flow influence on outlet guide vanes nearby the fusion blade and the inlet inflow condition. The design of the stay plate guide vane fusion blade 20 needs to consider the structural constraint of the internal communication pipeline, the flow influence of the outlet guide vanes near the blade and the inlet inflow condition. The outer culvert guide vane 30 is designed by considering the geometry of adjacent blades, inlet incoming flow conditions and outlet airflow parameters. Through different types of outer culvert guide vane arrangement and fusion blade profile optimization, geometric circumferential uniform transition is realized, and the method is suitable for incoming flow conditions.
As shown in fig. 4 to 8, the application discloses a method for fusing design of guide vanes of a partition support plate, which comprises the following steps:
step S1 And inputting three-dimensional blade modeling of all the fusion blades and the outer culvert guide blades of the complete ring.
And 3, designing and inputting three-dimensional blade models of all the fusion blades and the outer culvert guide vanes of the complete ring according to the internal structure size constraint, the incoming flow condition and the like.
Step S2 For a plurality of typical spanwise sections, into a planar leaf profile.
Preferably, the step S2 The method specifically comprises the following steps: the typical spanwise cross-section includes three-dimensional profiles of 0% spanwise, 20% spanwise, 50% spanwise, 80% spanwise and 100% spanwise, the planar profiles being spanwise as shown in fig. 3.
Step S3 Solving the inscribed circle radius and the center flow line (namely the center of the inscribed circle, as shown in fig. 4) of the channel formed by each adjacent blade aiming at the unfolded plane blade profile, and obtaining the channel expansion ratio change on the center flow line of each channel and the channel expansion ratio change of the inlet and the outlet of the adjacent channel, as shown in fig. 5 to 7.
Step S4 And carrying out expansion ratio circumferential distribution analysis.
Preferably, the step S4 The method further comprises the following steps: judging whether the attack angle distribution of the blade is reasonable according to the circumferential distribution of the expansion ratio, if so, entering a step S5 The method comprises the steps of carrying out a first treatment on the surface of the If not, optimizing the inlet attack angle and expansion ratio distribution, and returning to the step S1 。
Here, as shown in fig. 7, the expansion ratio of the inlet and the outlet of each channel is changed, which characterizes the circumferential transition uniformity of each channel, and the blade modeling scheme is adjusted to ensure that the expansion ratio of the inlet and the outlet of each channel is uniform in transition.
Said step S4 If the ratio AR of the expansion ratio of adjacent channels of the blade is larger than 1, the actual working attack angle of the blade is righted; if the ratio AR of the expansion ratios of adjacent channels of the blade is smaller than 1, the actual working attack angle of the blade is biased negative. The ratio AR of the expansion ratio of adjacent channels of the blade is preferably in the range of 0.85-1.15.
In this embodiment, the expansion ratio AR of a certain adjacent channel is defined as follows:
the expansion ratio of the inlet and the outlet of the back side channel of a certain blade is equal to the radius of the inscribed circle of the outlet of the back side of the blade to the radius of the inscribed circle of the inlet on the back side of the blade:
the expansion ratio of the inlet and the outlet of a certain blade basin side passage is equal to the radius of an inlet inscribed circle on the side outlet of the blade basin:
adjacent channel expansion ratio AR:
the actual working attack angle of the blade is influenced by the AR value, if the AR value is larger than 1, the actual working attack angle of the blade is positive, and if the AR value is smaller than 1, the actual working attack angle of the blade is negative, so that the AR value is preferably in the range of 0.85-1.15.
Step S5 And carrying out analysis of the internal expansion ratio of the channel.
Preferably, the step S5 The method further comprises the following steps: judging whether the load distribution of the blade is reasonable, if so, entering the step S6 The method comprises the steps of carrying out a first treatment on the surface of the If not, optimizing the expansion ratio of the inside of the blade channel, and returning to the step S1 。
As shown in FIG. 5, the expansion ratio change in the channel is represented, the larger the expansion ratio change slope is, the larger the representation load is, and the blade modeling scheme is adjusted to enable the expansion ratio in the channel to change uniformly.
Step S6 And developing full-circle three-dimensional calculation.
By carrying out full-circle three-dimensional calculation, flow field details such as isentropic Mach number distribution of all blade surfaces can be obtained.
Step S7 And combining the three-dimensional calculation result and the expansion ratio change of the inlet and the outlet of each channel (shown in figure 7), and optimizing the attack angle of the inlet of each blade.
Step S8 And combining the three-dimensional calculation result and expansion ratio change (shown in fig. 5) inside each channel, and optimizing the isentropic Mach number distribution of each blade surface.
Preferably, the stepStep S8 The method further comprises the following steps: judging whether optimization is finished, and ending if the optimization is finished; if not, returning to the step S1 。
According to the description, the application provides a dimension reduction analysis method, which can reduce full-loop three-dimensional numerical simulation calculation and accelerate design convergence.
The application discloses a method for designing a division wall support plate and guide vane fusion, which uses a full-ring three-dimensional blade modeling result as input, performs angle-preserving transformation on a typical expanding section of a full-ring three-dimensional blade profile, and expands the full-ring three-dimensional blade profile into a full-ring plane blade profile (shown in figure 3). Before three-dimensional calculation is carried out, analysis is carried out on the internal expansion ratio of each channel of the typical exhibition height of the full-ring planar blade profile, and the internal expansion ratio, the channel load and the attack angle of the blade modeling result are optimized, so that the three-dimensional calculation times are reduced, and the design is quickly iterated and converged.
The surface load of the blade is initially optimized by analyzing the internal expansion ratio change of the channel, as shown in fig. 4 and 5, especially as shown in a blade profile channel (TD 6 channel and TD7 channel) formed by the fusion blade profile of a common OGV blade and a partition support plate guide blade in fig. 6.
Wherein R in FIG. 4I Characterizing inlet channel area for inlet inscribed circle radius, RO Characterizing the outlet passage area for the outlet inscribed circle radius, RM The internal passage area is characterized for the internal inscribed circle radius.
The ordinate in FIG. 5 isThe expansion ratio inside the channel is represented, and the abscissa is the central streamline coordinate. Fig. 5 characterizes the change in channel expansion ratio.
The circumferential channels of the method for designing the fusion of the guide vanes of the partition support plates must be uniformly transited, and if the transition is not uniform, the attack angles of adjacent blades can be too positive or too negative, which is not beneficial to the improvement of the culvert efficiency and the stability margin. As shown in fig. 6 and 7, analysis of the change of the expansion ratio of the channel is performed on the modeling result, and the expansion ratio distribution of the modeling result can be initially optimized by using fig. 7.
In fig. 6, 14 channel numbers TD1 to TD14 are shown.
Wherein FIG. 7 shows expansion ratio distribution of each channel, and the abscissa is channel inlet-outlet expansion ratioThe ordinate indicates the channel number.
Aiming at the problem of optimal design, the application provides a dimension-reducing design analysis method, which is used for rapidly analyzing the modeling result of the full-channel three-dimensional blade, reducing the calculation amount of three-dimensional analysis, improving the optimal design efficiency and enabling the design to be rapidly and iteratively converged.
In addition, the terms used in the present application are specifically explained as follows:
the support plate is used for transferring loads such as thrust and the like, transferring intermediate rigidity and the like after the outer culvert fan blades and the outer culvert guide vanes of the traditional aero engine.
The division wall (hanging) refers to the fact that the traditional aeroengine is externally provided with the division wall (hanging) for connecting an airplane and the engine, and accessories such as a precooler are installed.
The division wall support plate fusion guide vane means that the division wall support plate guide vane is fused with three structures of a division wall, a support plate and an external culvert guide vane into one structure, and functions of diversion diffusion, load transmission and structural connection are achieved.
The attack angle refers to the angle between the incoming flow angle of the blade and the metal angle of the inlet of the blade profile.
In summary, the method for designing the fusion of the guide vanes of the partition support plates has the following advantages:
1. the application provides a dimension reduction analysis means aiming at the complex design of the guide vane of the fusion split wall support plate, which is beneficial to reducing the complexity of designers and rapidly summarizing the design experience.
2. The application provides a parameter for describing circumferential geometric uniformity of a non-periodic blade, and after the full-ring modeling of the blade is completed, the modeling result can be analyzed and optimized through a channel expansion ratio.
3. According to the application, the three-dimensional modeling result is used as input, and before the full-circle three-dimensional calculation is carried out, the load and attack angle optimization of the full-circle blade can be carried out, so that the three-dimensional full-circle numerical simulation calculation in the process of optimizing the design is greatly reduced, the design efficiency is obviously improved, and the rapid convergence of the design is facilitated.
While specific embodiments of the application have been described above, it will be appreciated by those skilled in the art that these are by way of example only, and the scope of the application is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the principles and spirit of the application, but such changes and modifications fall within the scope of the application.