CN110410156B

CN110410156B - Method for lifting load of blade based on flow separation

Info

Publication number: CN110410156B
Application number: CN201910716087.5A
Authority: CN
Inventors: 张华良; 尹钊; 李耀阳; 张超炜
Original assignee: Institute of Engineering Thermophysics of CAS
Current assignee: Institute of Engineering Thermophysics of CAS
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2022-08-02
Anticipated expiration: 2039-08-02
Also published as: CN110410156A

Abstract

The present disclosure provides a flow separation based blade comprising a back arc and an inner arc, the back arc being a suction surface of the blade, the inner arc being a pressure surface; the suction surface is provided with a groove; also provided is a flow separation based blade and method of lifting loads thereof, comprising: step S1: acquiring the pressure distribution of the surface of the prototype blade, and acquiring the load based on the pressure distribution; step S2: modifying and digging a groove on the suction surface of the prototype blade, creating a local flow separation condition, maintaining a stable structure for separation, and determining the modified blade load by using the method; and step S3: the grooves are arranged according to different influencing factors, so that the local or overall load of the blade is increased.

Description

Method for lifting load of blade based on flow separation

Technical Field

The disclosure relates to the technical field of impeller mechanical blades and aircraft lifting wings, in particular to a blade based on flow separation and a load lifting method thereof.

Background

Turbomachines are widely used in industrial fields, such as aircraft engines, ground gas turbines, steam turbines, and mine ventilation and pipeline transportation, and increasing blade loads has an important role in increasing turbomachines efficiency and work capacity. However, in the conventional blade load improving method, the flow loss caused by flow separation is avoided to exert the blade effect, the load is rarely improved by utilizing the characteristic of flow separation, and a corresponding flow separation organization method is also lacked.

The lift wing is widely applied to the fields of aviation and ships, such as airplanes, hydrofoils and the like, and the improvement of wing-shaped lift force plays an important role in improving the performances of airplanes and ships. However, in the current methods for improving the airfoil lift, the flow loss caused by flow separation is avoided, the characteristics of the flow separation are rarely utilized to improve the lift, and a corresponding flow separation organization method is also lacked.

BRIEF SUMMARY OF THE PRESENT DISCLOSURE

Technical problem to be solved

Based on the above problems, the present disclosure provides a flow separation-based blade and a method for lifting a load thereof, so as to alleviate the technical problems in the prior art that it is difficult to effectively utilize the characteristics of flow separation to improve the blade load.

(II) technical scheme

In one aspect of the present disclosure, a flow separation based blade is provided, comprising a back arc and an inner arc, the back arc being a suction surface of the blade, the inner arc being a pressure surface; the suction surface is provided with a groove.

In an embodiment of the present disclosure, a cross-sectional shape of the groove includes: fan-shaped, rectangular, circular.

In the embodiment of the present disclosure, the number of the grooves is set to 1.

In the disclosed embodiment, the number of the grooves is set to be more than 1.

In another aspect of the present disclosure, there is provided a flow separation based blade and a method of lifting a load thereof, including:

step S1: acquiring the pressure distribution of the surface of the prototype blade, and acquiring the load based on the pressure distribution;

step S2: modifying and digging a groove on the suction surface of the prototype blade, creating a local flow separation condition, maintaining a stable structure for separation, and determining the modified blade load by using the method; and

step S3: the grooves are arranged according to different influencing factors, so that the local or overall load of the blade is increased.

In the embodiment of the present disclosure, in step S1, a numerical simulation is performed by using a computational fluid dynamics method, so as to obtain the static pressure distribution on the surface of the blade.

In the disclosed embodiment, in step S2, the surface pressure of the blade near the vortex is reduced after the vortex is formed inside the groove, and the surface pressure of the pressure surface is not changed, so that the blade load is increased.

In the embodiment of the present disclosure, the influencing factors in step S3 include: the position of the groove, the size of the groove, the number of the grooves and the cross-sectional shape of the groove.

In an embodiment of the present disclosure, the step S3 includes:

step S31: determining the position of the groove;

step S32: determining the size of the groove;

step S32: determining the number of grooves; and

step S32: the shape of the groove is determined.

In an embodiment of the present disclosure, a cross-sectional shape of the groove includes: fan-shaped and/or rectangular; the number of the grooves is more than or equal to 1.

(III) advantageous effects

From the above technical solutions, it can be seen that the blade based on flow separation and the method for lifting load thereof of the present disclosure have at least one or some of the following advantages:

(1) the universality is good, the practicability is strong, and the load improving effect is obvious;

(2) the blades can be lightened, and the weight is reduced.

Drawings

FIG. 1 is a flow chart illustrating a method for blade lift loading based on flow separation in accordance with an embodiment of the present disclosure;

FIG. 2 is a two-dimensional profile plot of a vane based on flow separation in an embodiment of the present disclosure; wherein FIG. 2(a) is a schematic view of a prototype blade and FIG. 2(b) is a schematic view of a blade with elliptical-shaped grooves; FIG. 2(c) is a schematic view of a blade with different sized grooves; FIG. 2(d) is a schematic view of a blade with a greater number of grooves; FIG. 2(e) is a schematic view of a blade with rectangular grooves;

FIG. 3 is a vane surface pressure profile of the profile shown in FIGS. 2(a) and 2(b) in accordance with an embodiment of the present disclosure;

FIG. 4 is a numerical calculated flow field map of a flow separation based blade in an embodiment of the present disclosure.

Detailed Description

The invention provides a flow separation-based blade and a load lifting method thereof.

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

The present disclosure provides a flow separation based blade, as shown in fig. 2, the flow separation based blade includes a back arc and an inner arc, the back arc is a suction surface of the blade, and the inner arc is a pressure surface; the suction surface is provided with a groove.

The cross-sectional shape of the groove includes: fan-shaped, rectangular, circular, oval.

The number of the grooves is set to be 1 or more than 1.

The present disclosure also provides a method for lifting a load based on a flow separation blade, which is shown in fig. 1 to 2, and includes the following steps:

step S1: a prototype blade surface pressure profile is obtained, and a load is obtained based on the pressure profile.

In the disclosed embodiment, the prototype blade geometry is shown in fig. 2(a), where the back arc is the suction side and the inner arc is the pressure side. And carrying out numerical simulation by using a computational fluid dynamics method so as to obtain the static pressure distribution of the surface of the blade. Meanwhile, drawing a pressure distribution curve chart of the blade surface, as shown by a dot curve in fig. 3, the area enclosed by the dot curve is the prototype blade load.

Step S2: modifying and digging a groove on the suction surface of the prototype blade, creating a local flow separation condition, maintaining a stable structure for separation, and determining the modified blade load by using the method;

the schematic diagram of the modified blade with the grooves is shown in fig. 2(b), and a part of the surface of the suction surface is dug, so that the fluid can form vortices inside the grooves, which can be seen from the flow field calculation result in fig. 4.

As shown in the square point curve in FIG. 3, the area enclosed by the square point curve is the blade load after the groove is dug in a modified mode. The internal vortex formation can reduce the surface pressure of the blade near the vortex, and the surface pressure of the pressure surface is unchanged, so that the blade load is increased.

The influencing factors include: the position of the groove, the size of the groove, the number of the grooves and the cross-sectional shape of the groove. The local or overall load is increased by solving the acute calculation of the grooves under different setting conditions.

The method comprises the following substeps:

step S31: determining the position of the groove;

according to the preferred embodiment, the method further comprises the step of determining the selection of the groove position, and the specific steps are as follows: a blade load graph with different groove positions is obtained through a computational fluid mechanics method, wherein the grooves are located on a suction surface, molded lines enabling blade loads to be increased are selected, and then the groove installation positions are determined.

Step S32: determining the size of the groove;

according to the preferred embodiment, the method further comprises the step of determining the size selection of the groove, and the specific steps are as follows: the blade load graph with different groove sizes is obtained through a computational fluid dynamics method, wherein the grooves are located on a suction surface, molded lines which enable the blade load to be increased are selected, and then the size of the grooves is determined, and the sizes of the grooves are different, for example, as shown in fig. 2(b) and fig. 2 (c).

Step S32: determining the number of grooves;

according to the preferred embodiment, the method further comprises the step of determining the number of the grooves to select, and the specific steps are as follows: obtaining a blade load graph with different groove sizes by a computational fluid dynamics method, wherein the grooves are positioned on a suction surface, selecting a molded line which increases the blade load, and further determining the number of the grooves, wherein the different groove numbers are as shown in fig. 2(b) and fig. 2 (d).

Step S32: determining the shape of the groove;

according to the preferred embodiment, the method further comprises the step of determining the shape selection of the groove, and the specific steps are as follows: obtaining a blade load graph with different groove shapes by a computational fluid dynamics method, wherein the grooves are positioned on a suction surface, selecting a molded line which increases the blade load, and further determining the shapes of the grooves, wherein the different groove shape pairs are shown in fig. 2(b) and fig. 2 (e). The grooves have a specific shape, the predetermined shape being configured such that the blade has an increased load in the operational state, the shape including, but not limited to, a sector, an ellipse, a rectangle, etc.

The location, size, number and shape of the grooves are among the factors that influence blade loading, and embodiments provided according to the present disclosure may include one or all of the above factors.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It is to be noted that, in the attached drawings or in the description, the implementation modes not shown or described are all the modes known by the ordinary skilled person in the field of technology, and are not described in detail. Further, the above definitions of the various elements and methods are not limited to the various specific structures, shapes or arrangements of parts mentioned in the examples, which may be easily modified or substituted by those of ordinary skill in the art.

From the above description, those skilled in the art should clearly recognize that the present disclosure is based on a flow separation blade and a method of lifting loads thereof.

In summary, the present disclosure provides a blade based on flow separation and a method for lifting a load thereof, in which a groove is formed in a suction surface of the blade, so that a vortex structure is formed in the groove by a fluid, the surface pressure of the suction surface is reduced, and the load of the blade is further increased.

It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", and the like, used in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present disclosure. Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure.

And the shapes and sizes of the respective components in the drawings do not reflect actual sizes and proportions, but merely illustrate the contents of the embodiments of the present disclosure. Furthermore, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.

In addition, unless steps are specifically described or must occur in sequence, the order of the steps is not limited to that listed above and may be changed or rearranged as desired by the desired design. The embodiments described above may be mixed and matched with each other or with other embodiments based on design and reliability considerations, i.e., technical features in different embodiments may be freely combined to form further embodiments.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that is, the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this disclosure.

The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.

Claims

1. A method of blade lift loading based on flow separation, comprising:

step S1: carrying out numerical simulation by using a computational fluid dynamics method to obtain the pressure distribution of the surface of the prototype blade, and obtaining the load based on the pressure distribution;

step S3: numerical simulation is carried out by using a computational fluid mechanics method, and the grooves are arranged according to different influence factors, so that the local or overall load of the blade is increased; in step S2, after the vortex is formed in the groove, the surface pressure of the blade near the vortex is reduced, and the surface pressure of the pressure surface is unchanged, so that the load of the blade is increased;

the step S3 includes:

step S31: determining the position of the groove;

step S32: determining the size of the groove;

step S33: determining the number of grooves; and

step S34: determining the shape of the groove;

in step S31, a blade load graph with different groove positions is obtained through a computational fluid dynamics method, a molded line which enables the blade load to be increased is selected, and then the groove positions are determined;

in step S32, blade load graphs with different groove sizes are obtained through a computational fluid dynamics method, molded lines enabling blade loads to be increased are selected, and then the size of the groove is determined;

in step S33, blade load graphs with different groove numbers are obtained through a computational fluid dynamics method, molded lines enabling blade loads to be increased are selected, and the groove numbers are further determined;

in step S34, blade load graphs with different groove shapes are obtained through a computational fluid dynamics method, molded lines enabling blade loads to be increased are selected, and then the shapes of the grooves are determined;

the cross section of the groove is selected from a circle, a fan and a rectangle; the number of the grooves is more than or equal to 1.