阅读说明：本技术 一种抑制叶尖泄漏涡的方法及离心压气机 (Method for inhibiting tip leakage vortex and centrifugal compressor ) 是由 洪树立 向鑫 陆惟煜 张志广 于 2020-07-03 设计创作，主要内容包括：本发明公开了一种抑制叶尖泄漏涡的方法,在叶片前缘叶尖前方的腔壁上固定涡流发生器,涡流发生器与叶轮上叶片分离式安装,利用腔壁与叶片旋转的相对运动,来实现涡流发生器对叶片叶尖流动的周期性激励作用,实现非定常的控制效果；且利用涡流发生器产生与主叶片叶尖泄漏涡反向运动的漩涡,使其与叶尖泄漏涡发生耦合,以抑制或大幅度削弱泄露涡,有效减少叶尖气流的泄漏量,并将上述方法应用至离心压气机。(The invention discloses a method for inhibiting tip leakage vortex, which is characterized in that a vortex generator is fixed on a cavity wall in front of a tip of a front edge of a blade, the vortex generator and the blade on an impeller are installed in a separated mode, and the periodic excitation effect of the vortex generator on the flow of the tip of the blade is realized by utilizing the relative motion of the cavity wall and the rotation of the blade, so that the abnormal control effect is realized; and the vortex generator is used for generating a vortex which moves in a reverse direction with the main blade tip leakage vortex, so that the vortex is coupled with the blade tip leakage vortex to inhibit or greatly weaken the leakage vortex, the leakage amount of the blade tip airflow is effectively reduced, and the method is applied to the centrifugal compressor.)

1. A method of suppressing tip leakage vortices, comprising: a vortex generator is fixed on a cavity wall in front of a blade tip of the front edge of the blade, and a vortex with the direction opposite to that of a blade tip leakage vortex is generated by the vortex generator so as to inhibit the leakage amount of the airflow.

2. The utility model provides a centrifugal compressor, includes the impeller of quick-witted casket and inside setting, is provided with a plurality of blades on the impeller, its characterized in that: the vortex generator is fixed on the wall of a casing cavity in front of the blade tip of the front edge of the blade, and generates a vortex in a direction opposite to the direction of the tip leakage vortex so as to inhibit the leakage amount of the airflow.

3. A centrifugal compressor as claimed in claim 2, wherein: the blades comprise main blades and splitter blades, and vortex generators are fixed on the wall of a casing cavity in front of the front edge tips of the main blades.

4. A centrifugal compressor as claimed in claim 3, wherein: the vortex generators are multiple and are arranged on the wall of the casing cavity at equal intervals along the circumferential direction.

5. A centrifugal compressor as claimed in claim 4, wherein: the number of vortex generators is N1, the number of main blades is N2, and N1/N2 is 0.4-0.6.

6. A centrifugal compressor as claimed in claim 3, wherein: the ratio of the thickness T1 of the vortex generator to the thickness T2 of the main blade is 0.5-1.2.

7. A centrifugal compressor as claimed in claim 3, wherein: the vortex generator is rectangular, and the ratio of the long side B to the short side A is 0.3-0.5;

or the vortex generator is triangular, the edge of the vortex generator contacting with the cavity wall is a mounting edge D, the edge of the vortex generator facing the main blade is a radial edge C, the ratio of the length of the mounting edge D to the length of the radial edge C is 0.3-0.5, and the included angle A2 between the mounting edge D and the radial edge C is 70-110 degrees.

8. A centrifugal compressor as claimed in claim 7, wherein: the ratio of the length of the long side B or the mounting side D to the front edge leaf height H1 of the main blade 3 is 0.2-0.5.

9. A centrifugal compressor as claimed in claim 7, wherein: the ratio of the perpendicular distance D1 between the point on the long side B or the mounting side D and the front edge surface of the main blade to the blade height H1 of the front edge of the main blade is 0.2-0.5.

10. A centrifugal compressor as claimed in claim 2, wherein: the mounting angle a1 of the vortex generator is-50 to 40.

Technical Field

The invention relates to the technical field of turbines, in particular to a method for inhibiting tip leakage vortex and a centrifugal compressor.

Background

For the turbine device, a gap exists between the blade tip and the cavity wall, and leakage vortex is easily generated due to the blade tip gap, so that blade tip airflow leakage is caused, and the efficiency of the turbine device is reduced.

Taking a centrifugal compressor as an example, the centrifugal compressor is widely applied to military and civil fields, such as a propulsion system of a guided missile and an unmanned aerial vehicle, an auxiliary power device of an airplane, a distributed energy power system, a turbocharger for a vehicle and the like. The mach number of the blade tip air flow of the centrifugal compressor is high, and a complex vortex system structure can be formed by the mutual influence of an end wall boundary layer, blade tip leakage flow and main flow. Even if part of the vortex system is formed in the blade root or the blade leaf area, the part of the vortex system develops to the blade tip due to the meridian flow channel curvature, the larger centrifugal force and the like of the centrifugal compressor, so that the whole performance of the compressor can be obviously improved and the stable working range of the compressor can be improved by applying control and improvement on the flow field of the blade tip.

In contrast, the unsteady excitation control means can apply excitation with a certain frequency to the flow field, and the instability of the flow field is utilized to couple the excitation with the unsteady flow field, so that the sequence planning mechanism of the flow field is changed to be more orderly, the phenomena of rotating stall, surging and the like are prevented, and the stability margin is enlarged. Because the energy injected by the unsteady excitation is small, the influence of the unsteady excitation on the main flow is small, the influence on the efficiency can be reduced while the stability is expanded, and the efficiency can be improved under certain working conditions.

The current application is more in a steady jet or steady suction mode, and although a great benefit is obtained by adopting the excitation mode, in order to realize the control mode, a complex pipeline structure, a control valve and sometimes an additional air source and the like are needed, so that the weight and the cost of the power device are increased, the use is also complex, and the improvement is needed.

Disclosure of Invention

In order to solve the technical defects, the invention provides a method for inhibiting tip leakage vortex, wherein a vortex generator is fixed on a cavity wall in front of a tip of a front edge of a blade, and the vortex generator is used for generating vortex in a direction opposite to that of the tip leakage vortex so as to inhibit the leakage amount of airflow.

The vortex generator and the blade on the impeller are installed in a separated mode, and the periodic excitation effect of the vortex generator on the flowing of the blade tip is realized by utilizing the relative movement of the cavity wall and the rotation of the blade, so that the abnormal control effect is realized; and the vortex generator is used for generating vortex which moves in a reverse direction with the main blade tip leakage vortex, so that the vortex generator is coupled with the tip leakage vortex to inhibit or greatly weaken the leakage vortex and effectively reduce the leakage amount of tip airflow.

The second aspect of the present application provides a centrifugal compressor, including a casing and an inside impeller that sets up, be provided with a plurality of blades on the impeller, still include vortex generator, it fixes on the casing chamber wall in blade leading edge apex the place ahead, utilizes vortex generator to produce and the apex leaks the swirl that the vortex direction is opposite to restrain the air current and leak the quantity.

The method for inhibiting the tip leakage vortex is applied to the centrifugal compressor, specifically, the vortex generator is fixed on the wall of a casing cavity in front of the tip of the front edge of the blade, and the periodic excitation effect of the vortex generator on the flow of the tip of the compressor is realized by utilizing the relative motion of the casing and the rotation of the blade, so that the abnormal control effect is realized; vortex generated by the outer vortex generator is coupled with leakage vortex to inhibit or greatly weaken the leakage vortex, so that leakage amount of airflow at the blade tip is effectively reduced, stable working range of the centrifugal compressor is improved, the structure is simple, and the effect is obvious.

Furthermore, the blades comprise main blades and splitter blades, a vortex generator is fixed on the wall of the casing cavity in front of the front edge tips of the main blades, the long blades and the short blades are arranged at intervals, the distribution of a flow field in the impeller can be effectively improved, and the stable working range of the centrifugal compressor is further enlarged by matching with the vortex generator.

Furthermore, the vortex generators are arranged at equal intervals on the wall of the casing cavity along the circumferential direction, so that the unsteady excitation effect is improved, and the leakage of the blade tip is reduced.

Furthermore, the number of the vortex generators is N1, the number of the main blades is N2, and the number of the main blades is N1/N2 is 0.4-0.6, so that the strength of the leakage vortex is further inhibited or weakened, the unsteady excitation effect is improved, and the blade tip leakage amount is reduced.

Further, the ratio of the thickness T1 of the vortex generator to the thickness T2 of the main blade is 0.5-1.2, which is convenient for generating vortex to inhibit or weaken the intensity of leakage vortex and reduce the leakage amount of the blade tip.

Furthermore, the vortex generator is rectangular, and the ratio of the long side B to the short side A of the vortex generator is 0.3-0.5;

or the vortex generator is triangular, the edge of the vortex generator contacting with the cavity wall is a mounting edge D, the edge of the vortex generator facing the main blade is a radial edge C, the ratio of the length of the mounting edge D to the length of the radial edge C is 0.3-0.5, and the included angle A2 between the mounting edge D and the radial edge C is 70-110 degrees.

The structure of the vortex generator is optimized, so that the vortex can be generated better, the strength of the leakage vortex is restrained or weakened, and the leakage amount of the blade tip is reduced.

Of course, other shapes of vortex generators may be used as appropriate.

Further, the ratio of the length of the long side B or the mounting side D to the front edge height H1 of the main blade 3 is 0.2-0.5, so that the unsteady excitation effect is improved.

Furthermore, the ratio of the vertical distance D1 between the point on the long side B or the mounting side D and the front edge surface of the main blade to the blade height H1 of the front edge of the main blade is 0.2-0.5, so that the unsteady excitation effect is improved.

Further, the installation angle A1 of the vortex generator is-50 degrees to 40 degrees, and the mode of changing the installation angle of the vortex generator is adopted in the scheme, so that the vortex opposite to the rotation direction of the leakage vortex is generated when the airflow passes through the vortex generator.

Compared with the prior art, the technical scheme of the invention has the beneficial effects that:

1. the invention adopts the installation mode of the vortex generator and the blades on the impeller, simplifies the structure, inhibits or greatly weakens the leakage vortex, can achieve the periodic and abnormal control effect, effectively reduces the leakage amount of the airflow at the blade tip, and further improves the stable working range of the centrifugal compressor.

2. The invention utilizes the unsteady excitation effect of flow control, has small influence on the original flow field of the centrifugal compressor, has small influence on the efficiency of the centrifugal compressor, and even improves the efficiency of the compressor.

3. The invention has simple structure, convenient installation and wide application range.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a view of a vortex generator mounting structure in a centrifugal compressor;

FIG. 2 is a schematic view of the location of a vortex generator in a centrifugal compressor;

FIG. 3 is a schematic view of the location of vortex generators in a centrifugal compressor;

FIG. 4 is a schematic view of the shape of a vortex generator in a centrifugal compressor;

wherein the reference numerals are:

1. a case; 2. a vortex generator; 3. a main blade; 4. and a splitter blade.

Detailed Description

The invention is further described with reference to the following figures and specific examples.

Taking a common centrifugal compressor as an example

As shown in fig. 1, the impeller is rotatably installed in the casing, the blades on the impeller include main blades and splitter blades, which are arranged at intervals, a vortex generator is fixed on the casing wall in front of the front edge tip of the main blade at the position where the airflow enters the casing cavity, and the vortex generator is used to generate a vortex opposite to the tip leakage vortex direction so as to suppress the airflow leakage amount, so that the periodic excitation effect of the vortex generator on the flow of the compressor tip is realized by the relative motion of the casing and the rotation of the blades, and the abnormal control effect is realized.

The number, the shape, the installation position and the scale relation with the main blade of the vortex generators are as follows:

1. in terms of quantity

The number of the vortex generators is N1, the number of the main blades is N2, and the number of the main blades is N1/N2 and is 0.4-0.6.

2. In terms of shape

As shown in FIG. 4, the vortex generator is rectangular, the ratio of the length of the long side B to the short side A is 0.3-0.5, and the ratio of the thickness T1 of the rectangular body to the thickness T2 of the main blade is 0.5-1.2.

Preferably, the ratio of the length of the long side B to the height H1 of the leading edge of the main blade 3 is 0.2-0.5.

Secondly, the vortex generator is triangular, the edge of the vortex generator contacting with the cavity wall is a mounting edge D, the edge of the vortex generator facing the main blade is a radial edge C, the ratio of the length of the mounting edge D to the length of the radial edge C is 0.3-0.5, the included angle A2 between the mounting edge D and the radial edge C is 70-110 degrees, and the ratio of the thickness T1 of the triangular body to the thickness T2 of the main blade is 0.5-1.2.

More preferably, the ratio of the length of the mounting edge D to the height H1 of the leading edge of the main blade 3 is 0.2-0.5.

3. In terms of mounting position

First, the mounting angle a1 of the vortex generator is-50 ° to 40 ° in terms of mounting angle.

Secondly, regarding the vortex generator as a rectangle, taking the long side B as a mounting side, wherein the ratio of the vertical distance D1 between the upper point of the vortex generator and the front edge surface of the main blade to the front edge height H1 of the main blade is 0.2-0.5; for the case of the vortex generator being triangular, the ratio of the perpendicular distance D1 between the point on the mounting edge D and the leading edge surface of the main blade to the blade height H1 of the leading edge of the main blade is 0.2-0.5.