CN106089808A - A kind of blade diffuser with trailing edge structures before swallow-tail form and formative method thereof - Google Patents

Abstract

The invention discloses a vane diffuser with a dovetail-shaped front and rear edge structure and a molding method thereof, comprising a diffuser disc, a diffuser wheel cover, a built-in radial diffuser blade, a built-in axial diffuser The radial diffuser blades and the axial diffuser blades are uniformly distributed between the diffuser wheel disc and the diffuser wheel cover along the circumferential direction. The diffuser can be creatively transformed from the traditional vane diffuser. It has the advantages of convenient shape, low cost and simple processing. Adaptability, thereby greatly improving the efficiency and stable working margin of high-pressure ratio centrifugal compressors; the anti-fouling coating of its blades can effectively reduce the generation of fouling, maintain sufficient air circulation area, reduce flow friction, thereby reducing compressed air The surge problem of the machine can be solved, and the safety of the air compressor can be improved. It can be especially suitable for the high-pressure ratio centrifugal air compressor of small and medium-sized aero-engines.

Description

A vaned diffuser with a dovetail-shaped leading and trailing edge structure and its modeling method

technical field

The invention belongs to the field of high-pressure ratio centrifugal compressors, and relates to a vane diffuser with a dovetail-shaped front and rear edge structure and a modeling method thereof.

Background technique

Due to the advantages of compact structure, high pressure ratio, high reliability, convenient manufacture, low cost, good manufacturability and wide stable working margin, centrifugal compressors have been widely used in small and medium-sized engines. In order to further improve the thrust-to-weight ratio/power-to-weight ratio of the engine and improve the performance under various flight conditions at high altitude, higher requirements are placed on the pressure ratio of the centrifugal compressor; The outlet width of the centrifugal impeller is very small, and the diffuser inlet is very close to the impeller outlet. There is a strong unsteady interaction between the two, which deteriorates the matching between the centrifugal impeller and the diffuser, and greatly reduces the efficiency and stable working range of the centrifugal compressor. , the diffuser design with compact structure and low loss is very challenging, which has become the main technical obstacle restricting the application of high-pressure ratio centrifugal compressors in engineering practice.

The dovetail-shaped leading edge formed by the intersecting walls of two adjacent tubular diffusers can better adapt to the high-speed non-uniform flow at the rotor outlet, and compared with the traditional vane diffuser, the same passage The flow area has a smaller wall area, which reduces friction loss and is conducive to improving the efficiency and stable working margin of the high-pressure ratio centrifugal compressor. North American General Motors and Pratt & Whitney have successfully applied the tubular diffuser to the actual model middle. However, for the tubular diffuser in which the radial diffuser and the axial diffuser are designed to be integrated, there is generally a phenomenon that the axial outlet air flow is extremely uneven along the circumferential direction, and the compressor surge problem caused by it is also It brings safety hazards to the application of the compressor. In addition, the tubular diffuser also has problems such as difficult processing, high cost, and difficulty in guaranteeing processing accuracy. Therefore, there is an urgent need for a new diffuser structure that is beneficial to both controlling the cost and improving the performance of the centrifugal compressor.

Contents of the invention

The purpose of the present invention is to provide a new diffuser structure which is beneficial to control the cost and improve the performance of the centrifugal compressor, and provide a modeling method.

In order to achieve the above purpose, a centrifugal compressor vane diffuser with a dovetail-shaped front and rear edge structure, including axial diffuser blades, diffuser discs, diffuser wheel covers, diffuser connecting bolts, Radial diffuser blades, the radial diffuser blades and axial diffuser blades are evenly distributed in the circumferential direction between the diffuser disc and the diffuser wheel cover, the radial diffuser The device blade has a dovetail-shaped leading edge and a dovetail-shaped trailing edge structure, and its modeling method is:

1) Based on the traditional vane diffuser, sweep the quadratic curve along the profile line of the diffuser vane end wall with scanning modeling, and then perform Boolean subtraction operation with the traditional diffuser body to obtain the dovetail-shaped leading edge and dovetail-shaped Centrifugal compressor vane diffuser with trailing edge structure;

2) The endpoints of the above-mentioned quadratic curve for scanning modeling are the intersection points of the diffuser blade leading edge and blade root section, and the intersection points of blade leading edge and blade tip section respectively, and the plane where the scanning modeling quadratic curve is located is perpendicular to the diffuser The pressure side of the blade bends towards the suction side of the blade.

Further, the diffuser is arranged at the airflow outlet of the centrifugal compressor, and the ratio of the radial diffuser inlet radius R3 to the centrifugal impeller outlet radius R2 is 1.03-1.1.

Further, the cross-sectional area of the expansion channel of the diffuser can be obtained by changing the shape of the quadratic curve and the wedge angle θ of the traditional vane diffuser used for modeling, so as to adjust the ratio of the area of the diffuser to the inlet and outlet.

Further, the wedge angle θ of the traditional vane diffuser used for shaping is not less than 8°.

Further, the diffuser blades are coated with an anti-scaling and anti-corrosion coating, which can effectively reduce the serious problem of fouling of the diffuser blades, and overcome the surge problem of the compressor caused by the reduction of the air circulation area caused by the fouling .

Further, the anti-scaling and anti-corrosion coating coated on the diffuser blade is an aluminum oxide ceramic composite coating containing 1% Ti nanoparticles sprayed by the HVOF spraying process, which can improve the anti-scaling, anti-corrosion and anti-friction of the blade. performance.

The advantages of the present invention are: the vane diffuser with dovetail-shaped leading edge and trailing edge structure has good adaptability to high-speed airflow, and the anti-fouling coating can effectively reduce the generation of fouling and maintain sufficient The air circulation area reduces the flow friction, thereby reducing the surge problem of the compressor and improving the safety performance of the compressor; and the invention is convenient in shape, low in cost, simple in processing and good in safety, and can greatly improve the performance of the centrifugal compressor. Efficiency and stable working margin, especially suitable for small and medium-sized aeroengine high pressure ratio centrifugal compressors.

Description of drawings

Fig. 1 is a schematic structural view of a vaned diffuser with a dovetail-shaped front and rear edge structure;

Fig. 2a and Fig. 2b are traditional wedge-shaped diffuser modeling parameters and diffuser three-dimensional schematic diagram of the present invention;

Fig. 3 is a schematic diagram of structural parameters used in the modeling method of the present invention;

Fig. 4 is a three-dimensional schematic diagram of a vaned diffuser with a dovetail-shaped front and rear edge structure of the present invention;

Among them, 1-axial diffuser blade; 2-diffuser disc; 3-diffuser wheel cover; 4-diffuser connecting bolt; 5-radial diffuser blade; 6-dovetail leading edge ;7-dovetail trailing edge; 8-conic curve for scanning modeling; 9-traditional diffuser leading edge; 10-diffuser suction surface; 11-diffuser pressure surface; 12-diffuser blade end wall profile; 13 - conventional wedge diffuser blades.

detailed description

Below, in conjunction with accompanying drawing 1～4 and embodiment, the specific embodiment of the present invention is described in detail:

Figure 1 shows the embodiment of the vane diffuser with dovetail-shaped front and rear edge structure of the present invention, including a diffuser disc 2, a diffuser wheel cover 3 and a number of built-in radial diffuser blades 5 and Axial diffuser blade 1, diffuser connecting bolts 4 fix radial diffuser blade 5 between diffuser disc 2 and diffuser wheel cover 3, this embodiment is suitable for high pressure ratio centrifugal compressor . The radial diffuser vane 5 has a dovetail-shaped leading edge 6 and a dovetail-shaped trailing edge 7 , which is creatively modified based on the traditional vane-type diffuser vane 13 . The radial diffuser blade 5 is coated with an anti-scaling and anti-corrosion coating, and the anti-scaling and anti-corrosion coating is an aluminum oxide ceramic composite coating containing 1% Ti nanoparticles sprayed by the HVOF spraying process, which improves The anti-scaling, anti-corrosion and anti-friction performance of the blade can effectively reduce the serious problem of fouling of the diffuser blade, and overcome the surge problem of the compressor caused by the reduction of the air circulation area caused by the fouling.

Figure 2a and Figure 2b show the shape parameters of the traditional wedge-shaped diffuser blade 13 and the three-dimensional schematic diagram of the diffuser, R3 and R4 are respectively the inlet and outlet of the diffuser, θ is the wedge angle of the blade shape, and α is the geometric inlet angle; where , the ratio of the radial diffuser inlet radius R3 to the centrifugal impeller outlet radius R2 is 1.03-1.1, and the wedge angle θ is not less than 8°.

Described radial diffuser vane 5, its modeling method is:

(1) Based on the traditional vane diffuser 13, sweep along the profile line 12 of the diffuser vane end wall with a quadratic curve 8 in a certain scanning shape, and then perform Boolean subtraction with the body of the traditional vane diffuser 13 to obtain A centrifugal compressor vane diffuser 5 having both a dovetail-shaped leading edge 6 and a dovetail-shaped trailing edge 7;

(2) The endpoints of the above-mentioned scanning modeling with the quadratic curve 8 are respectively the intersection point of the diffuser blade leading edge 9 and the blade root section, the intersection point of the blade leading edge 9 and the blade tip section, and the scanning modeling uses the plane where the quadratic curve 8 is located. Perpendicular to the pressure surface 11 of the diffuser, the scanning shape uses a conic curve 8 to bend toward the suction surface 10 of the blade, as shown in Fig. 3 and Fig. 4 .

The present invention is not limited to the above-mentioned embodiments, and without departing from the essence of the present invention, any deformation, improvement, and replacement conceivable by those skilled in the art fall within the scope of the present invention.

Claims (6)

1. A centrifugal compressor vane diffuser with a dovetail front and rear edge structure, characterized in that it comprises an axial diffuser blade (1), a diffuser disc (2), a diffuser wheel cover (3), diffuser connecting bolts (4), radial diffuser blades (5), the radial diffuser blades (5) and axial diffuser blades (1) are evenly distributed along the circumferential direction Between the diffuser disc (2) and the diffuser cover (3), the radial diffuser vane (5) has a dovetail-shaped leading edge (6) and a dovetail-shaped trailing edge (7) structure , whose modeling method is: 1) Based on the traditional vane diffuser (13), use the conic curve (8) to sweep along the end wall profile (12) of the diffuser vane with sweeping modeling, and then perform Boolean analysis with the traditional diffuser body (13) Subtraction operation, obtain the centrifugal compressor vane type diffuser with dovetail-shaped leading edge (6) and dovetail-shaped trailing edge (7) structure; 2) The endpoints of the quadratic curve (8) used for the above scanning modeling are respectively the intersection point of the diffuser blade leading edge (9) and the blade root section, the intersection point of the blade leading edge (9) and the blade tip section, and the scanning modeling uses two The plane where the secondary curve (8) is located is perpendicular to the pressure surface (11) of the diffuser, and the curve bends toward the blade suction surface (10). 2. A centrifugal compressor vane diffuser with a dovetail-shaped front and rear edge structure as claimed in claim 1, wherein the diffuser is arranged at the air outlet part of the centrifugal compressor, and radially expands The ratio of the compressor inlet radius R3 to the centrifugal impeller outlet radius R2 is 1.03-1.1. 3. a kind of centrifugal compressor vane type diffuser with dovetail-shaped leading and trailing edge structure as claimed in claim 1, is characterized in that, the cross-sectional area of described diffuser expansion passage can be changed quadratic curve ( 8) The shape and wedge angle θ of a traditional vaned diffuser (13) used for modeling is obtained. 4. A kind of centrifugal compressor vane diffuser with dovetail front and rear edge structure as claimed in claim 3, it is characterized in that, the traditional vane diffuser (13) wedge angle θ Not less than 8°. 5. A kind of centrifugal compressor vane type diffuser with dovetail front and rear edge structure as claimed in claim 1, it is characterized in that, described radial diffuser vane (5) is coated with anti-fouling and anti-corrosion coating layer. 6. A kind of centrifugal compressor vane diffuser with dovetail front and rear edge structure as claimed in claim 5, it is characterized in that, the anti-scaling and anti-corrosion coating coated on the radial diffuser vane (5) The coating is an aluminum oxide ceramic composite coating containing 1% Ti nanoparticles sprayed by the HVOF spraying process.