High-low pressure counter-rotating turbine stage
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AECC COMML AIRCRAFT ENGINE CO LTD
- Filing Date
- 2022-05-23
- Publication Date
- 2026-06-26
Smart Images
Figure CN117145584B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of turbine stage transition section design, and particularly to a high-low pressure counter-rotating turbine stage transition section. Background Technology
[0002] In conventional aero engines, the high-pressure and low-pressure rotors rotate in the same direction. Currently, advanced civilian and military aero engines abroad widely employ counter-rotating turbine technology, such as the GENx and F119-PW-100 engines. In counter-rotating turbines, the high-pressure and low-pressure rotors rotate in opposite directions. The downstream rotor can utilize the upstream rotor's outlet pre-rotation, thus reducing the number of downstream guide vanes and the blade deflection angle, thereby lowering aerodynamic losses. Simultaneously, the use of counter-rotating high-pressure and low-pressure rotors in aero engines helps suppress gyroscopic torque effects, enhancing aircraft maneuverability.
[0003] Figure 1 This is a schematic diagram of the high- and low-pressure turbine. Figure 1 As shown, the high-pressure and low-pressure turbines include, in sequence, a high-pressure turbine first-stage guide vane 10, a high-pressure turbine first-stage moving blade 11, a high-pressure turbine second-stage guide vane 12, a high-pressure turbine second-stage moving blade 13, a transition section rectifier blade 14, a low-pressure turbine first-stage guide vane 15, and a low-pressure turbine first-stage moving blade 16. The high-bypass turbine is higher than that of civilian turbofan engines. A transition section / interstage casing is generally arranged between the high-pressure and low-pressure turbines to provide a support frame for the rear end of the high-pressure rotor. The oil supply, return, and ventilation pipelines also need to pass through the transition section, so hollow rectifier blades need to be designed in the transition section to provide passage for the pipelines. To reduce the mainstream flow losses of the engine, the rectifier blades need to have a good aerodynamic shape to avoid flow separation in the transition section.
[0004] Figure 2 This is a schematic diagram of the arrangement of conventional turbine blades. Figure 2 As shown, the transition section rectifier blades of conventional high and low pressure rotors rotating in the same direction generally adopt an axisymmetric blade shape, and the circumferential deflection angle of the outlet airflow is close to 90 degrees (0 degrees is defined as being in the same direction as the engine's central axis).
[0005] Figure 3 This is a schematic diagram of the arrangement of blades in a counter-rotating turbine. (For example...) Figure 3 As shown, unlike conventional rectifier blade design, in order to avoid excessive deflection angle of the downstream low-pressure turbine guide vanes, the outlet airflow of the rectifier blades in the transition section of the counter-rotating turbine needs to deviate from the axial direction in the direction of rotation of the low-pressure turbine rotor.
[0006] The design of the transition section flow channel needs to take into account the radial height difference between the high- and low-pressure turbines and rationally arrange the flow area to avoid excessively high flow velocities in the channel, which could lead to blockages and supersonic phenomena. At the same time, a reasonable flow channel curvature distribution is required to avoid excessively low local flow velocities and flow separation.
[0007] In view of this, the inventors of this application have designed a transition section between high and low pressure counter-rotating turbine stages in order to overcome the above-mentioned technical problems. Summary of the Invention
[0008] The technical problem to be solved by the present invention is to overcome the defects of the high difficulty and poor effect of the flow channel design and rectifier blade design of the transition section between high and low pressure counter-rotating turbine stages in the prior art, and to provide a transition section between high and low pressure counter-rotating turbine stages.
[0009] The present invention solves the above-mentioned technical problems through the following technical solution:
[0010] A high-low pressure counter-rotating turbine stage transition section is characterized in that the high-low pressure counter-rotating turbine stage transition section includes an inner wall surface of the flow channel, an outer wall surface of the flow channel, and a plurality of hollow rectifier blades located in the flow channel, wherein the hollow rectifier blades are respectively arranged between the inner wall surface of the flow channel and the outer wall surface of the flow channel at intervals.
[0011] The hollow rectifier blade includes a first shaped section and a second shaped section. The first shaped section is the blade tip section, and the second shaped section is the blade root section. The first shaped section and the second shaped section extend 2mm to 3mm beyond the flow channel surface, respectively.
[0012] According to one embodiment of the present invention, the maximum thickness of the blade profile at the blade tip section is 0.2 times the axial chord length of the blade profile at the blade tip section, and the maximum thickness of the blade profile at the blade root section is 0.2 times the axial chord length of the blade profile at the blade root section.
[0013] According to one embodiment of the present invention, the axial position of the maximum thickness of the blade tip section is 0.2 times the axial chord length of the blade tip section from the leading edge point of the blade tip section;
[0014] The axial position of the maximum thickness of the blade at the blade root section is 0.2 times the axial chord length of the blade at the blade root section from the leading edge point of the blade root section.
[0015] According to one embodiment of the present invention, the axial chord length of the blade tip section is equal to 1.08 times the axial chord length of the blade root section.
[0016] According to one embodiment of the present invention, the leading edge of the blade tip and the blade root of the hollow rectifier blade are both elliptical arc structures, and the ratio of the major axis to the minor axis of the elliptical arc structure is 1.5.
[0017] According to one embodiment of the present invention, the blade tip section has a leading edge construction angle range of 90±5 degrees, and the leading edge construction angle of the blade tip section is the angle between the leading edge of the blade and the axial direction;
[0018] The blade root section has a blade leading edge construction angle in the range of 10±5 degrees, and the blade leading edge construction angle is the angle between the blade leading edge and the axial direction.
[0019] According to one embodiment of the present invention, the effective exit angle range of the blade tip section is 53±0.5 degrees, and the effective exit angle is the arcsine of the ratio of throat width to grid pitch.
[0020] The throat width is the shortest distance between two adjacent blades; the grid pitch is the circumference length of the characteristic position divided by the number of blades, that is: blade tip section grid pitch = (2π × blade tip position airfoil exit radius) / number of blades;
[0021] Blade root section pitch = (2π × blade root position airfoil exit radius) / number of blades;
[0022] The effective exit angle range of the blade root section is 49±0.5 degrees, and the effective exit angle is the arcsine of the ratio of throat width to grid pitch.
[0023] According to one embodiment of the present invention, the tip and root airfoil installation angles of the hollow rectifier blade are in the range of 77±1 degrees.
[0024] According to one embodiment of the present invention, the flow channel of the transition section between the high and low pressure counter-rotating turbine stages includes an upper flow channel protrusion and a lower flow channel depression, wherein the upper flow channel protrusion and the lower flow channel depression are circumferentially symmetrical.
[0025] According to one embodiment of the present invention, the axial position of the highest point of the upper flow channel protrusion and the highest point of the lower flow channel depression is 0.2 times the axial chord length from the leading edge point.
[0026] According to one embodiment of the present invention, the transition section between the high and low pressure counter-rotating turbine stages satisfies the following condition: the flow area of a single channel of the blade cascade at different axial positions / (inlet ring area / blade)
[0027] Number)=-0.0973x3-0.1408x2+0.345x+0.8786;
[0028] Where x is (a certain axial position - the axial position of the blade tip leading edge) / axial chord length;
[0029] The single-channel blade cascade is the airflow channel between two adjacent blades, and the inlet annular area is the annular area of the transition section inlet.
[0030] The positive and progressive effects of this invention are as follows:
[0031] The present invention adopts an axially asymmetrical transition section rectifier blade design in the transition section between high and low pressure counter-rotating turbine stages, which reduces the turning angle of the guide blades of the low-pressure turbine in the counter-rotating turbine. The flow channel adopts local convex and concave features and rationally arranges the flow area of the transition section.
[0032] The axially asymmetric transition section rectifier blade design achieves a circumferential deflection angle of 75 degrees at the transition section outlet, reducing the deflection angle of the low-pressure turbine guide vanes in the counter-rotating turbine. CFD calculations show no significant flow channel separation within the flow channel, with a total pressure recovery coefficient of 0.9916 for the transition section. Attached Figure Description
[0033] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:
[0034] Figure 1 This is a schematic diagram of the high- and low-pressure turbine.
[0035] Figure 2 This is a schematic diagram of the arrangement of conventional turbine blades.
[0036] Figure 3 This is a schematic diagram of the arrangement of the blades of a counter-rotating turbine.
[0037] Figure 4 This is a schematic diagram of the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0038] Figure 5a This is a schematic diagram of the pressure surface of the streamlines on the surface of the rectifier blade in the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0039] Figure 5b This is a schematic diagram of the suction surface of the streamlines on the surface of the rectifier blade in the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0040] Figure 6 This is a schematic diagram of the rectifier blade profile in the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0041] Figure 7 This is a schematic diagram of the leading edge shape of the rectifier blade in the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0042] Figure 8 This is a schematic diagram of the flow channel in the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0043] Figure 9 This is a schematic diagram illustrating the control law of the blade cascade flow area in the transition section between high and low pressure counter-rotating turbine stages of the present invention.
[0044] Figure 10This is a schematic diagram of two adjacent blades in the transition section between the high and low pressure counter-rotating turbine stages of the present invention. Detailed Implementation
[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0046] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are shown in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts.
[0047] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.
[0048] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.
[0049] Figure 4 This is a schematic diagram of the transition section between the high and low pressure counter-rotating turbine stages of the present invention. Figure 5a This is a schematic diagram of the pressure surface of the streamlines on the surface of the rectifier blade in the transition section between the high and low pressure counter-rotating turbine stages of the present invention. Figure 5b This is a schematic diagram of the suction surface of the streamlines on the surface of the rectifier blade in the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0050] Figure 6 This is a schematic diagram of the rectifier blade profile in the transition section between the high and low pressure counter-rotating turbine stages of the present invention. Figure 7 This is a schematic diagram of the leading edge shape of the rectifier blade in the transition section between the high and low pressure counter-rotating turbine stages of the present invention. Figure 8 This is a schematic diagram of the flow channel in the transition section between the high and low pressure counter-rotating turbine stages of the present invention. Figure 9 This is a schematic diagram illustrating the control law of the blade cascade flow area in the transition section between high and low pressure counter-rotating turbine stages of the present invention. Figure 10 This is a schematic diagram of two adjacent blades in the transition section between the high and low pressure counter-rotating turbine stages of the present invention.
[0051] like Figures 4 to 10As shown, this invention discloses a transition section between high and low pressure counter-rotating turbine stages, comprising an inner wall surface 20 of a flow channel, an outer wall surface 30 of the flow channel, and a plurality of hollow rectifier blades 40 located within the flow channel. The hollow rectifier blades 40 are respectively and spaced apart between the inner wall surface 20 and the outer wall surface 30 of the flow channel. Each hollow rectifier blade 40 has a first shaped cross section and a second shaped cross section. The first shaped cross section is a blade tip cross section 41, and the second shaped cross section is a blade root cross section 42. Both the first and second shaped cross sections extend 2mm to 3mm beyond the flow channel surface. The hollow inner cavity of the hollow rectifier blade 40 is used for the oil and gas pipelines required for lubrication of the load-bearing support plate and the fulcrum.
[0052] Here, the first and second profile sections determine the blade profile at the tip and root positions of the rectifier blade. A counter-rotating turbine refers to a turbine with upstream and downstream rotors rotating in opposite directions; the transition section refers to the portion between the high-pressure and low-pressure turbines.
[0053] Preferably, the maximum thickness of the blade tip section 41 is 0.2 times the axial chord length of the blade tip section 41, and the maximum thickness of the blade root section 42 is 0.2 times the axial chord length of the blade root section 42. Here, axial refers to the direction of the engine's central axis.
[0054] The axial position of the maximum thickness of the blade profile at the tip section 41 is 0.2 times the axial chord length of the blade profile at the tip section 41. The axial position of the maximum thickness of the blade profile at the root section 42 is 0.2 times the axial chord length of the blade profile at the root section 42.
[0055] Furthermore, the axial chord length of the blade tip section 41 is equal to 1.08 times the axial chord length of the blade root section 42.
[0056] More preferably, the leading edge of the blade tip and root of the hollow rectifier blade 40 is an elliptical arc structure, and the ratio of the major axis to the minor axis of the elliptical arc structure is 1.5.
[0057] The preferred range of the leading edge construction angle of the blade tip section 41 is 90±5 degrees, and the leading edge construction angle of the blade tip section 41 is the angle between the leading edge of the blade and the axial direction. The preferred range of the leading edge construction angle of the blade root section 42 is 10±5 degrees, and the leading edge construction angle of the blade root section 42 is the angle between the leading edge of the blade and the axial direction.
[0058] Here, the leading edge of the airfoil refers to the curve connecting the pressure and suction surfaces of the airfoil's inlet edge, typically a segment of a circular or elliptical curve. Furthermore, the mid-arc line of the airfoil refers to the line connecting the centers of the inscribed circles of the airfoil. The leading edge point is the intersection of the mid-arc line and the leading edge. The geometric construction angle is the acute angle (angle) between the tangent lines to the mid-arc line at the leading and trailing edges and the frontal line, respectively called the leading edge construction angle and the trailing edge construction angle. The frontal line is the line connecting two adjacent leading or trailing edge points of the airfoil.
[0059] In addition, the effective exit angle range of the blade tip section 41 is preferably 53±0.5 degrees, and the effective exit angle is the arcsine of the ratio of throat width to grid pitch.
[0060] The throat width is the shortest distance between two adjacent blades, for example... Figure 10 The diameter of the inscribed circle between two adjacent blades shown is 1. The grid pitch is the circumference length of the characteristic position divided by the number of blades, that is: blade tip section grid pitch = (2π × blade tip position airfoil exit radius) / number of blades;
[0061] Blade root section spacing = (2π × blade root position, blade exit radius) / number of blades.
[0062] The effective exit angle range of the blade profile with blade root section 42 is preferably 49±0.5 degrees, and the effective exit angle of the blade profile is the arcsine of the ratio of throat width to grid pitch.
[0063] Furthermore, the blade tip and root airfoil installation angles of the hollow rectifier blade 40 are preferably within the range of 77±1 degrees. The airfoil installation angle refers to the angle between the airfoil chord line and the heading line.
[0064] like Figure 8 As shown, the transition section flow channel includes the leading edge 43 of the rectifier blade, the trailing edge 44 of the rectifier blade, and the axial position A of the highest point of the upper flow channel protrusion and the highest point of the lower flow channel depression. The flow channel of the high-low pressure counter-rotating turbine stage transition section includes an upper flow channel protrusion and a lower flow channel depression, which are circumferentially symmetrical. Circumferential refers to the direction around the engine's central axis (perpendicular to the axis and also perpendicular to the radial direction).
[0065] The axial position A of the highest point of the upper flow channel protrusion and the highest point of the lower flow channel depression is 0.2 times the axial chord length from the leading edge point.
[0066] like Figure 9 As shown, the degree of bulge in the upper flow channel and depression in the lower flow channel is controlled by the distribution law of the flow area in the transition section.
[0067] More preferably, the transition section between the high- and low-pressure counter-rotating turbine stages satisfies the following condition: the flow area of a single channel of the blade cascade at different axial positions / (inlet ring area / number of blades) = -0.0973x 3 -0.1408x2 +0.345x+0.8786;
[0068] Where x is (a certain axial position - the axial position of the blade tip leading edge) / axial chord length.
[0069] The single-channel blade cascade is the airflow channel between two adjacent blades, and the inlet annular area is the annular area of the transition section inlet.
[0070] Based on the above description, in the transition section between the high and low pressure counter-rotating turbine stages of this invention, the circumferential deflection angle of the outlet airflow reaches 75 degrees. CFD calculation results show that there is no obvious flow channel separation within the flow channel, and the total pressure recovery coefficient of the transition section is 0.9916. The total pressure recovery coefficient of the transition section refers to the ratio of the total pressure at the outlet of the transition section to the total pressure at the inlet.
[0071] In addition, it should be noted that, Figure 5a The pressure surface shown refers to the concave side of the blade surface or the blade profile curve. The airflow pressure is higher along this surface, which is also called the blade basin. Figure 5b The mid-suction surface refers to the side of the blade that convexes outward from the curved surface or blade shape. The airflow pressure is lower along this surface, which is also known as the blade back.
[0072] In summary, the present invention adopts an axially asymmetric transition section blade design for the transition section between high and low pressure counter-rotating turbine stages, which reduces the turning angle of the guide blades of the low-pressure turbine in the counter-rotating turbine. The flow channel adopts local convex and concave features and rationally arranges the flow area of the transition section.
[0073] The axially asymmetric transition section rectifier blade design achieves a circumferential deflection angle of 75 degrees at the transition section outlet, reducing the deflection angle of the low-pressure turbine guide vanes in the counter-rotating turbine. CFD calculations show no significant flow channel separation within the flow channel, with a total pressure recovery coefficient of 0.9916 for the transition section.
[0074] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.
Claims
1. A transition section between high- and low-pressure counter-rotating turbine stages, characterized in that, The high-low pressure counter-rotating turbine stage transition section includes an inner wall surface of the flow channel, an outer wall surface of the flow channel, and a plurality of hollow rectifier blades located in the flow channel. The hollow rectifier blades are respectively arranged between the inner wall surface of the flow channel and the outer wall surface of the flow channel at intervals. The hollow rectifier blade includes a first shaped section and a second shaped section. The first shaped section is a blade tip section, and the second shaped section is a blade root section. The first shaped section and the second shaped section extend 2mm to 3mm beyond the flow channel surface, respectively. The blade tip section has a leading edge construction angle range of 90±5 degrees, and the leading edge construction angle of the blade tip section is the angle between the leading edge of the blade and the axial direction; the effective exit angle range of the blade tip section is 53±0.5 degrees. The blade root section has a leading edge construction angle ranging from 10±5 degrees, and the leading edge construction angle of the blade root section is the angle between the leading edge of the blade and the axial direction; the effective exit angle of the blade root section is ranging from 49±0.5 degrees. The flow channel of the transition section between the high and low pressure counter-rotating turbine stages includes an upper flow channel protrusion and a lower flow channel depression, and the upper flow channel protrusion and the lower flow channel depression are circumferentially symmetrical.
2. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The maximum thickness of the blade profile at the tip section is 0.2 times the axial chord length of the blade profile at the tip section, and the maximum thickness of the blade profile at the root section is 0.2 times the axial chord length of the blade profile at the root section.
3. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The axial position of the maximum thickness of the blade tip section is 0.2 times the axial chord length of the blade tip section from the leading edge point of the blade tip section; The axial position of the maximum thickness of the blade at the blade root section is 0.2 times the axial chord length of the blade at the blade root section from the leading edge point of the blade root section.
4. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The axial chord length of the blade tip section is equal to 1.08 times the axial chord length of the blade root section.
5. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The hollow rectifier blade has an elliptical arc structure at both the tip and root leading edge, with the ratio of the major axis to the minor axis of the elliptical arc structure being 1.
5.
6. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The effective exit angle of the blade profile is the arcsine of the ratio of throat width to grid pitch; The throat width is the shortest distance between two adjacent blades; the grid pitch is the circumference length of the characteristic position divided by the number of blades, that is: blade tip section grid pitch = (2π × blade tip position airfoil exit radius) / number of blades; Blade root section pitch = (2π × blade root position airfoil exit radius) / number of blades; The effective exit angle of the blade profile is the arcsine of the ratio of throat width to grid pitch.
7. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The blade tip and root airfoil installation angle range of the hollow rectifier blade is 77±1 degrees.
8. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The axial position of the highest point of the upper flow channel protrusion and the highest point of the lower flow channel depression is 0.2 times the axial chord length from the leading edge point.
9. The high-low pressure counter-rotating turbine stage transition section as described in claim 1, characterized in that, The high-low pressure counter-rotating turbine stage transition section satisfies the following condition: Flow area at different axial positions in a single blade channel / (Inlet ring area / Number of blades) = -0.0973x 3 -0.1408x 2 +0.345x+0.8786; Where x is (a certain axial position - the axial position of the blade tip leading edge) / axial chord length; The single-channel blade cascade is the airflow channel between two adjacent blades, and the inlet annular area is the annular area of the transition section inlet.