Design method of squeeze film damper

Abstract

The application provides a design method of an extrusion oil film damper, which comprises the following steps: S1, starting to design the extrusion oil film damper, determining the value range of an oil film shaft diameter, an oil film width and a target value of damping; S2, determining the value range of an oil film radius gap; S3, selecting an oil film oil supply mode, obtaining the values of the oil film width, the oil film radius gap and the damping, and making a relationship diagram among the oil film width, the oil film radius gap and the damping; S4, selecting appropriate oil film width and oil film radius gap, so that the value of the damping is close to the target value; and S5, outputting a design result. The design method of the extrusion oil film damper can reasonably consider the influence of the piston ring end sealing on the damping, meanwhile, the influence of the oil supply mode on the damping can be considered, and the value range of the influence coefficient is given, the design method is simple and practical, and has engineering application value.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and in particular to a design method for a squeeze film damper. Background Technology

[0002] Extrusion film dampers, with their excellent vibration reduction effect, especially their significant vibration reduction effect when the rotor passes the critical speed, have been widely used in aero engines.

[0003] However, some working mechanisms of the extrusion oil film damper still require further research, such as the damping nonlinearity caused by factors like cavitation. Foreign patents reveal extensive research by foreign manufacturers on end-sealing technology for oil film dampers, resulting in numerous patents for various end-sealing structures. Therefore, the effect of the damper end seal on damping needs to be fully considered; piston ring sealing is a common end-sealing structure in civil aviation engines.

[0004] Generally, extrusion film dampers can be divided into centering extrusion film dampers and non-centering extrusion film dampers. Centering extrusion film dampers usually have elastic support, which keeps the outer ring and inner ring of the oil film concentric. The squirrel cage elastic support (referred to as "elastic support") is a common centering structure.

[0005] Classic design theories for extrusion oil films include the long bearing theory and the short bearing theory. However, the bearing theory assumes that the extrusion oil film ends are unsealed and the pressure is zero, while the long bearing theory assumes that the extrusion oil film ends are completely sealed and the pressure is consistent with that in the middle of the oil film.

[0006] However, piston rings actually possess a certain degree of sealing, meaning that the pressure at the end of the squeeze film is neither zero nor consistent with the middle of the film. Therefore, the classic long bearing theory and short bearing theory are not very suitable for the design of squeeze film dampers that rely on spring support centering and piston ring sealing.

[0007] In view of this, the present invention provides a design method for an extrusion oil film damper 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 shortcomings of the classic long bearing theory and short bearing theory in the prior art, which are not very suitable for the design of extrusion oil film dampers with spring support centering and piston ring sealing, and to provide a design method for extrusion oil film dampers.

[0009] The present invention solves the above-mentioned technical problems through the following technical solution:

[0010] A design method for a squeeze film damper, characterized in that the design method includes the following steps:

[0011] S1. Begin designing the extrusion oil film damper, determining the range of values ​​for the oil film shaft diameter and oil film width, as well as the target value for damping;

[0012] S2. Determine the range of values ​​for the oil film radius clearance;

[0013] S3. Select the oil film supply method, obtain the values ​​of the oil film width, the oil film radius gap and the damping, and create a relationship diagram of the oil film width, the oil film radius gap and the damping;

[0014] S4. Select appropriate oil film width and oil film radius gap so that the damping value is close to the target value;

[0015] S5. Output the design results.

[0016] According to an embodiment of the present invention, step S3 specifically includes the following steps:

[0017] S 31 1. Determine the oil film supply method. If the oil film supply method is orifice supply, proceed to step S. 32 If the oil film supply method is orifice / groove supply, then proceed to step S. 33 ;

[0018] S 32 Design of a squeeze film damper for orifice oil supply;

[0019] S 33 Design of a squeeze film damper for slotted oil supply.

[0020] According to an embodiment of the present invention, step S 32 Specifically, it includes the following steps:

[0021] S 321 Determine the range of the piston ring end seal influence coefficient k1;

[0022] S 322 Within the range of the piston ring end seal influence coefficient k1, select a value for k1;

[0023] S 323 Using formulas Design and create a relationship diagram between the oil film width, the oil film radius clearance, and the damping, where R represents the oil film shaft diameter; Cr represents the oil film radius clearance; L represents the oil film width; k1 represents the piston ring end seal influence coefficient; D represents the damping; and μ represents the dynamic viscosity of the extrusion oil.

[0024] S 3241. Determine whether the obtained oil film width and oil film radius gap are within the range of values; if yes, proceed to step S4; if no, return to step S5. 322 .

[0025] According to one embodiment of the present invention, the range of the piston ring end seal influence coefficient k1 is:

[0026] According to an embodiment of the present invention, step S 32 Specifically, it includes the following steps:

[0027] S 321 '1. Determine the range of the piston ring end seal influence coefficient k2;'

[0028] S 322 Within the range of the piston ring end seal influence coefficient k2, select a value for k2;

[0029] S 323 Using formulas Design and create a relationship diagram between the oil film width, the oil film radius clearance, and the damping, where R represents the oil film shaft diameter; Cr represents the oil film radius clearance; L1 and L2 represent the oil film width, which ranges from [L1, L2]; k1 represents the piston ring end seal influence coefficient; D represents the damping; and μ is the dynamic viscosity of the extrusion oil.

[0030] S 324 1. Determine whether the obtained oil film width and oil film radius gap are within the range; if yes, proceed to step S4; if no, return to step S5. 322 '.

[0031] According to one embodiment of the present invention, the range of the piston ring end seal influence coefficient k2 is [0.5, 4].

[0032] According to one embodiment of the present invention, the design result output in step S5 includes the values ​​of the oil film width and the oil film radius gap.

[0033] According to an embodiment of the present invention, step S4 specifically includes the following steps: on the line corresponding to the target value of the damping in the relationship diagram of the relationship between the oil film width, the oil film radius gap and the damping, select a point, and take the rectangular range around the point as the design result of the extrusion oil film damper.

[0034] According to one embodiment of the present invention, the target value of the damping is 80.

[0035] The positive and progressive effects of this invention are as follows:

[0036] The design method of the extrusion oil film damper of this invention can reasonably consider the influence of piston ring end sealing on damping. At the same time, it can consider the influence of oil supply method on damping, and gives the range of values ​​of the influence coefficient. The design method is simple and practical and has engineering application value. Attached Figure Description

[0037] 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:

[0038] Figure 1 A schematic diagram of a squeeze film damper for elastic centering and piston ring sealing.

[0039] Figure 2 An enlarged view of the oil film supplying oil to the oil film orifice in the extrusion oil film damper.

[0040] Figure 3 A schematic diagram of the structure for supplying oil to the oil film groove in the extrusion oil film damper.

[0041] Figure 4 A schematic diagram of the key structural parameters of the oil film damper for supplying oil to the orifice and applying pressure.

[0042] Figure 5 A schematic diagram of the key structural parameters of the oil film damper for supplying oil to the slot.

[0043] Figure 6 This is a flowchart illustrating the design method of the extrusion oil film damper of the present invention.

[0044] Figure 7 This is an L-Cr-D diagram created in the design method of the extrusion oil film damper of the present invention.

[0045] [Attached image labels]

[0046] 10 bullets

[0047] Piston ring 20

[0048] Oil film outer ring 30

[0049] Oil film supply hole 31

[0050] Oil supply annular groove 32

[0051] Oil supply port 33

[0052] Oil supply tank 34

[0053] Oil film width L

[0054] Oil film shaft radius R

[0055] Oil film radius gap Cr

[0056] Damping target value D0

[0057] Damping D Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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.

[0061] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0062] Figure 1 A schematic diagram of a squeeze film damper for elastic centering and piston ring sealing. Figure 2 An enlarged view of the oil film supplying oil to the oil film orifice in the extrusion oil film damper. Figure 3 A schematic diagram of the structure for supplying oil to the oil film groove in the extrusion oil film damper. Figure 4 A schematic diagram of the key structural parameters of the oil film damper for supplying oil to the orifice and applying pressure. Figure 5 A schematic diagram of the key structural parameters of the oil film damper for supplying oil to the slot.

[0063] like Figures 1 to 5 As shown, the structure of the squeeze oil film damper with spring support centering and piston ring sealing includes a spring support 10, a piston ring 20, and an outer oil film ring 30 forming an oil film space called a squeeze oil film. Oil in the squeeze oil film enters through oil film supply holes 31 in the outer oil film ring 30. The outer oil film ring 31 has multiple supply holes 31. The oil in the oil film supply holes 31 of the outer oil film ring 30 is supplied by an external oil supply annular groove 32, while the oil in the oil supply annular groove 32 flows in through a single general oil supply hole 33 (e.g., ...). Figure 2 (As shown).

[0064] Figure 2 The image shows a "hole-supply" extrusion oil film damper. For the internal extrusion oil film, the oil enters from the oil film supply hole 31. Figure 3 The oil film device shown can be considered a "groove-supply" extrusion oil film damper. For the internal extrusion oil film, part of the oil originates from the oil film supply orifice.

[0065] 31, part of it comes from the oil supply groove 34. Of course, the oil in the oil supply groove 34 still comes from multiple oil supply holes 31. The advantage of the oil supply groove 34 is that its flow resistance is relatively small, and the extruded oil can flow more easily in the circumferential direction in the oil supply groove 34.

[0066] A schematic diagram of the key structural parameters of the orifice-supply pressurized oil film damper is shown below. Figure 4 As shown, this includes the oil film width L, the oil film axis radius R, and the oil film radius gap Cr.

[0067] A schematic diagram of the key structural parameters of the slotted oil supply pressurized oil film damper is shown below. Figure 5 As shown, apart from the oil film shaft radius R and the oil film radius gap Cr, the oil film length is divided into two parts, L1 and L2. The oil in the squeeze oil film damper flows out from the break in the piston ring.

[0068] Figure 6 This is a flowchart illustrating the design method of the extrusion oil film damper of the present invention. Figure 7 This is an L-Cr-D diagram created in the design method of the extrusion oil film damper of the present invention.

[0069] like Figure 6 As shown, when designing an oil film generator, the oil film shaft radius R and the target damping value D0 are generally known, while the oil film length L is unknown, but its possible range of values ​​is known. Similarly, the oil film radius clearance Cr is also unknown, but its possible range of values ​​can be estimated.

[0070] This invention discloses a design method for an extrusion oil film damper, characterized in that the design method includes the following steps:

[0071] S1. Begin designing the extrusion oil film damper, determining the range of values ​​for the oil film shaft diameter and oil film width, as well as the target value for damping.

[0072] S2. Determine the range of values ​​for the oil film radius clearance.

[0073] S3. Select the oil film supply method, obtain the values ​​of the oil film width, the oil film radius gap and the damping, and create a relationship diagram (i.e., L-Cr-D diagram) between the oil film width, the oil film radius gap and the damping.

[0074] Preferably, step S3 specifically includes the following steps:

[0075] S 31 1. Determine the oil film supply method. If the oil film supply method is orifice supply, proceed to step S. 32 If the oil film supply method is orifice / groove supply, then proceed to step S. 33 ;

[0076] S 32 Design of a squeeze film damper for orifice oil supply;

[0077] S 33 Design of a squeeze film damper for slotted oil supply.

[0078] More preferably, step S 32 Specifically, it includes the following steps:

[0079] S 321 Determine the range of the piston ring end seal influence coefficient k1;

[0080] S 322 Within the range of the piston ring end seal influence coefficient k1, select a value for k1;

[0081] S 323 Using formulas Design and create a relationship diagram (i.e., L-Cr-D diagram) between the oil film width, the oil film radius clearance, and the damping, where R represents the oil film shaft diameter; Cr represents the oil film radius clearance; L represents the oil film width; k1 represents the piston ring end seal influence coefficient; D represents the damping; and μ represents the dynamic viscosity of the extrusion oil.

[0082] S 324 1. Determine whether the obtained oil film width and oil film radius gap are within the range of values; if yes, proceed to step S4; if no, return to step S5. 322 .

[0083] The preferred range of the piston ring end seal influence coefficient k1 is as follows.

[0084] Step S 32 Specifically, it includes the following steps:

[0085] S 321 '1. Determine the range of the piston ring end seal influence coefficient k2;'

[0086] S 322 Within the range of the piston ring end seal influence coefficient k2, select a value for k2;

[0087] S 323 Using formulas Design and create a relationship diagram (L-Cr-D diagram) between the oil film width, the oil film radius clearance, and the damping, where R represents the oil film shaft diameter; Cr represents the oil film radius clearance; L1 and L2 represent the oil film width, which ranges from [L1, L2]; k1 represents the piston ring end seal influence coefficient; D represents the damping; and μ is the dynamic viscosity of the extrusion oil.

[0088] S 324 1. Determine whether the obtained oil film width and oil film radius gap are within the range; if yes, proceed to step S4; if no, return to step S5. 322 '.

[0089] The piston ring end seal influence coefficient k2 is preferably in the range of [0.5, 4].

[0090] S4. Select appropriate oil film width and oil film radius gap so that the damping value is close to the target value.

[0091] Preferably, step S4 specifically includes the following steps: on the line corresponding to the target value of the damping in the relationship diagram (L-Cr-D diagram) between the oil film width, the oil film radius gap and the damping, select a point, and take the rectangular area around that point as the design result of the extrusion oil film damper.

[0092] For example, such as Figure 7 As shown, assuming the target damping value D0 is 80, a point can be selected on this line, and a small rectangular area can be selected around this point as the design result of the squeeze film damper.

[0093] S5. Output the design results.

[0094] Preferably, the design results output in step S5 include the values ​​of the oil film width and the oil film radius gap.

[0095] Based on the above description, the special feature of the design method of the extrusion oil film damper of the present invention is:

[0096] I. The design formula takes into account the influence of piston ring seals on damping;

[0097] II. The design formula takes into account the influence of the oil film supply method on damping;

[0098] III. Design formulas for oil film generators under orifice oil supply are given;

[0099] IV. Design formulas for oil film generators under orifice-groove oil supply are given;

[0100] V. The range of values ​​for the piston ring end seal influence coefficient under oil film orifice oil supply is given;

[0101] VI. The range of values ​​for the piston ring end seal influence coefficient under oil film orifice groove oil supply is given;

[0102] VII. The design process is given.

[0103] In summary, the design method of the extrusion oil film damper of the present invention can reasonably consider the influence of piston ring end sealing on damping. At the same time, it can consider the influence of oil supply method on damping, and gives the range of values ​​of the influence coefficient. The design method is simple and practical and has engineering application value.

[0104] 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 design method for a squeeze film damper, characterized in that, The design method of the extrusion oil film damper includes the following steps: S1. Begin designing the extrusion oil film damper, determining the range of values ​​for the oil film shaft diameter and oil film width, as well as the target value for damping; S2. Determine the range of values ​​for the oil film radius clearance; S3. Select the oil film supply method, obtain the values ​​of the oil film width, the oil film radius gap and the damping, and create a relationship diagram of the oil film width, the oil film radius gap and the damping; S4. Select appropriate oil film width and oil film radius gap so that the damping value is close to the target value; S5. Output the design results; Step S3 specifically includes the following steps: S 31 1. Determine the oil film supply method. If the oil film supply method is orifice supply, proceed to step S. 32 If the oil film supply method is orifice / groove supply, then proceed to step S. 33 ; S 32 Design of a squeeze film damper for orifice oil supply; S 33 Design of a squeeze film damper for slotted oil supply; The step S 32 Specifically, it includes the following steps: S 321 Determine the range of the piston ring end seal influence coefficient k1; S 322 Within the range of the piston ring end seal influence coefficient k1, select a value for k1; S 323 Using formulas Design and create a relationship diagram between the oil film width, the oil film radius clearance, and the damping, where R represents the oil film shaft diameter; Cr represents the oil film radius clearance; L represents the oil film width; k1 represents the piston ring end seal influence coefficient; D represents the damping; and μ represents the dynamic viscosity of the extrusion oil. S 324 1. Determine whether the obtained oil film width and oil film radius gap are within the range of values; if yes, proceed to step S4; if no, return to step S5. 322 ; The range of the piston ring end seal influence coefficient k1 is: The step S 32 Specifically, it also includes the following steps: S 321 '1. Determine the range of the piston ring end seal influence coefficient k2;' S 322 Within the range of the piston ring end seal influence coefficient k2, select a value for k2; S 323 Using formulas Design and create a relationship diagram between the oil film width, the oil film radius clearance, and the damping, where R represents the oil film shaft diameter; Cr represents the oil film radius clearance; L1 and L2 represent the oil film width, which ranges from [L1, L2]; k1 represents the piston ring end seal influence coefficient; D represents the damping; and μ is the dynamic viscosity of the extrusion oil. S 324 1. Determine whether the obtained oil film width and oil film radius gap are within the range; if yes, proceed to step S4; if no, return to step S5. 322 '; The range of the piston ring end seal influence coefficient k2 is [0.5, 4].

2. The design method of the extrusion oil film damper as described in claim 1, characterized in that, The design results output in step S5 include the oil film width and the value of the oil film radius gap.

3. The design method of the extrusion oil film damper as described in claim 1, characterized in that, Step S4 specifically includes the following steps: on the line corresponding to the target value of the damping in the relationship diagram of the oil film width, the oil film radius gap and the damping, select a point, and take the rectangular range around that point as the design result of the extrusion oil film damper.

4. The design method of the extrusion oil film damper as described in claim 3, characterized in that, The target value for damping is 80.

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