Combined fuel pump with serially connected runners

Abstract

The utility model discloses a combined fuel pump with serially-connected runners, belongs to the technical field of aviation fuel pumps, and solves the problem that high-altitude fuel supply is difficult due to the fact that the aviation fuel pump is prone to cavitation during fuel suction. The centrifugal pump comprises a volute pump body, a bearing support and a gear pump body, a centrifugal impeller is rotationally arranged in the volute pump body, the bearing support is fixed to the end face of the volute pump body and provided with a transition flow channel hole communicated with an oil outlet of the volute pump body, and the gear pump body is fixed to the bearing support and communicated with the transition flow channel hole of the bearing support. The gear fuel pump is stable in fuel conveying flow, has the advantages of being good in anti-cavitation performance and high in high-altitude fuel conveying reliability, and compared with a traditional gear fuel pump, the volute pump body with the centrifugal impeller is arranged in the front and connected with a flow channel of the gear pump body in series. The cavitation phenomenon of fuel oil in the gear pump body is reduced under the pressurization of the centrifugal impeller, so that the gear pump body can stably convey the fuel oil.

Description

Technical Field

[0001] The utility model relates to the technical field of aviation fuel pumps, in particular to a combined fuel pump with flow channels connected in series. Background Art

[0002] The stability of the aircraft fuel supply system at high altitude is one of the difficulties that restrict the flight altitude of the aircraft. Due to the lower atmospheric pressure in the high-altitude environment, cavitation is easily generated when the aviation fuel pump sucks oil, resulting in the inability to deliver fuel.

[0003] In order to solve the problem of high-altitude fuel supply difficulties of aviation fuel pumps in the prior art, two methods of high-pressure rubber airbag pressurization and centrifugal pump pressurization are often used. The high-pressure rubber airbag pressurization method has been used in aerospace at home and abroad for decades and is a mature and reliable technology, but it has problems such as large fuel tank volume, complex structure, heavy weight, easy failure of pressure relief valve, and high cost. Although the centrifugal pump pressurization method has the advantages of small fuel tank volume, simple structure, light weight, high reliability, and low cost, it also has problems such as the instantaneous start-up of the centrifugal pump and gear pump, the centrifugal pump is cut off when two pumps are connected in series or multiple pumps are connected in series and parallel, the pressure drop in the pipeline between pumps, and the complex control sequence.

[0004] Therefore, there is an urgent need for a supercharging technology that can provide reliable and efficient oil supply while having a simple structure, simple control logic, and a high power-to-weight ratio. Utility Model Content

[0005] In view of the above problems in the prior art, the utility model provides a combined fuel pump with flow channels connected in series, which solves the problem that aviation fuel pumps are prone to cavitation when sucking oil, resulting in difficulty in high-altitude fuel supply.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] Provided is a combined fuel pump with flow channels in series, comprising: a volute pump body, a centrifugal impeller being rotatably arranged inside the volute pump body; a bearing support, the bearing support being fixed on the end face of the oil outlet of the volute pump body and the bearing support being provided with a transition flow channel hole communicating with the oil outlet of the volute pump body, a rotating shaft being rotatably arranged inside the bearing support, and the centrifugal impeller being fixed on one end of the rotating shaft; a gear pump body, the gear pump body being fixed on the bearing support and the oil inlet of the gear pump body being communicated with the transition flow channel hole of the bearing support, a gear set for pressurizing fuel being arranged inside the gear pump body, the gear set comprising a driving gear fixed on the rotating shaft, and a motor for providing power to the rotating shaft being fixed outside the gear pump body.

[0008] The working principle of this scheme is that the motor drives the rotating shaft to rotate, and the rotating shaft synchronously drives the centrifugal impeller and the gear set to rotate, so that the fuel enters the gear pump body from the oil inlet of the volute pump body through the boost of the centrifugal impeller. The fuel is pressurized by the centrifugal impeller to reduce the cavitation phenomenon occurring in the gear pump body. The gear set can stably boost and transport the fuel out of the gear pump body, and has the advantages of good anti-cavitation performance and high reliability of high-altitude oil transportation.

[0009] Furthermore, sliding bearings are fixed in the adjacent wall surface of the bearing support and the middle of the gear pump body, and the inner rings of the two sliding bearings are fixed on the rotating shaft. The sliding bearings work smoothly and noiselessly, and have high rotation accuracy and load-bearing capacity.

[0010] Furthermore, an axial oil hole connected to the central channel of the centrifugal impeller is provided inside the rotating shaft, and radial oil holes are provided through the two sliding bearings on the rotating shaft, and the axial oil hole is connected to the two radial oil holes respectively. When the rotating shaft rotates, the fuel enters from the front end of the axial oil hole and flows out from the sliding bearing through the radial oil hole, so that the fuel will form a dynamic pressure oil film to lubricate and cool the friction pair of the sliding bearing.

[0011] Furthermore, one end of the rotating shaft is provided with an external thread and is threadedly connected to the centrifugal impeller. The threaded connection is convenient for fixing.

[0012] Furthermore, a flat key is embedded on the rotating shaft, the flat key is located between two sliding bearings, the driving gear is sleeved on the rotating shaft and fixedly connected to the rotating shaft through the flat key. The flat key is not only accurately positioned and can effectively transmit torque, but also has a simple structure and is easy to process.

[0013] Furthermore, the rotating shaft is sleeved with two retaining springs respectively located on both sides of the driving gear. The arrangement of the retaining springs can limit the axial displacement of the rotating shaft.

[0014] Furthermore, an O-ring is provided on the connecting end surface between the volute pump body and the bearing support.

[0015] Furthermore, a connecting groove is provided on the outer end surface of the volute pump body, a skeleton oil seal structure is provided in the connecting groove, and one end of the rotating shaft passes through the volute pump body and the skeleton oil seal structure in sequence and is fixedly connected to the output shaft of the motor.

[0016] Furthermore, an oil outlet nozzle is provided on the oil outlet of the gear pump body, and the oil outlet nozzle can guide the direction of the fuel and reduce noise and vibration.

[0017] The utility model discloses a combined fuel pump with flow channels connected in series, and its beneficial effects are as follows:

[0018] The utility model has the advantages of stable fuel delivery flow, good anti-cavitation performance and high reliability of high-altitude oil delivery. Compared with the traditional gear fuel pump, the utility model places the volute pump body with a centrifugal impeller in front and connects it in series with the flow channel of the gear pump body. The cavitation phenomenon occurring in the gear pump body is reduced under the pressure of the centrifugal impeller, so that the gear pump body can deliver fuel stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a combined fuel pump;

[0020] Figure 2 is a structural schematic diagram of the rotating shaft;

[0021] Figure 3 is a schematic diagram of the internal flow passage of the combined fuel pump;

[0022] Figure 4 This is a comparison chart of cavitation simulation calculations between a gear fuel pump and a combined fuel pump;

[0023] Among them: 1. Volute pump body; 2. Centrifugal impeller; 3. Bearing support; 31. Transition flow channel hole; 4. Oil outlet nozzle; 5. Gear pump body; 6. Motor; 7. Skeleton oil seal structure; 8. Sliding bearing; 9. Gear set; 10. Rotating shaft; 11. External thread; 12. Axial oil hole; 13. Radial oil hole; 14. Flat key; 15. Retaining ring. DETAILED DESCRIPTION

[0024] The specific implementation methods of the utility model are described below to facilitate technical personnel in this technical field to understand the utility model, but it should be clear that the utility model is not limited to the scope of the specific implementation methods. For ordinary technical personnel in this technical field, as long as various changes are within the spirit and scope of the utility model defined and determined by the attached claims, these changes are obvious, and all utility model creations using the concept of the utility model are protected.

[0025] Example 1

[0026] refer to Figure 1 This embodiment provides a combined fuel pump with flow channels in series, including a volute pump body 1, a bearing support 3 and a gear pump body 5.

[0027] A centrifugal impeller 2 is rotatably arranged inside the volute pump body 1, and the centrifugal impeller 2 is used for initially pressurizing the fuel.

[0028] The bearing support 3 is used to rotatably set the rotating shaft 10 and connect the volute pump body 1 and the gear pump body 5. The bearing support 3 is fixed on the oil outlet end face of the volute pump body 1 and a transition flow channel hole 31 connected with the oil outlet of the volute pump body 1 is opened on the bearing support 3. The rotating shaft 10 is rotatably set in the bearing support 3, and an external thread 11 is set on one end of the rotating shaft 10 and is threadedly connected with the centrifugal impeller 2.

[0029] The gear pump body 5 is fixed on the bearing support 3 and the oil inlet of the gear pump body 5 is connected to the transition flow channel hole 31 of the bearing support 3. A gear set 9 for pressurizing the fuel is arranged inside the gear pump body 5. The gear set 9 includes a driving gear and a driven gear in meshing connection. The driving gear is fixed on the rotating shaft 10. A motor 6 for providing power to the rotating shaft 10 is fixed outside the gear pump body 5. An oil outlet nozzle 4 is arranged on the oil outlet on the gear pump body 5. The oil outlet nozzle 4 can guide the direction of the fuel and reduce noise and vibration.

[0030] As a specific structure in which the rotating shaft 10 is rotatably arranged in the bearing support 3, sliding bearings 8 are fixed in the adjacent walls of the bearing support 3 and the middle of the gear pump body 5, and the inner rings of the two sliding bearings 8 are fixed on the rotating shaft 10. The sliding bearings 8 work smoothly and noiselessly, and have high rotation accuracy and load-bearing capacity.

[0031] In order to lubricate and cool the sliding bearing 8, refer to Figure 2 The interior of the rotating shaft 10 is provided with an axial oil hole 12 connected to the central channel of the centrifugal impeller 2, and radial oil holes 13 are provided through the rotating shaft 10 at the two sliding bearings 8, and the axial oil hole 12 is connected to the two radial oil holes 13 respectively. When the rotating shaft 10 rotates, the fuel enters from the front end of the axial oil hole 12 and flows out at the sliding bearing 8 through the radial oil holes 13, so that the fuel will form a dynamic pressure oil film, which can lubricate and cool the friction pair of the sliding bearing 8.

[0032] As a specific structure for fixing the driving gear on the rotating shaft 10, a flat key 14 is embedded on the rotating shaft 10, and the flat key 14 is located between the two sliding bearings 8. The driving gear is sleeved on the rotating shaft 10 and fixedly connected to the rotating shaft 10 through the flat key 14. The flat key 14 is not only accurately positioned and can effectively transmit torque, but also has a simple structure and is easy to process. In addition, two retaining springs 15 are sleeved on the rotating shaft 10 and are respectively located on both sides of the driving gear. The setting of the retaining spring 15 can limit the axial displacement of the rotating shaft 10.

[0033] In order to ensure the sealing performance, the connection end surfaces of the volute pump body 1 and the gear pump body 5 with the bearing support 3 in this embodiment are all provided with O-rings. In order to ensure the sealing performance between the motor 6 and the rotating shaft 10, a connection groove is provided on the outer end surface of the volute pump body 11, and a skeleton oil seal structure 7 is provided in the connection groove. One end of the rotating shaft 10 passes through the volute pump body 11 and the skeleton oil seal structure 7 in sequence and is fixedly connected with the output shaft of the motor 6. The skeleton oil seal structure 7 is a prior art. Since it is a prior art, this embodiment will not repeat its specific working principle and connection relationship.

[0034] In summary, the working principle of this embodiment is:

[0035] refer to Figure 3 The motor 6 drives the rotating shaft 10 to rotate, and the rotating shaft 10 synchronously drives the centrifugal impeller 2 and the gear set 9 to rotate, so that the fuel enters the gear pump body 5 from the oil inlet of the volute pump body 1 through the boost of the centrifugal impeller 2. The fuel is pressurized by the centrifugal impeller 2 to reduce the cavitation phenomenon occurring in the gear pump body 5. The gear set 9 can stably boost the fuel and deliver it out of the gear pump body 5, and has the advantages of good anti-cavitation performance and high reliability of high-altitude oil transportation.

[0036] Example 2

[0037] This embodiment further provides a specific experimental example based on the combined fuel pump of Embodiment 1.

[0038] This embodiment compares the performance of a flow channel series combined fuel pump and a traditional gear fuel pump when operating at high altitude.

[0039] Referring to Table 1, when the gear pump body 5 and the gear set 9 are the same, the combined fuel pump has a significant improvement in high-altitude boosting performance compared to the gear fuel pump.

[0040] Table 1 High altitude performance comparison

[0041]

[0042] As the aircraft altitude increases, the atmospheric pressure decreases. At lower altitudes, the delivery flow rates of the combined fuel pump and the gear fuel pump are similar. When the flight altitude increases and the atmospheric pressure drops to 30.7 kPa, the delivery flow rate of the combined fuel pump does not change significantly, while the anti-cavitation performance of the gear fuel pump is weak, the delivery flow rate decreases, and the volumetric efficiency decreases by about 14%. As the flight altitude further increases, the delivery flow rate of the combined fuel pump also begins to decrease, but compared with the gear fuel pump, it still has a higher delivery flow rate, good anti-cavitation performance, and high reliability in high-altitude fuel delivery.

[0043] For further comparison, this embodiment performs cavitation simulation calculation comparison on two fuel pumps, referring to Figure 4 , Figure 4This is a comparison chart of cavitation simulation calculations of a gear fuel pump and a combined fuel pump under the same high-altitude atmospheric pressure. Figure 4 a is a gear fuel pump, Figure 4 b is a combined fuel pump.

[0044] When the flight altitude is high and the atmospheric pressure is low, intense fuel vaporization occurs at the inlet of the gear fuel pump at this altitude, resulting in a decrease in the delivery performance. Figure 4 The light-colored area in a is where fuel vaporization occurs. However, the combined fuel pump only slightly vaporizes fuel in the gear meshing jet area, and still maintains a good fuel delivery capacity.

[0045] Although the specific implementation of the utility model is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A combined fuel pump with flow channels in series, characterized in that: include: A volute pump body (1), wherein a centrifugal impeller (2) is rotatably arranged inside the volute pump body (1); A bearing support (3), the bearing support (3) being fixed on the oil outlet end face of the volute pump body (1) and having a transition flow channel hole (31) in communication with the oil outlet of the volute pump body (1), a rotating shaft (10) being rotatably arranged in the bearing support (3), and the centrifugal impeller (2) being fixed on one end of the rotating shaft (10); A gear pump body (5) is fixed on a bearing support (3) and an oil inlet of the gear pump body (5) is connected to a transition flow channel hole (31) of the bearing support (3). A gear set (9) for increasing the pressure of the fuel is arranged inside the gear pump body (5). The gear set (9) includes a driving gear fixed on a rotating shaft (10). A motor (6) for providing power to the rotating shaft (10) is fixed outside the gear pump body (5).

2. The combined fuel pump according to claim 1, characterized in that: Sliding bearings (8) are fixed in the adjacent wall surfaces in the middle of the bearing support (3) and the gear pump body (5), and the inner rings of the two sliding bearings (8) are fixed on the rotating shaft (10).

3. The combined fuel pump according to claim 2, characterized in that: An axial oil hole (12) communicating with the central channel of the centrifugal impeller (2) is provided inside the rotating shaft (10), and radial oil holes (13) are provided through the two sliding bearings (8) on the rotating shaft (10), and the axial oil hole (12) is respectively communicated with the two radial oil holes (13).

4. The combined fuel pump according to claim 3, characterized in that: An external thread (11) is provided on one end of the rotating shaft (10) and is threadably connected to the centrifugal impeller (2).

5. The combined fuel pump according to claim 3, characterized in that: A flat key (14) is embedded on the rotating shaft (10), and the flat key (14) is located between the two sliding bearings (8). The driving gear is sleeved on the rotating shaft (10) and fixedly connected to the rotating shaft (10) via the flat key (14).

6. The combined fuel pump according to claim 5, characterized in that: The rotating shaft (10) is sleeved with two retaining springs (15) respectively located on both sides of the driving gear.

7. The combined fuel pump with series flow channels according to claim 3, characterized in that: An O-ring is provided on the connecting end surface between the volute pump body (1) and the bearing support (3).

8. The combined fuel pump according to claim 1, characterized in that: A connecting groove is provided on the outer end surface of the volute pump body (1), a skeleton oil seal structure (7) is provided in the connecting groove, and one end of the rotating shaft (10) passes through the volute pump body (1) and the skeleton oil seal structure (7) in sequence and is fixedly connected to the output shaft of the motor (6).

9. The combined fuel pump according to claim 1, characterized in that: An oil outlet nozzle (4) is provided on the oil outlet on the gear pump body (5).

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