Efficient compact hydraulic structure for ultra-large-flow LNG ship loading pump

Abstract

The invention relates to an efficient compact hydraulic structure for an ultra-large flow LNG (Liquefied Natural Gas) shipping pump, which is characterized in that a rectification guide vane is arranged between an inducer and a first-stage impeller, and blades of the rectification guide vane are designed to be axially arranged so as to absorb energy pulsation of inlet liquid and smooth liquid impact loss. The spiral guide vanes of the flat type axial flow guide vanes of the guide shell are distributed in a diffusion mode, so that the axial spiral angles of the vanes are slowed down, the sectional area of the flat type axial flow guide vanes is increased, medium filling is more uniform, few vortexes exist in a low-speed area, the pressure pulsation level is lower, and hydraulic vibration is smaller. Meanwhile, a flow guide hydraulic flow channel is directly designed in the corresponding outlet section, an internal blade is directly cast into a second outer barrel of the flow guide type outlet section by casting a 3D printing process model, a secondary flat type axial flow guide blade does not need to be additionally arranged independently, the distance of the axial size is greatly shortened, the overall gravity center of a pump unit is reduced, and the flow guide efficiency is improved. The applicability and effectiveness of axial space hydraulic flow are improved, and effective space is saved.

Description

Technical Field

[0001] The invention relates to the technical field of cryogenic pumps, and in particular to a highly efficient and compact hydraulic structure for an ultra-large flow LNG ship loading pump. Background Art

[0002] With the development of my country's LNG industry, the scale of natural gas supply and utilization has gradually increased, and the demand for reverse transportation and loading has continued to increase. Ultra-large flow LNG loading pumps can be widely used in LNG tankers, large LNG liquefaction plants, FLNG, LNG receiving stations, etc. due to their large flow, small number of equipment configurations, low equipment idle rate, low BOG generation, and convenient operation. They are the "heart" of the LNG transportation process, a major core equipment in the industrial chain, and a key equipment for the future development of offshore oil and gas resources in my country and the world. In order to maximize the efficiency of LNG transportation within the effective space of a specific pump well, a >2000m 3 / h ultra-large flow ship loading pump modeling, structural design and product development, realize the localization of ultra-large flow cryogenic submersible pumps, and ensure the energy security of the LNG industry.

[0003] The invention design of the high-efficiency and compact hydraulic structure for ultra-large flow LNG loading pumps can improve the overall efficiency of the pump unit under low-temperature conditions, effectively shorten the axial distance of the pump unit, lower the center of gravity, meet the requirements of low-vibration stable operation, and ensure a uniform flow field.

[0004] At present, the guide vane hydraulics of the existing LNG cryogenic submersible pumps are of traditional structure. Due to the applicability of the rated flow, they are not fully designed in the direction of shortening the axial distance and lowering the overall center of gravity. If this traditional hydraulic structure is still used in the ultra-large flow LNG loading pump, there will be uneven flow field and easy generation of hydraulic vortex when the pump is running, which will lead to the risk of increased pump vibration and the possibility of reduced hydraulic efficiency. In addition, the existing LNG ultra-large flow cryogenic pumps have large pump body structure size and weight due to their large flow, and the vibration caused will affect the operating stability and affect the selection of crane lifting weight during hoisting construction. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a high-efficiency and compact hydraulic structure for an ultra-large flow LNG loading pump, which can improve the overall efficiency of the pump unit under low temperature conditions, effectively shorten the axial distance of the pump unit, lower the center of gravity, meet the requirements of low-vibration stable operation, and ensure a uniform flow field.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The high-efficiency and compact hydraulic structure for the ultra-large flow LNG loading pump of the present invention comprises: a shaft; a motor assembly, which is sleeved outside the shaft and has an interference fit with the shaft, and is used to drive the shaft to rotate; a flow-guiding outlet section, which is sleeved outside the shaft and located below the motor assembly, and an intermediate bearing is provided between the flow-guiding outlet section and the shaft; the flow-guiding outlet section has a first flow channel; a secondary impeller, which is sleeved outside the shaft and fixedly connected to the shaft, and the secondary impeller is located in the flow-guiding outlet section and rotates with the shaft; a flow-guiding shell, which is provided below the flow-guiding outlet section and is tightly connected to the flow-guiding outlet section The guide shell is a flat axial flow guide vane, which is sleeved outside the shaft and has a second flow channel, and the second flow channel is connected to the first flow channel; the first-stage impeller is sleeved outside the shaft and fixedly connected to the shaft, the first-stage impeller is located in the guide shell, and rotates with the shaft; the straightening guide vane is arranged below the guide shell and fixedly connected to the guide shell; the inducer is sleeved outside the shaft and fixedly connected to the shaft, and the inducer is located below the straightening guide vane; the suction section is sleeved outside the straightening guide vane and the inducer to form a whole, and the upper end of the suction section is fixedly connected to the guide shell.

[0008] The efficient and compact hydraulic structure for the ultra-large flow LNG loading pump preferably further comprises a balancing disc, which is sleeved outside the shaft and located between the flow-guiding outlet section and the secondary impeller; the balancing disc is fixedly connected to the flow-guiding outlet section.

[0009] The efficient and compact hydraulic structure for the ultra-large flow LNG loading pump preferably also includes a motor end cover, which is arranged above the motor assembly and fixedly connected to the motor assembly on the outer side, and an upper bearing is arranged between the inner side and the shaft.

[0010] The efficient and compact hydraulic structure for the ultra-large flow LNG loading pump preferably also includes a flow stabilizer, and several flow stabilizers are arranged around the outer circumference of the motor assembly. The upper end of each flow stabilizer is connected to the motor end cover, and the lower end is connected to the flow-guiding outlet section.

[0011] The high-efficiency and compact hydraulic structure for the ultra-large flow LNG loading pump preferably comprises a motor assembly including a motor housing, a cryogenic motor stator and a cryogenic motor rotor; the motor housing is sleeved outside the shaft; the cryogenic motor stator and the cryogenic motor rotor are arranged in the motor housing, and the positions of the cryogenic motor stator and the cryogenic motor rotor correspond to each other; the cryogenic motor rotor is sleeved outside the shaft and has an interference fit with the shaft.

[0012] In the highly efficient and compact hydraulic structure for the ultra-large flow LNG loading pump, preferably, the rectifying guide vanes are located between the suction section and the shaft, and are arranged circumferentially around the shaft.

[0013] In the highly efficient and compact hydraulic structure for the ultra-large flow LNG loading pump, preferably, the flat axial flow guide vanes include spiral guide vanes, and a plurality of spiral guide vanes are diffusely distributed.

[0014] The described high-efficiency and compact hydraulic structure for the ultra-large flow LNG loading pump, preferably, the described guide outlet section includes a second inner cylinder, a second outer cylinder and an arc-shaped guide outlet blade; the second outer cylinder is sleeved outside the second inner cylinder, and a first flow channel is formed between the second outer cylinder and the second inner cylinder; a plurality of arc-shaped guide outlet blades are arranged around the circumference of the second outer cylinder and at intervals.

[0015] The present invention adopts the above technical solution, which has the following advantages:

[0016] (1) The present invention operates more stably, significantly reduces hydraulic energy loss, and improves the efficiency of the pump unit;

[0017] (2) The present invention effectively shortens the axial distance of the pump group, reduces the weight of the pump body, lowers the center of gravity, and satisfies the requirements of low-vibration stable operation while ensuring a uniform flow field. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

[0019] Figure 1 It is a cross-sectional view showing the overall structure of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the rectifying guide vane of the present invention;

[0021] Figure 3 It is a structural schematic diagram of the guide shell flat axial flow guide vane of the present invention;

[0022] Figure 4 It is a structural schematic diagram of the flow-guiding outlet section of the present invention.

[0023] The symbols in the accompanying drawings are as follows:

[0024] 1-shaft; 2-motor assembly; 201-motor housing; 202-cryogenic motor stator; 203-cryogenic motor rotor; 3-flow-guiding outlet section; 301-second inner cylinder; 302-second outer cylinder; 303-arc-shaped flow-guiding outlet blade; 4-intermediate bearing; 5-secondary impeller; 6-flow-guiding shell; 601-spiral flow-guiding blade; 7-first-stage impeller; 8-rectifying guide vane; 9-inducing wheel; 10-intake section; 11-balance disc; 12-motor end cover; 13-upper bearing; 14-flow-stabilizing plate. DETAILED DESCRIPTION

[0025] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0026] The present invention provides a highly efficient and compact hydraulic structure for an ultra-large flow LNG loading pump. The rectifying guide vane is arranged between the inducer and the first-stage impeller, and the blades of the rectifying guide vane are designed to be arranged axially, so as to absorb the energy pulsation of the inlet liquid and smooth the liquid impact loss. The guide shell is designed as a flat axial flow structure, and the spiral guide vanes of the flat axial flow guide vane are diffusely distributed, so as to smooth the axial spiral angle of the blade and increase the cross-sectional area of ​​the flat axial flow guide vane, so that the medium is filled more evenly, there are fewer vortices in the low-speed zone, the pressure pulsation level is lower, and the hydraulic vibration is smaller. At the same time, the corresponding outlet section is directly designed with a diversion hydraulic flow channel (i.e., the first flow channel) inside, and the internal blades are directly cast into the second outer cylinder of the diversion outlet section through a casting 3D printing process model, without adding a second-level flat axial flow guide vane separately, which greatly reduces the distance of the axial dimension, reduces the overall center of gravity of the pump unit, increases the applicability and effectiveness of the hydraulic flow in the axial space, saves effective space, and enables the medium to flow in a limited space, with small continuous transition loss and stable flow state. The flow stabilizer at the outlet stabilizes the direction of liquid outflow, optimizes and reduces the impact loss of radial liquid flow, reduces the vortex in the hydraulic flow field, and improves the efficiency and stability of axial liquid discharge. Through the design of the above overall structure, the overall size of the pump unit can be optimized and reduced while meeting the hydraulic performance, thereby improving the stability of pump operation.

[0027] like Figure 1As shown, the high-efficiency and compact hydraulic structure for the ultra-large flow LNG loading pump provided by the present invention comprises: a shaft 1; a motor assembly 2, which is sleeved outside the shaft 1 and is interference-fitted with the shaft 1, and is used to drive the shaft 1 to rotate; a flow-guiding outlet section 3, which is sleeved outside the shaft 1 and is located below the motor assembly 2, and an intermediate bearing 4 is provided between the flow-guiding outlet section 3 and the shaft 1; the flow-guiding outlet section has a first flow channel; a secondary impeller 5, which is sleeved outside the shaft 1 and is fixedly connected to the shaft 1, and the secondary impeller 5 is located in the flow-guiding outlet section 3, and rotates with the rotation of the shaft 1; a flow-guiding shell 6, which is provided below the flow-guiding outlet section 3 and is connected to the flow-guiding outlet section 3 is fastened, the guide shell is a flat axial flow guide vane, the flat axial flow guide vane is sleeved outside the shaft 1 and has a second flow channel, and the second flow channel is connected with the first flow channel; the first-stage impeller 7 is sleeved outside the shaft 1 and fixedly connected to the shaft 1, the first-stage impeller 7 is located in the guide shell 6, and rotates with the rotation of the shaft 1; the rectifying guide vane 8 is arranged below the guide shell 6 and is fixedly connected to the guide shell 6; the inducer 9 is sleeved outside the shaft 1 and fixedly connected to the shaft 1, and the inducer 9 is located below the rectifying guide vane 8; the suction section 10 is sleeved outside the rectifying guide vane 8 and the inducer 9 to form a whole, and the upper end of the suction section 10 is fixedly connected to the guide shell 6.

[0028] In the above embodiment, preferably, the present invention further includes a balancing disk 11, which is sleeved outside the shaft 1 and located between the guide outlet section 3 and the secondary impeller 5. The balancing disk is fixedly connected to the guide outlet section 3 to support the guide outlet section 3 to make it stable.

[0029] In the above embodiment, preferably, the present invention further comprises a motor end cover 12, which is arranged above the motor assembly 2 and fixedly connected to the motor assembly 2 on the outside, and an upper bearing 13 is arranged between the inner side and the shaft 1. Thus, the upper end of the motor assembly can be sealed to protect the motor assembly.

[0030] In the above embodiment, preferably, the present invention further includes a flow stabilizer 14, and a plurality of flow stabilizers 14 are arranged around the outer circumference of the motor assembly 2, wherein the flow stabilizer is integrally cast with the motor housing 201, and the upper end of each flow stabilizer 14 is connected to the motor end cover 12, and the lower end thereof is connected to the flow-guiding outlet section 3. The flow stabilizer is used to make the liquid flowing out of the flow-guiding outlet section 3 more stable.

[0031] In the above embodiment, preferably, the motor assembly 2 includes a motor housing 201, a low-temperature motor stator 202 and a low-temperature motor rotor 203; the motor housing 201 is sleeved outside the shaft 1; the low-temperature motor stator 202 and the low-temperature motor rotor 203 are arranged in the motor housing 201, and the positions of the low-temperature motor stator 202 and the low-temperature motor rotor 203 correspond to each other; the low-temperature motor rotor 203 is sleeved outside the shaft 1 and has an interference fit with the shaft 1.

[0032] In the above embodiment, preferably, Figure 2 As shown, the straightening guide vane 8 is located between the suction section 10 and the shaft 1, and is arranged circumferentially around the shaft 1; thus, the guide vane is completely axially arranged in the liquid flow field, which can form a certain liquid flow guiding and collecting function, and stabilize the liquid flow pulsation and impact at the suction port.

[0033] In the above embodiment, preferably, Figure 3 As shown, the guide shell 6 includes spiral guide blades 601, which are diffusely distributed to greatly smooth the axial spiral angle of the blades, thereby increasing the cross-sectional area of ​​the flat axial flow guide blades and forming an extremely small volume fluid structure, directly reducing its axial spatial size.

[0034] In the above embodiment, preferably, Figure 4 As shown, the flow-guiding outlet section 3 includes an inner cylinder 301, an outer cylinder 302 and an arc-shaped flow-guiding outlet blade 303; the outer cylinder 302 is sleeved outside the inner cylinder 301, and forms a first flow channel with the inner cylinder 301; a plurality of arc-shaped flow-guiding outlet blades 303 are arranged circumferentially and at intervals around the outer cylinder 302. Thus, the arc-shaped flow-guiding outlet blades are directly cast into the inner part of the outer cylinder of the outlet section, so that the outlet section and the original two-stage flat axial flow guide vane are integrated into a whole, which greatly shortens the axial and radial dimensions and reduces the center of gravity of the unit.

[0035] The working process of the present invention is:

[0036] The shaft is driven to rotate by a motor. After a large flow of LNG is introduced through the suction section 10 at the bottom, it passes through the inducer 9 that can effectively optimize its cavitation performance. At the same time, through the axial blade action of the rectifying guide vane 8, the energy transmitted by the inducer 9 is absorbed. Under the action of the specially designed axial blades, the flow field of the liquid before the first-stage impeller 7 works is stabilized. After the first-stage impeller 7 rotates and works, the LNG flows through the flat axial flow guide vane, which increases the guide cross-sectional area by smoothing the axial spiral angle, reduces the hydraulic vortex and pressure pulsation, and smoothly transitions to the guide outlet section 3. The pressurized liquid is then stabilized by the flow stabilizer 14, and a stable hydraulic flow field channel is finally formed.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An efficient and compact hydraulic structure for a large-volume LNG loading pump, characterized in that: include: axis; The motor assembly is sleeved outside the shaft and has an interference fit with the shaft, and is used to drive the shaft to rotate; A flow-guiding outlet section is sleeved outside the shaft and located below the motor assembly, and an intermediate bearing is provided between the flow-guiding outlet section and the shaft; the flow-guiding outlet section has a first flow channel; A secondary impeller is sleeved outside the shaft and fixedly connected to the shaft, the secondary impeller is located in the flow-guiding outlet section and rotates with the shaft; A flow guide shell is arranged below the flow guide outlet section and is tightly connected to the flow guide outlet section. The flow guide shell is a flat axial flow guide vane. The flat axial flow guide vane is sleeved outside the shaft and has a second flow channel. The second flow channel is connected to the first flow channel. A first-stage impeller is sleeved outside the shaft and fixedly connected to the shaft. The first-stage impeller is located in the guide casing and rotates with the shaft. The rectifying guide vane is arranged below the guide shell and is fixedly connected to the guide shell; An inducer wheel is sleeved outside the shaft and fixedly connected to the shaft, and the inducer wheel is located below the rectifying guide vane; The suction section is sleeved outside the rectifying guide vane and the inducer to form a whole, and the upper end of the suction section is fixedly connected to the guide shell.

2. The high-efficiency and compact hydraulic structure for the ultra-large flow LNG loading pump according to claim 1 is characterized in that: It also includes a balancing disk, which is sleeved outside the shaft and located between the guide outlet section and the secondary impeller; The balancing disc is fixedly connected to the flow-guiding outlet section.

3. The high-efficiency and compact hydraulic structure for the ultra-large flow LNG loading pump according to claim 1 is characterized in that: It also includes a motor end cover, which is arranged above the motor assembly and fixedly connected to the motor assembly on the outer side, and an upper bearing is arranged between the inner side and the shaft.

4. The high-efficiency and compact hydraulic structure for a super-large flow LNG loading pump according to claim 1 is characterized in that: It also includes a flow stabilizing plate, and a plurality of flow stabilizing plates are arranged around the outer circumference of the motor assembly. The upper end of each flow stabilizing plate is connected to the motor end cover, and the lower end thereof is connected to the flow-guiding outlet section.

5. The high-efficiency and compact hydraulic structure for a super-large flow LNG loading pump according to claim 1 is characterized in that: The motor assembly includes a motor housing, a cryogenic motor stator and a cryogenic motor rotor; The motor housing is sleeved outside the shaft; The low temperature motor stator and the low temperature motor rotor are arranged in the motor housing, and the positions of the low temperature motor stator and the low temperature motor rotor correspond to each other; The low-temperature motor rotor is sleeved outside the shaft and is interference fit with the shaft.

6. The high-efficiency and compact hydraulic structure for a super-large flow LNG loading pump according to claim 1 is characterized in that: The straightening guide vanes are located between the suction section and the shaft, and are arranged circumferentially around the shaft.

7. The high-efficiency and compact hydraulic structure for a super-large flow LNG ship loading pump according to claim 1 is characterized in that: The flat axial flow guide vane includes a spiral guide vane, and a plurality of spiral guide vanes are distributed in a diffusion manner.

8. The high-efficiency and compact hydraulic structure for a super-large flow LNG ship loading pump according to claim 1 is characterized in that: The guide outlet section comprises a second inner cylinder, a second outer cylinder and an arc-shaped guide outlet blade; The second outer cylinder is sleeved outside the second inner cylinder, and a first flow channel is formed between the second outer cylinder and the second inner cylinder; A plurality of arc-shaped guide outlet blades are arranged around the circumference of the second outer cylinder and at intervals.

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