CN205387960U - Radial seal structure suitable for cantilever rotor - Google Patents

Abstract

The utility model relates to a radial sealing structure suitable for a cantilever rotor. The specific content is: a turbomachinery that supports the rotor with a cantilever is provided with a radially distributed sealing structure in the leakage chamber between the moving and stationary blades, the sealing body is fixed on the stationary part, and the sealing body and the moving impeller disc The cooperation between them seals the high-pressure fluid leaked from the dynamic and static interface. While completing the sealing function, the utility model significantly reduces the axial space of the main shaft occupied by the sealing body, makes the rotor dynamics design of the equipment more flexible, and the structure is more compact, and at the same time reduces the axial thrust and The frictional power consumption of the thrust bearing improves the energy conversion efficiency of the equipment, and is suitable for various types of impeller machinery with a cantilever rotor structure.

Description

A radial sealing structure suitable for cantilever rotor

technical field

The utility model relates to a sealing structure of an impeller machine, in particular to a radial sealing structure suitable for a cantilever rotor.

Background technique

There are many types of sealing structures for turbomachinery, and the applicable working medium types, pressures, temperatures, etc. are different, but the sealing of the leakage chamber between the moving and stationary blades is generally arranged in the axial direction near the surface of the main shaft.

When the sealing pressure is high, structures such as carbon rings, labyrinth, honeycomb or brush seals occupy a large axial space on the main shaft, which affects the design of the rotor dynamics scheme and the compactness of the equipment structure, while the performance of dry gas seals is excellent Although the advanced mechanical seal device can use a short axial length to complete the sealing of the high-pressure working fluid, it also has limitations in the working temperature and the minimum radial dimension, and the application is limited. In addition, when the sealing structure is arranged axially near the surface of the main shaft, high-pressure working fluid is filled from the position of the wheel hub (that is, the inlet of the leakage chamber) to the inlet of the sealing structure, so that the axial thrust of the rotor is relatively large, thereby increasing the pressure on the rotor. The friction of the thrust bearing consumes work, or an additional complex structure must be used to counteract the excessive axial thrust.

In order to reduce the axial space of the main shaft occupied by the axial sealing body and the axial thrust of the rotor, the utility model proposes a radial sealing structure suitable for the cantilever rotor.

Utility model content

The utility model discloses a radial sealing structure suitable for cantilever rotors, which relates to the sealing structure of impeller machinery. The application of the structure can reduce the axial space occupied by the main shaft by the sealing body and the axial thrust of the rotor, so that the equipment The structural design of the utility model is more flexible, and can improve its efficiency and operation stability, and has broad application prospects.

In order to achieve the above object, the technical solution of the present utility model is as follows:

A radial sealing structure suitable for a cantilever rotor, the radial sealing structure is set on a turbomachinery adopting a cantilever rotor structure, the turbomachinery includes a casing and a cantilever rotor, and the cantilever rotor includes a moving shaft arranged on a main shaft The impeller disc, the casing is fixed with the stationary blade coaxial with the moving impeller disc and its ring seat, which is characterized in that a radial The sealing body is distributed to the direction, and the sealing body is fixed on the stationary part, and the high-pressure fluid leaked from the dynamic and static interface is sealed through the cooperation between the sealing body and the rotor disk.

Preferably, the torque transmission between the impeller disc and the main shaft is accomplished through end face teeth, triangular shafts, single or double keys, and the impeller disc and the main shaft are fixed by shaft nuts or equipped with tie rods on the basis of shaft nuts.

Preferably, the sealing body is fixed on stationary parts such as the casing, the vane ring seat, or the bearing box through seams or bolts, so as to ensure accurate and firm positioning of the main steam seal and small deformation.

Preferably, the radial sealing structure can be a single labyrinth seal (comb type, vertical tree type or J type), carbon ring seal, honeycomb seal or brush seal, and can also be a combination of the above sealing structures .

Preferably, the side of the impeller disc close to the sealing body can be provided with grooves, protrusions, or can be set as a flat, inclined or curved surface, so as to cooperate with the radial sealing body to complete the sealing function.

The high-pressure fluid leaked from the dynamic and static interface is sealed through the cooperation between the sealing body and the moving impeller disc, which only occupies a small axial length on the main shaft. The impeller is connected to the main shaft along the axial direction, which is convenient for matching, installation and clearance measurement with the radial sealing body.

Due to the use of the radial sealing structure, the leakage cavity between the moving and stationary blades is from the inlet of the leakage cavity to the surface of the main shaft, and the fluid pressure is gradually decreasing. Compared with the axial sealing structure, the axial thrust of the rotor Significantly reduced. Under the premise of ensuring the sealing effect, the larger the average radius of the sealing body installation, the more obvious the effect of reducing the axial thrust.

Preferably, an axial oil seal or auxiliary sealing structure is further provided between the housing and the main shaft of the cantilever rotor. The radial sealing structure can be integrated with the axial oil seal or auxiliary sealing structure, that is, the sealing body has both radial and axial sealing functions.

Preferably, the impeller machine is a compression or expansion type impeller machine, the impeller type of the impeller machine can be centripetal, mixed flow and axial flow, the working medium can be gas, liquid or multiphase flow, and the impeller can be Single or multi-level.

The above content not only ensures the rationality of the equipment structure design, but also reduces the axial length of the sealing body and the axial thrust of the rotor, which can improve its operation stability and energy utilization efficiency.

Compared with the prior art, the utility model has the advantages and beneficial effects as follows:

1. The adoption of the radial seal structure reduces the axial length of the main shaft occupied by the seal body, making the rotor dynamics design of the equipment more flexible and the structure more compact;

2. The radial seal structure reduces the average pressure of the static and dynamic handover leakage chamber, so that the axial thrust of the rotor is significantly smaller than the commonly used axial seal structure at present, and also reduces the friction power consumption of the thrust bearing ;

3. The radial sealing structure can perform all or part of the sealing function, and can be used in combination with the axial sealing according to actual needs.

Description of drawings

Figure 1 is a schematic diagram of the structure of a cantilever rotor with a radial seal structure;

Fig. 2 is the partial enlarged view of I among Fig. 1;

Fig. 3 is the variation curve of the pressure of the working fluid in the leakage chamber with the radius of gyration.

detailed description

Below in conjunction with the accompanying drawings, the structure and technical solutions of the utility model will be further described in detail, and an embodiment of the utility model will be provided.

As an embodiment of the present utility model, as shown in Figures 1 and 2, an axial flow turbine adopting a cantilever rotor structure, the axial flow turbine includes an inlet volute 2 and a cantilever rotor, and the cantilever rotor includes 5, the rotor disk 6 on the inlet volute 2 is fixed with stationary vanes coaxial with the rotor disk 6 and its ring seat 8, and the rotor blade 9 is arranged on the outer circumference of the rotor disk 6. The moving impeller disc 6 is connected with the main shaft 5 through end face teeth, pull rods and shaft head lock nut 7 . The inlet of the intake volute 2 is provided with an inlet flange 1 , and the outlet is provided with an exhaust flange 3 , and the main shaft 5 is supported by a supporting bearing 4 .

The radial sealing body 11 composed of high and low teeth is fixed on the intake volute 2 and the stationary vane ring through the seam. The side of the moving impeller disk 6 close to the radial sealing body 11 is provided with a groove to cooperate with the high and low teeth. The gap between it and the surface of the rotor disk 6 is 0.15-0.35mm, and the high-pressure fluid leaked between the rotor and the stator is sealed through the radial labyrinth.

The oil seal (or secondary seal structure) 10 is used to isolate lubricating oil or auxiliary seal, which can be selected according to needs, and can be integrated with the radial seal structure, that is, a seal body with both radial and axial sealing functions.

The radial sealing structure only occupies a small axial length of the main shaft while completing the sealing function.

When assembling the equipment, first ensure the relative positions of the intake volute 2, bearing 4, main shaft 5, oil seal 10, vane ring 8 and radial sealing body 11, and then use the pull rod and shaft nut 7 to fix the blisks (6 and 9) Lock with spindle 5.

For this radial sealing structure, since the flow area of the gap between the comb teeth and the surface of the wheel disk decreases with the decrease of the radius of gyration, when the comb teeth are evenly arranged in the radial direction, the change curve of the fluid pressure in the leakage chamber with the radius of gyration Generally, as shown in Figure 3, the pressure drop effect at the small radius position is more obvious, assuming that it roughly satisfies the law of logarithmic function. Further assume that the total inlet pressure of the axial flow turbine is 75bar (absolute pressure, the same below), the expansion ratio is 3.5, and the pressure at the outlet of the sealing structure (that is, position b, close to the surface of the main shaft, and the radius of gyration is 40mm) is 1bar, then the inlet of the leakage chamber (i.e. position a, radius of gyration 160mm) the static pressure is 27bar, the static pressure of the leakage cavity behind the moving blade is 21bar, and the axial thrust on the moving blade is about 51kN. According to the above parameters, if only the surface near the main shaft is used In the axial seal structure, the axial thrust of the rotor is about 85.5kN. If the radial seal shown in the embodiment is used to seal the high-pressure working fluid, the axial thrust of the rotor is about 57.3kN. A drop of 28.2kN (33% of the ratio) is significant.

In addition, under the premise of ensuring the sealing effect, the larger the average radius of gyration installed by the radial sealing body, the more obvious the effect of reducing the axial thrust. When the law is shown in Figure 3, the reduction of axial thrust will be more significant.

The above content completes a radial sealing structure arrangement of an axial flow turbine with a cantilever rotor. The sealing body only occupies a small axial length of the main shaft, which not only significantly reduces the axial thrust of the rotor, but also reduces the Frictional power loss in a push bearing. The embodiment of the utility model is suitable for all kinds of impeller machines supported by cantilever.

Through the above embodiments, the purpose of the utility model is effectively achieved. Those skilled in the art can understand that the present invention includes but is not limited to the contents described in the accompanying drawings and the above specific embodiments. Although the utility model has been described with regard to the most practical and preferred embodiment considered at present, it should be known that the utility model is not limited to the disclosed embodiment, and any modification that does not deviate from the function and structural principles of the utility model will include within the scope of the claims.

Claims (7)

1. A radial sealing structure suitable for a cantilever rotor, the radial sealing structure is arranged on a turbomachinery adopting a cantilever rotor structure, the turbomachinery includes a casing and a cantilever rotor, and the cantilever rotor includes a The rotor disk of the rotor blade, the casing is fixed with the stationary blade coaxial with the rotor disk and its ring seat, and it is characterized in that: the leakage chamber between the rotor blade and the stator blade of the turbomachinery is set The radially distributed sealing body is fixed on the stationary part, and the high-pressure fluid leaked from the dynamic and static interface is sealed through the cooperation between the sealing body and the rotor disc. 2 . The radial sealing structure according to claim 1 , wherein the sealing body is fixed on the casing, the vane ring seat or the bearing box of the cantilever rotor through seams or bolts. 3 . 3. The radial sealing structure according to claim 1, characterized in that: the radial sealing structure is a labyrinth seal, carbon ring seal, honeycomb seal or brush seal structure, or a combination of the above seal structures. 4. The radial sealing structure according to claim 1, characterized in that: the side of the moving impeller disk close to the sealing body is provided with a groove or a protrusion, or is provided as a plane, an inclined surface or a curved surface, so as to be compatible with the The sealing body cooperates to complete the sealing function. 5 . The radial sealing structure according to claim 1 , wherein an axial oil seal or auxiliary sealing structure is further arranged between the housing and the main shaft of the cantilever rotor. 6. The radial sealing structure according to claim 1, characterized in that: the sealing medium of the radial sealing structure is gas, liquid or multi-phase flow, and the number of impeller stages is single stage or multistage. 7. The radial sealing structure according to claim 1, characterized in that: the torque transmission between the moving impeller disc and the main shaft is completed through end face teeth, triangular shafts, single or double keys, and the moving vane disc and the main shaft pass through the shaft head Nut or on the basis of the shaft head nut equipped with a tie rod fixed.