A cantilevered rotor assembly and method of designing the same, industrial exhaust turbine

Abstract

The application discloses a cantilever rotor assembly and a design method thereof and an industrial exhaust turbine, and solves the technical problems of long rotor, large weight and high production cost of the existing industrial exhaust turbine. The cantilever rotor assembly comprises a main shaft, a first supporting bearing, a second supporting bearing, a counterweight, a wheel disc and at least one stage of moving blades; one end of the main shaft is connected with an external unit, the first supporting bearing is installed on the main shaft close to one end of the external unit, the other end is installed with the wheel disc, and the second supporting bearing is installed on the main shaft close to one end of the wheel disc; the counterweight is sleeved on the main shaft and located between the first supporting bearing and the second supporting bearing, so that the axial distance S between the center of gravity of the rotor assembly and the center of the second supporting bearing is greater than or equal to d / 2; the wheel disc is coaxially installed with the main shaft; each stage of moving blades comprises a plurality of blades which are uniformly distributed on the outer circumference of the wheel disc; and the two adjacent stages of moving blades are arranged side by side and are provided with an axial gap. The rotor assembly has a compact structure and a relatively light weight.

Description

TECHNICAL FIELD

[0001] The present application relates to an industrial exhaust turbine, in particular to a cantilever rotor assembly, a design method thereof and an industrial exhaust turbine. BACKGROUND

[0002] The industrial exhaust turbine is a device that uses the energy in the exhaust gas or tail gas discharged by industry to drive the rotation of a turbine, and then drives the generator or other mechanical equipment to work. It is mainly used to recover and utilize the waste heat or exhaust gas energy generated in the industrial production process to achieve the purpose of energy saving and environmental protection. Therefore, the industrial exhaust turbine is of great significance to improve energy utilization efficiency, reduce energy waste and reduce the impact of industrial exhaust gas emission on the environment.

[0003] The rotor of the traditional industrial exhaust turbine is composed of a main shaft, a moving blade, a blade locking device and the like. The moving blade is installed at the middle hub part of the main shaft, and positions for installing supporting bearings and thrust bearings are reserved on both sides of the main shaft. The industrial exhaust turbine is suitable for high-power and high-flow occasions. It has a lower-in lower-out structure and a large number of stages, so the overall rotor is long and heavy, and the manufacturing cost of the whole machine is high. SUMMARY

[0004] The purpose of the present application is to solve the technical problems of the long rotor, heavy weight and high production cost of the existing industrial exhaust turbine, and to provide a cantilever rotor assembly, a design method thereof and an industrial exhaust turbine.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows:

[0006] A cantilever rotor assembly, characterized in that it comprises a main shaft, a first supporting bearing, a second supporting bearing, a counterweight, a wheel disc and at least one stage of moving blades.

[0007] One end of the main shaft is used to connect an external unit, and the first supporting bearing is installed on the main shaft near the end of the external unit. The other end of the main shaft is used to install the wheel disc, and the second supporting bearing is installed on the main shaft near the end of the wheel disc.

[0008] The counterweight is sleeved on the main shaft and located between the first supporting bearing and the second supporting bearing, so that the axial distance between the center of gravity of the rotor assembly and the center of the second supporting bearing is S, and S≥d / 2, where d is the axial width of the second supporting bearing.

[0009] The wheel disc is a disc structure and is coaxially installed with the main shaft. Each stage of moving blades comprises a plurality of blades, and the plurality of blades are uniformly distributed on the outer circumference of the wheel disc. Adjacent two stages of moving blades are arranged side by side, and an axial gap is provided between them.

[0010] Further, the main shaft and the counterweight are of an integral structure.

[0011] Further, the shaft diameter of the second support bearing is greater than the shaft diameter of the first support bearing.

[0012] Further, a thrust disc is coaxially installed on the main shaft and is in an integral structure with the main shaft; the thrust disc is located on the inner side or the outer side of the first support bearing or on the inner side or the outer side of the second support bearing.

[0013] Further, the blade of the moving blade is a twisted blade structure.

[0014] Meanwhile, the application also provides a design method of the cantilever rotor assembly, comprising the following steps:

[0015] Step 1: according to the preset requirements, the weight of the wheel disc, the number of stages of the moving blade, the number of blades of each stage of the moving blade, the shaft diameter of the first support bearing and the second support bearing are determined, and the adjustable parameters are preliminarily determined; the adjustable parameters include the size of the main shaft, the weight of the counterweight, and the relative installation positions of the first support bearing, the second support bearing and the counterweight;

[0016] Step 2: on the basis of step 1, the center of gravity position of the rotor assembly is determined in combination with the overall structure layout of the industrial exhaust gas turbine, and it is checked whether the axial distance S between the center of gravity position and the center of the second support bearing satisfies S≥d / 2, d being the axial width of the second support bearing; if yes, step 3 is entered; if no, one or more adjustable parameters are adjusted and step 1 is returned to;

[0017] Step 3: whether the rotor assembly meets the design requirements is calculated according to rotor dynamics; if yes, the design of the cantilever rotor assembly is completed; otherwise, one or more adjustable parameters are adjusted and step 1 is returned to until the design of the cantilever rotor assembly is completed.

[0018] Further, in steps 2 and 3, the adjustment of one or more adjustable parameters means that one or more parameters of the size of the main shaft, the weight of the counterweight, and the installation positions of the first support bearing, the second support bearing and the counterweight are adjusted based on the design requirements and the deviation of the axial distance S from the actual requirements.

[0019] In addition, the application also provides an industrial exhaust gas turbine, which is special in that it comprises a casing, a bearing box, at least one stage of stationary blade and the above-mentioned cantilever rotor assembly.

[0020] The casing and the bearing box are respectively sleeved on the main shaft, wherein the first support bearing, the counterweight and the second support bearing are located in the bearing box, and the wheel disc and the moving blade are located in the casing.

[0021] The static vane is installed on the inner wall of the casing, and the number of static vane stages matches the number of dynamic vane stages; each static vane is located on the side of the corresponding dynamic vane close to the second support bearing, and an axial gap is left between the static vane and the adjacent dynamic vane, and a radial gap is left between the outer circle of the wheel disc and the static vane.

[0022] Further, a sealing sleeve is installed at the connection between the casing and the main shaft, and an axial end sealing element is arranged between the sealing sleeve and the main shaft.

[0023] Further, a first sealing element is arranged between the tip of each blade of the dynamic vane and the inner wall of the casing; and a second sealing element is arranged between the outer circle of the wheel disc and the tip of the static vane.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] 1. The cantilever rotor assembly provided by the present application comprises a main shaft, a first support bearing, a second support bearing, a counterweight, a wheel disc and at least one dynamic vane, wherein the wheel disc is installed at the end of the main shaft to form a cantilever structure, and on this basis, the axial distance S between the center of gravity of the rotor assembly and the center of the second support bearing is greater than or equal to d / 2 by reasonably designing the shaft width of the second support bearing and the weight of the counterweight, thereby shortening the overall length of the rotor assembly, reducing the overall weight, and reducing the manufacturing cost.

[0026] 2. In the cantilever rotor assembly provided by the present application, the counterweight and the main shaft are of an integrated structure, and the length and the outer diameter of the counterweight can be determined in advance according to the design requirements, so that the main shaft can be integrally machined, thereby reducing the manufacturing cost.

[0027] 3. The cantilever rotor assembly provided by the present application further comprises a thrust disc, which is coaxially installed on the main shaft and is of an integrated structure with the main shaft, and is located on the inner side or the outer side of the first support bearing or on the inner side or the outer side of the second support bearing, thereby improving the adaptability of the rotor assembly to other equipment.

[0028] 4. The design method of the cantilever rotor assembly provided by the present application has strong universality, and can obtain a rotor assembly with corresponding structure and size according to actual requirements, and the rotor assembly obtained by the design has high matching performance with other parts of the industrial tail gas turbine.

[0029] 5. The industrial tail gas turbine provided by the present application requires small process parameters, is suitable for small models, and has low overall manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 FIG. 1 is a structural schematic diagram of an embodiment of the cantilever rotor assembly of the present application.

[0031] The reference signs are explained as follows:

[0032] 1 - main shaft, 2 - first support bearing, 3 - second support bearing, 4 - counterweight, 5 - wheel disc, 6 - blade, 7 - thrust disc, 8 - shaft end seal, 9 - first seal, 10 - second seal. DETAILED DESCRIPTION

[0033] In order to make the objects, advantages and features of the present application more clear, the present application is described in detail below in combination with the drawings and specific embodiments. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not used to limit the protection scope of the present application.

[0034] As shown in the drawings, the present embodiment provides a cantilever rotor assembly, which comprises a main shaft 1, a first support bearing 2, a second support bearing 3, a counterweight 4, a wheel disc 5 and at least one stage of moving blades. Figure 1

[0035] One end of the main shaft 1 is used to connect an external unit, and the first support bearing 2 is installed on the main shaft 1 near the end of the external unit. The other end (i.e. the cantilever end) of the main shaft 1 is used to install the wheel disc 5, and the second support bearing 3 is installed on the main shaft 1 near the end of the wheel disc 5.

[0036] The counterweight 4 is sleeved on the main shaft 1 and located between the first support bearing 2 and the second support bearing 3, so that the axial distance between the center of gravity of the rotor assembly and the center of the second support bearing 3 is S, and S≥d / 2, wherein d is the axial width of the second support bearing 3. In order to meet this requirement, the shaft diameter of the second support bearing 3 is generally larger than the shaft diameter of the first support bearing 2, and the specific width-diameter ratio is designed according to actual requirements.

[0037] The wheel disc 5 is a disc structure, and the inner circle is coaxially installed with the main shaft 1, or the wheel disc 5 and the main shaft 1 can be designed as an integral structure.

[0038] The present embodiment can also install a thrust disc 7 on the main shaft 1 according to assembly requirements, and the two are generally an integral structure. The thrust disc 7 can be arranged near the first support bearing 2, located on the inner side or the outer side of the first support bearing 2, or arranged near the second support bearing 3, located on the inner side or the outer side of the second support bearing 3, thereby improving the adaptability of the rotor assembly to other equipment.

[0039] The present embodiment takes two stages of moving blades as an example for description, each stage of moving blades comprises a plurality of blades 6, and the plurality of blades 6 are uniformly distributed on the outer circumference of the wheel disc 5. The blade 6 can adopt a twisted blade structure, and the blade tip (i.e. the outer end of the blade 6) is provided with a shroud for reducing the loss of leakage. The blade 6 can also be selected according to requirements. The two stages of moving blades are arranged side by side along the main shaft 1, and an axial gap is provided between the two stages of moving blades.

[0040] ​In the embodiment, the main shaft 1 and the counterweight 4 are in an integrated structure, that is, the middle part of the main shaft 1 is thickened, so as to determine the gravity center position of the rotor assembly and make the rotor assembly balance in operation. The rotor assembly has compact structure, light weight, good overall rigidity and stability of the rotor, and is beneficial to meet the requirement of the critical speed of the rotor.

[0041] In the embodiment, the rotor assembly has the wheel disc 5 and the blades installed at one end of the main shaft 1, so that the overall weight of the wheel disc 5 side is large, and the weight of the connecting side (that is, the side connected to the external unit) is light. In order to ensure the balance of the rotor assembly, the embodiment further provides a design method of the cantilever rotor assembly, including the following steps.

[0042] Step 1: According to the preset requirement, the weight of the wheel disc 5, the number of stages of the blades, the number of the blades 6 on each stage of the blades, the shaft diameter of the first support bearing 2 and the second support bearing 3 are determined, and the adjustable parameters are preliminarily determined, which mainly include the size of the main shaft 1, the weight of the counterweight 4, and the relative installation positions of the first support bearing 2, the second support bearing 3 and the counterweight 4.

[0043] Step 2: On the basis of step 1, the gravity center position of the rotor assembly is determined in combination with the overall structure layout of the industrial exhaust turbine. The gravity center position is generally between the first support bearing 2 and the second support bearing 3. In the embodiment, the axial distance S between the gravity center position of the rotor assembly and the center of the second support bearing 3 should satisfy S≥d / 2, wherein d is the axial width of the second support bearing 3. If the condition is satisfied, step 3 is entered. If the condition is not satisfied, the corresponding adjustable parameters are adjusted according to the design requirement and the deviation amount of the axial distance S from the actual requirement, and step 1 is returned. Generally, the above deviation amount can be satisfied by adjusting the length and the outer diameter of the counterweight 4. Of course, the length of the main shaft 1, the positions of the first support bearing 2 and the second support bearing 3 and other parameters can be adjusted according to the actual situation to adjust the above deviation amount.

[0044] Step 3: In addition to satisfying the requirement of the gravity center position, the design of the rotor assembly also needs to satisfy the calculation requirement of the rotor dynamics. Therefore, whether the above rotor assembly meets the design requirement is calculated according to the principle of the rotor dynamics. If the design requirement is met, the design of the cantilever rotor assembly is completed. Otherwise, one or more adjustable parameters are adjusted, and step 1 is returned until the design of the cantilever rotor assembly is completed.

[0045] In addition, the embodiment further provides an industrial exhaust turbine, which includes a casing, a bearing box, at least one stage of stationary blades and the cantilever rotor assembly.

[0046] The casing and the bearing box are sleeved on the main shaft 1, wherein the first supporting bearing 2, the counterweight 4 and the second supporting bearing 3 are located in the bearing box, and the wheel disc 5 and the moving blade are located in the casing. The bearing box and the casing are matched by the guide key, so as to ensure the stability and centring during operation. During the operation of the industrial tail gas turbine, the casing, the main shaft 1, the wheel disc 5 and the moving blade located in the casing are located in the high temperature zone, and the components in the bearing box are located in the low temperature zone, so as to reduce the operation risk of the bearing.

[0047] The stationary blade is installed on the inner wall of the casing, and the number of stationary blade stages matches the number of moving blade stages, that is, two moving blade stages match two stationary blade stages, and each stationary blade is located at the side of the corresponding moving blade close to the second supporting bearing 3 (that is, each stationary blade is located at the front end of the corresponding moving blade). The stationary blade and the adjacent moving blade are provided with an axial gap, and the outer circle of the wheel disc 5 is provided with a radial gap.

[0048] In order to improve the sealing performance of the turbine, a sealing sleeve is installed at the connection between the casing and the main shaft 1, and an axial end sealing element 8 is arranged between the sealing sleeve and the main shaft 1. The axial end sealing element 8 can adopt a Labyrinth seal, is nested on the main shaft 1, and cooperates with the sealing sleeve to form a small gap, so as to prevent the gas in the casing from leaking.

[0049] The first sealing element 9 is arranged between the tip of each blade 6 in each moving blade stage and the inner wall of the casing, that is, the Labyrinth sealing tooth is arranged on the tip, so as to form a small gap with the flow passage in the casing. On the one hand, the amount of gas leakage can be reduced, and the efficiency of the unit can be improved. On the other hand, the blade 6 and the casing can be prevented from being scratched during the operation of the unit.

[0050] The second sealing element 10 is arranged between the outer circle of the wheel disc 5 and the tip of the stationary blade, so that a small gap is formed between the wheel disc 5 and the stationary blade, so as to reduce the gas leakage loss and improve the efficiency of the unit.

[0051] The industrial tail gas turbine of the embodiment has high turbine efficiency, meets the requirements of the new process, is energy-saving and environment-friendly, has low manufacturing cost, and meets the market demand.

[0052] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A design method for a cantilever rotor assembly, based on a cantilever rotor assembly comprising a main shaft (1), a first support bearing (2), a second support bearing (3), a counterweight (4), a wheel (5), a thrust plate (7), and at least one stage of moving blades; one end of the main shaft (1) is used to connect to an external unit, and the first support bearing (2) is mounted on the main shaft (1) near the end of the external unit; the other end of the main shaft (1) is used to mount the wheel (5), and the second support bearing (3) is mounted on the main shaft (1) near the end of the wheel (5); the counterweight (4) is sleeved on the main shaft (1) and is located between the first support bearing (2) and the second support bearing (3), such that the center of gravity of the rotor assembly is axially aligned with the center of the second support bearing (3). The axial distance is S, and S≥d / 2, where d is the axial width of the second support bearing (3); the wheel (5) is a disc structure and is coaxially mounted with the main shaft (1); each stage of moving blades includes multiple blades (6), and the multiple blades (6) are evenly distributed on the outer circumference of the wheel (5); adjacent two stages of moving blades are arranged side by side, and there is an axial gap between them; the main shaft (1) and the counterweight (4) are an integral structure; the shaft diameter of the second support bearing (3) is larger than the shaft diameter of the first support bearing (2); the thrust plate (7) is coaxially mounted on the main shaft (1) and is an integral structure with the main shaft (1); the thrust plate (7) is located inside or outside the first support bearing (2), or inside or outside the second support bearing (3); the blades (6) of the moving blades are twisted blade structures; Its features are, Includes the following steps: Step 1: According to the preset requirements, determine the weight of the wheel (5), the number of stages of the moving blades, the number of blades (6) of each stage of the moving blades, and the shaft diameter of the first support bearing (2) and the second support bearing (3), and at the same time preliminarily determine the adjustable parameters; the adjustable parameters include the size of the main shaft (1), the weight of the counterweight (4), and the relative installation positions of the first support bearing (2), the second support bearing (3), and the counterweight (4); Step 2: Based on Step 1, and in conjunction with the overall structural layout of the industrial exhaust turbine, determine the center of gravity position of the rotor assembly, and check whether the axial distance S between the center of gravity position and the center of the second support bearing (3) satisfies: S≥d / 2, where d is the axial width of the second support bearing (3). If satisfied, proceed to Step 3; if not satisfied, return to Step 1 to adjust one or more adjustable parameters. Step 3: Calculate whether the rotor assembly meets the design requirements based on rotor dynamics. If it does, the design of the cantilever rotor assembly is completed; otherwise, return to step 1 to adjust one or more adjustable parameters until the design of the cantilever rotor assembly is completed.

2. The design method of the cantilever rotor assembly according to claim 1, characterized in that: In steps 2 and 3, adjusting one or more adjustable parameters refers to adjusting one or more parameters of the main shaft (1), the weight of the counterweight (4), and the installation positions of the first support bearing (2), the second support bearing (3), and the counterweight (4) based on the design requirements and the deviation between the axial distance S and the actual requirements.

Images