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CN-122014368-A - A spiral case and pneumatic turbine for pneumatic turbine

CN122014368ACN 122014368 ACN122014368 ACN 122014368ACN-122014368-A

Abstract

The invention relates to the technical field of pneumatic turbines, in particular to a volute for a pneumatic turbine and the pneumatic turbine, and solves the problems that the conventional volute is difficult to realize stable conversion from circumferential uniform air inlet to axial annular air outlet, and large flow loss is caused. The spiral case comprises a spiral case body, wherein the spiral case body is provided with an inlet flow passage in the circumferential direction and an outlet flow passage with an axial circular section, a seat ring cavity which is used for accommodating an axial opening of a primary seat ring is arranged in the case body, and the outlet flow passage is opposite to the seat ring cavity and is directly communicated with the seat ring cavity, so that air flow can enter the primary seat ring without turning. In the pneumatic turbine comprising the volute, the central flow surfaces of the multistage seat ring and the runner are positioned on the same cylindrical surface with the central flow surface of the outlet runner, and the diameters of the runners at all stages are mutually matched. The invention reduces the air flow turning loss, ensures the uniform and axially symmetrical output of the air flow and improves the overall efficiency of the pneumatic turbine.

Inventors

  • QU BO
  • FAN ZHIWEI
  • GUO KEJIANG
  • WANG JINAN
  • QU JINGYU
  • WANG YISU

Assignees

  • 河海大学
  • 浙江苏捷制阀科技有限公司

Dates

Publication Date
20260512
Application Date
20260325

Claims (11)

  1. 1. A volute for a pneumatic turbine comprises a volute body (1) and is characterized in that the volute body (1) is provided with an inlet runner (101) in the circumferential direction and an axial outlet runner (102), the outlet runner (102) is of a circular cross section, a seat ring cavity (103) for accommodating a first-stage seat ring (3) is arranged in the volute body (1), the seat ring cavity (103) is an axially opened circular ring cavity, and the outlet runner (102) is opposite to and directly communicated with the seat ring cavity (103) in the axial direction, so that gas flowing out of the outlet runner (102) can enter the first-stage seat ring (3) in the seat ring cavity (103) without turning.
  2. 2. A volute for a pneumatic turbine according to claim 1 wherein the central flow surface of the outlet flow passage (102) is on the same cylindrical surface as the central flow surface of the primary seat ring (3).
  3. 3. A volute for use in a gas turbine engine according to claim 2, wherein the primary seat ring (3) has a primary nozzle flow passage (302) therein, and the diameter of the inner and outer circumferential surfaces of the outlet flow passage (102) is the same as the diameter of the inner and outer circumferential surfaces of the primary nozzle flow passage (302).
  4. 4. A volute for a pneumatic turbine as in claim 3 wherein an inlet chamber (108) is provided between the inlet flow passage (101) and the outlet flow passage (102), the inlet chamber (108) having a longitudinal cross-section of a full elliptical cross-section (104) and a longitudinal cross-section that decreases gradually in the direction of air flow, wherein the inlet flow passage (101) is provided on a circumferential side wall of the inlet chamber (108), and the outlet flow passage (102) is provided on an axial end face of the inlet chamber (108).
  5. 5. The ratio of the long axis to the short axis of the full elliptical cross section (104) of the air inlet cavity (108) changes linearly from the inlet to the outlet.
  6. 6. A volute for use in a gas turbine engine according to claim 4, wherein the longitudinal section of the junction of the inlet flow passage (101) and the inlet chamber (108) is circular in cross-section (105).
  7. 7. The volute casing for a pneumatic turbine according to any one of claims 1 to 5, wherein a positioning groove (106) is formed in the outer peripheral surface of the seat ring cavity (103) in an outward recessed mode, a limiting convex ring (303) is formed in the outer peripheral surface of the primary seat ring (3) in an outward protruding mode, and the limiting convex ring (303) axially abuts against the positioning groove (106).
  8. 8. The volute for a pneumatic turbine according to any one of claims 1-5, wherein a bearing seat (107) is formed in the middle of the volute body (1), and a bearing gland (2) is fixedly connected to the outer end of the bearing seat (107).
  9. 9. A pneumatic turbine comprises a volute for the pneumatic turbine according to any one of claims 1-7, and is characterized in that a second-stage seat ring (4), a third-stage seat ring (5) and a fourth-stage seat ring (6) are sequentially and fixedly connected to a volute body (1) along the axial direction, the second-stage seat ring (4), the third-stage seat ring (5) and the fourth-stage seat ring (6) are respectively provided with a second-stage nozzle runner (402), a third-stage nozzle runner (502) and a fourth-stage nozzle runner (602), and the central flow surfaces of the second-stage nozzle runner (402), the third-stage nozzle runner (502) and the fourth-stage nozzle runner (602) are positioned on the same cylindrical surface with the central flow surface of an outlet runner (102).
  10. 10. A pneumatic turbine as set forth in claim 8, wherein a primary runner (7), a secondary runner (8), a tertiary runner (9) and a quaternary runner (10) are respectively arranged among the primary seat ring (3), the secondary seat ring (4), the tertiary seat ring (5) and the quaternary seat ring (6), and the primary runner (7), the secondary runner (8), the tertiary runner (9) and the quaternary runner (10) are respectively provided with a primary blade runner (702), a secondary blade runner (802), a tertiary blade runner (902) and a quaternary blade runner (1002), and the central flow surfaces of the primary blade runner (702), the secondary blade runner (802), the tertiary blade runner (902) and the quaternary blade runner (1002) are positioned on the same cylindrical surface with the central flow surface of the outlet runner (102).
  11. 11. A pneumatic turbine as set forth in claim 9 wherein said primary nozzle runner (302) has an inlet diameter corresponding to an outlet diameter of the outlet runner (102), said primary nozzle runner (302) has an outlet diameter corresponding to an inlet diameter of the primary bucket runner (702), said secondary nozzle runner (402) has an inlet diameter corresponding to an outlet diameter of the primary bucket runner (702), said secondary nozzle runner (402) has an outlet diameter corresponding to an inlet diameter of the secondary bucket runner (802), said tertiary nozzle runner (502) has an inlet diameter corresponding to an outlet diameter of the secondary bucket runner (802), said tertiary nozzle runner (502) has an outlet diameter corresponding to an inlet diameter of the tertiary bucket runner (902), and said quaternary nozzle runner (602) has an inlet diameter corresponding to an outlet diameter of the tertiary bucket runner (902) and said quaternary bucket runner (1002).

Description

A spiral case and pneumatic turbine for pneumatic turbine Technical Field The invention relates to the technical field of pneumatic turbines, in particular to a volute for a pneumatic turbine and the pneumatic turbine. Background The underground coal seam contains rich gas and water, and is released during coal mining, so that the mine outer surface layer is provided with enough compressed air for ensuring the safety of the mining process, the compressed air is conveyed to the working tunnel of the coal seam through a pipeline, the gas in the tunnel is discharged by utilizing the displacement effect, and the water seepage of the coal seam is forcedly discharged out of the working tunnel through a water pump. Because the coal seam is mostly located at the position from hundreds of meters to thousands of meters underground and is long and narrow, the working surface of the mining operation presents a long and narrow semi-closed space, the temperature is higher, generally more than 30 ℃, and the working environment is poorer. Because the gas overflowed from the coal seam, the electric water pump for draining water in the working tunnel has explosion-proof requirement, and meanwhile, the temperature in the working tunnel can be increased due to the heat effect of the motor. The diaphragm pump which is commonly used in the coal mining working tunnel and works by using compressed air at present cannot meet the drainage requirement due to low efficiency. Therefore, the high-efficiency full-runner pneumatic turbine dragging water pump drainage is developed, the drainage requirements of most coal mining work can be met, the cooled exhaust gas after working is directly introduced into a coal mining tunnel, the effect of strongly exhausting gas is achieved, the environment temperature in the coal mining tunnel can be reduced, the drainage pump dragged by the high-efficiency full-runner pneumatic turbine is cut when drainage is needed, and the drainage pump is cut when drainage is not needed, so that the safety requirements in the coal mining process are met. The volute is used as an air inlet and initial flow guiding core component of the pneumatic turbine, and the structural design of the volute directly influences the initial distribution state of air flow and the energy conversion efficiency. In the field of pneumatic turbines, the volute needs to meet the stable introduction and reasonable distribution of high-pressure and high-speed air flow, and provides uniform and stable flow conditions for subsequent multi-stage expansion work. The existing volute technology is mainly concentrated on fluid machines such as pumps, ventilators and compressors, and the design targets of the existing volute technology are mainly single-stage efficiency improvement, noise reduction or manufacturability improvement, but the existing volute technology is applied to a multistage efficient pneumatic turbine and has the following remarkable defects: The volute assembly disclosed in CN116221181a adopts a removable design of the volute tongue to improve the flow channel smoothness, but still belongs to a traditional centrifugal or mixed flow volute structure, the air flow is generally radial or tangential air inlet, axial air outlet, and the outlet is mostly circular or rectangular in section. The spiral case can not realize the flow channel layout of uniform air inlet in the circumferential direction and axial annular air outlet, and is difficult to realize turning-free and coaxial butt joint with the follow-up multi-stage annular nozzle flow channel and the runner flow channel, so that unnecessary turning loss and flow separation are generated before the airflow enters the working stage, and the overall efficiency is reduced. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a volute for a pneumatic turbine and the pneumatic turbine. Aiming at the defects of the prior volute, the novel volute for the pneumatic turbine and the pneumatic turbine comprising the volute are provided by combining the actual working condition and the flow passage characteristics of the high-efficiency full-flow passage pneumatic turbine. The volute can realize seamless joint with the seat ring cavity and ensure the axially symmetrical and uniform output of air flow by optimizing the geometric shapes of the inlet and outlet flow channels, thereby providing ideal initial flow conditions for multistage high-efficiency energy conversion and meeting the multiple requirements of the pneumatic turbine on high efficiency, stability, explosion prevention and cooling in severe environments such as coal mines. The spiral case for the pneumatic turbine comprises a spiral case body, wherein the spiral case body is provided with an inlet runner in the circumferential direction and an axial outlet runner, the outlet runner is of a circular cross section, a seat ring cavity for accommodating a first-stage seat ring is arranged in t