Search

CN-120969010-B - Impact water turbine and nozzle thereof

CN120969010BCN 120969010 BCN120969010 BCN 120969010BCN-120969010-B

Abstract

The application relates to the technical field of hydroelectric generation, in particular to an impulse turbine and a nozzle thereof. The inner wall of the nozzle is provided with spiral rifling which is used for rotating high-speed water flow passing through the nozzle so as to realize separation of sediment in the water flow by centrifugal force. By means of the method of arranging bolt rifling inside the nozzle at the tail end of the water distribution pipe of the impulse turbine, separation and layering of high-density sediment are achieved in high-speed fluid, sediment mixed water without a regular distribution is changed into layered separated water with a regular distribution of sediment outer edges, and accordingly basis is provided for accurate abrasion-resistant and impact-resistant material setting, shape and thickness compensation design of the inner layer of the water bucket. The anti-sediment performance of the impulse turbine wheel can be greatly improved, and the service life of the impulse turbine wheel under the running conditions of sediment accumulation, high water head and large capacity can be greatly prolonged.

Inventors

  • LIANG BO
  • XIONG WEIJUN
  • LI CHENGHUANG
  • HU DINGHUI
  • HE CHANGYAN
  • LU JIE

Assignees

  • 长江勘测规划设计研究有限责任公司

Dates

Publication Date
20260508
Application Date
20251010

Claims (9)

  1. 1. Nozzle for impulse turbines, characterized in that the inner wall of the nozzle (3) is provided with spiral rifling (31); the spiral rifling (31) is used for rotating the high-speed water flow passing through the nozzle (3) so as to realize the separation of sediment in the water flow by centrifugal force; the parameters of the spiral rifling (31) are determined by the following method: Determining flow field characteristics required for enabling sediment particles to migrate to the outer edge of jet flow based on a physical principle of particle movement in a rotating flow field; Establishing a relation model of geometric parameters of spiral rifling (31) and the flow field characteristics; Parameters of the spiral rifling (31) are determined according to the relation model, including pitch, male thread (311) width, female thread (312) width and depth of the spiral rifling (31).
  2. 2. Nozzle of an impulse turbine as claimed in claim 1, characterized in, that the spiral rifling (31) comprises alternately arranged male (311) and female (312) wires, which male (311) and female (312) wires extend helically in the axial direction of the nozzle (3).
  3. 3. Nozzle for impulse turbine as claimed in claim 2, characterized in, that the inner wall of the nozzle (3) is provided with a spiral rib constituting the male line (311), the inner wall surface between adjacent spiral ribs constituting the female line (312), or The inner wall of the nozzle (3) is provided with spiral grooves, the spiral grooves form the female line (312), and the inner wall surfaces between adjacent spiral grooves form the male line (311).
  4. 4. Nozzle of an impulse turbine as claimed in claim 2, characterized in, that the width of the male line (311) is smaller or equal to the width of the female line (312).
  5. 5. Nozzle of an impulse turbine as claimed in claim 1, characterized in, that the spiral rifling (31) is a progressive rifling, the pitch of the spiral rifling (31) gradually decreasing in the direction of the water flow.
  6. 6. Nozzle of an impulse turbine as claimed in claim 1, characterized in, that the spiral rifling (31) has a rotation direction coinciding with the direction of rotation of the turbine.
  7. 7. Nozzle of an impulse turbine as claimed in claim 1, characterized in, that the number of spiral rifling (31) is an integer multiple of 12.
  8. 8. Impulse turbine, characterized in, that it comprises a runner, a water distribution coil (5) and a nozzle (3) as claimed in any one of the claims 1-7, said nozzle (3) being connected to said water distribution coil (5).
  9. 9. Impulse turbine as claimed in claim 8, characterized in, that the wheel comprises a wheel hub (2) and water hoppers (1) evenly distributed on the wheel hub (2), wherein the working surface of the water hoppers (1) is provided with a partition material adding layer (118), and the position of the partition material adding layer (118) corresponds to the jet flow outer edge sediment impact area treated by the spiral rifling (31).

Description

Impact water turbine and nozzle thereof Technical Field The application relates to the technical field of hydroelectric generation, in particular to an impulse turbine and a nozzle thereof. Background In the field of high-head (more than 700 m) hydroelectric generation, impulse turbines have become the preferred model under the working condition due to the unique design principle and energy conversion characteristics of the impulse turbines. However, high capacity, high speed impulse turbines operating under sediment-laden river conditions face significant runner wear challenges. The hard particles such as sediment, broken stone and the like carried in the high-speed jet flow have continuous impact and abrasion effects on the rotating wheel bucket, so that the bowl-shaped working surface of the bucket is gradually damaged such as dent, deformation and the like, and even structural failure is caused when serious. The abrasion not only reduces the energy conversion efficiency of the water turbine, but also forms a direct threat to the structural integrity of the rotating wheel and the safe and stable operation of the unit. At present, an effective solution of a system is not formed aiming at the problem of erosion of the impulse turbine under the condition of high sediment. The sediment content, particle size distribution and incoming flow conditions in the river have obvious irregularity and randomness, so that the expected effect is difficult to realize by the traditional protective measures. Most of the prior art focuses on hardening treatment of the material surface or local optimization of structural form, but the problem of separating sediment particles in jet flow cannot be fundamentally solved. The technical bottleneck severely restricts the popularization and application of the impulse turbine under the condition of high sediment, and breakthrough is realized by innovative technical means. Disclosure of Invention In view of the above, the embodiment of the application provides an impulse turbine and a nozzle thereof, which can change sediment mixed water without distribution into layered separated water flow with sediment outer edge distribution, thereby providing basis for accurate wear-resistant and impact-resistant material setting and shape and thickness compensation design of the inner layer of the water bucket and further improving the wear resistance of the water bucket. A first aspect of an embodiment of the present application provides a nozzle for an impulse turbine, the inner wall of the nozzle being provided with spiral rifling; the spiral rifling is used for enabling high-speed water flow passing through the nozzle to rotate so as to separate sediment in the water flow through centrifugal force. In one embodiment, the spiral rifling comprises alternating male and female wires extending helically along the axis of the nozzle. In one embodiment, the inner wall of the nozzle is provided with a spiral rib constituting the male line, the inner wall surface between adjacent spiral ribs constituting the female line, or The inner wall of the nozzle is provided with a spiral groove, the spiral groove forms the female line, and the inner wall surface between the adjacent spiral grooves forms the male line. In one embodiment, the width of the male line is less than or equal to the width of the female line. In one embodiment, the spiral rifling is a progressive rifling, the pitch of the spiral rifling gradually decreasing in the direction of water flow. In one embodiment, the spiral rifling is rotated in a direction that is coincident with the direction of rotation of the turbine. In one embodiment, the number of flights of the spiral rifling is an integer multiple of 12. In one embodiment, the parameters of the spiral rifling are determined by: Determining flow field characteristics required for enabling sediment particles to migrate to the outer edge of jet flow based on a physical principle of particle movement in a rotating flow field; establishing a relation model of spiral rifling geometric parameters and flow field characteristics; And determining parameters of the spiral rifling, including the pitch, the width of the male thread, the width of the female thread and the depth of the spiral rifling according to the relation model. A second aspect of an embodiment of the application provides a impulse turbine comprising a runner, a water distribution coil, and a nozzle according to the first aspect of an embodiment of the application, the nozzle being connected to the water distribution coil. In one embodiment, the runner comprises a hub and water hoppers uniformly distributed on the hub, a partition material adding layer is arranged on the working surface of the water hoppers, and the position of the partition material adding layer corresponds to the sediment impact area of the outer edge of the jet flow after being processed by the spiral rifling. The nozzle of the impulse turbine is provided