An optimization device and method for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid

Abstract

The present invention discloses a hump zone optimization device for a pump-turbine in pump operation considering fluid compressibility, which includes a volute (1), a draft tube (2), a runner (3), a first guide vane (4), and a second guide vane (5). The second guide vane is arranged radially outside the first guide vane. It is characterized in that: the first guide vane includes a first guide vane body (41), an adjusting rotating shaft (42), a first channel (43), a second channel (44), a third channel (45), and a fourth channel (46); the second guide vane includes a first second guide vane body (51), a second second guide vane body (52), a rotating body (53), a rotating body rotating shaft (54), a fifth channel (55), and a sixth channel (56). The first channel and the third channel form a first water injection channel structure, the second channel and the fourth channel form a second water injection channel structure, and the fifth channel and the sixth channel form a third water injection channel structure. The present invention can more effectively improve / suppress the occurrence and development of unstable phenomena in the hump zone.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic turbines, and particularly relates to an optimization device and method for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid. Background Art

[0002] As a key device for energy conversion in pumped-storage power stations, reversible pump-turbines are developing towards higher head, higher specific speed, and higher capacity. At this time, the flow velocity and pressure of the internal fluid will also increase accordingly, and the compressibility of water cannot be ignored in the operation stability of pump-turbines. During the numerical simulation process, if an incompressible model is used for calculation, although the unstable flow phenomena inside the turbine can be captured by this model, there is a large error compared with the actual results.

[0003] When the pump-turbine operates at part load in the pump condition, various flow instability structures such as rotating stall, jet wake, and stator-rotor interaction are likely to induce the generation of hump instability phenomena. The hump instability phenomena will cause severe pressure pulsation and vibration of the pump-turbine unit, seriously affecting the safe and stable operation of the pumped-storage power station. In recent years, the optimization design concept based on CFD has been gradually applied to pump-turbines. By adjusting the geometric coefficients to change the structure / contour of the runner and / or guide vanes, the hump instability has been improved to a certain extent.

[0004] The prior art CN109058023A discloses a method for broadening the operation stability region of a pump-turbine and a pump-turbine, and the prior art CN113969855A discloses a blade modification method for suppressing the hump in the pump condition of a pump-turbine, and the prior art CN114576065A discloses a runner of a pump-turbine with bend-twist-sweep characteristics. The deficiencies of the above prior arts are as follows: (1) The weak compressibility of water is not considered, that is, the influence of the density change of water during the operation of the pump-turbine on the performance of the unit; (2) The optimization and flow control of the runner and / or guide vanes are mostly based on the structure and flow characteristics of the unit itself to determine the optimization scheme, and the optimization time and processing cost are relatively high.

[0005] The prior art JP2018080616A discloses a hydraulic turbine and its operation method, which improves / suppresses the hump instability phenomenon by setting a flow regulating mechanism and a water injection hole structure. However, this prior art (JP2018080616A) still has the following deficiencies: (1) The weak compressibility of water is not considered, that is, the influence of the density change of water during the operation of the pump-turbine on the performance of the unit; (2) It does not focus on the influence of the water injection hole structure on the hump region under the pump condition of the pump-turbine, and its improvement effect on the hump region instability is average and needs to be further optimized and improved. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies existing in the prior art and provide an optimization device and method for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid. By considering the weak compressibility of water, that is, the influence of the density change of water during the operation of the pump-turbine on the unit performance, and focusing on the influence of the injection channel structure on the hump region under the pump condition of the pump-turbine, through the design of the injection channel structure, the flow separation at the guide vane cascade can be reduced, thereby suppressing the occurrence and development of various unstable flows during the pump condition operation of the pump-turbine, and further suppressing or delaying the formation of the hump region. Therefore, it can more effectively improve / suppress the unstable phenomenon in the hump region, which has good reference significance for expanding the safe and stable operation range of the pump-turbine in engineering design.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] An optimization device for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid, which includes a spiral case, a draft tube, a runner, a first guide vane, and a second guide vane. The draft tube is connected to the lower end of the spiral case. The second guide vane is arranged on the radially outer peripheral side of the first guide vane. The runner is arranged on the radially inner peripheral side of the first guide vane. The first guide vane is an adjustable guide vane. It is characterized in that: the first guide vane includes a first guide vane body, an adjusting rotating shaft, a first channel, a second channel, a third channel, and a fourth channel. The adjusting rotating shaft is used to drive the first guide vane body to rotate. The first channel and the second channel are arranged in the adjusting rotating shaft. The third channel and the fourth channel are arranged in the first guide vane body. The first channel and the second channel are respectively communicated with the third channel and the fourth channel. The outlet end of the third channel is located at the radially inner end of the first arc surface of the first guide vane body. The outlet end of the fourth channel is located at the radially outer end of the first arc surface of the first guide vane body. The second guide vane includes a first second guide vane body, a second second guide vane body, a rotating body, a rotating body rotating shaft, a fifth channel, and a sixth channel. The first second guide vane body, the rotating body, and the second second guide vane body are sequentially connected to form the second guide vane. The rotating body rotating shaft is used to drive the rotating body to rotate relative to the first second guide vane body or the second second guide vane body. The first second guide vane body and the second second guide vane body are fixed guide vanes. The fifth channel is arranged in the rotating body rotating shaft. The sixth channel is arranged in the rotating body. The fifth channel is communicated with the sixth channel.

[0009] Furthermore, the first channel and the third channel form a first injection channel (injection hole) structure, the second channel and the fourth channel form a second injection channel (injection hole) structure, and the fifth channel and the sixth channel form a third injection channel (injection hole) structure.

[0010] Further, the rotating body has a cylindrical structure and is disposed between the first second guide vane body and the second second guide vane body, and is in arc transition with them. That is, a plurality of transition arcs are provided at the radially outer end of the first second guide vane body for arc transition with the outer peripheral surface of the rotating body, and a plurality of transition arcs are provided at the radially inner end of the second second guide vane body for arc transition with the outer peripheral surface of the rotating body.

[0011] Further, a first regulating valve is connected to the first channel, and a second regulating valve is connected to the second channel. The first regulating valve and the second regulating valve are respectively used to control the on / off and flow rate of the third channel and the fourth channel.

[0012] Further, a third regulating valve is connected to the fifth channel, and the third regulating valve is used to control the on / off and flow rate of the sixth channel.

[0013] Further, in the circumferential direction, the water jet direction at the outlet end of the third channel or the fourth channel is opposite to the water jet direction at the outlet end of the sixth channel. That is, the water jet direction at the outlet end of the third channel or the fourth channel is clockwise, and the water jet direction at the outlet end of the sixth channel is counterclockwise.

[0014] Further, under the turbine condition, the third channel is controlled to open by the first regulating valve, the fourth channel is controlled to close by the second regulating valve, and the water jet angle at the outlet end of the third channel can be adjusted by adjusting the rotating shaft. At the same time, the rotating body is driven to rotate by the rotating body rotating shaft so that the outlet end of the sixth channel rotates or approaches to one side of the first second guide vane body, and the jet water flow at the outlet end of the sixth channel merges with the jet water flow at the outlet end of the third channel at the downstream end of the first guide vane. Under the pump condition, the third channel is controlled to close by the first regulating valve, the fourth channel is controlled to open by the second regulating valve, and the water jet angle at the outlet end of the fourth channel can be adjusted by adjusting the rotating shaft. At the same time, the rotating body is driven to rotate by the rotating body rotating shaft so that the outlet end of the sixth channel rotates or approaches to one side of the second second guide vane body, and the jet water flow at the outlet end of the sixth channel merges with the jet water flow at the outlet end of the fourth channel at the downstream end of the second guide vane.

[0015] A control method for an optimization device in the hump region under the pump condition of a pump-turbine considering fluid compressibility includes the following steps:

[0016] Step (1): Under the turbine condition, the third channel is controlled to open by the first regulating valve, the fourth channel is controlled to close by the second regulating valve, and the water jet angle at the outlet end of the third channel can be adjusted by adjusting the rotating shaft. At the same time, the rotating body is driven to rotate by the rotating body rotating shaft so that the outlet end of the sixth channel rotates or approaches to one side of the first second guide vane body, and the jet water flow at the outlet end of the sixth channel merges with the jet water flow at the outlet end of the third channel at the downstream end of the first guide vane.

[0017] Step (2): Adjust the water jet flow rate or pressure of the third channel through the first regulating valve, and adjust the water jet flow rate or pressure of the sixth channel through the third regulating valve;

[0018] Step (3): Under pump conditions, control the third channel to close through the first regulating valve, control the fourth channel to open through the second regulating valve, and adjust the water jet angle at the outlet end of the fourth channel by adjusting the rotating shaft; meanwhile, drive the rotating body to rotate through the rotating body shaft so that the outlet end of the sixth channel rotates or approaches one side of the second guide vane body II, and the jet water at the outlet end of the sixth channel merges with the jet water at the outlet end of the fourth channel at the downstream end of the second guide vane;

[0019] Step: Adjust the water jet flow rate or pressure of the fourth channel through the second regulating valve, and adjust the water jet flow rate or pressure of the sixth channel through the third regulating valve.

[0020] An optimization device and method for the hump region under pump conditions of a pump-turbine considering fluid compressibility according to the present invention, by considering the weak compressibility of water, that is, the influence of the change in water density on the unit performance during the operation of the pump-turbine, and focusing on the influence of the injection channel structure on the hump region under pump conditions of the pump-turbine. Through the design of the injection channel (injection hole) structure (specifically, the first channel and the third channel form the first injection channel structure, the second channel and the fourth channel form the second injection channel structure, and the fifth channel and the sixth channel form the third injection channel structure), it can reduce the flow separation at the guide vane grid, thereby suppressing the occurrence and development of various unstable flows during the pump condition operation of the pump-turbine, and further suppressing or delaying the formation of the hump region. Therefore, it can more effectively improve / suppress the unstable phenomenon in the hump region, and has good reference significance for expanding the safe and stable operation range of the pump-turbine in engineering design. Brief Description of the Drawings

[0021] Figure 1 Schematic diagram of the structure of a prior art pump-turbine;

[0022] Figure 2 Schematic diagram of the partial structure of the pump-turbine of the present invention;

[0023] Figure 3 Schematic diagram of the partial structure of the pump-turbine of the present invention;

[0024] Figure 4 Schematic diagram of the partial structure of the pump-turbine of the present invention (turbine condition);

[0025] Figure 5 Schematic diagram of the partial structure of the pump-turbine of the present invention (pump condition);

[0026] Figure 6Performance curve graphs showing the comparison between incompressible and compressible numerical simulations and experiments;

[0027] Figure 7 Hydraulic loss diagrams showing each component of the compressible model;

[0028] Figure 8 Performance curve comparison graphs for 4 different injection water flow rates;

[0029] Figure 9 Total hydraulic loss diagrams of the pump - turbine under 4 different injection water flow rates and different flow conditions of the performance curves.

[0030] In the figure: spiral case 1, draft tube 2, runner 3, first guide vane 4, second guide vane 5, first guide vane body 41, adjusting rotating shaft 42, first channel 43, second channel 44, third channel 45, fourth channel 46, first second - guide vane body 51, second second - guide vane body 52, rotating body 53, rotating body rotating shaft 54, fifth channel 55, sixth channel 56. Detailed implementation manners

[0031] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings.

[0033] As Figures 1-5As shown in the figure, an optimization device for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid, which comprises a volute 1, a draft tube 2, a runner 3, a first guide vane 4, and a second guide vane 5. The draft tube 2 is connected to the lower end of the volute 1. The second guide vane 5 is arranged on the radially outer peripheral side of the first guide vane 4, and the runner 3 is arranged on the radially inner peripheral side of the first guide vane 4. The first guide vane 4 is an adjustable guide vane / movable guide vane. It is characterized in that: the first guide vane 4 includes a first guide vane body 41, an adjusting rotating shaft 42, a first channel 43, a second channel 44, a third channel 45, and a fourth channel 46. The adjusting rotating shaft 42 is used to drive the first guide vane body 41 to rotate. The first channel 43 and the second channel 44 are arranged in the adjusting rotating shaft 42. The third channel 45 and the fourth channel 46 are arranged in the first guide vane body 41. The first channel 43 and the second channel 44 are respectively communicated with the third channel 45 and the fourth channel 46. The outlet end of the third channel 45 is located at the radially inner end of the first arc surface of the first guide vane body 41, and the outlet end of the fourth channel 46 is located at the radially outer end of the first arc surface of the first guide vane body 41. The second guide vane 5 includes a first second guide vane body 51, a second second guide vane body 52, a rotating body 53, a rotating body rotating shaft 54, a fifth channel 55, and a sixth channel 56. The first second guide vane body 51, the rotating body 53, and the second second guide vane body 52 are sequentially connected to form the second guide vane 5. The rotating body rotating shaft 54 is used to drive the rotating body 53 to rotate relative to the first second guide vane body 51 or the second second guide vane body 52. The first second guide vane body 51 and the second second guide vane body 52 are fixed guide vanes. The fifth channel 55 is arranged in the rotating body rotating shaft 54, and the sixth channel 56 is arranged in the rotating body 53. The fifth channel 55 is communicated with the sixth channel 56.

[0034] The first channel 43 and the third channel 45 form a first water injection channel (water injection hole) structure. The second channel 44 and the fourth channel 46 form a second water injection channel (water injection hole) structure. The fifth channel 55 and the sixth channel 56 form a third water injection channel (water injection hole) structure.

[0035] Further, the rotating body 53 has a cylindrical structure. The rotating body 53 is arranged between the first second guide vane body 51 and the second second guide vane body 52, and is arc-transitioned with them. That is, a plurality of transition arcs are arranged at the radially outer end of the first second guide vane body 51 to be arc-transitioned with the outer peripheral surface of the rotating body 53, and a plurality of transition arcs are arranged at the radially inner end of the second second guide vane body 52 to be arc-transitioned with the outer peripheral surface of the rotating body 53.

[0036] Further, a first regulating valve / control valve is connected to the first channel 43, and a second regulating valve / control valve is connected to the second channel 44. The first regulating valve and the second regulating valve are respectively used to control the on-off and flow rate of the first channel 43 / the third channel 45 and the second channel 44 / the fourth channel 46.

[0037] Further, a third regulating valve / control valve is connected to the fifth channel 55, and the third regulating valve is used to control the on / off and flow rate of the fifth channel 55 / the sixth channel 56.

[0038] Further, in the circumferential direction, the water flow injection direction at the outlet end of the third channel 45 or the fourth channel 46 is opposite to the water flow injection direction at the outlet end of the sixth channel 56, that is, the water flow injection direction at the outlet end of the third channel 45 or the fourth channel 46 is clockwise, and the water flow injection direction at the outlet end of the sixth channel 56 is counterclockwise.

[0039] As Figures 4-5 shown, further, in the water turbine condition, the third channel 45 is controlled to open by the first regulating valve, the fourth channel 46 is controlled to close by the second regulating valve, and the water flow injection angle at the outlet end of the third channel 45 can be adjusted by adjusting the rotating shaft 42; meanwhile, the rotating body 53 is driven to rotate by the rotating body rotating shaft 54 so that the outlet end of the sixth channel 56 rotates or approaches to one side of the first guide vane body 51, and the injected water flow at the outlet end of the sixth channel 56 merges with the injected water flow at the outlet end of the third channel 45 at the downstream end of the first guide vane 4 ("→" indicates the water flow direction); in the pump condition, the third channel 45 is controlled to close by the first regulating valve, the fourth channel 46 is controlled to open by the second regulating valve, and the water flow injection angle at the outlet end of the fourth channel 46 can be adjusted by adjusting the rotating shaft 42; meanwhile, the rotating body 53 is driven to rotate by the rotating body rotating shaft 54 so that the outlet end of the sixth channel 56 rotates or approaches to one side of the second guide vane body 52, and the injected water flow at the outlet end of the sixth channel 56 merges with the injected water flow at the outlet end of the fourth channel 46 at the downstream end of the second guide vane 5 ("→" indicates the water flow direction).

[0040] A control method for an optimization device in the hump region under the pump condition of a pump-turbine considering fluid compressibility, which includes the following steps:

[0041] Step (1): In the water turbine condition, the third channel 45 is controlled to open by the first regulating valve, the fourth channel 46 is controlled to close by the second regulating valve, and the water flow injection angle at the outlet end of the third channel 45 can be adjusted by adjusting the rotating shaft 42; meanwhile, the rotating body 53 is driven to rotate by the rotating body rotating shaft 54 so that the outlet end of the sixth channel 56 rotates or approaches to one side of the first guide vane body 51, and the injected water flow at the outlet end of the sixth channel 56 merges with the injected water flow at the outlet end of the third channel 45;

[0042] Step (2): Adjust the water flow injection flow rate or pressure of the third channel 45 through the first regulating valve, and adjust the water flow injection flow rate or pressure of the sixth channel 56 through the third regulating valve;

[0043] Step (3): Under pump operating conditions, control the third channel 45 to close via the first regulating valve, control the fourth channel 46 to open via the second regulating valve, and adjust the water jet angle at the outlet end of the fourth channel 46 by adjusting the rotating shaft 42; meanwhile, drive the rotating body 53 to rotate via the rotating body rotating shaft 54 so that the outlet end of the sixth channel 56 rotates towards or approaches one side of the second guide vane body two 52, and the jet water flow at the outlet end of the sixth channel 56 merges with the jet water flow at the outlet end of the fourth channel 46 at the downstream end of the second guide vane 5;

[0044] Step (4): Adjust the water jet flow rate or pressure of the fourth channel 46 via the second regulating valve, and adjust the water jet flow rate or pressure of the sixth channel 56 via the third regulating valve.

[0045] As Figure 6 shown, it shows the performance curve graph of the comparison between incompressible and compressible numerical simulations and experiments. It can be found that the compressible model can better predict the performance curve in the hump region (0.68QDes - 0.80QDes), which further verifies the necessity of adding the compressible model in engineering calculations.

[0046] As Figure 7 shown, it shows the hydraulic loss graph of each component of the compressible model. When entering the initial hump condition (0.80QDes), the hydraulic loss in the guide vane cascade is the largest, which is closely related to the formation of the hump region.

[0047] As Figure 8 shown, it gives the comparison graph of performance curves at 4 different injection water flow rates (10, 20, 30, 40 m / s). It can be found that all 4 flow rates can effectively suppress or delay the formation of the hump region. Among them, the injection water flow rates of 10, 30, and 40 m / s delay the formation of the hump region to a smaller flow condition (the hump inflection point is delayed from 0.75QDes to 0.68QDes). It should be noted that when the injection water flow rate is 30 m / s, although the hump region develops with a delay, the hump region expands (i.e., at 0.59QDes, the positive slope still exists). When the injection water flow rate is 20 m / s, the formation of the hump region is delayed to a smaller flow condition compared to the other 3 injection water flow rates (the hump inflection point is delayed from 0.75QDes to 0.65QDes).

[0048] As Figure 9 shown, it gives the total hydraulic loss graph of the pump-turbine under 4 different injection water flow rates and different flow conditions of the performance curve (where the abscissa 0 represents the hydraulic loss without water injection).

[0049] "Axial" is the direction of the rotation axis of the pump-turbine, and "radial" is the direction of the diameter / radius of the runner.

[0050] An optimization device and method for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid according to the present invention. By considering the weak compressibility of water, that is, the influence of the density change of water during the operation of the pump-turbine on the performance of the unit, and focusing on the influence of the injection channel structure on the hump region under the pump condition of the pump-turbine, through the design of the injection channel (injection hole) structure (specifically, the first channel 43 and the third channel 45 constitute the first injection channel structure, the second channel 44 and the fourth channel 46 constitute the second injection channel structure, the fifth channel 55 and the sixth channel 56 constitute the third injection channel structure), the flow separation at the guide vane cascade can be reduced, thereby suppressing the occurrence and development of various unstable flows during the pump condition operation of the pump-turbine, and further suppressing or delaying the formation of the hump region. Therefore, it can more effectively improve / suppress the unstable phenomenon in the hump region, and has good reference significance for expanding the safe and stable operation range of the pump-turbine in engineering design.

[0051] It should be noted that all directional indications (such as up, down, left, right, front, back, horizontal, vertical, etc.) in the embodiments of the present invention are only used to explain the relative position relationship and motion conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly. The "connection" can be a direct connection or an indirect connection. The "setting", "set on", and "set in" can be directly set or indirectly set.

[0052] The above embodiments are descriptions of the present invention, not limitations of the present invention. It can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An optimization device for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid, which comprises a spiral case (1), a draft tube (2), a runner (3), a first guide vane (4), and a second guide vane (5). The draft tube is connected to the lower end of the spiral case. The second guide vane is arranged on the radially outer peripheral side of the first guide vane. The runner is arranged on the radially inner peripheral side of the first guide vane. The first guide vane is an adjustable guide vane; It is characterized in that: The first guide vane (4) comprises a first guide vane body (41), an adjusting rotating shaft (42), a first channel (43), a second channel (44), a third channel (45), and a fourth channel (46). The adjusting rotating shaft is used to drive the first guide vane body to rotate. The first channel and the second channel are arranged in the adjusting rotating shaft. The third channel and the fourth channel are arranged in the first guide vane body. The first channel and the second channel are respectively communicated with the third channel and the fourth channel. The outlet end of the third channel is located at the radially inner end of the first arc surface of the first guide vane body. The outlet end of the fourth channel is located at the radially outer end of the first arc surface of the first guide vane body. The second guide vane (5) comprises a first second guide vane body (51), a second second guide vane body (52), a rotating body (53), a rotating body rotating shaft (54), a fifth channel (55), and a sixth channel (56). The first second guide vane body, the rotating body, and the second second guide vane body are sequentially connected to form the second guide vane. The rotating body rotating shaft is used to drive the rotating body to rotate relative to the first second guide vane body or the second second guide vane body. The first second guide vane body and the second second guide vane body are fixed guide vanes. The fifth channel is arranged in the rotating body rotating shaft. The sixth channel is arranged in the rotating body. The fifth channel is communicated with the sixth channel.

2. An optimization device for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid as described in claim 1, It is characterized in that, The rotating body (53) has a cylindrical structure. The rotating body is arranged between the first second guide vane body and the second second guide vane body and is arc-transitioned with them. That is, a plurality of transition arcs are arranged at the radially outer end of the first second guide vane body to be arc-transitioned with the outer peripheral surface of the rotating body. A plurality of transition arcs are arranged at the radially inner end of the second second guide vane body to be arc-transitioned with the outer peripheral surface of the rotating body.

3. An optimization device for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid as described in claim 2, It is characterized in that, A first regulating valve is connected to the first channel (43), and a second regulating valve is connected to the second channel (44). The first regulating valve and the second regulating valve are respectively used to control the on-off and flow rate of the third channel (45) and the fourth channel (46).

4. An optimization device for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid as described in claim 3, It is characterized in that, A third regulating valve is connected to the fifth channel (55). The third regulating valve is used to control the on-off and flow rate of the sixth channel (56).

5. An optimization device for the hump region under the pump condition of a pump-turbine considering the compressibility of fluid as described in claim 4, It is characterized in that, In the circumferential direction, the water flow ejection direction at the outlet end of the third channel (45) or the fourth channel (46) is opposite to the water flow ejection direction at the outlet end of the sixth channel (56), that is, the water flow ejection direction at the outlet end of the third channel or the fourth channel is clockwise, and the water flow ejection direction at the outlet end of the sixth channel is counterclockwise.

6. An optimization device for the hump region under the pump condition of a water pump turbine considering fluid compressibility according to claim 5, characterized in that under the turbine condition, the third channel (45) is controlled to open through the first regulating valve, the fourth channel (46) is controlled to close through the second regulating valve, and the water flow ejection angle at the outlet end of the third channel can be adjusted by adjusting the rotating shaft (42); meanwhile, the rotating body (53) is driven to rotate by the rotating body rotating shaft (54) so that the outlet end of the sixth channel (56) rotates or approaches to one side of the first second guide vane body (51), and the ejected water flow at the outlet end of the sixth channel merges with the ejected water flow at the outlet end of the third channel at the downstream end of the first guide vane; under the pump condition, the third channel (45) is controlled to close through the first regulating valve, the fourth channel (46) is controlled to open through the second regulating valve, and the water flow ejection angle at the outlet end of the fourth channel (46) can be adjusted by adjusting the rotating shaft; meanwhile, the rotating body is driven to rotate by the rotating body rotating shaft (54) so that the outlet end of the sixth channel (56) rotates or approaches to one side of the second second guide vane body (52), and the ejected water flow at the outlet end of the sixth channel merges with the ejected water flow at the outlet end of the fourth channel (46) at the downstream end of the second guide vane.

7. A control method for an optimization device for the hump region under the pump condition of a water pump turbine considering fluid compressibility, which includes an optimization device for the hump region under the pump condition of a water pump turbine considering fluid compressibility according to claim 4 or 5, and it comprises the following steps: Step (1): Under the water turbine condition, control the third channel (45) to open through the first regulating valve, control the fourth channel (46) to close through the second regulating valve, and adjust the water jet angle at the outlet end of the third channel (45) by adjusting the rotating shaft (42); meanwhile, drive the rotating body (53) to rotate through the rotating body rotating shaft (54) so that the outlet end of the sixth channel (56) rotates or approaches to one side of the first second guide vane body (51), and the jet water flow at the outlet end of this sixth channel merges with the jet water flow at the outlet end of the third channel at the downstream end of the first guide vane; Step (2): Adjust the water jet flow rate or pressure of the third channel (45) through the first regulating valve, and adjust the water jet flow rate or pressure of the sixth channel (56) through the third regulating valve; Step (3): Under the pump condition, control the third channel (45) to close through the first regulating valve, control the fourth channel (46) to open through the second regulating valve, and adjust the water jet angle at the outlet end of the fourth channel (46) by adjusting the rotating shaft (42); meanwhile, drive the rotating body (53) to rotate through the rotating body rotating shaft (54) so that the outlet end of the sixth channel (56) rotates or approaches to one side of the second second guide vane body (52), and the jet water flow at the outlet end of this sixth channel merges with the jet water flow at the outlet end of the fourth channel at the downstream end of the second guide vane; Step (4): Adjust the water jet flow rate or pressure of the fourth channel (46) through the second regulating valve, and adjust the water jet flow rate or pressure of the sixth channel (56) through the third regulating valve.

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