JPS6044515B2 - How to spin a runner - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for idling a runner.

The idling method of the runner in a conventional pump or water turbine is explained with reference to Fig. 1.A is the upper cover, is the lower cover, c is the runner, d is the suction pipe, e is the guide vane, f is the air supply pipe, and the pump When performing condenser operation on a car or water turbine, or when starting the pump of a pump water turbine,
With the guide vane e fully closed, pressurized air g is sent from the air supply pipe f to the direction of the suction pipe d, pushing down the water level in the suction pipe d to position A, and idling the runner c. I tried to reduce the required torque.

However, this method had a problem in that when the runner c idled, the water surface moved and came into contact with the outlet end Cl of the runner c. That is, when the runner c idles, an air current is generated in the space above the water surface in the suction pipe d. This airflow is mainly a swirling flow as shown in Fig. 2, but a highly turbulent secondary flow i occurs near the runner blades. This highly turbulent secondary flow i does not have the effect of causing waves with large wavelengths on the water surface, but the swirling flow induces waves with large wavelengths in the suction pipe d. This phenomenon is based on the same principle that causes waves to occur when the wind blows in a fixed direction for a long period of time on the sea surface. The induced wave gradually grows and travels in the circumferential direction of the suction pipe d, forming a swirling wave B having a wavelength equal to the circumferential length of the suction pipe d (see Figures 1 and 3).
become. The swirling period of this swirling wave B is determined by the size and shape of the suction pipe d and has a specific value. This swirling wave B further develops depending on the operating conditions, and the wave crest comes into contact with the outlet end Cl of the runner c, generating abnormal noise. In this case, the wave height temporarily decreases due to the impact of the contact, and the contact is no longer made, but the wave height immediately increases and the contact occurs again, and the operation is repeated. Therefore, there was a problem in that abnormal noises were generated periodically. Further, there was a problem in that the above-mentioned contact increased the idling torque of the runner c. The present invention addresses the above-mentioned problems by sending pressurized air from the air supply pipe toward the suction pipe while keeping the guide vane fully closed, and by pushing down the water level in the suction pipe, the pump car or When idling the runner of a water turbine, assuming that the runner's outlet diameter is d) and the distance from the runner's 7th end Cl to the water surface is 1, the water surface is maintained so that 1≦0.2d to prevent fluctuations in the water surface. Relating to a runner idling method characterized by preventing the runner from idling,
The purpose of this invention is to provide an improved method for idling a runner that can prevent abnormal noise and an increase in torque that occur when the runner is idling.

Next, the runner idling method according to the present invention will be explained with reference to an embodiment shown in FIG. 4. 1 is an upper cover, 2 is a lower cover,
3 is the runner, 3a is the outlet end of the runner 3, 4 is the suction pipe,
5 is an air vane, 6 is an air supply pipe, and the outlet end 3a of the runner 3
Assuming that the diameter of is d1 and the distance from the outlet end 3a to the water surface is 1, pressurized air is fed from the air supply pipe 6 toward the suction pipe 4 while keeping the guide vane 5 fully closed. When pushing down the water surface and idling the runner 3 of the pump or water wheel, 1≦0.

Keep the water surface at 2d.

The water surface at this time is indicated by A''. Conventionally, the water surface was set at position A so as to be as far away from the outlet end 3a of the runner 3 as possible so as not to contact the outlet end 3a of the runner 3 even if the water surface fluctuated. However, above this position A, there is a swirling flow h
exists, and as mentioned above, long-period waves are generated,
The wave height became higher and came into contact with the outlet end 3a of the runner 3, causing problems such as noise generation and increased idling torque.However, even if there is a secondary flow i at the N position, the swirling flow h is not exist. Therefore, long-period waves are not generated and the crests of the waves do not come into contact with the outlet end 3a of the runner 3, thereby preventing the generation of abnormal noise and an increase in idling torque. The results of the experiment are shown in Figure 5.

Runner 3 with outlet end 3a diameter of 250f at 1000 rpm
When idling at m, the wave height ΔH is short at 1 as is clear from the curve! As the temperature increased, it gradually became lower, but as it entered the shaded area, it rapidly decreased. In this way, the wave height ΔH
It is thought that the reason why the value rapidly decreases is due to the secondary flow i.
The shape of this secondary flow i changes somewhat depending on the shape of the runner 3, but assuming there is no major change, w=COrlSt. According to the above experimental results, 10=feather=, d=250f
Therefore, W=0.15, but in the present invention, l is set to 0.2d or 0 in consideration of measurement errors.

? It is as follows. If the set A'' position changes due to air leakage, this change is detected by a water surface detection relay or the like, and air is reconnected from the air connection pipe 6 to maintain the water surface at the A'' position. As described above, the present invention sends pressurized air from the air supply pipe toward the suction pipe while keeping the guide vane fully closed, and presses down the water surface in the suction pipe for a long period of time. When idling, La 4
The outlet diameter of the runner is d1.If the distance from the outlet end C1 of the runner to the water surface is 1, then 1≦0. ? (maintain the water surface in a position where there is no swirling flow even if there is a secondary flow), prevent the generation of long-period waves, and prevent the wave crest from contacting the runner outlet end. We are trying to prevent
This has the effect of preventing abnormal noise and an increase in torque that occur when the runner idles. Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional side view showing a conventional runner idling method, Fig. 2 is an explanatory diagram showing swirling flow and secondary flow, Fig. 3 is a perspective view showing long-period waves caused by swirling flow, and Fig. 4 FIG. 5 is a longitudinal sectional side view showing an embodiment of the runner idling method according to the present invention, and FIG. 5 is an explanatory view showing experimental results of the runner idling method according to the present invention. 3...Runner, 3a...Exit end of runner 3, A''...Setting position of water surface.

Claims (1)

[Claims] 1 With the guide vane fully closed, pressurized air is sent from the air supply pipe toward the suction pipe, and the water level in the suction pipe is pushed down for a long period of time to cause the runner of a pump or water turbine to idle. A runner characterized by maintaining the water surface so that 1≦0.2d, where d is the outlet diameter and 1 is the distance from the outlet end c_1 of the runner to the water surface, thereby preventing the water surface from oscillating when the runner idles. How to idle.