JPS6079177A - Idle revolution of a movable-vane propeller water- wheel - Google Patents

Abstract

PURPOSE:To reduce the amount of the compressed air necessary for idle revolution by controlling the pushed-down water-surface through a water-level detector so as to be always at a proper position, when the water level is pushed- down by feeding the compressed air into the periphery of a runner when said runner is idle-revolved. CONSTITUTION:The pressurized-water in a casing 1 is introduced into a runner upper-surface chamber 5 surrounded by the upper and lower covers 3 and 4 through a guide vane 2 and allowed to flow into a plurality of runner vanes 7a positioned in a discharge ring 6 and revolves a runner 7, and then allowed to flow into a draft tube 8. In this case, a plurality of sensors 9a-9c of a water- level detector 9 are installed into the upper part of the discharge ring 6 and the tube 8, and the pushed-down water-level is observed. Said pushed-down water surface is controlled so that the pushed down water-surface 10 is always lower than the lowest edge part of the runner vane 7a and over the lowest edge part of a runner cone 7b. Thus, the amount of the compressed air necessary for idle revolution is reduced by carrying-out the idle revolution of the runner 7.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an idling operation in which the water surface is appropriately pushed down when the runner of a movable blade propeller water turbine is idled, thereby suppressing the reaction torque of the launch and improving economical efficiency. .

[Technical background of the invention and its problems]

Generally, when operating a water turbine with phase control, compressed air is introduced around the launch to cause the runner to idle. Phase-adjusting operation of movable blade propeller water turbines has been conventionally performed, and therefore, there is no established technology regarding this. However, with the recent diversification of electric power systems, there has been an increasing demand for phase-adjusted operation even in movable blade propeller water turbines. Generally, in movable blade propeller water turbines, as shown in Figure 3, pressurized water in the casing (1) is directed to the upper cover (3) and lower cover (4) via guide vanes (2) whose opening can be freely adjusted. It is guided into the enclosed runner upper chamber (5), flows into a plurality of launch vanes (7 m) located in the discharge ring (6), rotates the launch (7), and then flows into the draft tube (8). It's leaking out. In such a movable blade propeller water turbine, when compressed air is sent into the launch chamber and the upper part of the draft tube to remove water around the launch (7) and perform idling operation, it is preferable to push down and keep the water surface position as high as possible. This means that the amount of air to be fed can be reduced, leading to the downsizing of the compressor, air tank, and piping (not shown) required for this purpose.

However, in this case, in order to reduce the shaft torque, the launch impeller (
It is necessary to set the position so that stirring of the water due to step 7a) can be avoided.

[Purpose of the invention]

When the runner of a movable blade propeller water turbine is idled, water around the runner is removed using compressed air.The present invention determines the optimal position for pushing down the water surface, and determines the optimum position for pushing down the water surface, and adjusts the air volume by adjusting the appropriate value of the compressed air capacity required for idling. The objective is to provide an idle operation method that reduces the size of compression tanks, compressors, etc., contributes to lower equipment costs, and also reduces the reaction torque of the runner blades.

[Summary of the invention]

In the present invention, when the runner of a movable blade propeller water turbine is operated idly, when compressed air is introduced around the runner to push down the water surface, the pushed-down water surface is always below the bottom end of the runner blade and the runner cone reaches the bottom. Idling operation is performed by controlling via a water level detector so that the position is above the lower end.1: This reduces the amount of compressed air required and also reduces the reaction torque of the launch vane. It is.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained in Figures 2 to 1'&4.
This will be explained with reference to the figures. In these figures, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted.

In this embodiment, senna (9m), (9b), (9c) of the water level detector (9) are provided on the upper part of the discharge ring (6) and the draft tube (8) to monitor the lowered water level and are not shown. The air compression tank, compressor, etc. are controlled so that the pressed water level (II) is always below the bottom line of the runner blade (7a) and above the bottom line of the runner cone (7b). The water level is lowered to the position of the third sensor (9c) and the runner cone (7c) is controlled.
b) When the water surface Ql is about to move away from the lower end, reduce the amount of compressed air and return the water surface to a position near the second sensor (9b), so that the lower end of the runner cone (7b) enters the water. It is something.

Next, the effect will be explained.

The reason for operating with the above configuration is based on the following unique characteristics of movable impeller water turbines.

Generally, when the runner (7) is operated idly, the water surface 01 pushed down by the runner (7) causes a swinging motion because the launch blade (7a) stirs the surrounding air. When the height of the wave due to the rocking motion is ΔH, FIG. 3 shows the relationship between ΔH and the position where the water surface is pushed down based on the idling operation experiment.

FIG. 4 is an explanatory diagram showing the meaning of the horizontal axis in FIG. 3.

In Figure 4, Do is the outer diameter of the launch blade △H/D, and is the ratio of the water surface shaking wave height to the outer diameter of the launch blade X/D.
, is the ratio of the water surface pushing position (distance from the vane spindle position) to the launch vane outer diameter ΔH is the water surface swing wave height X is the distance from the vane spindle position to the water surface z-1 is the vane spindle center position.

According to the results of this experiment in which the launch blade was fully closed and idled, as shown in Fig. 4, the pushing down water surface (II is the runner blade (
7a) When in the position range above the lowest end (A range shown in the third figure), the water surface vibration wave height increases due to the forced vortex phenomenon stirred by the rotating runner blade (7a), and the stirring torque increases. also increases. Further, when the runner cone (7b) is in a position range below the lowest end (range B in the third diagram), the wave height value also increases due to the regular free vortex rocking phenomenon. In other words, from this result, the water surface Ql is the launch impeller (
If it is below 7a) and above the lowest end of the runner cone (7b), the influence effect of the runner cone (7b) rotating at the center suppresses the operation of the free vortex and changes it to a smaller wave height value. It turned out that it can be done. Therefore, the range excluding ranges A and B in FIG. 3 is the appropriate range for the water surface depression position. In this case, the water level 01 may rise due to air leakage at the lowest end line of the runner blade (7a), so
In reality, it is preferable to control at a position 1.5 to 2 times lower than the length l from the launch blade spindle center position z-2 to the lowest end of the runner blade.

〔Effect of the invention〕

As described above, according to the present invention, when a movable blade propeller water turbine is operated in a phase-controlled manner, the amount of compressed air can be reduced by controlling the pushing down water level at the above-mentioned position by supplying compressed air to the runner blade housing. Therefore, the compressor air tank, piping, etc. required for pushing down can be downsized, which greatly contributes to lowering the cost of the equipment, and also provides great effects such as suppressing the reaction torque of the runner blades.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a movable blade propeller water turbine subject to idling operation, and FIG. 2 is a longitudinal sectional view showing a movable blade propeller water turbine performing an idling operation method according to an embodiment of the present invention. FIG. 3 is a curve diagram of experimental values showing the relationship between the water surface shaking wave height and the water surface pushing position, which is the basis of the present invention;
FIG. 4 is an explanatory diagram showing the meaning of the horizontal axis in FIG. 3. 1... Casing 2... Guide vane 3... Upper cover 4-... Lower cover 5... Lunch top chamber 6... Discharge ring 7... Runner 7a... Runner blade 7b...・Runner cone 8...Draft tube 9...Water level detector 9a, 9b, 9c...Sensor 10...Water surface agent Patent attorney Mr. Inoue Figure 1 Figure 2

Claims (1)

[Claims] When idling the runner of a movable blade propeller water turbine,
When compressed air is sent around the runner to push down the water surface, the water level must be controlled via a water level detector so that the water surface is always below the lowest end of the launch vane and above the lowest end of the runner cone. A method for idling a movable blade propeller water turbine, which is characterized by idling.