JP2007107428A - Runner for hydraulic machine and hydraulic machine using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a runner for a hydraulic machine, having high runner efficiency while suppressing vibration to be generated by a combined number of guide vanes and runner vanes. <P>SOLUTION: The runner for the hydraulic machine comprises the runner vanes parted into long and short vanes, the parted long and short vanes being arranged in the peripheral direction of the runner. Two short vanes S<SB>1</SB>, S<SB>2</SB>are arranged between one long vane L<SB>1</SB>and the long vane L<SB>2</SB>adjacent thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic machine runner, and more particularly, to a hydraulic machine runner in which long blades and short blades are arranged along a circumferential direction of the runner and a hydraulic machine using the runner.

  In general, a hydraulic machine runner is one of the most important mechanical elements that convert fluid energy into power, and the quality of the hydraulic machine greatly affects the hydraulic efficiency of the entire hydraulic machine.

  Therefore, developing a highly efficient runner is an important issue in hydropower design, and a number of various measures for improving hydraulic efficiency have been proposed.

  In a normal hydraulic machine runner in which blades of the same wing shape are provided along the runner circumferential direction, as shown in FIG. 8, one streamline SL is rotated on the rotating shaft 2 of the runner 1 in the meridional section. When the blade 3 is cut along a curved surface obtained by rotation with a center, as shown in FIG. 9, the spiral blade 3 gradually forms a narrow open passage from the inlet side 4 to the outlet side 5 of the runner 1. Is arranged.

  In contrast, recently, as shown in FIG. 10, a so-called splitter runner in which long blades L and short blades S are alternately arranged along the circumferential direction of the runner 1 has been developed and put into practical use.

  Although this splitter runner has a larger number of blades than a normal runner, it has only a long blade L on the outlet side (inner diameter side) of the runner 1, so there is a gap between one blade and the adjacent blade. It has been confirmed that the advantages of the multi-blade type runner can be utilized to the maximum without being significantly reduced, and that it has excellent hydraulic efficiency.

  However, on the other hand, in the splitter runner shown in FIG. 10 in which the long blades L and the short blades S are alternately arranged, the total number of blades is an even number. Vibration easily occurs due to interference with the.

As a countermeasure against such a problem, for example, as seen in Patent Document 1 and Patent Document 2, there is a technique in which a plurality of short blades are arranged between the long blades without limiting the number of long blades. Proposed.
Japanese Patent Laid-Open No. 7-279808 JP 2000-54944 A

  In the hydraulic machine runner disclosed in Patent Document 1, the short blade is arranged between one long blade and the adjacent long blade itself, which is a pioneer as a splitter runner. This is made from the viewpoint of suppressing vibration caused by the combination of the number of blades of the blades, and the concept of the arrangement position of the short blades does not necessarily coincide with the appropriate position contributing to the hydraulic efficiency improvement measure.

  In addition, Patent Document 2 defines the ratio of the pitch of the short blades to the pitch between the long blades from the viewpoint of suppressing cavitation. The guarantee of improvement is unknown.

  The present invention has been made in view of such circumstances, and provides a hydraulic machine runner that achieves higher hydraulic efficiency while suppressing vibrations generated from a combination of the number of guide vanes and runner blades. The purpose is to do.

  In order to achieve the above-mentioned object, the runner of the hydraulic machine according to the present invention divides the wings of the runner into long wings and short wings, and divides the long wings and short wings along the circumferential direction of the runner. In the runner of the disposed hydraulic machine, two short blades are disposed between the one long blade and the adjacent long blade.

  In order to achieve the above-mentioned object, the runner of the hydraulic machine according to the present invention divides the wings of the runner into long wings and short wings, and the divided long wings and short wings are arranged in the circumferential direction of the runner. In a hydraulic machine runner arranged along the two long blades arranged between the one long blade and the adjacent long blade, and along the circumferential direction of the runner, The total number of all blades is set to nine.

  In the hydraulic machine runner according to the present invention, two short blades are arranged between one long blade and another adjacent long blade, the blade load of the short blade is increased, and the flow of power water is good. Since it was set as the structure made to become, higher hydraulic efficiency can be acquired, suppressing the vibration which generate | occur | produces during driving | operation.

  Further, according to the hydraulic machine employing the runner of the present invention, vibration due to the water flow flowing in the runner is reduced and cavitation is eliminated, so that highly efficient operation is possible, and as a result, a hydroelectric power plant with high power generation efficiency is achieved. Construction becomes possible.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a hydraulic machine runner according to the invention will be described with reference to the drawings and the reference numerals attached to the drawings.

[First Embodiment]
FIG. 1 is a conceptual diagram showing a first embodiment of a runner of a hydraulic machine according to the present invention.

The runner 10 of the hydraulic machine according to the present embodiment has two short blades S ₁ and S ₂ arranged between _one long blade L ₁ and the other adjacent long blade L _2. A blade group in which _two short blades S ₁ and S ₂ are combined between the long blades L and L is arranged along the circumferential direction of the runner.

In FIG. 1, for the sake of convenience, in order to avoid overlapping description of each blade, the blade group is limited to one pitch with the long blades L ₁ and L ₂ .

The total number of blades Zr of the long blades L ₁ and L ₂ and the short blades S ₁ and S ₂ as the blade group arranged along the circumferential direction of the runner is set to Zr = 9.

Further, the short blades S ₁ and S ₂ sandwiched between the long blades L ₁ and L ₂ are arranged so that the camber lines CLS ₁ and CLS ₂ are adjacent to each other in the radial direction position of the short blade outlet end L ₁ and L 2. _{The two} camber lines CLL are divided into three equal parts, and are installed at positions rotated by unequal pitch angles θ ₁ and θ _{2 in the} direction opposite to the water turbine driving rotation direction, respectively.

Here, the unequal pitch angles θ ₁ and θ ₂ satisfy the relationship of θ ₁ > θ ₂ , specifically, θ ₁ = 2 × θ ₂ .

Further, the blade thicknesses tS ₁ , tS ₂ of the short blades S ₁ , S ₂ are thinner than the blade thicknesses tL ₁ , tL ₂ of the long blades L ₁ , L _2. 60%.

Although the short blades S ₁ and S _{2 according} to the present embodiment handle the same profile (blade shape) for convenience, different profiles may be used.

Incidentally, in general, the splitter runner, when water turbine operation, short blade S _1, the blade loading of the S ₂ (work wings) of the long blade L _1, lower than the blade loading of L _2, does not contribute to the increase in blade loading Previous studies have shown that blade load (blade work) increases slightly when the short blades S ₁ and S ₂ are placed in the direction opposite to the runner rotation direction during turbine operation. .

  Let us consider this phenomenon in more detail now.

FIG. 2 is an example of _two short blades S ₁ and S ₂ having the same profile arranged at a position equally dividing the long blade L ₁ and the adjacent long blade L ₂ into three parts. It is a pressure distribution diagram which shows the blade surface pressure with respect to the distance from the waterwheel inlet-end side along.

In this diagram, the solid lines are the long wings L ₁ and L ₂ , the broken lines are the short wings S ₁ located on the rotation direction side during the water turbine operation, and the dash-dot lines are the short wings S located on the opposite side to the rotation direction during the water wheel operation. Each of the _two characteristics. The upper three lines indicate the pressure on the pressure surface side, and the lower three lines indicate the pressure on the blade suction surface side.

  The difference between the pressure on the blade pressure surface side and the pressure on the blade suction surface side is the blade load (blade work).

A pressure distribution diagram shown in FIG. 2, the splitter runner with a short blade S _1, S ₂ of two identical profiles, most small blade loading BLS ₁ short blades S _1, even when subjected to optimum design, It turned out that it is only about 40% compared with the blade load BLL of the long blades L ₁ and L ₂ .

In the pressure distribution diagram shown in FIG. 2, this means that the bending stress acting on the short blades S ₁ and S ₂ is low, and the blade thickness can be reduced according to the size of the blade load. Is shown.

  If the blade thickness is reduced, the flow area of the power water increases, the flow velocity decreases, and friction loss is reduced based on this, leading to weight reduction and increasing the natural frequency of the entire runner. A higher margin for vibration at the rated point can be ensured.

Moreover, it is the inflection area | region AR from FIG. 2 that a blade | wing load becomes small. This inflection region AR is in the vicinity of the turbine turbine inlet end and is associated with the local pressure drop on the blade pressure surface side. Cavitation is coupled with the increase in blade load on the short blades S ₁ and S _2. It is also effective in suppressing generation.

FIG. 3 is a pressure drop diagram showing a change in local pressure drop near the inlet end with respect to the unequal pitch angles θ ₁ and θ ₂ of the short blades S ₁ and S ₂ .

From FIG. 3, as the unequal pitch angles θ ₁ , θ ₂ become larger, the pressure drop of the short blades S ₁ , S ₂ is recovered, and in the short blade S ₁ , the unequal pitch angles θ ₁ are θ ₁ = Up to 720 × {(1 / Zr) − (1 / Zr + 3)}, and with the short blade S ₂ , the unequal pitch angle θ ₂ is θ ₂ = 360 × {(1 / Zr) − (1 / Zr + 3) }, It was found that pressure was recovered.

From the above equation, when the number Zr of the long blades is Zr = 9 and the unequal pitch angles θ ₁ and θ ₂ of the short blades S ₁ and S ₂ are obtained, θ ₁ = 20 °, θ ₂ = 10 It becomes °.

Further, from FIG. 3, in order to make the pressures of the short blades S ₁ and S ₂ to be equal to each other and to have more appropriate characteristics as the whole hydraulic machine, the unequal pitch angle θ ₁ of the short blade S ₁ is set to the short blade. it has been found that it is necessary to be larger than the unequal pitch angle theta ₂ of S _2.

Thus, in the present embodiment, since the two short blades S ₁ and S ₂ are arranged between _one long blade L ₁ and the adjacent long blade L ₂ , an even number of guide vanes and Even when combined, the vibration generated by the interference of the moving blades and stationary blades resulting from the combination of the number of sheets can be reduced, the natural frequency of the runner itself can be increased, and the hydraulic machine with excellent hydraulic performance A runner can be realized.

[Second Embodiment]
FIG. 4 is a conceptual diagram showing a second embodiment of the runner of the hydraulic machine according to the present invention.

  In addition, the same code | symbol is attached | subjected to the component same as the component of 1st Embodiment, and duplication description is abbreviate | omitted.

In the runner of the hydraulic machine according to the present embodiment, two short blades S ₁ and S ₂ are disposed between _one long blade L ₁ and the other adjacent long blade L _2, and the long blades L ₁ and L ₂ are arranged. _{The two} blades S ₁ and S ₂ have different profiles, and the long blades L ₁ and L _{2 have} a camber line CLL inlet end angle βL, and the short blades are located on the rotation direction side during water turbine operation. when .beta.S 2 the inlet end angle of camber lines CLS ₁ in S _1, the inlet end angle of camber lines CLS ₂ in short blade S ₂ located in the direction opposite to the rotation direction side when the water wheel operation and Betaesu2, each inlet end The angles βL, βS ₁ , βS ₂ are
[Equation 1]
βL> βS ₂ > βS ₁
This satisfies the relational expression.

In the present embodiment, the long blades L ₁ and L ₂ and the short blades S ₁ and S ₂ have their inlet ends arranged at an equal pitch P. However, the long blades L ₁ and L ₂ and the short blades S ₁ , S ₂ have different inlet end angles, so that the outlet end radial positions of the short blades S ₁ , S ₂ are between the camber lines CLL of the adjacent long blades L ₁ , L ₂ , as in the first embodiment. Are set to positions rotated by unequal pitch angles θ ₁ and θ _{2 in the} direction opposite to the rotation direction during the water turbine operation, respectively, with respect to the two curves ML.

Here, as in the first embodiment, the unequal pitch angles θ ₁ and θ ₂ are set at positions rotated so as to satisfy the relationship θ ₁ = 2 × θ ₂ .

Thus, in this embodiment, since the inlet ends of the long blades L ₁ and L ₂ and the short blades S ₁ and S ₂ are set to the equal pitch P, the guide vanes caused by the pitch imbalance can be obtained. The vibration generated based on the interference between the moving blade and the stationary blade can be suppressed.

On the other hand, inlet cavitation during water turbine operation occurs when the difference between the inflow angle of the power water to the blade and the blade inlet angle increases. In particular, since the blade load of the short blades S ₁ and S ₂ is smaller than the blade load of the long blades L and L, the splitter runner reduces the circulation around the blades and acts on the relative inflow flow to the blades. The deflection force to be reduced. For this reason, the power water flows into the wing at a smaller flow angle.

  Therefore, when the blade load is small, a local pressure drop tends to occur on the blade pressure surface side, and more cavitation is generated on the blade inlet end side.

In order to suppress the generation of cavitation, it is necessary to increase the blade load and match the inlet angle of the blade with the flow angle of the power water. When the long blade L ₁ and the two short blades S ₁ and S ₂ arranged between the adjacent long blades L have the same blade inlet angle, the cavitation is caused by the long blades L ₁ and L ₂ and the short blade S. _2, the characteristics is improved in the order of short blade _{S 1.}

  On the other hand, the cavitation characteristics of the hydraulic machine as a whole are limited based on the wings with the worst characteristics. Therefore, it is desirable that all wings have the same cavitation characteristics. It is not practical to improve just one wing.

Thus, the inlet angle .beta.L the Tsubasa Cho _L 1 _{(L 2),} the inlet angle .beta.S ₂ short blades _{S 2,} in relation to the inlet angle .beta.S ₁ short blades _{S 1,} if satisfied βL> βS _2> βS _2, There is no difference in cavitation between the blades L, S ₂ and S ₁ , and the characteristics of the hydraulic machine as a whole can be improved more favorably.

[Third Embodiment]
FIG. 5 is a conceptual diagram showing a third embodiment of the runner of the hydraulic machine according to the present invention.

  In addition, the same code | symbol is attached | subjected to the component same as the component of 1st Embodiment, and duplication description is abbreviate | omitted.

In the runner of the hydraulic machine according to the present embodiment, two short blades S ₁ and S ₂ are disposed between _one long blade L ₁ and the other adjacent long blade L _2, and the long blades L ₁ and L ₂ are arranged. ₂ and short blade _S 1 of two, with made different profiles and _{S 2,} the length LS ₂ short blades _{S 2} and shorter than the length LS ₁ of the short wing _{S 1,} also short blade S It compared the thickness of the _second outlet end to long blade L _{1 (L 2)} and short wings S thickness of ₁ the outlet end is obtained by thinning.

Both the short wings S ₁ and S ₂ overlap the camber lines CLS ₁ and CLS ₂ on the two curves ML that divide the camber lines CLL between the adjacent long wings L ₁ and L ₂ into three equal parts. This may be used as the unequal bitch angle described in the first magazine example or the second embodiment.

According to previous studies, the blade loading of the short blade _S 1, _{S 2} is dependent short blade _S 1, respective lengths _CLS 1 of _{S 2,} CLS ₂ to greater, short blade _S 1, _{S 2} It is said that the blade load will be reduced if becomes shorter.

Considering now two short blades S ₁ and S ₂ of the same length, the blade load BLS ₁ of the short blade S ₁ located on the rotational direction side during the water turbine operation is the pressure distribution line of FIG. as shown, small compared to the blade loading BLL of blade loading BLS ₂ and long blades L ₁ of the short wing S ₂ located in the direction opposite to the rotation direction side when water turbine operation _{(L 2).}

From such an event, the short blade S ₂ can reduce the margin of the cavitation characteristics and shorten the blade length until the blade load becomes the same as that of the short blade S ₁ . Shorter blades reduce the wetted area of the blade surface, reduce friction loss, and increase the gap between the blades near the outlet of the short blade, further reducing man-hours for runner manufacturing and maintenance. be able to. However, if the short blade S ₂ is shortened beyond a certain limit, the blade load BLS ₂ is smaller than the blade load of the short blade S ₁ , the cavitation characteristics of the short blade S ₂ are deteriorated, and the entire hydraulic machine Even worse.

Figure 7 is a blade loading diagram illustrating a blade length ratio of the short blade S ₂ for short blade S ₁ and the difference in blade loading of both short blades S _1, S _2.

If short blade _{S 2} is 60% or more of the short blade _{S 1,} without the blade loading is reversed, 60% of the blade length LS ₁ of the short blades _{S 2} blade length LS ₂ short wing _{S 1} It can be selected within a range of ˜100%, and a highly efficient runner can be realized while suppressing cavitation.

Next, the thickness of the outlet ends of the short blades S ₁ and S ₂ will be considered.

When short blade _S 1, _S each camber line _CLS 1 of _2, CLS ₂ power water along the flow, the inlet and outlet ends of the short blade _S 1, _{S 2} is affected by thinner stagnation point and Wake Becomes smaller and loss is reduced.

For this reason, in this embodiment, the exit ends of the short blades S ₁ and S ₂ are thinned to reduce loss.

  On the other hand, when the pump is operating, the relative inflow angle of the power water flowing into the blades varies depending on the operating point, and cavitation is generated when the difference between the inflow angle of the power water on the pump inlet side and the blade angle becomes large. For this reason, the runner blades are usually designed to increase the thickness of the blades on the pump inlet side so as not to be affected by changes in the inflow angle of the power water.

However, in the splitter runner, the short blades S ₁ and S ₂ are positioned on the downstream side of the rotation of the long blades L ₁ and L _2. The change of the inflow angle of the power water due to the change of the point is small, and there is little need to worry about the generation of cavitation.

  According to the hydraulic machine adopting the first to third embodiments described above, vibration due to the water flow flowing in the runner is reduced and cavitation is not generated, so that highly efficient operation is possible, and thus power generation efficiency is improved. Can be performed.

The conceptual diagram which shows 1st Embodiment of the runner of the hydraulic machine which concerns on this invention. The blade surface pressure distribution diagram which compares the blade surface pressure distribution of the long blade and the short blade in 1st Embodiment of the runner of the hydraulic machine which concerns on this invention. The pressure drop diagram which shows the change of the pressure drop in the inlet end of the short blade in 1st Embodiment of the runner of the hydraulic machine which concerns on this invention. The conceptual diagram which shows 2nd Embodiment of the runner of the hydraulic machine which concerns on this invention. The conceptual diagram which shows 3rd Embodiment of the runner of the hydraulic machine which concerns on this invention. The blade surface pressure distribution diagram which compares the blade surface pressure distribution of the long blade and the short blade in 3rd Embodiment of the runner of the hydraulic machine which concerns on this invention. The blade load diagram which shows the difference with the blade load of two short blades in 3rd Embodiment of the runner of the hydraulic machine which concerns on this invention. The partially cutaway sectional view showing the runner of the conventional hydraulic machine. The conceptual diagram which shows the runner of the conventional hydraulic machine which arrange | positions the blade | wing of the same shape along the circumferential direction of a runner. The conceptual diagram which shows the conventional splitter runner which arrange | positions a long blade and a short blade alternately along the circumferential direction of a runner.

Explanation of symbols

1 Runner 2 Rotating Shaft 3 Blade 4 Inlet Side 5 Outlet Side 10 Runner

Claims (11)

In the runner of a hydraulic machine in which the wings of the runner are divided into long wings and short wings, and the divided long wings and short wings are arranged along the circumferential direction of the runner, the one long wing and the adjacent long wing A hydraulic machine runner characterized in that two short blades are arranged between the two. In the runner of a hydraulic machine in which the wings of the runner are divided into long wings and short wings, and the divided long wings and short wings are arranged along the circumferential direction of the runner, the one long wing and the adjacent long wing A hydraulic machine runner characterized in that two short blades are arranged between the two blades, and the total number of long blades and short blades arranged along the circumferential direction of the runner is set to nine. The two short blades have a camber line in the radial direction position of the short blade outlet end in a direction opposite to the rotation direction during turbine operation with respect to two curves that divide the camber line of the adjacent long blade into three equal parts. 3. The hydraulic machine runner according to claim 1, wherein the runner is disposed at a position rotated by unequal pitch angles [theta] ₁ , [theta] ₂ . The unequal pitch angles θ ₁ and θ ₂ of the _two short blades are located in the rotation direction of the runner during the water turbine operation, with the total number of long blades and short blades being Zr at the radial position of the turbine exit end. The angle formed by the exit end of the short blade on the side and the curve dividing the camber line between adjacent long blades into three equal parts is the unequal pitch angle θ ₁ and is located in the direction opposite to the runner rotation direction during water turbine operation When the angle formed between the exit end of the short blade on the side and the curve dividing the camber line of the adjacent long blade into three equal parts is an unequal pitch angle θ ₂

The runner for a hydraulic machine according to claim 3, wherein the runner is set within the range. The hydraulic machine runner according to claim 4, wherein the unequal pitch angles θ ₁ and θ ₂ of the _two short blades satisfy a relational expression of θ ₁ > θ ₂ . The hydraulic machine runner according to claim 4, wherein the unequal pitch angles θ ₁ and θ ₂ of the _two short blades satisfy a relational expression of θ ₁ = 2 × θ ₂ . The two short blades have a camber line in the radial direction of the short blade outlet end in a direction opposite to the rotation direction during turbine operation with respect to two curves that divide the camber line of the adjacent long blade into three equal parts. While being arranged at a position rotated by unequal pitch angles θ ₁ and θ ₂ , the inlet end angle in the camber line of the long blades is βL, and of the two short blades, on the rotation direction side during water turbine operation When the inlet end angle of the camber line in the short blade located is βS ₁ and the inlet end angle of the camber line in the short blade located in the direction opposite to the rotation direction during the water turbine operation is βS ₂ , each inlet end angle is
[Equation 2]
βL> βS ₂ > βS ₁
3. The hydraulic machine runner according to claim 1, wherein the relational expression is satisfied, and the inlet ends of the blades are arranged at an equal pitch. 4. The length of the camber line of the short blade located on the side opposite to the rotation direction of the runner during the water turbine operation is LS _2, and the length of the camber line of the short blade located on the side opposite to the water turbine operation is LS. ₁ , the length ratio LS ₂ / LS ₁ between the _two short wing camber lines is
[Equation 3]
0.6 ≦ LS2 / LS1 ≦ 1.0
The runner for a hydraulic machine according to claim 1 or 2, wherein the runner is set within a range of. Of the blade thicknesses at the intermediate position between the inlet end and the outlet end on the two short blade camber lines, the smaller blade thickness is ts, and the inlet end and outlet end on the long blade camber line are When the blade thickness at the intermediate position is tL, the ratio ts / tL between the blade thickness ts of the short blade and the blade thickness tL of the long blade is
[Equation 4]
0.4 ≦ ts / tL ≦ 1.0
The runner for a hydraulic machine according to claim 1 or 2, wherein the runner is set within a range of. The runner of a hydraulic machine according to claim 1 or 2, wherein the thickness of the two turbine blade outlet ends of the short blades is set smaller than the thickness of the turbine blade outlet ends of the long blades. The hydraulic machine provided with the runner of the hydraulic machine of Claim 1 thru | or 10.

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