CN2665392Y

CN2665392Y - Mixed flow turbine rotary wheel

Info

Publication number: CN2665392Y
Application number: CNU032064039U
Authority: CN
Inventors: 张梁
Original assignee: BEIJING HONGSHU GUANJIE TECHNOLOGY Co Ltd
Current assignee: BEIJING HONGSHU GUANJIE TECHNOLOGY Co Ltd
Priority date: 2003-07-25
Filing date: 2003-07-25
Publication date: 2004-12-22
Anticipated expiration: 2013-07-25

Abstract

The utility model relates to a mixed-flow turbine runner, belonging to the hydro-electric installation technology. The turbine runner comprises a runner crown, runner blades and a runner band; wherein, the blade close to the crown protrudes outward; the obliquity of the blade is negative; the obliquity is defined as the angle formed by the inlet edge of the blade and the parallel line of a rotation shaft, the parallel line is the intersection of the inlet edge and the crown. When the turbine runner designed in the utility model is in operation, the water flow flows more smoothly in the flow passage between every two blades, the off-design operation efficiency is then improved. The water flow in the runner becomes evener, the load distribution also becomes evener, the load concentration on the blade close to the band is reduced, and the excess flow and the cavitation property of the runner can be easily improved. The outlet edge of the blade has a shorter semi-diameter, playing a steady role when being loaded partly and easing the pressure fluctuation of the water flow. The force stressed on the blade becomes more rational, the concentrated stress at the root of the blade is reduced, therefore, the runner is provided with good stress endurance.

Description

Francis turbine runner

Technical field

The utility model relates to a kind of francis turbine runner, belongs to the hydro-electric power generating equipment technical field.

Background technique

Hydroelectric power is meant that current pass through water turbine, and potential energy of self and kinetic energy are converted into rotating mechanical energy, drives the generator rotation, thereby water can be changed into electric energy.Wherein the runner of water turbine is the critical piece of transformation of energy, and francis turbine runner is present most widely used rotary wheel of water turbine.As shown below, current radial inflow runner bucket promotes the runner acting, and changes flow direction, flows out vertically, so be called the francis turbine runner blade.Be suitable for head from 50～700 meters, exert oneself from several ten thousand kilowatts to millions of kilowatts, the separate unit of Three Gorges water wheels unit is exerted oneself and has been surpassed 7,000,000 kilowatts.

The structure of tradition francis turbine runner blade as shown in Figure 1, among Fig. 1, the 1st, crown, the 2nd, blade, the 3rd, following ring, the 4th, blade crown limit, the 5th, blade outlet, the 6th, blade water inlet limit, the 7th, blade descends to encircle the limit, α is a blade tilt.The characteristics of this tradition francis turbine runner are:

1, the runner bucket inclination angle be α just, the inclination alpha of runner bucket is definition like this: the parallel lines of doing rotating shaft with the intersection point of water inlet limit and runner crown, then blade water inlet limit is the runner bucket inclination angle with the formed angle of this parallel lines, on the right of the deflection parallel lines for just.

2, the blade shape of conventional rotor in the whole blade zone is concave shape.

3, the conventional rotor blade goes out waterside 5 on meridian plane.

Because the said structure aspect, there is following problem in conventional rotor: there is crossing current in the working surface at runner bucket; There is local vortex on the runner crown 1; Blade exists stress to concentrate with following ring top attachment place.Therefore in service in the power station, crackle often appears in the blade of conventional rotor, even fracture, has caused various stability problems.Along with head and improving constantly of exerting oneself, the problem of stable aspect constantly occurs.

Summary of the invention

The purpose of this utility model is a kind of francis turbine runner of design, change the structure of existing rotary wheel of water turbine, with the crossing current of elimination runner bucket working surface and the local vortex of crown, improve the stress of runner bucket root and concentrate, improve the operation stability of water turbine.

The francis turbine runner of the utility model design, comprise crown, blade and following ring, the outside protruding drum of nearly crown part of blade, the runner bucket inclination angle is for negative, the inclination angle is defined as: make the parallel lines of rotating shaft with the intersection point of water inlet limit and runner crown, blade intake limit and the formed angle of this parallel lines.

The blade tilt of above-mentioned rotary wheel of water turbine can be spent 0 between-10 degree.

The francis turbine runner of the utility model design, its structural feature is: crown is shaped as the S type, and the blade import has " negative incidence ", and wing near the crown place simultaneously is negative cruvature.For adapting to the requirement of transformation of energy and exit condition, blade outlet is not on axial plane, but a space curve.The above characteristics of S type blade make it show good hydraulic and structural behaviour, and its advantage applies is in following several respects:

1, mobile in the vane channel is tending towards smooth and easy, eliminated positive common " crossing current " phenomenon of traditional blades, helps improving the operational efficiency of water turbine off-design behaviour.

2) flowing that runner is interior is more even, and Load distribution is tending towards evenly, has alleviated blade and has closely descended the load at ring place to concentrate, the cavitation performance that helps improving the inflow-rate of water turbine of runner and improve runner.

3, because the blade outlet radius is less, when sub load, produced stabilization, made the pressure pulsation of current more mild.

4, because the special shape of the stressed even more and blade crown on the blade makes the stressed of this blade be tending towards rationally, reduced the stress of root of blade and concentrated, made runner have mechanical characteristic preferably.

In sum, compare with traditional rotary wheel of water turbine, the blade in the rotary wheel of water turbine of the utility model design has many advantages such as high efficiency, high hydraulic performance.Along with the needs of the national economic development, in the construction and the transformation to old-fashioned power station thereof of medium waterpower generator station, the Francis turbine of using this kind employing S type blade rotary wheel will become inevitable trend.

Description of drawings

Fig. 1 is the structural representation of traditional francis turbine runner.

Fig. 2 is the schematic representation of traditional francis turbine runner crown.

Fig. 3 is the worm's eye view of Fig. 1.

Fig. 4 is the structural representation of traditional francis turbine runner blade.

Fig. 5 is the structural representation of the francis turbine runner of the utility model design.

Fig. 6 is the schematic representation of runner crown.

Fig. 7 is the worm's eye view of Fig. 5.

Fig. 8 is the structural representation of the runner bucket of the utility model design.

Among Fig. 1～Fig. 8, the 1st, crown, the 2nd, blade, the 3rd, following ring top, the 4th, blade crown limit, the 5th, blade outlet, the 6th, blade water inlet limit, the 7th, blade is the ring limit down, and α is a blade tilt.

Embodiment

The francis turbine runner of the utility model design, its structure as shown in Figure 5, its worm's eye view comprises crown 1, blade 2 and ring 3 down, the outside protruding drum of nearly crown part of blade 2 as shown in Figure 7.

The structure of runner bucket as shown in Figure 8, among Fig. 8, the 4th, blade crown limit, the 5th, blade outlet, the 6th, blade water inlet limit, the 7th, blade is the ring limit down, α is a blade tilt.The runner bucket inclination alpha is for negative, and the inclination angle is defined as: make the parallel lines of rotating shaft, blade water inlet limit 6 and the formed angle of these parallel lines with the water inlet limit 6 and the intersection point of runner crown.

The blade tilt α of above-mentioned rotary wheel of water turbine can spend 0 between-10 degree.

Francis turbine runner blade of the present utility model, its main design philosophy is to make full use of flow channel space, makes the pressure distribution of blade surface balanced as far as possible.If regard the pressure distribution on the runner bucket as a space problem, so, equalization not only is embodied in from the runner bucket import on this direction of outlet, also should be embodied in simultaneously from crown on the direction of encircling down.S type runner of the present utility model has embodied the idea of this general equilibriumization just.

As seen from Figure 6, the outside protruding drum of nearly crown part of S type runner bucket forms a S type, and this just S type shape that seems distortion has been eliminated the crossing current of face of blade, thereby made the pressure distribution on the blade more even.

When the α angle was positioned at the parallel lines left side, blade tilt was for negative, otherwise for just.To same vane type line and the test result of the different runner in inclination angle shows that the inclination angle can all have important effect to the adjustment of minimum pressure on the adjustment of the distribution of transformation of energy, blade mechanical structure, the blade etc.S type runner bucket inclination angle is for negative, and angular dimension is spent 0 between-10 degree.

As shown in Figure 8, S type blade outlet 5 is a space curve, can adjust accordingly going out the waterside according to designing requirement, makes the blade upward pressure uniform, and the outlet fluidised form is more reasonable.

S type blade shape is become the three dimendional blade shape of distortion by the two dimensional character of traditional blades.Blade is keeping the shape of conventional rotor blade with the near position of following articulating, and crown has become the negative cruvature blade to middle molded lines aerofoil profile partly by traditional positive camber shape, its working surface more resembles the back side of traditional blades, and the back side then resembles the working surface of conventional rotor blade.Blade area increases, reduced thickness.

Claims

1, a kind of francis turbine runner is characterized in that this runner comprises crown, blade and following ring, the outside protruding drum of nearly crown part of blade, and the runner bucket inclination angle is for negative.

2, rotary wheel of water turbine as claimed in claim 1, it is characterized in that wherein said runner bucket inclination angle spend 0-10 the degree between.