CN103422912A

CN103422912A - Turbine with moving blades with pits at blade tops

Info

Publication number: CN103422912A
Application number: CN2013103851383A
Authority: CN
Inventors: 高杰; 郑群; 姜斌; 张正一
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2013-08-29
Filing date: 2013-08-29
Publication date: 2013-12-04
Anticipated expiration: 2033-08-29
Also published as: CN103422912B

Abstract

The invention aims at providing a turbine with moving blades with pits at blade tops. The turbine comprises a case and a hub. The moving blades are uniformly installed along the circumferential direction of the hub. The hub and the moving blades are installed in the case. The pits are arranged at the blade tops of the moving blades. By designing the turbine blades with the pits at the blade tops, on one hand, the clearance leakage amount is reduced, the turbine efficiency is improved and the attack angle change applicability is good; on the other hand, the heat load on the surfaces of the blade tops and the heat transfer coefficient of local areas of the blade tops are reduced, the non-uniform extent of heat transfer of the blade tops is reduced and the service life of the blades is improved; the weight of the ends of the blade tops can be reduced, the rigidity produced when the blades rub the case is reduced and the working reliability of the gas turbine is improved.

Description

A kind of turbine that comprises the moving vane of the porose nest of leaf heading tape

Technical field

What the present invention relates to is a kind of turbine, specifically the turbine of aeroengine and gas turbine.

Background technique

Turbine blade tip clearance leakage flow is one of flow phenomenon the most general in the turbomachine rotor, leaf top surface lateral pressure difference causes the leakage flow from the pressure side to the suction surface, when leakage flow flows out from suction surface and the passage main flow interact to form leakage vortex, leakage flow and leakage vortex have very important impact to the non-stationarity in turbine pneumatic loss, heat transfer and flow field, downstream: at first, turbine leaf top leakage flow produces very large aerodynamic loss, in shrouded turbines not, leaf top leakage loss is the highest can account for respectively moving blade loss 45% and level loss 30%; Secondly, leakage flow and leakage vortex have larger impact to the non-stationarity in flow field, downstream, and it can cause blade structure vibration and noise, reduces reliability, and reduce engine life; Finally, leakage flow and leakage vortex have increased near the complexity of conducting heat turbine leaf top, in high-pressure turbine, high-temperature fuel gas is when flowing through gap, airspeed improves rapidly the jet effect caused and causes leaf to take one's place hot coefficient greatly improving, and leakage flow experiences separation, the complex flow process such as attached again in gap, makes leaf take one's place heat very complicated, in gap, under the impact of heat load, turbine blade is easy to occur ablation and fracture.

The negative effect brought in order to reduce the blade tip clearance gas leakage, turbine adopts the generation that the method inhibition tip leakage flows such as type are repaiied on movable vane leaf heading tape hat, movable vane leaf top mostly at present, although these methods can reduce the clearance leakage loss to a certain extent, improve the turbine channel internal flow, but its action effect is different because of the turbine blade of application-specific, such as the high and low pressure turbine blade, inferior, transonic speed gap stream, long and short blade etc., and under the variable parameter operation condition, the control poor effect of these methods to clearance leakage; In addition, although these methods can reduce leaf top surface mean heat transfer coefficient and heat load to a certain extent, increase the heat-transfer coefficient of leaf top regional area, increased the nonuniformity of conducting heat in the leaf top.Due to the deficiencies in the prior art, people wish a kind of improved turbine blade that can effectively reduce the negative effect that the petiolarea tip leakage flow brings.

Summary of the invention

The object of the present invention is to provide and can reduce gap leakage flow rate, and strengthen the angle of attack variation applicability, can effectively reduce the heat load of leaf top surface again, and reduce a kind of turbine that comprises the moving vane of the porose nest of leaf heading tape of the nonuniformity of leaf top heat transfer.

The object of the present invention is achieved like this:

A kind of turbine that comprises the moving vane of the porose nest of leaf heading tape of the present invention, comprise casing, wheel hub, and wheel hub evenly is equipped with moving vane along its circumferencial direction, and wheel hub and moving vane are installed in casing, it is characterized in that: the leaf top of moving vane arranges the hole nest.

The present invention can also comprise:

1, described hole nest is shaped as honeycomb or ball-and-socket.

2, when the hole nest is honeycomb shape, the core lattice size d of honeycomb _CellWith leaf top maximum ga(u)ge d _maxRatio be 0.1～0.5, honeycomb degree of depth h _CellWith leaf top maximum ga(u)ge d _maxRatio be 0.1～0.5, honeycomb degree of depth h _CellBe not less than honeycomb core lattice size d _Cell.

3, when the hole nest is the ball-and-socket shape, the diameter d of ball-and-socket _BallWith leaf top maximum ga(u)ge d _maxRatio be 0.1～0.5.

4, has a hole nest at least on blade tip clearance leakage flow direction.

Advantage of the present invention is: the present invention, from turbine blade petiolarea tip clearance leakage flow mechanism, uses for reference the characteristics that sealing configuration can increase flow resistance, at the leaf top end, a series of holes nest is set, and realizes the Passive Control of the interval gap leakage flow of blade end; Simultaneously, the jet effect that the reduction of blade tip clearance leakage current speed (leakage current intercepted layer by layer due to) has also suppressed hot combustion gas in the gap is on the inhomogeneous impact of conducting heat of leaf top; In addition, consider that, when gas turbine moves under the variable working condition condition, blade tip clearance leakage flow direction can change, therefore requiring leaf apical pore nest structure should be some sealing configurations very strong to leakage current direction adaptability, such as honeycomb, ball-and-socket etc.

The turbine blade of the porose nest of leaf heading tape of the present invention's design has reduced gap leakage flow rate on the one hand, has improved turbine efficiency, also has good angle of attack variation applicability simultaneously; Also reduce on the other hand the heat load of leaf top surface and the heat-transfer coefficient of leaf top regional area simultaneously, and then reduced the nonuniformity of conducting heat in the leaf top, thereby improved leaf longevity; And the present invention can alleviate vane tip petiolarea weight, the rigidity when minimizing blade rubs casing, thereby the reliability of raising gas turbine operation.

The accompanying drawing explanation

Fig. 1 is meridian view of the present invention;

Fig. 2 a is that the leaf top is the structural representation of honeycomb shape, and Fig. 2 b is that the leaf top is the structural representation of ball-and-socket shape;

The A that Fig. 3 a is Fig. 2 a is to view, and Fig. 3 b is the cellular structure schematic diagram, and Fig. 3 c is ball-and-socket shape leaf roof construction schematic diagram, and Fig. 3 d is the socket arrangement schematic diagram;

The B-B sectional view that Fig. 4 is Fig. 3 a.

Embodiment

Below in conjunction with accompanying drawing, for example the present invention is described in more detail:

As shown in Figure 1, the present invention is comprised of wheel hub 1, casing 2 and moving vane 3, and wherein moving vane is generated by the radially long-pending superimposing thread of primitive blade profile 4, comprises blade inlet edge line 5, trailing edge line 6 and leaf top end 7, between casing 2 and leaf top end 7, forms gap.

Mode of execution 1:

In conjunction with Fig. 2～3, manufacture the turbine blade of the porose nest of leaf heading tape of the present invention, at first adopt traditional design method to design gas-turbine blade.For the situations such as given blade loads distribution and operating conditions scope, the concrete structure parameter of leaf top honeycomb (honeycomb core lattice size d _CellWith honeycomb degree of depth h _Cell) can obtain by means of existing computational fluid dynamics software simulation or test, then, at the leaf top end, process the cellular structure as shown in Fig. 3 (a).The ratio of the core lattice size of honeycomb and leaf top maximum ga(u)ge is 0.1～0.5, and the ratio of the honeycomb degree of depth and leaf top maximum ga(u)ge is 0.1～0.5, and simultaneously, the honeycomb degree of depth is not less than honeycomb core lattice size.It will be appreciated by those skilled in the art that, turbine blade for application-specific, the target of choosing of the cellular structure parameter on leaf top is to increase as far as possible the leakage flow resistance, and will guarantee off design performance the best, takes into account factors such as considering structural strength, difficulty of processing, cost simultaneously.

Leaf apical pore nest structure of the present invention is carried out processing on the movable vane basis, can take moving vane is placed in to magnetic field, and the mode by electron beam process obtains, and also can adopt whole rotor blade cast form mode is obtained.

As shown in Figure 4, in the flow field, zone, impeller clearance of the porose nest of leaf heading tape, when leakage flow is flowed through leaf top " porous " end face, in the nest of hole, vortex motion and leakage flow interact, and by the kinetic transformation of leakage flow, are heat energy, and the leak fluid energy is dissipated; Simultaneously, at Ye Ding " porous " end face, also transient state exists the Complex Flows such as fluid radially flows to, outflow, also can produce inhibition to leak fluid, thereby can effectively reduce blade tip clearance, leaks.

It should be noted that ACTIVE CONTROL measures such as also can combining leaf top spray gas at the turbine blade tip of the porose nest of leaf heading tape of the present invention is leaked with further control gap and conduct heat in the leaf top.

Mode of execution 2:

As shown in Fig. 3 c, Fig. 3 d, leaf apical pore nest is shaped as ball-and-socket, and the ratio of the diameter of ball-and-socket and leaf top maximum ga(u)ge is 0.1～0.5, and other are with mode of execution 1.

Claims

1. a turbine that comprises the moving vane of the porose nest of leaf heading tape, comprise casing, wheel hub, and wheel hub evenly is equipped with moving vane along its circumferencial direction, and wheel hub and moving vane are installed in casing, it is characterized in that: the leaf top of moving vane arranges the hole nest.

2. a kind of turbine that comprises the moving vane of the porose nest of leaf heading tape according to claim 1 is characterized in that: described hole nest be shaped as honeycomb or ball-and-socket.

3. a kind of turbine that comprises the moving vane of the porose nest of leaf heading tape according to claim 2 is characterized in that: when the hole nest is honeycomb shape, and the core lattice size d of honeycomb _CellWith leaf top maximum ga(u)ge d _maxRatio be 0.1～0.5, honeycomb degree of depth h _CellWith leaf top maximum ga(u)ge d _maxRatio be 0.1～0.5, honeycomb degree of depth h _CellBe not less than honeycomb core lattice size d _Cell.

4. a kind of turbine that comprises the moving vane of the porose nest of leaf heading tape according to claim 2 is characterized in that: when the hole nest is the ball-and-socket shape, and the diameter d of ball-and-socket _BallWith leaf top maximum ga(u)ge d _maxRatio be 0.1～0.5.

5. according to the arbitrary described a kind of turbine that comprises the moving vane of the porose nest of leaf heading tape of claim 1-4, it is characterized in that: have a hole nest at least on blade tip clearance leakage flow direction.