CN103422912B

CN103422912B - Turbine with moving blades with pits at blade tops

Info

Publication number: CN103422912B
Application number: CN201310385138.3A
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: 2015-04-08
Anticipated expiration: 2033-08-29
Also published as: CN103422912A

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 comprising the moving vane of the porose nest of leaf heading tape

Technical field

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

Background technique

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

In order to reduce the negative effect that blade tip clearance gas leakage brings, current turbine adopts the methods such as movable vane leaf heading tape is preced with, type is repaiied on movable vane leaf top to suppress the generation of tip leakage flow mostly, although these methods can reduce clearance leakage loss to a certain extent, improve turbine channel internal flow, but its action effect is different because of the turbine blade of application-specific, such as high and low pressure turbine blade, sub-, transonic speed gap stream, long and short blade etc., and under variable parameter operation condition, these methods are not good to the control effects of clearance leakage; In addition, although these methods can reduce leaf top surface mean heat transfer coefficient and heat load to a certain extent, add the heat-transfer coefficient of leaf top regional area, add the nonuniformity of leaf top heat transfer.Due to the deficiencies in the prior art, people wish a kind of turbine blade that can effectively reduce the negative effect that petiolarea tip leakage flow brings of improvement.

Summary of the invention

The object of the present invention is to provide and can reduce gap leakage flow rate, and strengthen angle of attack variation applicability, effectively can reduce again the heat load of leaf top surface, and reduce a kind of turbine comprising 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 comprising the moving vane of the porose nest of leaf heading tape of the present invention, comprise casing, wheel hub, wheel hub is evenly provided 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 providing holes nest of moving vane.

The present invention can also comprise:

The shape of 1, described hole nest is honeycomb or ball-and-socket.

2, when 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 hole nest is 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, on clearance leakage of blade tip flow direction, a hole nest is had at least.

Advantage of the present invention is: the present invention, from turbine blade petiolarea tip clearance leakage flow mechanism, uses for reference the feature that sealing configuration can increase flow resistance, arranges a series of holes nest, realize the Passive Control of blade end district tip leakage flow at leaf top end; Meanwhile, the reduction (leakage current be subject to intercept layer by layer caused) of the clearance leakage of blade tip airspeed jet effect that also inhibits hot combustion gas in gap to be conducted heat uneven impact on leaf top; In addition, when considering that gas turbine runs under variable working condition condition, clearance leakage of blade tip flow direction can change, and therefore requires that 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 decreases gap leakage flow rate on the one hand, improves turbine efficiency, also has good angle of attack variation applicability simultaneously; Also decrease the heat load of leaf top surface and the heat-transfer coefficient of leaf top regional area on the other hand simultaneously, and then reduce the nonuniformity of leaf top heat transfer, thus improve leaf longevity; Further, the present invention can alleviate vane tip petiolarea weight, and minimizing blade rubs rigidity during casing, thus improves the reliability of gas turbine operation.

Accompanying drawing explanation

Fig. 1 is meridian view of the present invention;

The structural representation of Fig. 2 a to be leaf top be honeycomb shape, the structural representation of Fig. 2 b to be leaf top be ball-and-socket shape;

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

Fig. 4 is the B-B sectional view of Fig. 3 a.

Embodiment

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

As shown in Figure 1, the present invention is made up 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, forms gap between casing 2 and leaf top end 7.

Mode of execution 1:

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

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

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

It should be noted that also can combine the active control measures such as leaf top spray gas at the turbine blade tip of the porose nest of leaf heading tape of the present invention leaks and the heat transfer of leaf top with further control gap.

Mode of execution 2:

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

Claims

1. comprise a turbine for the moving vane of the porose nest of leaf heading tape, comprise casing, wheel hub, wheel hub is evenly provided 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 providing holes nest of moving vane;

The shape of described hole nest is honeycomb or ball-and-socket;

When 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;

When hole nest is 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;

Clearance leakage of blade tip flow direction has at least a hole nest.