CN101173613A - Top clearance leakage restraint structure of centripetal turbine wheel impeller - Google Patents
Top clearance leakage restraint structure of centripetal turbine wheel impeller Download PDFInfo
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- CN101173613A CN101173613A CNA2007100188839A CN200710018883A CN101173613A CN 101173613 A CN101173613 A CN 101173613A CN A2007100188839 A CNA2007100188839 A CN A2007100188839A CN 200710018883 A CN200710018883 A CN 200710018883A CN 101173613 A CN101173613 A CN 101173613A
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- impeller
- centripetal turbine
- leakage
- turbine wheel
- top clearance
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Abstract
The invention discloses a leakage inhabitation structure of top part clearance of the centripetal turbine impeller, which is a sealed structure of a series of grooves in circumferential direction or a series of axial grooves or a series of spiral grooves or a honeycomb. The leakage inhabitation structure is arranged on the inner wall surface of the solid wall enclosing cover of the top part of the impeller, and is positioned in the range of thirty percents to one hundred and twenty percents of the length of the meridional string at the top part of the impeller. The invention has the advantages of effectively reducing the lateral leakage in the clearance, increasing the output power of the turbine, improving the turbine efficiency, and achieving the purposes of energy-saving and consumption reducing. According to the prior verification results by numerical simulation, the output power of the centripetal turbine can be increased by about 2 percents under the situation of ensuring the efficiency of the centripetal turbine to be improved a bit.
Description
Technical field
The present invention relates to top clearance leakage restraint structure of centripetal turbine wheel impeller, be particularly related to several at sealing configurations such as the real wall wheel cap of conventional centripetal turbine inwall layout peripheral groove, axial groove, spiral chute or honeycombs, by reducing the transverse leakage amount of working medium in the impeller top clearance, reduce gap loss, increase the turbine output rate, improve turbine efficiency, reach energy saving purposes.
Background technique
The existence of impeller top clearance makes that leakage flow by the gap and the gap loss brought thus are inevitable, no matter is to axial flow, or centripetal turbine is not always the case.Turbine wheel is when work, there is certain pressure reduction between blade pressure surface and the suction surface, under the effect of this pressure reduction, the part working medium of blade pressure surface side will be leaked to the blade suction surface side by the vane tip gap, the working medium of leaking out does not promote the blade acting on the one hand, has caused the certain power loss to turbine, this part working medium of leaking out on the other hand can with main flow generation blending, form blade tip clearance leakage loss, cause the reduction of through-flow efficient to turbine.
The centripetal turbine impeller can be divided into three kinds of enclosed, semi-open type and open types by the structural type of its runner.Double shrouded wheel is because its impeller inlet linear velocity allowable is low, and application area is severely limited.Semi-open type and unshrouded impeller are because the wheel cap that vane tip does not rotate with blade, its force-bearing situation is improved, its impeller inlet linear velocity allowable can be very high, the impeller that adopts the cast superalloy precision casting to go out at present, its impeller inlet linear velocity even up to about 600m/s.As everyone knows, high impeller rotational speed can be brought the increase of specific power and reducing of size.Therefore, the impeller of these two kinds of runner forms of semi-open type and open type all has on equipment such as turbosupercharger, aeroengine subsidiary engine and miniature gas turbine quite widely and uses.
What all adopt at semi-open type and unshrouded impeller top at present is real wall wheel cap form, does not promptly do any structure and handles, and has smooth internal surface, the gap between the internal surface of this wheel cap and the impeller blade top be generally local leaf high about 1～3%.Though the force-bearing situation of this structural type impeller is improved, make in the vane tip gap more that the horizontal crossfire of multiplex's matter becomes possibility, bring power loss and gap loss to centripetal turbine.
Have only radial clearance different with the axial flow turbine impeller top with hat not, centripetal turbine impeller top clearance has axially and two kinds of gaps radially simultaneously, as shown in Figure 1.
Difference in view of gap structure, centripetal turbine impeller axial clearance and radial clearance are inconsistent to the influence of its complete machine overall performance, the impeller top axle that the foreign scholar obtains by test method to radial clearance to always-test result of total efficiency and mass flow rate influence degree is as shown in table 1.
Table 1 impeller top axle to radial clearance to level overall performance impact test result
| - | Always-total efficiency | Flow/% | ||
| + 1% axial clearance | + 1% radial clearance | + 1% axial clearance | + 1% radial clearance | |
| Futral and Holeski | -0.15 | -1.6 | -0.1 | +0.3 |
| Ricardo | -0.2 | -0.5 | -0.1 | +0.5 |
| Ishimo et al | -0.2 | -1.2 | - | +0.6 |
| Krylov and Spunde | -0.1 | -0.6 | -0.1 | -0.2 |
The claimant is as shown in table 2 by the result of study that method for numerical simulation obtains to certain centripetal turbine impeller top clearance, obviously, with result shown in the table 1 is consistent: (1) impeller top radial clearance and axial clearance are different to the influence of centripetal turbine stage efficiency, radial clearance exports the high increase 1% of leaf relatively, stage efficiency reduces by 1.5%, and the relative impeller inlet width of axial clearance increases 1%, and stage efficiency reduces by 0.15% approximately; (2) impeller top radial clearance is different to the influence of centripetal turbine through-current capability with axial clearance, radial clearance exports the high increase 1% of leaf relatively, the level through-current capability improves 0.24%, and the relative impeller inlet width of axial clearance increases 1%, and the level through-current capability reduces by 0.06%.
Table 2 impeller top axle to the numerical simulation result of radial clearance to the level overall performance impact
| - | Axial clearance/% radial clearance/% | Always-total efficiency/% | Efficiency change | Flow/kgs -1 | Changes in flow rate/% |
| |
1 1 | 92.721 | - | 1.0263 | - |
| |
2 1 | 92.568 | -0.153 | 1.0257 | -0.058 |
| |
1 2 | 91.455 | -1.266 | 1.0288 | +0.244 |
| Gap 4 | 2 2 | 91.166 | -1.555 | 1.0284 | +0.205 |
At present, Chinese scholars to this Study on Problems generally believes, (1) in the impeller top clearance, " scraping " stream that relative movement between pressure reduction between vane tip pressure side and the suction surface and vane tip and the wheel cap causes plays main influence to the flow field, gap, is jointly controlling flow field, impeller top clearance; (2) in the active wheel top area, working medium from the suction surface side inflow gap in gap, goes out from the pressure side effluent under the effect of " scraping ", and relative pressure face side is to the pressure reduction of suction surface side, and " scraping " acts on this zone and have comparative advantage; (3) in the tangential central region in impeller top clearance, because the wheel cap speed of related movement reduces, " scraping " effect weakens, blade loads strengthens gradually, the pressure side side increases to the pressure reduction of suction surface side, the suction surface that causes of " scraping " effect is arranged to the flowing of pressure side side in the gap, mobile to the suction surface side of pressure side that pressure reduction causes arranged too; (4) in the inducer top area, impeller blade both sides pressure reduction is bigger, and " scraping " effect becomes more weak, almost all is the air-flow that leaks from pressure side side direction suction surface side in the top clearance.
Clearance leakage flow under three kinds of gap sizes that Fig. 2 obtains by certain flow field, centripetal turbine impeller top clearance of research for the inventor is along the variation relation curve of meridian chordwise location, wherein leakage rate is that the different chordwise location of cambered surface obtain by integration in the gap, the leakage rate of regulation from the pressure side to the suction surface be on the occasion of.From figure, can obviously find out, (1) the impeller top clearance is more little, " scraping " effect of active wheel top area is strong more, in the gap is 1% o'clock, the suction surface side that the leakage flow from the pressure side side to the suction surface side that is caused by pressure reduction in the gap causes in 45% chordwise location and " scraping " balances each other to the leakage flow of pressure side side, and leakage rate is along tangential linear increase basically thereafter; And be 2% o'clock in the gap, the equinoctial point of leakage rate has been advanced to 20% chordwise location, is 3% o'clock in the gap, and then this is more forward.(2) gap leakage flow rate mainly occurs in the posterior segment of meridian chord length, almost increases along the meridian chord length is linear in this part leakage rate.(3) be 2% o'clock at gap size, gap leakage flow rate relative level mass flow rate is 6.5%, has accounted for sizable ratio.
With respect to centripetal turbine impeller top clearance flow characteristic, be not with crownshaft stream turbine wheel top clearance to increase by 1%, stage efficiency will reduce about 2%, to be greater to level Effect on Performance degree than centripetal turbine radial clearance, and axial flow is the principal mode that large-scale motility mechanical is taked, and its blade tip clearance flow characteristic and leak suppressing structure also are one of research focuses always.Yet, for the centripetal turbine that generally is in auxiliary motility mechanical status, along with being becoming tight the day of energy problem and adopting the miniature gas turbine progressively extensive use of centripetal turbine as the core drive parts, the aeroperformance research of centripetal turbine associated components has also received the concern of Chinese scholars in recent years gradually, and the leak suppressing structure research of impeller top clearance is one of hot research content.
Centripetal turbine and axial flow turbine are different impeller top clearance structure, cause the flow characteristic of centripetal turbine impeller top clearance to be different from axial flow turbine fully, therefore need be at the leak suppressing structure of its distinctive leakage characteristics structure centripetal turbine impeller top clearance.
Summary of the invention
Cause the problem of output power loss and gap energy loss at the horizontal crossfire of working medium in semi-open type or the open type centripetal turbine impeller top clearance, the present invention proposes a kind of top clearance leakage restraint structure of centripetal turbine wheel impeller, this structure can effectively suppress the leakage flow of working medium in semi-open type or the unshrouded impeller top clearance, reduce gap loss, increase the centripetal turbine output power, improve its pneumatic efficiency, reach energy-saving and cost-reducing.
In order to realize above-mentioned task, the present invention takes following technical solution:
A kind of top clearance leakage restraint structure of centripetal turbine wheel impeller is characterized in that, described leak suppressing structure is a series of peripheral grooves or a series of axial groove or a series of spiral chute or honeycomb seal; This leakage internal face of structural configuration real wall wheel cap of drawing up at the impeller top, and be positioned at impeller top meridian chord length 30%～120% scope.
Top clearance leakage restraint structure of centripetal turbine wheel impeller of the present invention can reduce the transverse leakage amount in the gap effectively, reduces gap loss, increases the turbine output rate, improves turbine efficiency, has reached energy saving purposes.
The numerical simulation of sealing construct validity checking is at present finished substantially, can guarantee to increase centripetal turbine output power about 2% under the situation that centripetal turbine efficient slightly improves.
Description of drawings
Fig. 1 be centripetal turbine impeller top axle to the radial clearance position view;
Fig. 2 is that certain three kinds of gap size next tops of centripetal turbine impeller design operating mode gap leakage flow rate is along the meridian chord length distribution;
Fig. 3 is a centripetal turbine impeller top peripheral groove sealing configuration;
Fig. 4 is that centripetal turbine impeller top axle is to slot sealing arrangement;
Fig. 5 is an A-A sectional view among Fig. 4;
Fig. 6 is a centripetal turbine impeller top spiral groove seal structure;
Fig. 7 is a centripetal turbine impeller top honeycomb seal structure;
Fig. 8 is that B among Fig. 7 is to view;
The present invention is described in further detail below in conjunction with accompanying drawing and know-why.
Embodiment
Concrete structure of the present invention is referring to accompanying drawing 3～8, technical thought of the present invention is, arrange sealing configuration in the semi-open type of routine or the real wall wheel cap inwall of open type centripetal turbine, horizontal crossfire in the impeller blade top clearance is suppressed, and guaranteeing under the prerequisite that impeller top clearance overall dimension does not change, increase the centripetal turbine output power, improve centripetal turbine efficient, reach energy saving purposes.
According to inventor's subtend vortex cordis wheel impeller top clearance Study on Flow Field gained conclusion, the horizontal crossfire in the impeller clearance mainly occurs in the mid-rear portion of meridian chord length, and the sealing configuration that therefore is arranged in real wall wheel cap inwall must be positioned at the mid-rear portion of meridian chord length.
Described meridian chord length mid-rear portion is meant 30%～120% chordwise location.
Described sealing configuration has two classes, and a class is to obtain certain sealing configuration by directly removing the part material at the real wall wheel cap inwall of routine, and another kind of is by transforming existing real wall wheel cap and adding cellular structure.
The described sealing configuration that is obtained by the conventional real wall wheel cap inner-wall material of removal part has three kinds, a kind of is to form a series of circumferential conduit at real wall wheel cap inwall along circumferentially removing the part material, second kind is to remove the part material vertically at real wall wheel cap inwall to form a series of axial slot, and the third is to remove the part material at real wall wheel cap inwall to form a series of spiral channel.
Referring to Fig. 1, centripetal turbine is when proper functioning, working medium expands through guider (not shown in the accompanying drawing) after the acceleration, most of in the passage that the turbine wheel blade forms, reexpand and the thermal power transfer of working medium is become mechanical energy, sub-fraction in all the other working medium goes out centripetal turbine by the clearance leakage that forms between the impeller back side and the thermal shield, another major part is then by in the impeller top clearance that forms between impeller blade and the wheel cap " crossfire ", not participating in heat energy influences each other to the conversion of mechanical energy and with acting working medium in the passage, cause the loss of power and the reduction of efficient to centripetal turbine, the present invention is intended to guarantee under the condition that the centripetal turbine stage efficiency do not reduce, reduce the horizontal crossfire amount in the impeller top clearance, increase the output power of centripetal turbine.
According to Chinese scholars subtend vortex cordis wheel impeller top about axial clearance and radial clearance conclusion to its overall performance impact degree, and the inventor is to the result of study of leakage rate in the impeller top clearance etc., leak the mid-rear portion mainly occur in impeller meridian chord length, therefore arrange that at the mid-rear portion of the real wall wheel cap inwall impeller meridian chord length of routine sealing configuration is the most effective.
In centripetal turbine impeller top clearance, the flow abnormalities complexity, the pressure reduction that in impeller meridian chord length mid-rear portion zone then mainly is clearance pressure face side and suction surface side plays a decisive role to Clearance Flow, it promptly mainly is leakage flow from clearance pressure face side to the suction surface side, this is flowing under the influence of impeller passage main flow, its flow direction with circumferentially become certain included angle, and be partial to the impeller outlet position.
For suppressing the generation of above-mentioned leakage flow, the kinetic energy dissipation of leakage flow need be fallen, so proposed the dissipate kinetic energy of leakage current of some novel sealing configurations, make it become heat energy, reduce leakage rate, increase the centripetal turbine output power, improve centripetal turbine efficient.
Based on above result of study, a solution is peripheral groove, axial groove, spiral chute or a honeycomb of arranging some at the mid-rear portion of the real wall wheel cap inwall impeller meridian chord length of routine, to suppressing through the leakage current in the impeller top clearance.The peripheral groove sealing configuration as shown in Figure 3, axial groove sealing result as shown in Figure 4 and Figure 5, the spiral groove seal structure as shown in Figure 6, and honeycomb seal structure is as shown in Figure 7 and Figure 8.
Know-why of the present invention is as follows:
During centripetal turbine work, the working medium that flows out through the stator parts flows into impeller passage, wherein most working medium are discharged after expanding and doing work vertically, another fraction working medium leaks into the adjacent vanes passage through the top clearance near the impeller blade top area, do not participate in the hot merit conversion, and working medium that this part leaks out from the top clearance and passage main flow cross, and form the clearance leakage loss.
Utilize leakage flow direction and the characteristic that circumferentially forms an angle, by at real wall wheel cap inwall according to a series of circumferential conduit of certain regular arrangement, axial slot or spiral channel, make near most of leakage current cavity that inlet channel forms the pressure side side in gap, on the one hand because the sudden expansion of flow area causes the deceleration of leakage current, bump with circumferential conduit wall on the other hand, flow direction changes and form the whirlpool structure in cavity, the kinetic energy dissipation of leakage current is transformed into heat energy, suppressed the generation of leaking, leakage rate is reduced, improved the centripetal turbine output power, reduce leakage loss, improved centripetal turbine efficient.
Honeycomb seal is a kind of sealing configuration that is evenly equipped with a series of regular hexagon honeycomb holes on axial and circumferential both direction, as shown in Figure 8, this structure is very strong to the adaptability of leakage current direction, it is a kind of sealing configuration efficiently, its know-why is identical with above-mentioned conduit sealing principle, has therefore just repeated no more.
The claimant shows the patent search result of relevant both at home and abroad centripetal turbine top clearance leak suppressing structure, does not find the seal arrangement close with structure characteristic of the present invention.
Claims (8)
1. a top clearance leakage restraint structure of centripetal turbine wheel impeller is characterized in that, described leak suppressing structure is a series of peripheral grooves or a series of axial groove or a series of spiral chute or honeycomb seal; This leakage internal face of structural configuration real wall wheel cap of drawing up at the impeller top, and be positioned at impeller top meridian chord length 30%～120% scope.
2. top clearance leakage restraint structure of centripetal turbine wheel impeller as claimed in claim 1 is characterized in that, the groove depth of described peripheral groove and groove width ratio are 1.0～6.0, and pitch of grooves and groove width ratio are 1.0～6.0;
3. top clearance leakage restraint structure of centripetal turbine wheel impeller as claimed in claim 1 is characterized in that, the groove depth of described axial groove is 1.0～5.0 with the ratio of groove width, and pitch of grooves is 1.0～5.0 with the ratio of groove width;
4. top clearance leakage restraint structure of centripetal turbine wheel impeller as claimed in claim 1, it is characterized in that described spiral fluted quantity is 1～8, rotation direction is identical with the impeller sense of rotation or opposite, groove depth and groove width ratio are 0.5～5.0, and pitch of grooves and groove width ratio are 0.5～5.0;
5. top clearance leakage restraint structure of centripetal turbine wheel impeller as claimed in claim 1 is characterized in that, the honeycomb degree of depth of described honeycomb seal and regular hexagon honeycomb opposite side distance ratio are 0.5～5.0;
6. top clearance leakage restraint structure of centripetal turbine wheel impeller as claimed in claim 2 is characterized in that, the conduit cross section of described peripheral groove is semicircle, and triangle is trapezoidal, zigzag fashion or rectangle.
7. top clearance leakage restraint structure of centripetal turbine wheel impeller as claimed in claim 3 is characterized in that, the conduit cross section of described axial groove is semicircle, and triangle is trapezoidal, zigzag fashion or rectangle.
8. top clearance leakage restraint structure of centripetal turbine wheel impeller as claimed in claim 4 is characterized in that, described spiral fluted conduit cross section is semicircle, and triangle is trapezoidal, zigzag fashion or rectangle.
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| CNA2007100188839A CN101173613A (en) | 2007-10-16 | 2007-10-16 | Top clearance leakage restraint structure of centripetal turbine wheel impeller |
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| CNA2007100188839A CN101173613A (en) | 2007-10-16 | 2007-10-16 | Top clearance leakage restraint structure of centripetal turbine wheel impeller |
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| CN101173613A true CN101173613A (en) | 2008-05-07 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014005678A1 (en) * | 2012-07-06 | 2014-01-09 | Ihi Charging Systems International Gmbh | Turbine and corresponding exhaust gas turbocharger |
| CN106932031A (en) * | 2017-03-29 | 2017-07-07 | 苏州亚思科精密数控有限公司 | A kind of accurate measurement fluid flowmeter |
| CN107063361A (en) * | 2017-03-29 | 2017-08-18 | 苏州亚思科精密数控有限公司 | A kind of fluid flowmeter |
| CN108757045A (en) * | 2018-04-28 | 2018-11-06 | 江苏锡宇汽车有限公司 | Has the turbocharger rotor body of noise reduction insulative properties |
| CN111441827A (en) * | 2020-03-19 | 2020-07-24 | 中国科学院工程热物理研究所 | Closed centripetal turbine wheel cover-casing cavity structure for inhibiting leakage loss |
| CN111622816A (en) * | 2020-05-18 | 2020-09-04 | 一汽解放汽车有限公司 | Sealing structure for improving efficiency of turbine of turbocharger and design method |
| CN113266431A (en) * | 2021-06-03 | 2021-08-17 | 西安交通大学 | Radial turbine blade tip clearance ultrasonic sealing structure |
-
2007
- 2007-10-16 CN CNA2007100188839A patent/CN101173613A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014005678A1 (en) * | 2012-07-06 | 2014-01-09 | Ihi Charging Systems International Gmbh | Turbine and corresponding exhaust gas turbocharger |
| CN106932031A (en) * | 2017-03-29 | 2017-07-07 | 苏州亚思科精密数控有限公司 | A kind of accurate measurement fluid flowmeter |
| CN107063361A (en) * | 2017-03-29 | 2017-08-18 | 苏州亚思科精密数控有限公司 | A kind of fluid flowmeter |
| CN108757045A (en) * | 2018-04-28 | 2018-11-06 | 江苏锡宇汽车有限公司 | Has the turbocharger rotor body of noise reduction insulative properties |
| CN111441827A (en) * | 2020-03-19 | 2020-07-24 | 中国科学院工程热物理研究所 | Closed centripetal turbine wheel cover-casing cavity structure for inhibiting leakage loss |
| CN111622816A (en) * | 2020-05-18 | 2020-09-04 | 一汽解放汽车有限公司 | Sealing structure for improving efficiency of turbine of turbocharger and design method |
| CN113266431A (en) * | 2021-06-03 | 2021-08-17 | 西安交通大学 | Radial turbine blade tip clearance ultrasonic sealing structure |
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Open date: 20080507 |