CN202673372U - Blade backside groove structure of open centripetal turbine - Google Patents
Blade backside groove structure of open centripetal turbine Download PDFInfo
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- CN202673372U CN202673372U CN 201220277391 CN201220277391U CN202673372U CN 202673372 U CN202673372 U CN 202673372U CN 201220277391 CN201220277391 CN 201220277391 CN 201220277391 U CN201220277391 U CN 201220277391U CN 202673372 U CN202673372 U CN 202673372U
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- shouldered
- shouldered wall
- turbine
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Abstract
The utility model discloses a blade backside groove structure of an open centripetal turbine, which includes open centripetal turbine blades and a wheel disc, wherein a series of grooves are formed in the backsides of the turbine blades, and the shapes of the grooves include a common groove type, a pressure surface shoulder wall groove type, a suction surface shoulder wall groove type and a central arc line shoulder wall groove type. According to the blade backside groove structure designed by the utility model, the leakage flow in each backside clearance of the turbine blades is reduced on one hand, so that the efficiency of the turbine is improved; and on the other hand, the heat transfer coefficient and the thermal load of the backsides of the turbine blades are reduced and the service life of the blades is improved, so that the turbine can run more stably and reliably.
Description
Technical field
The utility model belongs to that the centripetal turbine of field of fluid machinery is pneumatic, heat transfer and structural design, relates to a kind of blade back groove structure that improves centripetal turbine aeroperformance and heat-transfer character, is specially adapted to miniature gas turbine.
Background technique
Miniature gas turbine refers to the gas turbine of power between 25-500kW, generally is made of parts such as centrifugal compressor, centripetal turbine, firing chamber, regenerators.That miniature gas turbine has is simple and compact for structure, maintenance cost is low, fuel diversification, discharging are low, operation flexibly, the heat utilization rate high, be widely used in the auxiliary power unit of distributing-supplying-energy system, for subsequent use and portable power source, various uses.
Under the prerequisite that guarantees the reliable and stable work of miniature gas turbine, how to improve the efficient of gas turbine, become the challenge that the gas turbine artificer faces.An effective way that improves the micro-gas-turbine engine efficiency is to increase turbine inlet temperature (TIT), and along with the raising of turbine inlet temperature (TIT), the difficult problem that turbine design person faces is: how to guarantee centripetal turbine reliable and stable work under high rotating speed, high inlet temperature.Another effective way that improves gas turbine proficiency is the clearance leakage loss that reduces turbine and compressor part, because centripetal turbine Clearance Flow situation is very complicated, how better to understand turbine internal clearance flow characteristic, find out the approach that reduces gap loss, become another hang-up that the centripetal turbine artificer faces.
Characteristics such as (the single-stage centripetal turbine can replace two-stage even more axial flow turbine) that centripetal turbine has is simple and compact for structure, cost is low, performance is higher, easy for installation, the single-stage pressure ratio is higher are very suitable for the miniature gas turbine that structural compactness is had higher requirements.But centripetal turbine blade tip rotating speed higher (generally can reach 600m/s), root of blade and wheel disk stress are larger, and along with the raising of turbine inlet temperature (TIT), the centripetal turbine strength problem is particularly outstanding.
The larger position of centripetal turbine rotor stress concentrates on respectively blade import root, wheel disk center, blade exit root three places.In order to solve the centripetal turbine strength problem, modern miniature gas turbine adopts the structure of open type centripetal turbine (also being the star-disc turbine in the turbosupercharger) mostly, as shown in Figure 1 and Figure 2.The open type centripetal turbine is cut wheel disc to root of blade on the basis of conventional centripetal turbine, has reduced to greatest extent rotor weight, has reduced wheel disc and root stress.
The open type centripetal turbine has advantage and in pneumatic new loss---the gap, back of having introduced in intensity.Correlative study both at home and abroad shows, gap loss is the chief component of turbomachine loss, and the back gap loss accounts for whole gap loss proportion over half.As seen study the flow characteristic in gap, back, it is necessary finding out the measure that reduces the back gap loss.
High-temperature fuel gas is when flowing through turbine clearance, and airspeed improves rapidly the jet effect that causes and causes leaf to take one's place hot coefficient greatly improving; On the other hand, leakage flow experiences separation, the complex flow process such as attached again in the gap, and heat transfer coefficients distribution is very complicated.Under the impact of heat load, turbine blade is easy to occur ablating and fracture, so the heat-transfer character in the turbine clearance is the popular content of Chinese scholars research always in the gap.
Finding out the measure that reduces open type centripetal turbine back gap heat transfer coefficient extremely is necessary, this is because not only there is higher heat load in the gap, back, and the gap, back near the higher blade import root of centrifugal stress (by contrast, although heat-transfer coefficient is higher in the blade tip clearance, but centrifugal stress is less near the leaf top), if can not guarantee that heat load is below specified value in the gap, back, with being easy to cause ablation and the fracture of blade import root, affect the normal operation of whole gas turbine.
As fully visible, how to reduce centripetal turbine back clearance leakage flow, reducing the back gap heat transfer coefficient is the challenge that centripetal turbine is pneumatic and structural design person faces.
Summary of the invention
For the shortcoming and defect of prior art, the utility model has designed a kind of open type centripetal turbine blade back groove structure, has reduced open type centripetal turbine blade back tip leakage flow amount on the one hand, thereby has improved turbine efficiency; Reduced on the other hand heat-transfer coefficient and the heat load at open type centripetal turbine blade back, improved leaf longevity, made the turbine can more reliable and stable operation.
In order to achieve the above object, the utility model is taked following technical solution:
A kind of open type centripetal turbine blade back groove structure comprises a plurality of turbine blades and wheel disc, has the back clearance C between the blade back of described turbine blade and the back casing, it is characterized in that, the blade back of each described turbine blade offers groove,
The distance away between the axis of the top of the axis of described open type centripetal turbine and described open type centripetal turbine of described groove is 80%～100% of tip radlus R, distance between the bottom of the close described axis of described groove and the described axis is the 60%-80% of tip radlus R, described tip radlus R is the distance of described turbine blade tip and described axis
Distance between the end face at the bottom surface of described groove and described blade back, namely depth of groove is 20%～100% of back clearance C,
The shouldered wall thickness of described groove is 20%～100% of described depth of groove.
The utility model arranges groove at open type centripetal turbine blade back by the way, can reduce the liquid speed in the gap, blade back, has reduced the clearance leakage flow on the one hand, has improved turbine efficiency; Significantly reduced on the other hand blade back heat-transfer coefficient, very favourable to the raising of centripetal turbine rotor life; In addition, described centripetal turbine has also reduced leaf weight to a certain extent owing to having added groove at the blade back, has reduced the turbine centrifugal stress.
Preferably, the shape of described groove is sealed, and the left and right shouldered wall of groove is respectively pressure side shouldered wall and suction surface shouldered wall.
Preferably, described groove be shaped as pressure side shouldered wall groove, groove is nonocclusive, only has the pressure side shouldered wall, described pressure side shouldered wall has one at least, the pressure side shouldered wall has when a plurality of, a plurality of pressure side shouldered walls be arranged in parallel; Or, described groove be shaped as suction surface shouldered wall groove, groove is nonocclusive, only has the suction surface shouldered wall, described suction surface shouldered wall has one at least, the suction surface shouldered wall has when a plurality of, a plurality of suction surface shouldered walls be arranged in parallel; Or, described groove be shaped as mean camber line shouldered wall groove, groove is nonocclusive, only has the mean camber line shouldered wall, described mean camber line shouldered wall has one at least, the mean camber line shouldered wall has when a plurality of, a plurality of mean camber line shouldered walls be arranged in parallel.
Preferably, for described mean camber line shouldered wall groove, the radial direction of described mean camber line shouldered wall and described turbine blade can have certain angle.
Preferably, when described pressure side shouldered wall, suction surface shouldered wall or mean camber line shouldered wall have when a plurality of, the width between adjacent two shouldered walls be the shouldered wall width 1-10 doubly.
Preferably, the intersection of the bottom surface of described groove and groove shouldered wall can have certain circle of leading.
Compare with prior art, open type centripetal turbine blade of the present utility model back groove structure has following significant advantage: reduced turbine blade back clearance leakage flow on the one hand, thereby improved turbine efficiency; Reduced on the other hand heat-transfer coefficient and the heat load at turbine blade back, improved leaf longevity, made the turbine can more reliable and stable operation; Simultaneously, centripetal turbine has also reduced leaf weight to a certain extent owing to having added groove at the blade back, has reduced the turbine centrifugal stress.
Description of drawings
Fig. 1 is open type centripetal turbine meridian schematic cross-section;
Fig. 2 is the open type centripetal turbine schematic diagram of unslotted;
Fig. 3 (a) is the open type centripetal turbine schematic diagram of generic grooves of the present utility model, and Fig. 3 (b) is partial enlarged drawing;
Fig. 4 is the various groove shapes schematic diagram in open type centripetal turbine blade of the present utility model back, (a) be the generic grooves schematic diagram, (b) be pressure side shoulder arm groove schematic diagram, (c) be suction surface shoulder arm groove schematic diagram, (d) be mean camber line shoulder arm groove schematic diagram, (e) be pressure side both shoulders arm groove schematic diagram, (f) suction surface both shoulders arm groove schematic diagram.
Embodiment
For making the purpose of this utility model, technological scheme and advantage clearer, referring to the accompanying drawing embodiment that develops simultaneously, the utility model is further described.
Open type centripetal turbine as shown in Figure 1 and Figure 2 is after integral casting forming, at first pressure side 15 and the suction surface 16 of its blade 1 are polished, then use milling cutter that blade 1 leaf top 7 and back 5 are processed, guarantee its luminosity and required precision, guarantee simultaneously the back clearance C of blade tip clearance, blade back 5 and the back casing 4 of blade and blade top 7 and leaf top casing 8, can mill out groove at blade back 5 with that, form the open type centripetal turbine of the blade back band generic grooves 9 shown in Fig. 3 (a), Fig. 3 (b).When processing generic grooves 9, the distance R U away between the axis of the top of the axis of described open type centripetal turbine and described open type centripetal turbine of described groove 9 is 80%～100% of tip radlus R, distance R D between the bottom of the close described axis of described groove and the described axis is the 60%-80% of tip radlus R, and described tip radlus R is the distance of described turbine blade tip 6 and described axis.Distance between the end face at the bottom surface of described groove 9 and described blade back 5, namely depth of groove L3 is 20%～100% of back clearance C, the shouldered wall thickness L1 of described groove is 20%～100% of described depth of groove L3.
The groove of the various shapes in blade back as shown in Figure 4, can be generic grooves 9, pressure side shouldered wall groove 10, suction surface shouldered wall groove 11, mean camber line shouldered wall groove 12, pressure side both shoulders wall groove 13, suction surface both shoulders wall groove 14, its bottom portion of groove and recess sidewall intersection 17 can have certain circle of leading, and recess sidewall intersection 18 can have certain circle of leading.
The selection of depth of groove L3 need to consider impact pneumatic and that conduct heat.Because along with the increase of depth of groove L3, the vortex intensity of air-flow in groove strengthens, and flow losses increase to some extent, and this is disadvantageous to turbine efficiency.If yet depth of groove L3 is too little, gap internal leakage stream is attached can not well the inhibition again, and the reduction amplitude of blade back heat-transfer coefficient is not obvious.The selection of groove shouldered wall thickness L1 need to consider the impact of machining accuracy and heat transfer.In theory, L1 is less for shouldered wall groove thickness, and the groove area occupied is then larger, and this is favourable to reducing blade back heat-transfer coefficient.But shouldered wall groove thickness L1 also is subject to the restriction of milling cutter machining accuracy, processes too small shouldered wall groove thickness L1 meeting so that turbine blade machining deformation occurs at dorsal area.
Groove top radial location RU of living in chooses, and mainly is the impact of Consideration of Heat Transfer coefficient and machining accuracy.Because if radial location RU of living in is too high for groove top, recess width L2 will be very little, and milling cutter can't be processed.And if groove top radial location RU of living in is excessively low, will be so that the groove area occupied diminish, this is disadvantageous to reducing heat-transfer coefficient.The residing radial location RD of bottom portion of groove chooses, and need to consider the impact of heat transfer and rotor stress.Because if residing radial location RD is excessive for bottom portion of groove, will be so that the groove area occupied diminish, this is disadvantageous to reducing heat-transfer coefficient.Yet, if the residing radial location RD of bottom portion of groove is too small, bottom portion of groove will be very close wheel disc upper end 3, this will cause stress raisers, and will be very unfavorable to turbine rotor intensity.
In sum, for the selection of depth of groove L3, groove shouldered wall thickness L1, groove top radial location RU of living in and the residing radial location RD of bottom portion of groove, need to consider the impact of pneumatic, heat transfer, rotor stress and machining accuracy.Actually add man-hour, should be according to the result of numerical calculation under the different groove geometric parameters, consider the optimum value that above-mentioned factor is chosen how much of grooves.
The above only is preferred embodiment of the present utility model, and is in order to limit the utility model, not all within spirit of the present utility model and principle, any modification of making, is equal to replacement, improvement etc., all should be included within the scope of the present utility model.
Claims (7)
1. open type centripetal turbine blade back groove structure, comprise a plurality of turbine blades and wheel disc, have the back clearance C between the blade back of described turbine blade and the back casing of described centripetal turbine, it is characterized in that, the blade back of each described turbine blade offers groove
The distance away between the axis of the top of the axis of described open type centripetal turbine and described open type centripetal turbine of described groove is 80%～100% of tip radlus R, distance between the bottom of the close described axis of described groove and the described axis is the 60%-80% of tip radlus R, described tip radlus R is the distance of described turbine blade tip and described axis
Distance between the end face at the bottom surface of described groove and described blade back, namely depth of groove is 20%～100% of described back clearance C,
The shouldered wall thickness of described groove is 20%～100% of described depth of groove;
The intersection of the bottom surface of described groove and groove shouldered wall is led circle.
2. open type centripetal turbine blade as claimed in claim 1 back groove structure is characterized in that, the shape of described groove is sealed, and the left and right shouldered wall of groove is respectively pressure side shouldered wall and suction surface shouldered wall.
3. open type centripetal turbine blade as claimed in claim 1 back groove structure, it is characterized in that, described groove be shaped as pressure side shouldered wall groove, groove is nonocclusive, only has the pressure side shouldered wall, described pressure side shouldered wall has one at least, and the pressure side shouldered wall has when a plurality of, and a plurality of pressure side shouldered walls be arranged in parallel.
4. open type centripetal turbine blade as claimed in claim 1 back groove structure, it is characterized in that, described groove be shaped as suction surface shouldered wall groove, groove is nonocclusive, only has the suction surface shouldered wall, described suction surface shouldered wall has one at least, and the suction surface shouldered wall has when a plurality of, and a plurality of suction surface shouldered walls be arranged in parallel.
5. open type centripetal turbine blade as claimed in claim 1 back groove structure, it is characterized in that, described groove be shaped as mean camber line shouldered wall groove, groove is nonocclusive, only has the mean camber line shouldered wall, described mean camber line shouldered wall has one at least, and the mean camber line shouldered wall has when a plurality of, and a plurality of mean camber line shouldered walls be arranged in parallel.
6. open type centripetal turbine blade as claimed in claim 5 back groove structure is characterized in that, the radial direction of described mean camber line shouldered wall and described turbine blade has certain angle.
7. such as each described open type centripetal turbine blade back groove structure of claim 3 to 5, it is characterized in that, when shouldered wall has when a plurality of, the width between adjacent two shouldered walls be the shouldered wall width 1-10 doubly.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220277391 CN202673372U (en) | 2012-06-12 | 2012-06-12 | Blade backside groove structure of open centripetal turbine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220277391 CN202673372U (en) | 2012-06-12 | 2012-06-12 | Blade backside groove structure of open centripetal turbine |
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| CN202673372U true CN202673372U (en) | 2013-01-16 |
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| CN 201220277391 Expired - Fee Related CN202673372U (en) | 2012-06-12 | 2012-06-12 | Blade backside groove structure of open centripetal turbine |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109090002A (en) * | 2018-09-12 | 2018-12-28 | 浙江海洋大学 | Zero energy consumption shrimp culture pond automatic dirt cleaning device of one kind |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109090002A (en) * | 2018-09-12 | 2018-12-28 | 浙江海洋大学 | Zero energy consumption shrimp culture pond automatic dirt cleaning device of one kind |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130116 Termination date: 20200612 |
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| CF01 | Termination of patent right due to non-payment of annual fee |