EP0892149B1 - Cooling system for the leading edge of a hollow blade for a gas turbine engine - Google Patents
Cooling system for the leading edge of a hollow blade for a gas turbine engine Download PDFInfo
- Publication number
- EP0892149B1 EP0892149B1 EP97810474A EP97810474A EP0892149B1 EP 0892149 B1 EP0892149 B1 EP 0892149B1 EP 97810474 A EP97810474 A EP 97810474A EP 97810474 A EP97810474 A EP 97810474A EP 0892149 B1 EP0892149 B1 EP 0892149B1
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- EP
- European Patent Office
- Prior art keywords
- ribs
- height
- leading edge
- cooling system
- blade
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000001816 cooling Methods 0.000 title claims description 23
- 230000007423 decrease Effects 0.000 claims description 2
- 239000002826 coolant Substances 0.000 description 16
- 239000007789 gas Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 230000001419 dependent effect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000007664 blowing Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000012809 cooling fluid Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003319 supportive effect Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/14—Form or construction
- F01D5/18—Hollow blades, i.e. blades with cooling or heating channels or cavities; Heating, heat-insulating or cooling means on blades
- F01D5/187—Convection cooling
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2260/00—Function
- F05D2260/20—Heat transfer, e.g. cooling
- F05D2260/221—Improvement of heat transfer
- F05D2260/2214—Improvement of heat transfer by increasing the heat transfer surface
- F05D2260/22141—Improvement of heat transfer by increasing the heat transfer surface using fins or ribs
Definitions
- the invention relates to a cooling system for the leading edge region of a hollow Gas turbine blade, which extends from the blade root to the blade tip a longitudinally flowed channel extends in the area of the airfoil on the one hand from the inner walls of the front edge, the suction side and the Pressure side and on the other hand from a connecting the pressure side with the suction side Web is limited, the inner walls of the suction side and the Print page with a plurality of oblique and at least approximately parallel Ribs are provided, and the suction side above the blade height Ribs and the pressure-side ribs are offset from one another.
- the invention thus relates generally to a system for cooling a curved wall, which on one side of a hot medium and on a coolant flows around its other side.
- Cooling is a particular problem of the leading edge area of such blades.
- a cooling system of the type mentioned is known from DE-C2 32 48 162.
- the area under consideration is equipped with ribs on its inner walls, which run radially outwards from the front edge to the web. These ribs have a height that is anywhere between 10% and 33% of the local Height of the coolant channel is. This is also intended for a narrow channel Leading edge area can be cooled effectively.
- the ribs to trigger turbulence and promotion provided, and the cooling fluid should be without large Resistance to be conducted through the blade. Due to the oblique arrangement of the Ribs in a defined direction are intended to create vortices on the ribs have a speed component towards the leading edge.
- This is the actual front edge is rib-free. It has one on the inside cylindrical shape with a radius that is about the height of the subsequent Ribs corresponds. The distance between the ribs and the leading edge has a value between one to five times the height of the ribs.
- the present invention has for its object a cooling system of the beginning to create the type mentioned, by increasing the turbulence in the leading edge area and other measures significantly increase the Heat transfer coefficients can be achieved.
- the ratio of the height of the ribs to the local one Height of the channel increases from the front edge towards the web or over the length of the ribs is constant.
- a further relief of the web area is achieved if - again in contrast to the prior art mentioned at the beginning - the height of the ribs in the area of the web is reduced so early that the rib does not reach Bridge is enough. The turbulence then missing in this area has an advantageous effect reduced cooling of the web in the connection area.
- the cast blade shown in Fig. 1 has three inner chambers a, b, and c on that from a coolant, such as steam or air, perpendicular to Flow through the drawing plane. In doing so, the inside of the blade contour forming wall W - hot gases flow around it on both sides is flowed around by the coolant and give their heat to the coolant.
- a coolant such as steam or air
- numerous are not here at least in the two front chambers a, b shown tools such as guide ribs, flow channels, inserts for impingement cooling and the like can be provided to improve wall cooling.
- the coolant circulates in a closed circuit, by which is meant is that neither on the front edge, the suction side, the pressure side nor in Blowing out coolant into the flow channel in the area of the rear edge he follows.
- FIG. 2 and 3 show the cooling system for the leading edge region of a hollow Gas turbine blade. It extends from the blade root 1 to the blade tip 2 a longitudinally flowed channel 3, which corresponds to chamber a in FIG. 1. in the Area of the airfoil 4 is this channel from the inner walls of the Front edge, the suction side 6 and the pressure side 7 and one of the pressure side limited with web 8 connecting the suction side.
- the inner walls of the The suction side and the pressure side are inclined with a plurality and at least provided approximately parallel ribs 9, which are above the blade height are staggered. As from the schematic illustration in FIG. 3 The ribs on the suction side and the pressure side are visible above the bucket height Ribs offset by half a division.
- the rib structure creates a secondary flow in the duct, the warm air transported from the immediate area of the leading edge to the center of the channel. This warm air is replaced by colder air from the center of the duct.
- the ribs in the leading edge area are tighter than in the Middle area of the canal. This leads to a very strong increase in heat transfer in this area by increasing turbulence and by Generation of investment points of the flow behind recirculation areas that arise behind the ribs.
- the ratio of the height h of the ribs to the local height H of the channel 3 decreases from the leading edge 5 towards web 8.
- This increase in height is in the example chosen so that between the front edge and web in each axial plane a free flowed channel is about the same width. With this measure a uniform coolant distribution over the entire cross-section through which the flow passes reached.
- the local location-dependent rib height creates a flow in the channel that also in the narrow leading edge area flows because the flow resistances are now about the same as in the remaining channel.
- the design of the new ribs also affects the Cooling passage very positive and supportive of the secondary flow mentioned above in the duct, which the air from the leading edge to the rear Creates channel area.
- the high ribs in the rear channel area induce a very strong secondary flow.
- the height h of the ribs increases in the area of the web 8 steadily towards zero. It goes without saying that, due to the manufacturing process, sharp-edged Connections are hardly possible. As already mentioned, this configuration has the advantage that at the junction of the web with the inner walls the coolant flows along the walls almost without interference and thus less cooling effect developed. Of course, the intermediate bridge 8 may never get too hot. Should this be due to the selected configuration can occur, there is easily the possibility of the ribs up to Continuing the web with an adjusted height, i.e. with the same or reduced Height.
- the height h of the individual ribs staggered above the blade height can of course be adapted to the local heat load.
- a Enlargement of the ribs towards the tip of the blade is particularly then attached when the coolant passes through the channel has already warmed up strongly, so that the required temperature difference between wall to be cooled and coolant for the desired heat exchange smaller becomes.
- a similar effect can be achieved by spacing the ribs across the bucket height is made variable. Of course, both can also Measures are combined.
- Such a variable distance is shown schematically in Fig. 5 illustrates. The distance between the ribs and the tip of the blade is shown in the upper part increasingly larger. In the lower part the solution is shown, in which the Slant runs directly into the front edge, i.e. the distance d mentioned is here 0.
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- General Engineering & Computer Science (AREA)
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Description
Die Erfindung betrifft ein Kühlsystem für den Vorderkantenbereich einer hohlen Gasturbinenschaufel, bei welcher sich vom Schaufelfuss bis zur Schaufelspitze ein längsdurchströmter Kanal erstreckt, welcher im Bereich des Schaufelblattes einerseits von den Innenwandungen der Vorderkante, der Saugseite und der Druckseite und andererseits von einem die Druckseite mit der Saugseite verbindenden Steg begrenzt ist, wobei die Innenwandungen der Saugseite und der Druckseite mit einer Mehrzahl schräg und zumindest annähernd parallel verlaufender Rippen versehen sind, und wobei über der Schaufelhöhe die saugseitigen Rippen und die druckseitigen Rippen gegeneinander versetzt sind.The invention relates to a cooling system for the leading edge region of a hollow Gas turbine blade, which extends from the blade root to the blade tip a longitudinally flowed channel extends in the area of the airfoil on the one hand from the inner walls of the front edge, the suction side and the Pressure side and on the other hand from a connecting the pressure side with the suction side Web is limited, the inner walls of the suction side and the Print page with a plurality of oblique and at least approximately parallel Ribs are provided, and the suction side above the blade height Ribs and the pressure-side ribs are offset from one another.
Die Erfindung bezieht sich somit ganz allgemein auf ein System zum Kühlen einer gekrümmten Wand, welche an einer Seite von einem heissen Medium und an ihrer anderen Seite von einem Kühlmittel umströmt ist. The invention thus relates generally to a system for cooling a curved wall, which on one side of a hot medium and on a coolant flows around its other side.
Hohle, innengekühlte Turbinenschaufeln mit Flüssigkeit, Dampf oder Luft als Kühlmittel sind hinlänglich bekannt. Ein Problem stellt insbesondere die Kühlung des Vorderkantenbereiches von solchen Schaufeln dar.Hollow, internally cooled turbine blades with liquid, steam or air as Coolants are well known. Cooling is a particular problem of the leading edge area of such blades.
Ein Kühlsystem der eingangs genannten Art ist bekannt aus der DE-C2 32 48 162. Der betrachtete Bereich ist an seinen Innenwandungen mit Rippen bestückt, die von der Vorderkante bis hin zum Steg radial auswärts verlaufen. Diese Rippen weisen eine Höhe auf, die an jeder Stelle zwischen 10% und 33% der örtlichen Höhe des Kühlmittelkanals beträgt. Damit soll auch bei einem schmalen Kanal der Vorderkantenbereich wirksam gekühlt werden. Hierbei sind die Rippen zur Turbulenzauslösung und -förderung vorgesehen, und das Kühlfluid soll ohne grossen Widerstand durch die Schaufel geleitet werden. Durch die schräge Anordnung der Rippen in einer definierten Richtung sollen an den Rippen Wirbel entstehen, die eine Geschwindigkeitskomponente zur Vorderkante hin aufweisen. Dies soll dazu führen, dass das Kühlmittel insgesamt zum Vorderkantenbereich abgelenkt wird, womit dieser Bereich auch ohne Filmkühlung wirksam gekühlt wird. Dazu ist die eigentliche Vorderkante rippenfrei ausgeführt. Sie weist an der Innenseite eine zylindrische Form auf mit einem Radius, der etwa der Höhe der anschliessenden Rippen entspricht. Der Abstand der Rippen zur Vorderkante hat einen Wert zwischen einfacher bis fünffacher Rippenhöhe.A cooling system of the type mentioned is known from DE-C2 32 48 162. The area under consideration is equipped with ribs on its inner walls, which run radially outwards from the front edge to the web. These ribs have a height that is anywhere between 10% and 33% of the local Height of the coolant channel is. This is also intended for a narrow channel Leading edge area can be cooled effectively. Here are the ribs to trigger turbulence and promotion provided, and the cooling fluid should be without large Resistance to be conducted through the blade. Due to the oblique arrangement of the Ribs in a defined direction are intended to create vortices on the ribs have a speed component towards the leading edge. This is supposed to cause the coolant as a whole to be deflected towards the leading edge area, which effectively cools this area even without film cooling. This is the actual front edge is rib-free. It has one on the inside cylindrical shape with a radius that is about the height of the subsequent Ribs corresponds. The distance between the ribs and the leading edge has a value between one to five times the height of the ribs.
Weitere Überlegungen, wie mittels Rippen die Wärmeübertragung in sogenannten Dreieckskanälen - wie sie der Vorderkantenbereich einer Gasturbinenschaufel darstellt - verbessert werden kann, sind in der Zeitschrift "Journal of Thermophysics and Heat Transfer", Vol. 8, No. 3, July-Sept. 1994 auf den Seiten 574-579 in einem Artikel von Zhang et al dargelegt. Further considerations, such as using heat transfer in so-called Triangular channels - like the leading edge area of a gas turbine blade represents - can be improved, are in the journal "Journal of Thermophysics and Heat Transfer ", Vol. 8, No. 3, July-Sept. 1994, pages 574-579 in an article by Zhang et al.
Das Problem bei den mit Rippen gleicher Höhe bestückten Dreieckskanälen besteht indes darin, dass durch den grossen Querschnitt an der Basis des Dreiecks infolge des geringeren Widerstandes dort eine zu grosse Menge Kühlmittel durchströmt, was zu den in der Folge erläuterten Unzulänglichkeiten führen kann.The problem with the triangular channels equipped with ribs of the same height is that the large cross section at the base of the Triangle due to the lower resistance there too much Coolant flows through, which leads to the shortcomings explained below can lead.
Der vorliegenden Erfindung liegt die Aufgabe zugrunde, ein Kühlsystem der eingangs genannten Art zu schaffen, bei der durch Steigerung der Turbulenz im Vorderkantenbereich und weiterer Massnahmen eine beträchtliche Erhöhung des Wärmeübergangskoeffiezienten erzielt werden kann.The present invention has for its object a cooling system of the beginning to create the type mentioned, by increasing the turbulence in the leading edge area and other measures significantly increase the Heat transfer coefficients can be achieved.
Erfindungsgemäss wird dies mit den kennzeichnenden Merkmalen des Patentanspruchs 1 erreicht.This is according to the invention with the characterizing features of the patent claim 1 reached.
Besonders zweckmässig ist es, wenn das Verhältnis Höhe der Rippen zur örtlichen Höhe des Kanals von der Vorderkante in Richtung Steg zunimmt oder über die Längserstreckung der Rippen konstant ist. Mit dieser Massnahme kann in jeder Radialebene von der Vorderkante bis zum Steg ein Querschnitt mit zumindest annähernd gleicher Sperrung und somit gleichmässiger Strömungsverteilung erreicht werden. Dies hat den Vorteil, dass gegenüber dem eingangs erwähnten Stand der Technik die Vorderkante stärker beaufschlagt wird und gleichzeitig der Steg entlastet wird. Letzeres ist wichtig, um zu hohe Spannungen an den beidseitigen Verbindungsstellen des kühlen Steges mit den heissen Schaufelwandungen zu vermeiden.It is particularly useful if the ratio of the height of the ribs to the local one Height of the channel increases from the front edge towards the web or over the length of the ribs is constant. With this measure, in Every radial plane from the leading edge to the web has a cross-section with at least approximately the same blockage and thus even flow distribution can be achieved. This has the advantage that compared to the above State of the art the front edge is subjected to a greater load and at the same time the Web is relieved. The latter is important to avoid excessive tension on both sides Joints of the cool bar with the hot blade walls to avoid.
Eine weitere Entlastung des Stegbereiches wird dann erreicht, wenn - wiederum im Gegensatz zum eingangs erwähnten Stand der Technik - die Höhe der Rippen im Bereich des Steges frühzeitig so reduziert wird, dass die Rippe nicht bis zum Steg reicht. Die dann in diesem Bereich fehlende Turbulenz bewirkt eine vorteilhafte verminderte Kühlung des Steges im Verbindungsbereich.A further relief of the web area is achieved if - again in contrast to the prior art mentioned at the beginning - the height of the ribs in the area of the web is reduced so early that the rib does not reach Bridge is enough. The turbulence then missing in this area has an advantageous effect reduced cooling of the web in the connection area.
Weitere sinnvolle Ausbildungen der Erfindung ergeben sich aus den Unteransprüchen.Further useful embodiments of the invention result from the subclaims.
In der Zeichnung ist ein Ausführungsbeispiel der Erfindung anhand einer innengekühlten Gasturbinenschaufel vereinfacht dargestellt.Darin zeigen:
- Fig. 1
- eine Schaufel im Querschnitt;
- Fig. 2
- den Vorderkantenbereich der Schaufel nach Fig. 1;
- Fig. 3
- einen Längsschnitt durch den Vorderkantenbereich;
- Fig. 4
- eine perspektivische schematische Vorderansicht der Schaufelberippung im Vorderkantenbereich.
- Fig. 5
- eine schematische Abwicklung der Schaufelberippung im Vorderkantenbereich.
- Fig. 1
- a blade in cross section;
- Fig. 2
- the front edge region of the blade according to Fig. 1;
- Fig. 3
- a longitudinal section through the leading edge area;
- Fig. 4
- a perspective schematic front view of the fins in the leading edge area.
- Fig. 5
- a schematic development of the blade ribbing in the leading edge area.
Es sind nur die für das Verständnis der Erfindung wesentlichen Elemente gezeigt. Die Strömungsrichtung der beteiligten Medien ist mit Pfeilen bezeichnet.Only the elements essential for understanding the invention are shown. The direction of flow of the media involved is indicated by arrows.
Die in Fig. 1 dargestellte, gegossene Schaufel weist drei Innenkammern a, b, und c auf, die von einem Kühlmittel, beispielsweise Dampf oder Luft, senkrecht zur Zeichnungsebene durchströmt sind. Dabei werden die Innenseiten der die Schaufelkontur bildenden Wand W - die aussen beidseitig von heissen Gasen umströmt ist - vom Kühlmittel umströmt und geben ihre Wärme an das Kühlmittel ab. In der Regel sind zumindest in den zwei vorderen Kammern a, b zahlreiche hier nicht gezeigte Hilfsmittel wie Leitrippen, Strömungskanäle, Einsätze für Prallkühlung und dergleichen zur Verbesserung der Wandkühlung vorgesehen sein können. Im Beispielsfall zirkuliert das Kühlmittel im geschlossenen Kreis, worunter verstanden wird, dass weder an der Vorderkante, der Saugseite, der Druckseite noch im Bereich der Hinterkante ein Ausblasen von Kühlmittel in den Strömungskanal erfolgt.The cast blade shown in Fig. 1 has three inner chambers a, b, and c on that from a coolant, such as steam or air, perpendicular to Flow through the drawing plane. In doing so, the inside of the blade contour forming wall W - hot gases flow around it on both sides is flowed around by the coolant and give their heat to the coolant. In the As a rule, numerous are not here at least in the two front chambers a, b shown tools such as guide ribs, flow channels, inserts for impingement cooling and the like can be provided to improve wall cooling. in the For example, the coolant circulates in a closed circuit, by which is meant is that neither on the front edge, the suction side, the pressure side nor in Blowing out coolant into the flow channel in the area of the rear edge he follows.
In der Vorderkammer a gibt es zwei Problembereiche. Zum einen die eigentliche
Vorderkante, die von den heissen Gasen direkt angeströmt wird und deshalb einer
besonders sorgfältigen Kühlung bedarf und zum andern die Verbindungsstellen
des Steges 8 mit den Innenwandungen der Saugseite 6 sowie der Druckseite 7,
welche auf keinen Fall zu stark gekühlt werden sollen.There are two problem areas in the front chamber a. For one, the real one
Leading edge, which is directly flown by the hot gases and therefore one
particularly careful cooling and secondly the connection points
the
Unter Zuhilfenahme der an sich bekannten, mit der Schaufel vergossenen Rippen, indes in neuer Anordnung und Geometrie, löst die Erfindung mit ein und derselben Massnahme die vorherrschenden Probleme in beiden Bereichen.With the help of the well-known ribs cast with the shovel, however, in a new arrangement and geometry, the invention solves with one and the same Measure the prevailing problems in both areas.
Die Fig. 2 und 3 zeigen das Kühlsystem für den Vorderkantenbereich einer hohlen
Gasturbinenschaufel. Vom Schaufelfuss 1 bis zur Schaufelspitze 2 erstreckt sich
ein längsdurchströmter Kanal 3, welcher der Kammer a in Fig. 1 entspricht. Im
Bereich des Schaufelblattes 4 ist dieser Kanal von den Innenwandungen der
Vorderkante, der Saugseite 6 und der Druckseite 7 sowie von einem die Druckseite
mit der Saugseite verbindenden Steg 8 begrenzt. Die Innenwandungen der
Saugseite und der Druckseite sind mit einer Mehrzahl schräg und zumindest
annähernd parallel verlaufender Rippen 9 versehen, die über der Schaufelhöhe
gestaffelt angeordet sind. Wie aus der schematischen Darstellung in Fig. 3
erkennbar, sind über der Schaufelhöhe die saugseitigen Rippen und die druckseitigen
Rippen um eine halbe Teilung gegeneinander versetzt.2 and 3 show the cooling system for the leading edge region of a hollow
Gas turbine blade. It extends from the blade root 1 to the blade tip 2
a longitudinally flowed channel 3, which corresponds to chamber a in FIG. 1. in the
Area of the
Soweit sind berippte Kühlsysteme an sich bekannt. Gemäss der Erfindung verlaufen
die Rippen nun jedoch vom Steg 8 Richtung Vorderkante radial einwärts
unter einem Winkel von 45°. Es ist zu erwarten, dass Anstellwinkel zwischen 15°
und 60° geeignet sind. Darüberhinaus gehen die Rippen im Bereich der Vorderkante
in eine Ausrichtung senkrecht zur Hauptströmungsrichtung über. Diese Umlenkung der Rippen von der Schrägen in
eine Ausrichtung senkrecht zur Hauptströmungsrichtung erfolgt mit kleinstmöglichem Radius. Es ist auch möglich, dass die
Rippen schräg in die Vorderkante laufen und dabei umlenken. Dies bedeutet, dass
dann die Rippen aus gusstechnischen Gründen nicht mehr überall den
gleichen Querschnittsverlauf aufweisen, sondern im Bereich der stark
gekrümmten Vorderkantenwand "verwunden" sind. Daraus folgt, dass der Abstand
d von der Vorderkante bis zum Ort der Umlenkung zwischen 0% und 15% der
Länge des Kanals 3 sein kann.Die Wirkung dieser schräg angestellten Rippen und
ihrer Umlenkung ist folgende:So far, finned cooling systems are known per se. Run according to the invention
the ribs, however, radially inward from the
Die Rippenstruktur verursacht eine Sekundärströmung im Kanal, die warme Luft aus dem unmittelbaren Bereich der Vorderkante in die Mitte des Kanals befördert. Diese warme Luft wird durch kältere Luft aus der Kanalmitte ersetzt.The rib structure creates a secondary flow in the duct, the warm air transported from the immediate area of the leading edge to the center of the channel. This warm air is replaced by colder air from the center of the duct.
Weiterhin sind die umgelenkten Rippen ganz um die Vorderkante herumgeführt,
wie dies in den Fig. 2 und 4 erkennbar ist. Diese Lösung zusammen mit der
versetzen Anordnung der Rippen auf der Saugseite 6 und der Druckseite 7
bewirkt folgendes:Furthermore, the deflected ribs are led all the way around the front edge,
as can be seen in FIGS. 2 and 4. This solution along with the
offset arrangement of the ribs on the
Es entsteht eine engere Staffelung der Rippen im Vorderkantenbereich als im Mittelbereich des Kanals. Dies führt zu einer sehr starken Anfachung der Wärmeübertragung in diesem Gebiet durch eine Steigerung der Turbulenz und durch die Erzeugung von Anlagepunkten der Strömung hinter Rezirkulationsgebieten, die hinter den Rippen entstehen.The ribs in the leading edge area are tighter than in the Middle area of the canal. This leads to a very strong increase in heat transfer in this area by increasing turbulence and by Generation of investment points of the flow behind recirculation areas that arise behind the ribs.
Das Verhältnis Höhe h der Rippen zur örtlichen Höhe H des Kanals 3 nimmt von
der Vorderkante 5 in Richtung Steg 8 zu. Diese Höhenzunahme wird im Beispielsfall
so gewählt, dass zwischen Vorderkante und Steg in jeder Axialebene ein frei
durchströmter Kanal etwa gleicher Breite entsteht. Mit dieser Massnahme wird
eine gleichmässige Kühlmittelverteilung über dem gesamten durchströmten Querschnitt
erreicht. Erst durch das Einführen einer ortsabhängigen Rippenhöhe
werden die beiden vorher genannten Mechanismen zur Erhöhung der
Wärmeübertragung besonders wirksam. Die lokal ortsabhängige Rippenhöhe
schafft im Kanal eine Strömung, die auch in den engen Vorderkantenbereich
strömt, da hier die Strömungswiderstände nun etwa gleich gross sind wie im
restlichen Kanal. Weiterhin wirkt sich die Gestaltung der neuen Rippen in der
Kühlpassage sehr positiv und unterstützend auf die oben erwähnte Sekundärströmung
im Kanal aus, welche die Luft aus der Vorderkante in den hinteren
Kanalbereich schafft. Die hohen Rippen im hinteren Kanalbereich induzieren
hierbei eine sehr starke Sekundärströmung.The ratio of the height h of the ribs to the local height H of the channel 3 decreases from
the
Bei bestimmten Verhältnissen ist es günstig, wie experimentell nachgewiesen wurde, wenn das Verhältnis Höhe h der Rippen zur örtlichen Höhe H des Kanals über die Längserstreckung der Rippen konstant ist.In certain circumstances, it is favorable, as has been demonstrated experimentally was when the ratio height h of the ribs to local height H of the channel is constant over the length of the ribs.
Wie aus Fig. 2 ersichtlich, nimmt die Höhe h der Rippen im Bereich des Steges 8
stetig gegen null ab. Es versteht sich, dass herstellungsbedingt scharfkantige
Verbindungen kaum möglich sind. Wie bereits erwähnt, hat diese Konfiguration
den Vorteil, dass an der Verbindungsstelle des Steges mit den Innenwandungen
das Kühlmittel nahezu störungsfrei an den Wandungen entlang strömt und damit
weniger Kühlwirkung entwickelt. Selbstverständlich darf der Zwischensteg 8 niemals
zu heiss werden. Sollte aufgrund der gewählten Konfiguration dieser Fall
eintreten können, so besteht ohne weiteres die Möglichkeit, die Rippen bis zum
Steg mit einer angepassten Höhe weiterzuführen, d.h. mit gleicher oder reduzierter
Höhe.As can be seen from FIG. 2, the height h of the ribs increases in the area of the
Die Höhe h der einzelnen über der Schaufelhöhe gestaffelten Rippen kann selbstverständlich der lokal vorliegenden Wärmebelastung angepasst sein. Eine Vergrösserung der Rippen gegen die Schaufelspitze hin ist insbesondere dann angebracht, wenn das Kühlmittel sich im Verlauf seines Weges durch den Kanal bereits stark erwärmt hat, so dass die erforderliche Temperaturdifferenz zwischen zu kühlender Wand und Kühlmittel zum angestrebten Wärmeaustausch kleiner wird.The height h of the individual ribs staggered above the blade height can of course be adapted to the local heat load. A Enlargement of the ribs towards the tip of the blade is particularly then attached when the coolant passes through the channel has already warmed up strongly, so that the required temperature difference between wall to be cooled and coolant for the desired heat exchange smaller becomes.
Eine ähnliche Wirkung kann erzielt werden, indem der Abstand der Rippen über der Schaufelhöhe variabel gestaltet wird. Selbstverständlich können auch beide Massnahmen kombiniert werden. Ein derartig variabler Abstand ist schematisch in Fig. 5 illustriert. Im oberen Teil wird der Abstand der Rippen zur Schaufelspitze hin zunehmend grösser. Im unteren Teil ist die Lösung dargestellt, bei welcher die Schräge direkt in die Vorderkante verläuft, d.h. der erwähnte Abstand d beträgt hier 0.A similar effect can be achieved by spacing the ribs across the bucket height is made variable. Of course, both can also Measures are combined. Such a variable distance is shown schematically in Fig. 5 illustrates. The distance between the ribs and the tip of the blade is shown in the upper part increasingly larger. In the lower part the solution is shown, in which the Slant runs directly into the front edge, i.e. the distance d mentioned is here 0.
Bei gegebenen Bedingungen - d.h. Geometrie und Wandstärke der Vorderkante und der seitlichen Wandungen; Geometrie der vom Kühlmittel zu durchströmenden Kammer a; Wärmebelastung der Schaufelvorderkante; Art, Temperatur und Strömungsgeschwindigkeit des Kühlmittels - sind demnach die Wahl des Rippen-Anstellwinkels, die lokale Höhe der in den durchströmten Kanal hineinragenden Rippen, die Anzahl und die Teilung der in der Radialen über der Schaufelhöhe gestaffelten Rippen massgebend für konstante Metalltemperaturen über der Blatthöhe.Given conditions - i.e. Geometry and wall thickness of the leading edge and the side walls; Geometry of the coolant to flow through Chamber a; Thermal load on the blade leading edge; Type, temperature and Flow rate of the coolant - are therefore the choice of the fin angle of attack, the local height of the protruding into the channel Ribs, the number and division of those in the radial above the blade height staggered ribs decisive for constant metal temperatures above the Blade height.
- a, b, ca, b, c
- Innenkammern der SchaufelInner chambers of the shovel
- WW
- Schaufelwandblade wall
- 11
- Schaufelfussblade root
- 22
- Schaufelspitzeblade tip
- 33
- längsdurchströmter Kanallongitudinally flowed channel
- 44
- Schaufelblattairfoil
- 55
- Vorderkanteleading edge
- 66
- Saugseitesuction
- 77
- Druckseitepressure side
- 88th
- Stegweb
- 99
- Ripperib
- hH
- Höhe der RippeHeight of the rib
- HH
- örtliche Breite des Kanals 3local width of the channel 3
- dd
- Abstand zwischen 5 und UmlenkungDistance between 5 and redirection
Claims (8)
- Cooling system for the leading-edge region of a hollow gas-turbine blade, in which a duct (3), through which flow occurs longitudinally, extends from the blade root (1) up to the blade tip (2) and is defined in the region of the blade body (4) on the one hand by the inner walls of the leading edge (5), the suction side (6) and the pressure side (7) and on the other hand by a web (8) connecting the pressure side to the suction side, the inner walls of the suction side and the pressure side being provided with a plurality of ribs (9), which run slantwise and at least approximately in parallel, and the suction-side ribs and the pressure-side ribs being offset from one another by half a spacing over the blade height, characterized in that the ribs (9) run radially inward from the web (8) in the direction of the leading edge (5), are aligned perpendicularly with respect to the main direction of flow in the region of the leading edge and are led around the leading edge.
- Cooling system according to Claim 1, characterized in that the deviation of the ribs (9) from the slant into the radial is effected with the smallest possible radius.
- Cooling system according to Claim 1, characterized in that the distance (d) from the leading edge (5) to the location of the deviation is between 0% and 15% of the length of the duct (3).
- Cooling system according to Claim 1, characterized in that the height (h) of the ribs (9) increases from the leading edge (5) in the direction of the web (8).
- Cooling system according to Claim 1, characterized in that the ratio of the height (h) of the ribs (9) to the local height (H) of the duct (3) is constant over the longitudinal extent of the ribs.
- Cooling system according to Claim 1, characterized in that the height (h) of the ribs (9) decreases in the region of the web (8).
- Cooling system according to Claim 1, characterized in that the height (h) of the ribs (9) is variable over the blade height.
- Cooling system according to Claim 1, characterized in that the spacing between the ribs (9) is variable over the blade height.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP97810474A EP0892149B1 (en) | 1997-07-14 | 1997-07-14 | Cooling system for the leading edge of a hollow blade for a gas turbine engine |
| DE59709195T DE59709195D1 (en) | 1997-07-14 | 1997-07-14 | Cooling system for the leading edge area of a hollow gas turbine blade |
| US09/111,706 US6068445A (en) | 1997-07-14 | 1998-07-08 | Cooling system for the leading-edge region of a hollow gas-turbine blade |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP97810474A EP0892149B1 (en) | 1997-07-14 | 1997-07-14 | Cooling system for the leading edge of a hollow blade for a gas turbine engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0892149A1 EP0892149A1 (en) | 1999-01-20 |
| EP0892149B1 true EP0892149B1 (en) | 2003-01-22 |
Family
ID=8230296
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP97810474A Expired - Lifetime EP0892149B1 (en) | 1997-07-14 | 1997-07-14 | Cooling system for the leading edge of a hollow blade for a gas turbine engine |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US6068445A (en) |
| EP (1) | EP0892149B1 (en) |
| DE (1) | DE59709195D1 (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6406260B1 (en) * | 1999-10-22 | 2002-06-18 | Pratt & Whitney Canada Corp. | Heat transfer promotion structure for internally convectively cooled airfoils |
| US6554571B1 (en) * | 2001-11-29 | 2003-04-29 | General Electric Company | Curved turbulator configuration for airfoils and method and electrode for machining the configuration |
| US6672836B2 (en) | 2001-12-11 | 2004-01-06 | United Technologies Corporation | Coolable rotor blade for an industrial gas turbine engine |
| DE10316909B4 (en) * | 2002-05-16 | 2016-01-07 | Alstom Technology Ltd. | Coolable turbine blade with ribs in the cooling channel |
| GB0222352D0 (en) * | 2002-09-26 | 2002-11-06 | Dorling Kevin | Turbine blade turbulator cooling design |
| US8690538B2 (en) * | 2006-06-22 | 2014-04-08 | United Technologies Corporation | Leading edge cooling using chevron trip strips |
| US20070297916A1 (en) * | 2006-06-22 | 2007-12-27 | United Technologies Corporation | Leading edge cooling using wrapped staggered-chevron trip strips |
| EP1921269A1 (en) * | 2006-11-09 | 2008-05-14 | Siemens Aktiengesellschaft | Turbine blade |
| US8083485B2 (en) * | 2007-08-15 | 2011-12-27 | United Technologies Corporation | Angled tripped airfoil peanut cavity |
| US8376706B2 (en) * | 2007-09-28 | 2013-02-19 | General Electric Company | Turbine airfoil concave cooling passage using dual-swirl flow mechanism and method |
| EP2392775A1 (en) * | 2010-06-07 | 2011-12-07 | Siemens Aktiengesellschaft | Blade for use in a fluid flow of a turbine engine and turbine engine |
| US9388700B2 (en) | 2012-03-16 | 2016-07-12 | United Technologies Corporation | Gas turbine engine airfoil cooling circuit |
| US9334755B2 (en) * | 2012-09-28 | 2016-05-10 | United Technologies Corporation | Airfoil with variable trip strip height |
| US10316668B2 (en) | 2013-02-05 | 2019-06-11 | United Technologies Corporation | Gas turbine engine component having curved turbulator |
| US10215031B2 (en) * | 2013-03-14 | 2019-02-26 | United Technologies Corporation | Gas turbine engine component cooling with interleaved facing trip strips |
| US10358978B2 (en) | 2013-03-15 | 2019-07-23 | United Technologies Corporation | Gas turbine engine component having shaped pedestals |
| JP6245740B2 (en) * | 2013-11-20 | 2017-12-13 | 三菱日立パワーシステムズ株式会社 | Gas turbine blade |
| US10119404B2 (en) * | 2014-10-15 | 2018-11-06 | Honeywell International Inc. | Gas turbine engines with improved leading edge airfoil cooling |
| US10406596B2 (en) | 2015-05-01 | 2019-09-10 | United Technologies Corporation | Core arrangement for turbine engine component |
| US10352177B2 (en) | 2016-02-16 | 2019-07-16 | General Electric Company | Airfoil having impingement openings |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4775296A (en) * | 1981-12-28 | 1988-10-04 | United Technologies Corporation | Coolable airfoil for a rotary machine |
| GB2159585B (en) * | 1984-05-24 | 1989-02-08 | Gen Electric | Turbine blade |
| JPS62271902A (en) * | 1986-01-20 | 1987-11-26 | Hitachi Ltd | Cooled blade for gas turbine |
| JP3006174B2 (en) * | 1991-07-04 | 2000-02-07 | 株式会社日立製作所 | Member having a cooling passage inside |
-
1997
- 1997-07-14 EP EP97810474A patent/EP0892149B1/en not_active Expired - Lifetime
- 1997-07-14 DE DE59709195T patent/DE59709195D1/en not_active Expired - Lifetime
-
1998
- 1998-07-08 US US09/111,706 patent/US6068445A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0892149A1 (en) | 1999-01-20 |
| US6068445A (en) | 2000-05-30 |
| DE59709195D1 (en) | 2003-02-27 |
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