Modification and improvement of turbine blades for maximum cooling efficienc

Calvert, H. F.

Meyer, A. J., Jr.

English

NASA Technical Reports Server

. J. M AL. 
MODIFICATION AND IMPROVEMENTS TO COOLED BLADES 
5 Sheets-Sheet 1 Filed Aug. 20, 1959 
INVENTORS 
3. 
F. 
ATTORNEY 
N 
2 (ACCESSION NUMBER) (THRU) 
E 21' $ (NASA CR O R  T M X  OR A D  NUMBER) (CATEGORY) 
U. 
https://ntrs.nasa.gov/search.jsp?R=19700023953 2020-03-17T01:30:25+00:00Z
Oct. 9, 1962 A. J. MEYER, JR., ETAL 3,057,59 7 
MODIFICATION AED IMPROVEMENTS TO COOLED BLADES 
Filed Aug. 20, 1959 5 Sheets-Sheet 2 
4 
lNVENTORS 
ANDRE J. MEYER JR 
HOWARD E CALVERT 
BY 
ATTORNEY 
Oct. 9, l96F A. J. MEYER, JR., E T A 1  3,057,597 
MODIFICATION AND IMPROVEMENTS TO COOLED BLADES 
Filed Aug. 20, 1959 5 Sheets-Sheet 3 
u) 
0 
BY 
INVENTORS 
ANDRE J. MEYER JR 
HOWARD E CALVERT 
ATTORNEY 
Oct. 9, 1962 A. J. MEYER,.JR., E T A 1  3,057,597 
MODIFICATION AND IMPROVEMENTS TO COOLED BLADES 
Filed Aug. 20, 1959 5 Sheets-Sheet 4 
BY 
INVENTORS 
ANDRE J. MEYER JR 
HOWARD E CALVERT 
A. J. MEYER, JR., E T A L  3,057, 
MODIFICATION AND IMPROVEMENTS TO COOLED BLADES 
Filed Aug. 20, 1959 5 Sheets-Sheet 5 
I 
. -  
/i 
J. 
E 
BY 
ATTORNEY 
h. 
atenfe 
3,057,597 
~ O D ~ ~ C A ~ O N  ND ~~~~~~~~ 
TO COOLED BLADES 
Andre J. Meyer, Jr., Newport News, Va., and 
Calvert, Elyria, Ohio, assignors to the United States of 
America as represented by the Administrator of the 
Nationai Aeronautics and Space Administration 
Filed Aug. 20,1959, Ser. No. 835,146 
(Granted under Title 35, U,S. Code (1952), sec. 266) 
The invention described herein may be manufactured 
and used by or for the Government of the United States 
of America for governmental purposes without the pay- 
ment of any royalties thereon or therefor. 
The present invention relates to turbine rotor blading 
or stationary guide vanes and more particularly to :ir- 
cooled turbine blades and vanes wherein the cooling me- 
dium is exhausted into the main hot gas stream which 
propels the turbine. 
Previous to the present invention, in aircooled tur- 
bine configurations, the expended cooling air was ex- 
hausted along the entire chord at the rotor blade or 
guide vane tip. Experimental measurements and exam- 
ination of blades after operation in a turbine show that 
the static pressure of the hot gases in the leading edge 
tip region of the airfoil section of the vane or  blade is 
sometimes greater than the static supp!y prcssure of :he 
cooling medium. Under these conditions, hot gases ac .u- 
ally flow into the leading edge section of the hollow airfoil 
section and the cooling air is prevented from reaching and 
cooling the blade material of the leading edge region. 
As a result, the hotter material along the blade leading 
edge fails prematurely, thus shortening the life of the 
turbine assembly. 
An object of this invention is to cause the cooling 
medium to depart the blade in a region where the st: tic 
pressure of the main hot gas stream is always less than 
the cooling medium supply pressure and to prevent hot 
gases from entering the airfoil section where the external 
pressure is greater than the interfial coolant pressure. 
Another object of the invention is the effective cooling 
of the entire leading edge of the rator blades and the 
guide vanes in the turbine assembly. 
A further object of the invention is to prevent the bl: de 
leading edge from failing prematurely ldue to inadequate 
cooling. 
Still another object of the invention is the providing of 
a tip cap partially covering the normally open end of 
the rotor blade so as to let the cooling air to the leading 
edge discharge into a lower pressure region. 
A still further ,object of the invention is the provision 
of internal-corrugation configurations which are desigred 
either to have high internal surface area at the leading 
edge or to  direct a maximum amount of cooling air to 
the leading edge. 
Other objects and many attendant advantages of the 
present invention will be apparent from the follow,ng 
detailed description when taken together with the acccm- 
panying drawings in which: 
FIG. 1 is an exploded pictorial view of components 
of a conventional uncapped semistrut corrugated hir- 
cooled turbine blade. 
FIG. 2 is a strut enveloped by a vertical corrugakd 
member. 
FIG. 3 is FIG. 2 covered with an outer shell that has 
a tip cap. 
FIG. 4 is a strut enveloped ‘by -a slanted-corrugated 
member. 
FIG. 5 is FIG. 4 covered with the outer shell that has 
a tip cap. 
FIG. 6 is a cross-sectional view of a hollow airfoil 
shell in section mounted on a rotor showing the tip cap 
4 Claim. (el. 253-39.15) 
5 
10 
15 
20 
25 
30 
35 
40 
43 
50 
55 
in place and an opening for exhausting the cooling me- 
dium to the gas stream. 
FIG. 7 is a cross-sectional view of an airfoil shell 
having internal vertical corrugated finning and an exhaust 
opening along the trailing edge. 
FIG. 8 is a side view of a modification of the blade 
tip which has an exhaust opening adjacent to the trailing 
edge. 
FIG. 9 is a cross-sectional view of a rotor blad-e shell 
whereig the cooling medium is brought in the shell through 
the tip and exhausted along the trailing edge near the 
blade base. 
FIG. 10 is a cross-sectional view of a stationary guide 
vane with two internal partitions to direct the coolant 
and a plurality of exhaust openings. 
Referring now to the drawings, wherein like reference‘ 
characters designate like or  corresponding parts through- 
out the several views, there is shown in FIG. 1 a con- 
ventional strut, geqerally designated 10, two inner shells 
11, two vertical corrugations 12, and two outer shells 413. 
This is believed to .be representative of the cblades known 
in the art prior to applicant’s invention. 
Referring now to FIGS. 2 and 3, a vertical corrugated 
shell 14, the tip corners of which are removed so as 
to provide a small plenum chamber for the expended 
cooling air to exhaust into before moving through the 
blade tip, covers the strut 10 and inner shell P5 in FIG. 
2, whereas a completed unit is shown in FIG. 3, having 
a rotor 17 and a tip cap 18 which is attached to or in- 
tegrally formed with ‘blade shell 16 by any appropriate 
means, leaving an exhaust opening 32. 
Referring now to FIGS. 4 and 5, a slanted corrugated 
shell 19 covers the strut 10 and inner shell 15 in FIG. 4, 
whereas a completed unit is shown in FIG. 5, having a 
rotor 17 and a tip cap 20 integrally attached to and 
partially covering the outer blade shell 16, leaving an 
exhaust opening 33. 
The slanted corrugation arrangement induces a maxi- 
mum cooling flow rate to the leading edge. This is ac- 
complished, as seen in FIGS. 4 and 5, by having the base 
of the corrugated member extending to the trailing edge 
SO that no cooling air can enter there, thus the coolant 
is forced into the vacant space created in the region 
towards the leading edge and is directed toward the trail- 
ing edge by the corrugations. 
In the normal operation of the turbine, the main hot 
gas flows from right to left in FIGS. 2 to  5 and from 
left to right in FIGS. 6 to 10. These hot gases would 
normally enter the turbine blade with high static pres- 
sures in the leading edge 21 region of the blade. As 
work is removed by the turbine rotor and/or pressure 
is converted into higher velocities in passing ~bebetwedn 
or around the airfoil sections, the static pressure be- 
comes quite low in the trailing edge 22 region. In a 
self-contained unit such as an aircraft jet or turbopro- 
peller engine, the cooling air is also pumped ’by the main 
compressor that moves the main gas stream and there- 
fore is never higher in pressure than the pressure enter- 
ing the turbine. In fact, due to the arduous Dath of the 
I 
60,cooling air up to and through the guide vanes or tur- 
bine blades, the cooling air pressure as it leaves the air- 
foil is appreciably less than the turbine inlet main stream 
gas pressure. Furthermore, to conserve on the amount 
of cooling air expended in cooling the turbine parts and 
65 thus to maintain good engine efficiency, the cooling air 
supply is usually throttled to still lower pressures. To 
provide good coolant flow to all internal parts of the 
hollow airfoil shells, the cooling air must all be exhausted 
at locations where the ambient pressure is less than the 
70 cooling air supply pressure. Furthermore, the high pres- 
sure inlet hot gases must be prevented from entering the 
lower pressure interior of the hollow shells. These ob- 
I 
5,067,507 
3 4 .A 
jectives are accomplished by the tip caps and the ex- said Corrugated member to form a plural& of air 
haust openings on the trailing edge. passages extending outwardly from said air inlet; a cap 
Referring now to FIGS. 6 ,  7, and 8 which are i1lu;- at the tip of said outer shell remote from said abase and 
trative of three variations of possible tip cap and open- extending from said leading edge toward said trailing 
ing arrangements, in FIG. 6 ,  the tip cap 23 extents 5 edge; said cap having an ehd edge spaced from said trail- 
from the leading edge 21 partially covering the hollo,v ing edge to form an exhaust aperture adjacent said trail- 
blade shell 16 which is attached t o  the rotor 17 and a2 ing edge; said corrugated member having an inner edge 
exhaust opening 34 is provided on the blade tip ex- adjacent said base, an outer edge adjacent said cap, a 
tending to the trailing edge 22. An inlet aperture 40 s forward edge directed toward the leading edge of said 
provided in the base of the blade for admitting th: 10 turbine blade, and a rearward edge directed toward said 
coolant thereto. trailing edge; a portion of said corrugated member at 
In FIG. 7, the blade shell 96 encloses vertical corruga- the intersection of said outer edge and said forward edge 
tions 24 and the tip cap 25 extends from thc leadicg being in engagement with the fOrwardmost portion of 
edge 21 to a point short of the trailing edge 22, the e/r- said inner surface of said outer shell immediately adja- 
haust opening 35 comprising the corner formed by the 15 cent said leading edge, and a Portion of said corrugated 
tip cap 25 and the trailing edge 22. In FIG. 8, the lip member at the intersection of said lower edge and said 
cap 26 wholly covers the tip of the hollow blade shell forward edge 'being spaced from said forWarchmt POr- 
16 extending from the leading edge 21 to the t r d l l g  tion of said inner surface to form a plenum chamber 
edge 22, while the exhaust opening 36 is situated on between said air inlet and said passages; and a portion 
hollow shell 16 adjacent the corner formed by the trtil- 20 of said corrugated member at the intersection of said 
ing edge 22 and the tip cap 26. lower edge and said rearward edge being in engagement 
Referring now to FIG. 9, the cooling medium is caua,:d with the rearwardmost portion Of said innet Surface Of 
to flow radially inward toward the of rotation from said outer shell immediately adjacent said trailing edge, 
stationary piping through shroud 29. The sealing me&- and a portion of said corrugated member at the inter- 
anism 30 may be any usable gas seal which effectively 25 section of said outer edge and said trailing edge being 
prevents the coolant from flowing directly into the main Spaced from said rearwardmost portion of said inner Sur- 
gas stream without first traversing the hollow blade 16 face to  form a Plenum Chamber between said Passages 
and also prevents hot gases from the main gas stream and said exhaust 
from flowing into the coolant passages. n e  tip cap 2. A cooled turbine blade having a leading edge and a 
27 may be individual on each blade and straddled by the 30 trailing edge, said blade comprising: a base for operably 
seal mechanism 30 or may a continuous hoop affix d connecting said blade to a turbine rotor; said base having 
to the blade tips, The coolant, entering from the dire :- at k i s t  one air inlet; a Strut extending outward from said 
tion of the leading edge 21, and passing through t e. base; a corrugated member mounted on said strut; an 
shell 16 may be discharged through openings anywhe e Outer shell for encasing said corrugated member; said 
along the trailing edge 22 or  may traverse the full span 35 outer shell having an inner surface in engagement with 
of the blade and escape from the opening 37 shown said corrugated member to  form a plurality of air pas- 
positioned adjacent to the rotor 17. sages extending outwardly from said air inlet; a cap at the 
Although in both FIGS. 8 and 9 only a single exhaust tip Of said outer shell remote from said base and extend- 
opening is shown, a multiplicity of opening along the ing from said leading edge towards trailing edge; said cap 
trailing edge will accomplish the same purpose. 40 havin,g an end edge spaced from said trailing edge to form 
Referring finally to FIG. 10, the gas tight attachment an exhaust aperture adjacent said trailing edge; a cen- 
of the hollow guide vane shell 31 to the two stationary trally disposed portion of said corrugated member extend- 
shrouds 29 takes the place of a cap. The openings 38 ing to said exhaust aperture and an adjacent portion of 
along the trailing edge 22 of the shell are used to  vent said corrugated member being spaced from said cap to 
the expended cooling medium into the main fluid stream. 45 form a plenum chamber between a portion of said air 
Partitions 28 are inserted inside shell 31 to direct coolant passages and said exhaust aperture. 
to the remote corners of the shell before the coolant is 3. A cooled turbine blade, as in claim 2, wherein said 
vented to the main sream. corrugated member has corrugations extending radially 
Obviously, many modifications and variations of the outward from said base towards said exhaust aperture. 
present invention are possible in the light of the above 50 4. A cooled turbine blade, as in claim 2, wherein said 
teachings. It is, therefore, to be understood that within corrugated member has slanted corrugations extending 
the scope of the appended claims the invention may #be from said leading edge diagonally outward toward said 
practiced otherwise than as specifically described. trailing edge. 
a trailing edge, said blade comprising: a base for operably 
connecting said blade to a turbine rotor; said base hav- 2,514,105 momas _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  July 4, 1950 ing at least one air inlet; a strut extending outward from 2,647,368 Triebbnigg el al. Aug. 4, 1953 said base; a cmrugated member mounted on such strut 
and having slanted corrugations extending from said lead- 60 2,750,147 Smith _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  June 12, 1956 
ing edge diagonally outward towards said trailing edge; 2,888,243 Pollock __---__________ May 26, I959 
dn outer shell for encasing said Corrugated member; said 
outer shell having an inner surface in engagement with 
h What is claimed is: 1. A cooled turbine blade having a leading edge and 55 efemnces Cited in the e of this patent , 
UNITED STATES PATENTS 


Modification and improvements to cooled blades Patent

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