Film cooling for the trailing edge of a steam cooled nozzle

Abstract

A nozzle assembly (10) for a turbine engine includes an inner band (16) and an outer band (14) spaced apart from each other. An airfoil (12) installed between the bands has a leading edge (18) and a trailing edge (20). The airfoil has cavities formed in it for fluid flow through the nozzle assembly. A plurality of film cooling holes (1A-6H) are formed in a sidewall of the airfoil on a concave side of the assembly, and a plurality of film cooling holes (1J-1R) are formed in a sidewall of the nozzle on a convex side thereof. The holes are formed on each side of the airfoil, adjacent the trailing edge of the nozzle, in a plurality of rows of holes including at least a forward row (C, J), an aft row (A, L), and an intermediate row (B, K). The spacing between the intermediate row and aft row is substantially closer than the spacing between the forward row and the intermediate row.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

This invention relates to the cooling of an airfoil comprising a portion of a stator vane or nozzle of the first stage of a gas turbine engine; and more particularly, to the hole pattern formation in the airfoil for thin film cooling of a trailing edge of the airfoil.

In the construction of gas turbine engines, an annular array of turbine segments is provided to form a turbine stage. Generally, the turbine stage is defined by outer and inner annular bands spaced apart from each other with a plurality of vanes or airfoils extending between the bands and circumferentially spaced from one other. This construction, in turn, defines a path for a working fluid flowing through the turbine. In a gas turbine engine, this is a hot gas. As will be appreciated by those skilled in the art, the most extreme adverse operating conditions are generally encountered at the first stage of the turbine. That is because this stage is immediately downstream of the engine's combustion chamber and components comprising this stage must therefore withstand high thermal loads. As is known in the art, cooling systems for this engine stage utilize thin film cooling techniques to insure so adequate cooling is provided. Thin film cooling is accomplished by discharging air through orifices formed in portions of the nozzle. The discharged air then forms a protective thin film boundary layer between the hot stream of gases flowing through the first stage of the turbine and the surface of the nozzle.

Various problems with thin film cooling systems have been encountered and solutions to these problems have been addressed in U.S. Pat. Nos. 6,583,526, 6,561,757, 6,553,665, 6,527,274, 6,517,312, 6,506,013, 6,435,814, 6,402,466, 6,398,486, and 5,591,002, all of which are assigned to the same assignee as the present application.

The present invention is directed to an advanced film-cooling configuration for cooling the trailing edge of a nozzle used in the first stage of an advanced design gas turbine engine. The nozzle is a steam cooled component which operates at firing temperatures which require cooling of the airfoil to extend the low cycle fatigue (LCF), oxidation, and creep life of the component. While steam adequately cools the majority of the nozzle, it is not feasible for use in cooling the trailing edge of the nozzle. Rather, this requires a novel and advanced thin film cooling configuration in order for the trailing edge to not rapidly deteriorate once the turbine is in service which would require costly servicing or replacement of the nozzle and unacceptable down-time when the turbine is out of service.

BRIEF SUMMARY OF THE INVENTION

Briefly stated, the present invention is directed to thin film cooling of the trailing edge of a nozzle for the first stage of a gas turbine engine. Cooling is affected by use of a plurality of rows of film cooling holes located adjacent the trailing edge of the nozzle, on both the concave side and convex side of the nozzle. In particular, three rows of film cooling holes are formed in the sidewalls of the nozzle on the respective concave and convex sides thereof. A first and forward row of holes extends generally longitudinally of the nozzle and comprises holes of varying sizes and angles formed at predetermined locations on the nozzle. Second and third rows of holes also extend generally longitudinally of the nozzle and also comprise holes of varying sizes and angles formed at predetermined locations on the nozzle. The second row of holes comprises a middle row of holes and the third row an aft row. Holes comprising the second row are spaced a substantial distance from those comprising the first row. However, the second and third row of holes are formed relatively close together with the holes comprising the second row being staggered in location with respect to those comprising the third row. By placing the middle and aft rows of holes closer together, and staggering the hole arrangement in these two rows, an effective film flow is achieved which cools the trailing edge of the nozzle thereby to minimize cooling flow, optimize performance of the turbine engine, reduce NOx produced by the engine, prolong the service life of the nozzle and reduce service and repair costs.

Two embodiments of the invention are shown with the thin film cooling arrangement of the first embodiment including substantially more holes in each row than occurs in the second embodiment.

The foregoing and other objects, features, and advantages of the invention will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the accompanying drawings which form part of the specification:

FIG. 1A is an orthographic view of the concave side of a first embodiment of a first stage nozzle for a gas turbine, and FIG. 1B is an orthographic view of the nozzle from the convex side;

FIG. 2 is a sectional view of an airfoil portion of the nozzle illustrating steam and air flow paths through the air foil;

FIG. 3 is a sectional view of the airfoil;

FIG. 4 is a detail view of the airfoil illustrating a film hole pattern formed in the concave side of the airfoil;

FIG. 5 is a view of the flow path side of the outer band at the trailing edge further illustrating the film hole pattern on the concave side of the airfoil;

FIGS. 6 and 7 are views similar to those of FIGS. 4 and 5, respectively, for the convex side of the airfoil;

FIGS. 8A is an orthographic view of the concave side of a second embodiment of a first stage nozzle for a gas turbine, and FIG. 8B is an orthographic view of the nozzle from the convex side;

FIG. 9 is a detail view of the airfoil illustrating a film hole pattern formed in the concave side of the airfoil;

FIG. 10 is a view of the flow path side of the outer band at the trailing edge further illustrating the film hole pattern in the concave side of the airfoil; and,

FIGS. 11 and 12 are views similar to those of FIGS. 9 and 10, respectively, for the convex side of the airfoil.

Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

Referring to the drawings, the present invention is directed to thin film cooling for a first stage nozzle assembly, indicated generally 10 in FIGS. 1A and 1B, of a gas turbine engine. While not shown in the drawings, those skilled in the art will appreciate that nozzle assembly 10 is comprised of a plurality of circumferentially arranged vanes or airfoils indicated generally 12, the respective segments being connected to one another to form an annular array which defines a path for hot gasses passing through the first stage.

With respect to FIGS. 1A and 1B, a nozzle assembly includes an outer band 14 and an inner band 16 between which airfoil 12 is mounted. Each assembly is supported within a shell (not shown) of the turbine in which turbine components are installed. Referring to FIG. 3, airfoil 12 is shown to a have a curved airfoil shape with a rounded leading edge 18 and a trailing edge 20. A steam inlet manifold 22 and a steam outlet manifold 24 are mounted on outer band 14 to circulate steam through the airfoil. Referring to FIG. 2, airfoil 12 is constructed as is generally known in the art with a series of internal flow passages indicated generally P for steam to circulate through the airfoil from inlet manifold 22 to outlet manifold 24. These flow paths will not be described in detail. In addition to circulating steam through airfoil 12, the present invention includes an air inlet 26 in outer band 14 and a plurality of air outlet holes or slots 28 for thin film cooling of the trailing edge of the airfoil. As described hereinafter, these openings are arranged in a predetermined pattern to maximize the thin film cooling of airfoil 12. The openings are formed in the sidewalls of the airfoil on both the concave side and convex side of the airfoil. The size of each opening and its location are determined in accordance with the present invention. As shown in FIGS. 5 and 7, at the outer end of the airfoil adjacent band 14, the sidewalls of the airfoil curve or flare outwardly. In addition, the airfoil has a circumferentially extending rail 30. The holes or openings are formed in this portion of the nozzle assembly as well to provide sufficient thin film cooling at the trailing edge of the airfoil.

The hole pattern or arrangement of the present invention comprises three rows of openings which extend longitudinally of the airfoil, on both the concave and convex sides of the nozzle assembly, and spaced inwardly of the trailing edge. As particularly shown in FIG. 4, on the concave side of the airfoil are three rows indicated generally RA, RB, and RC, and on the convex side of the airfoil, as shown in FIG. 6, are three rows indicated RJ, RK, and RL. To further provide adequate thin film cooling of trailing edge 20, additional holes or slots are also formed in the curved portions of the airfoil adjacent outer band 14, and on the portion of rail 30 adjacent the trailing edge of the airfoil. On the concave side of the nozzle assembly, and as shown in FIGS. 4 and. 5, these additional openings are indicated 1D-6D, 1E, 1F-4F, 1G-5G, and 1H-6H. On the convex side of the assembly, and as shown in FIGS. 6 and 7, these additional openings are indicated 1M-6M, 1N-7N, 1P-4P, and 1R.

Referring again to FIGS. 4 and 6, the rows of holes or openings formed in the respective sidewalls of the airfoil include a forward row (the row furthest away from the trailing edge), an aft row (the row closest to the trailing edge), and an intermediate row. On the concave side of the assembly, row RC is the forward row and includes 31 openings. Row RB is the intermediate row and comprises 49 openings. The aft row is row RA which includes 43 openings. In accordance with the invention, the spacing between intermediate row RB and aft row RA is substantially closer than the spacing between forward row RC and intermediate row RB. Further, the holes comprising intermediate row RB and those comprising aft row RC are arranged in a staggered pattern as shown in FIG. 4. Similarly in accordance with the invention, on the convex side of the assembly, the spacing between intermediate row RK (which has 51 openings) and aft row RL (which has 44 openings) is substantially closer than the spacing between forward row RJ (which has 29 openings) and intermediate row RK. Again, the holes comprising intermediate row RK and those comprising aft row RL are arranged in a staggered pattern as shown in FIG. 6.

Table 1 is a listing of all the holes comprising rows RA-RC, RJ-RL, and the other holes formed in the bands 14 and 16 and rail 30. The table includes each hole designation, the angle of the opening with respect to the outer surface of airfoil 12, and the X, Y, Z coordinates determining the location of the hole. The distances are measured with respect to the reference point Q (0,0,0) shown in FIG. 1B.

TABLE 1
		ANGLE TO
	DIAMETER	SURFACE
HOLE #	(in.)	(°)	X (in.)	Y (in.)	Z (in.)
1A	0.032	30	−7.792	−2.253	.179
2A	0.032	30	−7.777	−2.137	.223
3A	0.032	30	−7.766	−2.021	.269
4A	0.032	30	−7.757	−7.905	.314
5A	0.032	30	−7.748	−1.788	.357
6A	0.032	30	−7.741	−1.670	.398
7A	0.032	30	−7.736	−1.559	.435
8A	0.032	30	−7.732	−1.453	.469
9A	0.032	30	−7.729	−1.347	.502
10A	0.032	30	−7.727	−1.241	.535
11A	0.032	30	−7.726	−1.135	.566
12A	0.032	30	−7.726	−1.028	.596
13A	0.032	30	−7.726	−.921	.625
14A	0.032	30	−7.728	−.814	.653
15A	0.032	30	−7.730	−.706	.680
16A	0.032	30	−7.732	−.598	.707
17A	0.032	30	−7.736	−.490	.732
18A	0.032	30	−7.740	−.382	.756
19A	0.032	30	−7.745	−.274	.780
20A	0.032	30	−7.750	−.165	.802
21A	0.032	30	−7.756	−.056	.822
22A	0.032	30	−7.762	.053	.840
23A	0.032	30	−7.770	.162	.860
24A	0.032	30	−7.780	.270	.882
25A	0.032	30	−7.790	.378	.906
26A	0.032	30	−7.802	.486	.929
27A	0.032	30	−7.812	.594	.950
28A	0.032	30	−7.822	.703	.968
29A	0.032	30	−7.832	.813	.983
30A	0.032	30	−7.843	.922	.997
31A	0.032	30	−7.855	1.043	1.012
32A	0.032	30	−7.870	1.174	1.028
33A	0.032	30	−7.884	1.305	1.043
34A	0.032	30	−7.898	1.437	1.057
35A	0.032	30	−7.912	1.568	1.070
36A	0.032	30	−7.931	1.744	1.085
37A	0.032	30	−7.956	1.964	1.102
38A	0.032	30	−7.980	2.164	1.114
39A	0.032	30	−8.002	2.345	1.122
40A	0.032	30	−8.031	2.553	1.130
41A	0.032	30	−8.060	2.762	1.128
42A	0.032	30	−8.091	2.969	1.136
43A	0.032	30	−8.066	3.162	1.244
1B	0.032	37	−7.894	−3.250	.074
2B	0.032	37	−7.906	−3.049	−.202
3B	0.032	30	−7.845	−2.827	−.157
4B	0.032	30	−7.790	−2.630	−.100
5B	0.032	30	−7.779	−2.544	−.060
6B	0.032	30	−7.744	−2.427	−.055
7B	0.032	30	−7.730	−2.311	−.010
8B	0.032	30	−7.715	−2.195	.033
9B	0.032	30	−7.702	−2.079	.077
10B	0.032	30	−7.691	−1.963	.122
11B	0.032	30	−7.682	−1.846	.167
12B	0.032	30	−7.675	−1.729	.210
13B	0.032	30	−7.668	−1.611	.251
14B	0.032	30	−7.664	−1.506	.286
15B	0.032	30	−7.660	−1.400	.320
16B	0.032	30	−7.658	−1.294	.352
17B	0.032	30	−7.657	−1.188	.384
18B	0.032	30	−7.657	−1.081	.415
19B	0.032	30	−7.658	−.974	.445
20B	0.032	30	−7.659	−.867	.474
21B	0.032	30	−7.661	−.760	.502
22B	0.032	30	−7.664	−.652	.529
23B	0.032	30	−7.667	−.544	.555
24B	0.032	30	−7.671	−.436	.580
25B	0.032	30	−7.676	−.328	.604
26B	0.032	30	−7.682	−.220	.627
27B	0.032	30	−7.687	−.111	.648
28B	0.032	30	−7.694	−.002	.668
29B	0.032	30	−7.702	.107	.687
30B	0.032	30	−7.711	.216	.707
31B	0.032	30	−7.721	.324	.729
32B	0.032	30	−7.733	.432	.752
33B	0.032	30	−7.745	.540	.775
34B	0.032	30	−7.756	.649	.795
35B	0.032	30	−7.766	.755	.812
36B	0.032	30	−7.777	.868	.827
37B	0.032	30	−7.788	.977	.841
38B	0.032	30	−7.802	1.108	.858
39B	0.032	30	−7.817	1.240	.873
40B	0.032	30	−7.832	1.371	.887
41B	0.032	30	−7.848	1.502	.900
42B	0.032	30	−7.863	1.634	.912
43B	0.032	30	−7.886	1.854	.931
44B	0.032	30	−7.910	2.074	.946
45B	0.032	30	−7.931	2.255	.956
46B	0.032	30	−7.954	2.435	.963
47B	0.032	30	−7.985	2.657	.970
48B	0.032	30	−8.014	2.866	.966
49B	0.032	30	−8.042	3.072	1.028
1C	0.032	105	−7.803	−3.190	−.429
2C	0.032	150	−7.811	−3.013	−.421
3C	0.032	150	−7.726	−2.763	−.348
4C	0.032	150	−7.674	−2.550	−.304
5C	0.032	150	−7.629	−2.335	−.267
6C	0.032	150	−7.584	−2.121	−.230
7C	0.032	150	−7.544	−1.908	−.190
8C	0.032	150	−7.514	−1.692	−.146
9C	0.032	150	−7.494	−1.476	−.098
10C	0.032	150	−7.482	−1.260	−.048
11C	0.032	150	−7.476	−1.043	−.001
12C	0.032	150	−7.470	−.824	.035
13C	0.032	150	−7.464	−.604	.062
14C	0.032	150	−7.465	−.383	.090
15C	0.032	150	−7.470	−.163	.120
16C	0.032	30	−7.481	.068	.148
17C	0.032	30	−7.494	.288	.169
18C	0.032	30	−7.508	.508	.186
19C	0.032	30	−7.523	.729	.198
20C	0.032	30	−7.539	.950	.209
21C	0.032	30	−7.558	1.170	.220
22C	0.032	30	−7.529	1.391	.230
23C	0.032	30	−7.598	1.612	.234
24C	0.032	30	−7.615	1.833	.234
25C	0.032	30	−7.632	2.054	.232
26C	0.032	30	−7.65 1	2.276	.228
27C	0.032	30	−7.667	2.496	.206
28C	0.032	30	−7.673	2.712	.152
29C	0.032	30	−7.678	2.919	.094
30C	0.032	30	−7.705	3.073	.102
31C	0.032	85	−7.655	3.210	.102
1D	0.030	30	−8.537	3.433	2.152
2D	0.030	30	−8.810	3.459	1.880
3D	0.030	30	−7.825	3.503	1.610
4D	0.030	30	−7.471	3.565	1.340
5D	0.030	108	−7.017	3.668	.993
6D	0.030	108	−6.714	3.751	.760
1E	0.032	30	−7.980	3.215	1.252
1F	0.032	30	−7.966	3.164	.929
2F	0.032	30	−7.833	3.252	.954
3F	0.032	30	−7.682	3.271	1.036
4F	0.032	30	−7.530	3.293	1.117
1G	0.032	30	−7.840	3.168	.558
2G	0.032	30	−7.711	3.274	.580
3G	0.032	30	−7.544	3.297	.664
4G	0.032	30	−7.396	3.323	.747
5G	0.032	30	−7.239	3.353	.830
1H	0.032	30	−7.558	3.290	.161
2H	0.032	30	−7.433	3.322	.247
3H	0.032	30	−7.293	3.348	.343
4H	0.032	30	−7.153	3.376	.439
5H	0.032	30	−7.013	3.407	.534
6H	0.032	30	−6.874	3.440	.630
1J	0.032	108	−8.349	−3.250	−.676
2J	0.032	150	−8.144	−2.937	−.568
3J	0.032	150	−8.091	−2.727	−.519
4J	0.032	150	−8.048	−2.515	−.480
5J	0.032	150	−8.014	−2.298	−.450
6J	0.032	150	−7.988	−2.080	−.424
7J	0.032	150	−7.970	−1.861	−.397
8J	0.032	150	−7.959	−1.643	−.365
9J	0.032	150	−7.956	−1.425	−.322
10J	0.032	150	−7.959	−1.208	−.276
11J	0.032	150	−7.961	−.990	−.240
12J	0.032	150	−7.693	−.770	−.216
13J	0.032	150	−7.966	−.549	−.193
14J	0.032	150	−7.971	−.329	−.166
15J	0.032	150	−7.979	−.110	−.137
16J	0.032	30	−7.986	.080	−.114
17J	0.032	30	−7.996	.300	−.090
18J	0.032	30	−7.005	.521	−.070
19J	0.032	30	−8.013	.742	−.054
20J	0.032	30	−8.021	.964	−.037
21J	0.032	30	−8.031	1.185	−.018
22J	0.032	30	−8.042	1.406	−.003
23J	0.032	30	−8.052	1.627	.004
24J	0.032	30	−8.061	1.849	.008
25J	0.032	30	−8.073	2.070	.016
26J	0.032	30	−8.084	2.292	.018
27J	0.032	30	−8.091	2.512	−.008
28J	0.032	30	−8.093	2.728	−.061
29J	0.032	30	−8.093	2.939	−.123
1K	0.032	30	−8.349	−3.250	−.676
2K	0.032	30	−8.144	−2.937	−.568
3K	0.032	30	−8.091	−2.727	−.519
4K	0.032	30	−8.048	−2.515	−.480
5K	0.032	30	−8.014	−2.298	−.450
6K	0.032	30	−7.988	−2.080	−.424
7K	0.032	30	−7.970	−1.861	−.397
8K	0.032	30	−7.959	−1.643	−.365
9K	0.032	30	−8.108	−2.206	−.088
10K	0.032	30	−8.102	−2.092	−.047
11K	0.032	30	−8.097	−1.972	−.004
12K	0.032	30	−8.093	−1.865	.038
13K	0.032	30	−8.090	−1.761	.075
14K	0.032	30	−8.089	−1.656	.111
15K	0.032	30	−8.088	−1.550	.145
16K	0.032	30	−8.088	−1.444	.179
17K	0.032	30	−8.089	−1.338	.211
18K	0.032	30	−8.091	−1.232	.243
19K	0.032	30	−8.094	−1.125	.273
20K	0.032	30	−8.096	−1.018	.303
21K	0.032	30	−8.100	−.911	.332
22K	0.032	30	−8.103	−.804	.359
23K	0.032	30	−8.106	−.696	.386
24K	0.032	30	−8.110	−.588	.412
25K	0.032	30	−8.114	−.480	.437
26K	0.032	30	−8.118	−.372	.462
27K	0.032	30	−8.123	−.264	.486
28K	0.032	30	−8.128	−.155	.508
29K	0.032	30	−8.132	−.046	.528
30K	0.032	30	−8.137	.063	.548
31K	0.032	30	−8.142	.172	.568
32K	0.032	30	−8.147	.281	.591
33K	0.032	30	−8.153	.389	.615
34K	0.032	30	−8.160	.497	.640
35K	0.032	30	−8.167	.605	.663
36K	0.032	30	−8.174	.714	.682
37K	0.032	30	−8.181	.834	.700
38K	0.032	30	−8.188	.953	.717
39K	0.032	30	−8.196	1.073	.734
40K	0.032	30	−8.203	1.192	.750
41K	0.032	30	−8.211	1.312	.764
42K	0.032	30	−8.219	1.432	.779
43K	0.032	30	−8.229	1.585	.796
44K	0.032	30	−8.239	1.738	.812
45K	0.032	30	−8.250	1.891	.826
46K	0.032	30	−8.262	2.072	.840
47K	0.032	30	−8.276	2.253	.853
48K	0.032	30	−8.294	2.474	.864
49K	0.032	30	−8.312	2.695	.872
50K	0.032	30	−8.328	2.887	.874
51K	0.032	30	−8.376	3.074	.924
1L	0.035	30	−8.164	−2.262	.065
2L	0.035	30	−8.156	−2.149	.107
3L	0.035	30	−8.149	−2.035	.150
4L	0.035	30	−8.144	−1.922	.193
5L	0.035	30	−8.140	−1.813	.232
6L	0.035	30	−8.137	−1.708	.268
7L	0.035	30	−8.135	−1.603	.302
8L	0.035	30	−8.133	−1.498	.336
9L	0.035	30	−8.133	−1.392	.369
10L	0.035	30	−8.134	−1.285	.400
11L	0.035	30	−8.136	−1.179	.431
12L	0.035	30	−8.138	−1.072	.461
13L	0.035	30	−8.140	−.965	.490
14L	0.037	30	−8.143	−.857	.518
15L	0.037	30	−8.146	−.750	.545
16L	0.037	30	−8.149	−.642	.572
17L	0.037	30	−8.153	−.534	.597
18L	0.037	30	−8.157	−.426	.622
19L	0.037	30	−8.161	−.318	.646
20L	0.037	30	−8.165	−.209	.668
21L	0.037	30	−8.170	−.100	.689
22L	0.037	30	−8.174	.008	.709
23L	0.037	30	−8.179	.118	.729
24L	0.037	30	−8.184	.226	.751
25L	0.037	30	−8.190	.335	.776
26L	0.037	30	−8.197	.443	.801
27L	0.035	30	−8.204	.551	.824
28L	0.035	30	−8.211	.660	.844
29L	0.035	30	−8.217	.774	.862
30L	0.035	30	−8.224	.893	.879
31L	0.035	30	−8.231	1.013	.895
32L	0.035	30	−8.238	1.133	.912
33L	0.035	30	−8.246	1.252	.928
34L	0.035	30	−8.253	1.372	.942
35L	0.035	30	−8.262	1.509	.958
36L	0.035	30	−8.272	1.661	.974
37L	0.035	30	−8.283	1.814	.988
38L	0.032	30	−8.294	1.981	1.002
39L	0.032	30	−8.308	2.162	1.015
40L	0.032	30	−8.324	2.363	1.027
41L	0.032	30	−8.343	2.584	1.040
42L	0.032	30	−8.360	2.793	1.038
43L	0.032	30	−8.380	2.983	1.053
44L	0.032	30	−8.476	3.146	1.096
1M	0.030	30	−8.964	3.524	−.771
2M	0.030	30	−8.964	3.529	−.264
3M	0.030	30	−8.964	3.528	.436
4M	0.030	30	−8.964	3.520	1.003
5M	0.030	125	−8.964	3.505	1.570
6M	0.030	125	−8.964	3.484	2.136
1N	0.032	30	−8.724	3.208	−.624
2N	0.032	30	−8.625	3.208	−.558
3N	0.032	30	−8.526	3.210	−.492
4N	0.032	30	−8.428	3.2 13	−.426
5N	0.032	30	−8.329	3.218	−.360
6N	0.032	30	−8.246	3.210	−.304
7N	0.032	74	−8.154	3.166	−.247
1P	0.032	30	−8.656	3.211	.072
2P	0.032	30	−8.572	3.211	.119
3P	0.032	30	−8.487	3.213	.164
4P	0.032	30	−8.402	3.215	.210
1R	0.032	30	−8.632	3.204	.878

In FIGS. 8A-12, a second embodiment of a nozzle assembly of the present invention is indicated generally 110. This nozzle assembly includes an outer band 114 and an inner band 116 between which an airfoil 112 is mounted. Again, airfoil 112 has a curved airfoil shape with a rounded leading edge 118 and a trailing edge 120. Steam inlet manifold 122 and steam outlet manifold 124 are mounted on outer band 114 to circulate air through the airfoil, and an air inlet 126 admits air into the airfoil for discharge through holes or openings 128 for thin film cooling of the trailing edge of the airfoil. As with the previously described embodiment, the openings are formed in both the concave side and convex side of the airfoil in a predetermined pattern to maximize thin film cooling. The size of each opening and its location are again determined in accordance with the present invention. As shown in FIGS. 10 and 12, at the trailing edge of the airfoil, adjacent band 114, the sidewalls of the airfoil curve or flare outwardly to a circumferentially extending rail 130, and holes or openings are formed in this portion of the nozzle assembly.

The hole pattern for this embodiment again comprises three rows of openings which extend longitudinally of the airfoil, on both the concave and convex sides of the nozzle assembly, and spaced inwardly of the trailing edge. As particularly shown in FIG. 9, on the concave side of the airfoil are three rows indicated generally RA′, RB′, and RC′, and on the convex side of the airfoil, as shown in FIG. 11, are three rows indicated RJ′, RK′, and RL′. To further provide adequate thin film cooling, additional holes or slots are formed in the curved portions of the airfoil adjacent outer band 114, and on the portion of rail 30 adjacent the trailing edge of the airfoil. On the concave side of the nozzle assembly, and as shown in FIGS. 9 and 10, these additional openings are indicated 1D′-6D′, 1E′, 1F′-4F′, 1G′-5G′, and 1H′-6H′. On the convex side of the assembly, and as shown in FIGS. 11 and 12, these additional openings are indicated 1M′-6M′, 1N′-7N′, 1P′-4P′, and 1R′.

As shown in FIGS. 9 and 11, the rows of holes in the respective sidewalls of the airfoil include a forward row, an intermediate row, and an aft row. On the concave side of the assembly, row RC′ is the forward row and includes 31 openings. Row RB′ is the intermediate row and comprises 9 openings. The aft row is row RA′ and includes 43 openings. As previously described, the spacing between intermediate row RB′ and aft row RA′ is substantially closer than the spacing between forward row RC′ and intermediate row RB′. Further, the holes comprising intermediate row RB′ and those comprising forward row RC′ are arranged in a staggered pattern as shown in FIG. 9. On the convex side of the assembly, the spacing between intermediate row RK′ which has 10 openings, and aft row RL′ which has 44 openings, is substantially closer than the spacing between forward row RJ′ which has 29 openings, and intermediate row RK′. Again, the holes comprising intermediate row RK′ and those comprising aft row RL′ are arranged in a staggered pattern as shown in FIG. 11.

Table 2 is a listing of all the holes comprising rows RA′-RC′, RJ′-RL′, and the other holes formed in the curved outer portion of the airfoil and rai 130. The table includes each hole designation, the angle of the opening with respect to the outer surface of airfoil 112, and the X,Y,Z coordinates of the hole locations. As with FIGS. 1A and 1B, the distances are measured with respect to the reference point Q (0,0,0) shown in FIG. 8B.

TABLE 2
		ANGLE
		TO
HOLE #	DIAMETER	SURFACE	X (AB)	Y (AA)	Z (AC)
1A	.027	30	−7.792	−2.253	.179
2A	.027	30	−7.777	−2.137	.223
3A	.027	30	−7.766	−2.021	.269
4A	.027	30	−7.757	−7.905	.314
5A	.027	30	−7.748	−1.788	.357
6A	.027	30	−7.741	−1.670	.398
7A	.027	30	−7.736	−1.559	.435
8A	.027	30	−7.732	−1.453	.469
9A	.027	30	−7.729	−1.347	.502
10A	.027	30	−7.727	−1.241	.535
11A	.027	30	−7.726	−1.135	.566
12A	.027	30	−7.726	−1.028	.596
13A	.027	30	−7.726	−.921	.625
14A	.027	30	−7.728	−.814	.653
15A	.027	30	−7.730	−.706	.680
16A	.027	30	−7.732	−.598	.707
17A	.027	30	−7.736	−.490	.732
18A	.027	30	−7.740	−.382	.756
19A	.027	30	−7.745	−.274	.780
20A	.027	30	−7.750	−.165	.802
21A	.027	30	−7.756	−.056	.822
22A	.027	30	−7.762	.053	.840
23A	.027	30	−7.770	.162	.860
24A	.027	30	−7.780	.270	.882
25A	.027	30	−7.790	.378	.906
26A	.027	30	−7.802	.486	.929
27A	.027	30	−7.812	.594	.950
28A	.027	30	−7.822	.703	.968
29A	.027	30	−7.832	.813	.983
30A	.027	30	−7.843	.922	.997
31A	.027	30	−7.855	1.043	1.012
32A	.027	30	−7.870	1.174	1.028
33A	.027	30	−7.884	1.305	1.043
34A	.027	30	−7.898	1.437	1.057
35A	.027	30	−7.912	1.568	1.070
36A	.027	30	−7.931	1.744	1.085
37A	.027	30	−7.956	1.964	1.102
38A	.027	30	−7.980	2.164	1.114
39A	.027	30	−8.002	2.345	1.122
40A	.027	30	−8.031	2.553	1.130
41A	.027	30	−8.060	2.762	1.128
42A	.027	30	−8.091	2.969	1.136
43A	.027	30	−8.066	3.162	1.244
1B	.027	37	−7.894	−3.250	.074
2B	.027	37	−7.906	−3.049	−.202
3B	.027	30	−7.845	−2.827	−.157
4B	.027	30	−7.790	−2.630	−.100
5B	.027	30	−7.779	−2.544	−.060
6B	.027	30	−7.744	−2.427	−.055
7B	.027	30	−7.730	−2.311	−.010
48B	.027	30	−8.014	2.866	.966
49B	.027	30	−8.042	3.072	1.028
1C	.029	105	−7.803	−3.190	−.429
2C	.029	150	−7.811	−3.013	−.421
3C	.029	150	−7.726	−2.763	−.348
4C	.029	150	−7.674	−2.550	−.304
5C	.029	150	−7.629	−2.335	−.267
6C	.029	150	−7.584	−2.121	−.230
7C	.029	150	−7.544	−1.908	−.190
8C	.029	150	−7.514	−1.692	−.146
9C	.029	150	−7.494	−1.476	−.098
10C	.029	150	−7.482	−1.260	−.048
11C	.029	150	−7.476	−1.043	−.001
12C	.029	150	−7.470	−.824	.035
13C	.029	150	−7.464	−.604	.062
14C	.029	150	−7.465	−.383	.090
15C	.029	150	−7.470	−.163	.120
16C	.029	30	−7.481	.068	.148
17C	.029	30	−7.494	.288	.169
18C	.029	30	−7.508	.508	.186
19C	.029	30	−7.523	.729	.198
20C	.029	30	−7.539	.950	.209
21C	.029	30	−7.558	1.170	.220
22C	.029	30	−7.529	1.391	.230
23C	.029	30	−7.598	1.612	.234
24C	.029	30	−7.615	1.833	.234
25C	.029	30	−7.632	2.054	.232
26C	.029	30	−7.651	2.276	.228
27C	.029	30	−7.667	2.496	.206
28C	.029	30	−7.673	2.712	.152
29C	.029	30	−7.678	2.919	.094
30C	.029	30	−7.705	3.073	.102
31C	.029	85	−7.655	3.210	.102
1D	.030	30	−8.537	3.433	2.152
2D	.030	30	−8.810	3.459	1.880
3D	.030	30	−7.825	3.503	1.610
4D	.030	30	−7.471	3.565	1.340
5D	.030	108	−7.017	3.668	.993
6D	.030	108	−6.714	3.751	.760
1E	.032	30	−7.966	3.215	1.252
1F	.032	30	−7.966	3.164	.929
2F	.032	30	−7.833	3.252	.954
3F	.032	30	−7.682	3.271	1.036
4F	.032	30	−7.530	3.293	1.117
1G	.032	30	−7.840	3.168	.558
2G	.032	30	−7.711	3.274	.580
3G	.032	30	−7.544	3.297	.664
4G	.032	30	−7.396	3.323	.747
5G	.032	30	−7.239	3.353	.830
1H	.032	30	−7.558	3.290	.161
2H	.032	30	−7.433	3.322	.247
3H	.032	30	−7.293	3.348	.343
4H	.032	30	−7.153	3.376	.439
5H	.032	30	−7.013	3.407	.534
6H	.032	30	−6.874	3.440	.630
1J	.028	108	−8.349	−3.250	−.676
2J	.028	150	−8.144	−2.937	−.568
3J	.028	150	−8.091	−2.727	−.519
4J	.028	150	−8.048	−2.515	−.480
5J	.028	150	−8.014	−2.298	−.450
6J	.028	150	−7.988	−2.080	−.424
7J	.028	150	−7.970	−1.861	−.397
8J	.028	150	−7.959	−1.643	−.365
9J	.028	150	−7.956	−1.425	−.322
10J	.028	150	−7.959	−1.208	−.276
11J	.028	150	−7.961	−.990	−.240
12J	.028	150	−7.693	−.770	−.216
13J	.028	150	−7.966	−.549	−.193
14J	.028	150	−7.971	−.329	−.166
15J	.028	150	−7.979	−.110	−.137
16J	.028	30	−7.986	.080	−.114
17J	.028	30	−7.996	.300	−.090
18J	.028	30	−7.005	.521	−.070
19J	.028	30	−8.013	.742	−.054
20J	.028	30	−8.021	.964	−.037
21J	.028	30	−8.031	1.185	−.018
22J	.028	30	−8.042	1.406	−.003
23J	.028	30	−8.052	1.627	.004
24J	.028	30	−8.061	1.849	.008
25J	.028	30	−8.073	2.070	.016
26J	.028	30	−8.084	2.292	.018
27J	.028	30	−8.091	2.512	−.008
28J	.028	30	−8.093	2.728	−.061
29J	.028	30	−8.093	2.939	−.123
1K	.028	30	−8.349	−3.250	−.676
2K	.028	30	−8.144	−2.937	−.568
3K	.028	30	−8.091	−2.727	−.519
4K	.028	30	−8.048	−2.515	−.480
5K	.028	30	−8.014	−2.298	−.450
6K	.028	30	−7.988	−2.080	−.424
7K	.028	30	−7.970	−1.861	−.397
8K	.028	30	−7.959	−1.643	−.365
50K	.027	30	−8.328	2.887	.874
51K	.027	30	−8.376	3.074	.924
1L	.029	30	−8.164	−2.262	.065
2L	.029	30	−8.156	−2.149	.107
3L	.029	30	−8.149	−2.035	.150
4L	.029	30	−8.144	−1.922	.193
5L	.029	30	−8.140	−1.813	.232
6L	.029	30	−8.137	−1.708	.268
7L	.029	30	−8.135	−1.603	.302
8L	.029	30	−8.133	−1.498	.336
9L	.029	30	−8.133	−1.392	.369
10L	.029	30	−8.134	−1.285	.400
11L	.029	30	−8.136	−1.179	.431
12L	.029	30	−8.138	−1.072	.461
13L	.029	30	−8.140	−.965	.490
14L	.030	30	−8.143	−.857	.518
15L	.030	30	−8.146	−.750	.545
16L	.030	30	−8.149	−.642	.572
17L	.030	30	−8.153	−.534	.597
18L	.030	30	−8.157	−.426	.622
19L	.030	30	−8.161	−.318	.646
20L	.030	30	−8.165	−.209	.668
21L	.030	30	−8.170	−.100	.689
22L	.030	30	−8.174	.008	.709
23L	.030	30	−8.179	.118	.729
24L	.030	30	−8.184	.226	.751
25L	.030	30	−8.190	.335	.776
26L	.030	30	−8.197	.443	.801
27L	.029	30	−8.204	.551	.824
28L	.029	30	−8.211	.660	.844
29L	.029	30	−8.217	.774	.862
30L	.029	30	−8.224	.893	.879
31L	.029	30	−8.231	1.013	.895
32L	.029	30	−8.238	1.133	.912
33L	.029	30	−8.246	1.252	.928
34L	.029	30	−8.253	1.372	.942
35L	.029	30	−8.262	1.509	.958
36L	.029	30	−8.272	1.661	.974
37L	.029	30	−8.283	1.814	.988
38L	.028	30	−8.294	1.981	1.002
39L	.028	30	−8.308	2.162	1.015
40L	.028	30	−8.324	2.363	1.027
41L	.028	30	−8.343	2.584	1.040
42L	.028	30	−8.360	2.793	1.038
43L	.028	30	−8.380	2.983	1.053
44L	.028	30	−8.476	3.146	1.096
1M	.030	30	−8.964	3.524	−.771
2M	.030	30	−8.964	3.529	−.264
3M	.030	30	−8.964	3.528	.436
4M	.030	30	−8.964	3.520	1.003
5M	.030	125	−8.964	3.505	1.570
6M	.030	125	−8.964	3.484	2.136
1N	.032	30	−8.724	3.208	−.624
2N	.032	30	−8.625	3.208	−.558
3N	.032	30	−8.526	3.210	−.492
4N	.032	30	−8.428	3.213	−.426
5N	.032	30	−8.329	3.218	−.360
6N	.032	30	−8.246	3.210	−.304
7N	.032	74	−8.154	3.166	−.247
1P	.032	30	−8.656	3.211	.072
2P	.032	30	−8.572	3.211	.119
3P	.032	30	−8.487	3.213	.164
4P	.032	30	−8.402	3.215	.210
1R	.032	30	−8.632	3.204	.878

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A nozzle assembly for a turbine engine comprising: an inner band and an outer band spaced apart from each other; a nozzle installed between the bands and having an inner segment and a trailing edge, the nozzle having cavities formed therein for fluid flow through the nozzle assembly; and, a plurality of film cooling holes formed in a sidewall of the nozzle on a concave side thereof and a plurality of film cooling holes formed in a sidewall of the nozzle on a convex side thereof, the film cooling holes being formed on each side of the nozzle adjacent the trailing edge of the nozzle in a plurality of rows of holes including at least a forward row, an aft row, and a row intermediate the forward and aft rows, the spacing between the intermediate row and aft row being substantially closer together than the spacing between the forward row and the intermediate row.

2. The nozzle assembly of claim 1, wherein the holes comprising the intermediate row and the holes comprising the aft row are arranged in a staggered pattern.

3. The nozzle assembly of claim 2, in which the nozzle assembly includes a circumferential rail adjacent the outer band and holes are formed in the rail on the concave side and convex side of the nozzle.

4. The nozzle assembly of claim 3, further including additional holes formed on both the concave side and convex side of the nozzle adjacent the outer band.

5. The nozzle assembly of claim 1, wherein the size and location of each hole are set forth in Table 1.

6. The nozzle assembly of claim 1, wherein the size and location of each hole are set forth in Table 2.

7. In a gas turbine engine, a first stage nozzle assembly comprising: a plurality of circumferentially arranged nozzle segments with the respective segments being connected to one another to form an annular array defining a path for hot gasses passing through the first stage; each segment including an inner band and an outer band spaced apart from each other with an airfoil installed between the bands, the airfoil having an inner segment and a trailing edge, and cavities formed therein for fluid flow through the airfoil; and, a plurality of film cooling holes formed in respective sidewalls of the airfoil on a concave side and a convex side of the airfoil, the film cooling holes being formed on each side of the airfoil, adjacent the trailing edge, in a plurality of rows of holes including a forward row, an intermediate row, and an aft row, with the spacing between the intermediate row and the aft row being substantially closer together than the spacing between the forward row and the intermediate row.

8. The turbine engine of claim 7, wherein the holes comprising the intermediate row and the holes comprising the aft row are arranged in a staggered pattern.

9. The turbine engine of claim 8, in which each nozzle segment includes a circumferential rail adjacent the outer band and holes are formed in the rail on the concave side and convex side of the airfoil.

10. The turbine engine of claim 9, further including additional holes formed on both the concave side and convex side of the airfoil adjacent the outer band.

11. The turbine engine of claim 7, wherein the size and location of each hole are set forth in Table 1.

12. The turbine engine of claim 7, wherein the size and location of each hole are set forth in Table 2.