This paper presents data showing the improvement in cooling effectiveness of turbine vanes through the application of water–air cooling technology in an industrial/utility engine application. The technique utilizes a finely dispersed water-in-air mixture that impinges on the internal surfaces of turbine airfoils to produce very high cooling rates. An airfoil was designed to contain a standard impingement tube, which distributes the water–air mixture over the inner surface of the airfoil. The water flash vaporizes off the airfoil inner wall. The resulting mixture of air–steam–water droplets is then routed through a pin fin array in the trailing edge region of the airfoil where additional water is vaporized. The mixture then exits the airfoil into the gas path through trailing edge slots. Experimental measurements were made in a three-vane, linear, two-dimensional cascade. The principal independent parameters—Mach number, Reynolds number, wall-to-gas temperature ratio, and coolant-to-gas mass flow ratio—were maintained over ranges consistent with typical engine conditions. Five impingement tubes were utilized to study geometry scaling, impingement tube-to-airfoil wall gap spacing, impingement tube hole diameter, and impingement tube hole patterns. The test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, gas-to-coolant temperature ratio, water-and air-coolant-to-gas mass flow ratios, and impingement tube geometry. Heat transfer effectiveness data obtained in this program demonstrated that overall cooling levels typical for air-cooled Vanes could be achieved with the water–air cooling technique with reductions of cooling air flow of significantly more than 50 percent.

1.
Biesiadny, T. J., Klann, G. A., Clark, D. A., and Berger, B. 1987. “Contingency Power for Turbo Small Turboshaft Engines Using Water Injection Into Turbine Cooling Air,” NASA TM 89817, AIAA Paper No. 87-1906.
2.
Dudley, J. C., Sundell, R. E., Goodwin, W. W., and Kercher, D. M., 1984, “Two-Phase Heat Transfer in Gas Turbine Bucket Cooling Passages: Part 1,” in: Heat and Mass Transfer in Rotating Machinery, Metzer and Agfan, eds., Hemisphere Publishing Corporation, pp. 463–472.
3.
Fiszdon, J. K., Florschuetz, L. W., and Janssen, J. M., 1994, “Heat Transfer to Two-Phase Air/Water Mixtures Flowing in Small Tubes With Inlet Disequilibrium,” in:Heat Transfer in Gas Turbines, Chyu and Nirmalan, eds., ASME HTD-Vol. 300, pp. 165–171.
4.
Hylton, L. D., Nirmalan, N. V., and Sweeney, P. C., 1995, “Advanced Cooling Concept,” NASA Contractor Report, Preliminary Draft, Allison EDR 16666.
5.
Kline, S. J., and McClintock, F. A., 1953. “Describing Uncertainties in Single-Sample Experiments,” Mechanical Engineering, Jan., pp. 3–8.
6.
Nealy
D. A.
,
Mihelc
M. S.
,
Hylton
L. D.
, and
Gladden
H. J.
,
1984
, “
Measurements of Heat Transfer Distribution Over the Surfaces of Highly Loaded Turbine Nozzle Guide Vanes
,”
ASME Journal of Engineering for Gas Turbines and Power
, Vol.
106
, pp.
149
158
.
7.
Nirmalan
N. V.
, and
Hylton
L. D.
,
1990
, “
An Experimental Study of Turbine Vane Heat Transfer With Leading Edge and Downstream Film Cooling
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
477
487
.
8.
Pedersen
C. O.
,
1970
, “
An Experimental Study of the Dynamic Behavior and Heat Transfer Characteristics of Water Droplets Impinging Upon a Heated Surface
,”
International Journal of Heat and Mass Transfer
, Vol.
13
, pp.
369
381
.
9.
Schmidt
E.
,
1951
, “
Heat Transmission by Natural Convection at High Centrifugal Accelerations in Water-Cooled Gas Turbine Rotor Blades
,”
Institute of Mechanical Engineers Proceeding
, Vol.
185
, pp.
219
222
.
10.
Sundell, R. E., Dudley, J. C., Grondhal, C. M., and Kercher, D. M., 1984, “Two-Phase Heat Transfer in Gas Turbine Bucket Cooling Passages: Part 2,” in: Heat and Mass Transfer in Rotating Machinery, Metzer and Agfan, eds., Hemisphere Publishing Corporation, pp. 473–484.
11.
Van Fossen, G. J., and Stepka, F. S., 1979, “Review and Status of Liquid Cooling Technology for Gas Turbines,” NASA RP 1038.
12.
Van Fossen
G. J.
,
1983
, “
The Feasibility of Water Injection Into the Turbine Coolant to Permit Gas Turbine Contingency Power for Helicopter Application
,”
ASME Journal of Engineering for Power
, Vol.
105
, pp.
635
642
.
13.
Wenglarz, R. A., Nirmalan, N. V., and Daehler, T. G., 1995, “Rugged ATS Turbines for Alternate Fuels,” ASME Paper No. 95-GT-73.
This content is only available via PDF.
You do not currently have access to this content.