Fluid Mechanics and Thermodynamics of Turbomachinery, 5e

C t
(a)
C P
(b)
2.5
2.0
1.5
1.0
0.5
0
20
15
10
5
0
0
0
Axial-flow Turbines: Two-dimensional Theory 135
g
0°
4°
6°
8°
10°
12°
0.5
g
0°
4°
6°
8°
10°
12°
0.5
FIG 4.30. Turbine characteristics under steady flow conditions: (a) Torque coefficient;
(b) Input power coefficient. (From Kim et al. 2002, with permission of Elsevier).
shown in Figure 4.31, the mean efficiency of the cycle can be computed. Figure 4.32
shows the mean efficiency as a function of the flow coefficient f for a range of g values
with c xi = 0.6cxo.
Compared to the basic Wells turbine (with g =0deg), the optimum result for g =10
deg shows an improved mean efficiency and an optimum flow coefficient of about 0.4.
It is apparent that further field testing would be needed to prove the concept.
f
f
1.0
1.0
1.5
1.5