Table 4

*X <= indicates hydraulically smooth flow, when X can be taken as 1 and drop in efficiency computed. Results thus obtained and given in the last column shows insignificant change.

Sl.No. Surface roughness Ra of various components (microns) Drop in hhP %
Spiral casing Guide vane Runner Draft tube Disc friction X as computed *X=1 if X 1
1 0.9 0.4 0.4 0.9 0.4 No drop No drop
2 0.9 0.8 0.8 0.9 0.8 0.04946 0.0700
3 0.9 1.6 1.6 0.9 1.6 0.1819 0.1956
4 0.9 3.2 3.2 0.9 3.2 0.3786 0.3923
5 0.9 6.4 6.4 0.9 6.4 0.6454 0.6591