On the Experimental Results of Model Francis Water Turbine

Abstract

Water stream at the guide vane exit of vertical shaft high speed type 3 KW model Francis water turbine was studied experimentally. For this purpose, four cylindrical Pitottubes were inserted parallel to the shaft at the guide vane exit, and measured the water velocity and its direction. Absolute, tangential and radial inward velocities were varied with water quantity in a straight line approximately. In the latter half of experiments, which are mainly refered to runaway speed, it was confirmed that the direction of water stream at runaway condition was not different from normal speed condition, as the assumption made to deduce the previously presented runaway speed calculation formula. It was also assured that in the high speed type Francis water turbine, there is some Ns division where there is no difference in the water quantity of runaway and normal speed condition.