| dc.description.abstract | The purpose of this master thesis was to take fieldmeasurements and find the energy distribution in the cross section at different distances from a Pelton turbine. According to IEC60041: 1991, thermodynamic efficiency measurements on Pelton turbines shall be done from 4 to 10 runner diameters away from the turbine center. This is due to inhomogeneous energy distribution.
For several reasons the assignment was changed. The new purpose was to measure the energy in a cross section with different numbers of injectors running, and see if and how the distribution changed. An uncertainty analysis was also made. The measurements were done at Ylja hydropower plant, and the energy was found by measuring the temperature. To measure the temperature, three SeaBird SBE38 sensors were used. The temperature was measured in 7 points in the cross section.
The measurements showed that the energy distribution in the outlet of a Pelton turbine was not homogeneous. Some areas in the cross section had a higher temperature than others. Could see some patterns in the energy distribution, but it changed according to the number of injectors that were running. Measurements and observations showed that in the upper layer of the outlet channel flow air and water were mixed together. Measurements in this area will give false values of the water temperature because the air heats up the water. Weighing all temperature measurements equally when finding the thermodynamic efficiency gives greater uncertainty and can give an incorrect result. To find out how much to weigh the different measurements, one must find the velocity distribution. | |
