Safe operation of hydrostation units with Kaplan turbines

Conclusions

• 1. The conditions of safe operating regimes of units with Kaplan turbines with respect to the possibility of uplifting of the rotor or discontinuity of the flow can be analyzed by means of the universal standard characteristics.

• 2. The universal standard characteristics plotted from the results of model investigations are the maximum with respect to the zones of limitation of the regimes and can be used for evaluating the allowable operating conditions of units of hydrostations under construction and being planned and also for the operation of hydrostations in the absence at them of devices for admitting air and in the presence of a considerable backwater from the lower pool side. The use of the model characteristics in the presence of vacuum breaker valves leads to the introduction of large margins and narrows the operating possibilities of the unit, and therefore the standard characteristics of such units should be corrected in conformity with their real operating conditions.

• 3. Refinement and correction of the standard characteristics to broaden the allowable zones of operation of the units should be carried out on the basis of prototype tests of turbines under real conditions with respect to the regime of air admission with direct measurement of the axial forces acting on the runner.