Question

there is table provided for help for the type of turbine

TIPO Min Max 1 Jacto PELTON 0.16 2 ou mais Jactos 0.30 0,10 FRANCIS Lenta 0,26 0,50 Normal 0,50 1,00 TURBINAS Rápida 1,00 2,50 5,50 KAPLAN HELICES 1,70 3,00 AXIAIS (de gás) 0.25 1,80 Centrífugas 120 0,15 ВОMBAS Mistas 1,20 2,50 Hélices 7,00 Radiais VENTILADORES 0.40 2,00 Ахiais 1,50 3. At a hydroelectric plant under design, a 40 m drop is available to drive three turbine-generator groups, for a hydraulic power of 300 MW, running at 120 rpm. The water level upstream and downstream of the dam is 43 m and 3 m, respectively, relative to the level of the river. a) Which type of turbine you would adopt and indicate approximately the diameter of the wheel and the volumetric flow rate delivered. b) Due to difficulties in digging the ground and to allow the installation of the diffusers, the turbines can not be placed at a level lower than 10 m, in relation to the river level. Can cavitation problems be expected under these conditions? c) What is the phenomenon of cavitation? How can this phenomenon affect the functioning of the turbomachinery.

Answer 1

Cavitation is the formation and collapsing of cavities or bubbles in a liquid mostly developed in the areas which have relatively low pressure around the pump impeller. It occurs in the absence of the net positive suction head the pump. It's the formation of bubbles in the liquid flowing in any Hydraulic Turbine.

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