Draft Tube!

@ammar-aziz-7MLZYl • Oct 15, 2024

Oct 15, 2024

1.1K

please explain me this line:
Draft tube has following purpose :- 1. It makes possible the installation of the turbine above the tail race level without the loss of head.

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mechky

@mechky-jbqpJD • Apr 19, 2012

Draft tube ensures an airtight closed circuit at turbine outlet thereby making possible to decrease the pressure at turbine outlet below atmospheric. For same working head, now it is possible to install the turbine above tail race water level. There is saving in excavation cost and maintenance cost. If there was no draft tube, the turbine would be installed below the tail race level and water had to be pumped out for maintenance of the runner. Therefore, draft tube helps to avoid the need of pumping out of water.
m.vivekanandan

@mvivekanandan-OjHrf9 • Apr 26, 2012

so wherever turbine is there will we have a draft tube????
mechky

@mechky-jbqpJD • Apr 27, 2012

m.vivekanandan
so wherever turbine is there will we have a draft tube????
Draft tubes are required for only reaction turbines as there is low pressure at the exit of the turbine. In case of impulse turbine the pressure at the inlet and the exit is essentially the same and higher than the pressure to which fluid is rejected thus it requires no draft tube.