AMIE * INSTITUTION OF ENGINEERS (INDIA) * MECHANICAL ENGINEERING * DESIGN AND CALCULATIONS: Q.1 What is Turbine? what are main Catogory of turbines?

Turbines: Machines that produce power by expansion of a continuosly flowing fluid to a lower pressure or head.

Main Catogories of turbines are:

1) Pelton wheel(Impulse turbine) : this is high head turbine.

Design rules for pelton

The specific speed $\eta_s$ of a turbine dictates the turbine's shape in a way that is not related to its size. This allows a new turbine design to be scaled from an existing design of known performance. The specific speed is also the main criterion for matching a specific hydro-electric site with the correct turbine type.
$n_s=n\sqrt{P}/H^{5/4}$ (dimensioned parameter), $n$ = rpm ^[1]
where:

$P$ = Power (kW)
$H$ = Water head (m)

The formula implies that the Pelton turbine is most suitable for applications with relatively high hydraulic head H, due to the 5/4 exponent being greater than unity, and given the characteristically low specific speed of the Pelton.^[2]

Pages

Q.1 What is Turbine? what are main Catogory of turbines?

Turbines: Machines that produce power by expansion of a continuosly flowing fluid to a lower pressure or head.

Main Catogories of turbines are:

1) Pelton wheel(Impulse turbine) : this is high head turbine.

Design rules for pelton

2) Francis Turbine(Reaction turbine): this is radial flow medium head turbine.

3)Kaplan turbine(reaction turbine): this is axial flow , low head turbine.