Steam enters a De laval steam turbine with an inlet velocity of 30 m/s and leaves with an outlet velocity of 10 m/s. The work done by 1 kg of steam is

Explanation:

Simple impulse Turbine (De Laval Turbine):

• It is the first working impulse turbine.
• It consists of a single set of the nozzle and moving blades. Therefore, total pressure drop from boiler pressure to condenser pressure takes place in a single nozzle which gives high rotational speed exceeding pressure limit of 3000 rpm.
• These turbines are mostly used in small power and high-speed purposes.

\(Work\;done = \frac{{V_2^2 - V_1^2}}{2} \)

Calculation:

Given:

V1 = 10 m/s, V2 = 30 m/s

\(Work\;done = \frac{{V_2^2 - V_1^2}}{2} = \frac{{{{30}^2} - {10^2}}}{2}\)

\(WD= \frac{{800}}{2} = 400~N - m\)