Thermodyanic

A steam turbine boiler plant operates on the Rankine Cycle. Steam is delivered from the boiler to the turbine at a pressure of 3.5 MN/m2 and with a temperature of 350˚C. Steam from the turbine exhausts into a condenser at a pressure of 10 kN/ m2. Condensate from the condenser is returned to the boiler using a feed pump. Neglect all the losses.

a)      Draw a diagram of the Rankine cycle for steam turbine boiler.

b)      Calculate the energy supplied in the boiler per kilogram of steam generated.

c)      Calculate the dryness fraction of the steam entering the condenser.

d)     Determine the Rankine efficiency.

One kilogram of air is taken through a Carnot cycle. The initial pressure and temperature of air are 1.73 MN/m2 and 300˚C, respectively. From the initial conditions, the air is expanded isothermally to three times its initial volume and then further expanded adiabatically to six times its initial volume. Isothermal compression, followed by adiabatic compression, completes the cycle. Determine

a)      The pressure, volume and temperature at each corner of the cycle.

b)      The thermal efficiency of the cycle.

c)      The work done per cycle.

d)     The work ratio.

Take R= 0.29 kJ/kg K, γ=1.4.

At a particular stage in a reaction turbine, the mean blade speed is 60 m/s and the steam is at a pressure of 350 kN/m2 with a temperature of 175 ˚C. Fixed and moving blades at this stage have inlet angles of 30˚ and exit angles of 20˚.

a)         Draw a velocity diagram represent this particular stage of reaction turbine.

b)      Determine the blade height at this stage if the blade height is one-tenth the mean blade-ring diameter and the steam flow is 13.5 kg/s.

c)         Calculate the power developed by a pair of fixed and moving blade rings at this stage.

Calculate the specific enthalpy drop in kJ/kg at the stage if the stage efficiency is 85%.