STUPIDSID
1(a)
Starting from the fundamentals, show that for the maximum
discharge through nozzle, the ratio of throat pressure to inlet pressure is given by [left ( dfrac{2}{n+1}
ight )^{dfrac{n}{n-1}}] , where "n" is the index of
isentropic expansion of steam, through nozzle.
7 M
1(b)
Dry saturated steam at pressure of 6 bar flows through nozzles at the rate of 4.5 kg/sec and discharges at a pressure of 1.6 bar. The loss due to friction occurs only in the diverging portion of the nozzle and its magnitude is 12% of the total isentropic enthalpy drop. Assume the isentropic index of expansion n=1.135, determine the cross-sectional area at the throat and exit of the nozzles.
7 M
2(a)
Explain with a neat diagram the working of a Binary Vapor
Cycle.
7 M
Solve any one question from Q.2(b) & Q.2(c)
2(b)
Explain throttle control governing of steam turbine and compare it with nozzle control governing.
7 M
2(c)
What do you understand by compounding of steam turbine?
Explain the two stage pressure compounded impulse steam
turbine with neat sketch.
7 M
Solve any one question from Q.3 & Q.4
3(a)
Define the blade efficiency and hence derive an expression for
maximum blade efficiency for a single stage impulse steam
Turbine.
7 M
3(b)
The isentropic enthalpy drop across an impulse turbine nozzle is 132.5 kJ/kg. The nozzle efficiency is 92%. The nozzle angle is 16° . The relative velocity is reduced by 9% due to the friction in the flow over the blade. Assuming equiangular blade and optimum blade speed, determine the blade angles, power developed for a flow rate of 40 kg/min and the blade and stage efficiencies.
7 M
4(a)
Explain ''Reheat factor'' and ''Internal efficiency''. Derive the
relation between the stage efficiency, internal efficiency and reheat factor.
7 M
4(b)
A 50% impulse-reaction turbine runs at 3000 rpm. The angles at
exit of fixed bladings and exit of moving bladings are 30° and 20° respectively. At a particular stage, the mean ring diameter is 0.7 m and the steam condition is 1.5 bar and 0.96 dry. Calculate:
(a) the required height of bladings to pass 50 kg/s of steam, and
(b) the power developed by the stage.
(a) the required height of bladings to pass 50 kg/s of steam, and
(b) the power developed by the stage.
7 M
Solve any one question from Q.5 & Q.6
5(a)
Draw the schematic diagram of an actual gas turbine cycle with
inter-cooling, regeneration and reheating. Also draw the cycle on T-s diagram and write the equation of cycle efficiency.
7 M
5(b)
A gas turbine power plant of 5 MW capacity is supplied with air at 157deg; C. The pressure ratio is 6. The maximum temperature is limited to 750° C. The compression is carried out in one stage
and the expansion is carried out in two stages with reheating to the original temperature. The suction and exhaust pressure are 1 bar. Taking the following data:
Cpa= 1 kJ/kg-K, Cpg= 1.15 kJ/kg-K, γ (air)= 1.4, γ (gas)= 1.33 ηc = 80%, η t1 = η t2 = 85%, C.V of fuel= 18500 kJ/kg
ε (effectiveness of heat exchanger)= 0.75
Determine the following:
(i) Cycle efficiency
(ii) A:F ratio entering in the first turbine
(iii) Fuel consumption of the plant per hour.
Cpa= 1 kJ/kg-K, Cpg= 1.15 kJ/kg-K, γ (air)= 1.4, γ (gas)= 1.33 ηc = 80%, η t1 = η t2 = 85%, C.V of fuel= 18500 kJ/kg
ε (effectiveness of heat exchanger)= 0.75
Determine the following:
(i) Cycle efficiency
(ii) A:F ratio entering in the first turbine
(iii) Fuel consumption of the plant per hour.
7 M
6(a)
Explain the regenerative feed heating cycle for steam power
plant with schematic diagram.
7 M
6(b)
A high pressure boiler delivers steam at 90 bar and 480° C. The steam is expanded in the first section of the steam turbine to 12 bar and then passed on to reheater, where it is is reheated to the initial temperature. The expansion now takes place in the
remaining section of steam turbine, down to the condenser
pressure of 0.07 bar. Determine the work output and the
efficiency of the ideal cycle for flow of 1 kg/sec of steam.
7 M
Solve any one question from Q.7 & Q.8
7(a)
Derive an expression for the optimum intermediate pressure in an open cycle gas turbine with reheating.
7 M
7(b)
With the help of neat diagram, explain the working principle of
rocket engines. What are the merits and demerits?
7 M
8(a)
Explain with neat sketches, any three methods of blade fixation
on the turbine rotor.
7 M
8(b)
Explain with neat diagram the importance, working and
application of back pressure steam turbine. When and why the steam is de-superheated?
7 M
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