MECHANICAL ENGINEERING DEPARTMENT, OITM

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5 Sem.:4 th Subject: Energy Conversion Paper: ME-201E UNIT-1 Q1. Explain the seismometer with its working principle. (Important Question) (20) Q2. Classify the fuels and define calorific value of fuels. (Important Question) (20) Q3 (a). Sample of dry anthracite has the following composition by mass: C: 90%;H: 30%; O: 2.5% ;N:1% ; S: 0.5%; ash 3% calculate the stoichiometric air fuel ratio. (10) M-06, MDU (b) Define the term Availability? Derive expression for it. (10) M-06, MDU UNIT-2 Q4 (a) Discuss how the steam generators are classified. Give examples of each classification. (6)(D-08, KUK) (b) with the help of neat sketch, explain the working of locomotive steam boiler. How is it different from a boiler used for locomotives? (14)(Dec.-08,KUK) Q5. (a) What is function of fusible plug? Explain its location in the steam boiler. (6) (Dec.-08,KUK) (b) The following particulars refers to a steam plant consisting of a boiler, economiser and a superheated: steam pressure=14 bar, Mass of steam generated=5000kg/h, Mass of coal used= 675kg/h, Calorific value of coal= 29800kj/kg of coal, Temperature of feed water entering the economiser = 30 o C, Temperature of feed water leaving the economiser = C, Dryness fraction of steam leaving the boiler = 0.97, Temperature of steam leaving the superheater = C. Determine the following: (i) Overall efficiency of the plant (ii) The percentage of available heat utilised in the boiler, economiser &superheater respectively. (14) (Dec.-08, KUK) Q6 (a) Explain working of Lancashire boiler by a neat diagrammatic sketch showing the path of hot flue gases. (10) (b) Define and differentiate between mountings and accessories? Give three examples of each. (10) (Dec-11, KUK) Q7 (a) Calculate the height of chimney required to produce a draught equivalent to 1.7 cm of water if the flue gas temp. is C and ambient temperature is 22 0 C and minimum amount of air per kg of fuel is 17 kg. (10) (b) What do you understand by Chimney draught? How is it classified?(10)(dec.-11, KUK)

6 Q8 (a). Find the draft in mm of water column produced by chimney 30mm high when the mean temperature of hot gases is 300 o C, the temperature of outside air is 27 o C and 19 kg of air is supplied per kg of fuel burnt in the furnace. (10) (Sep. 11, Kuk) (b). Derive an expression for height of chimney. Take suitable example. (10) (Sep. 11, Kuk) UNIT-3 Q9 (a). What are continuous systems? Give three examples. (5) (b) Explain role of boundary conditions in continuous systems. (5) (c) Derive expressions for longitudinal vibrations of rods. (10) (D-08, KUK) Q10 (a) Describe different operations of Rankine engine cycle. Derive also expression for its efficiency. (10) (b). In a steam power cycle, the steam supply is at 15 bar and dry saturated. The condenser pressure is 0.4 bar. Calculate the carnot and rankine efficiencies of the cycle. Neglect pump work. (10) (D-08, KUK) Q11. A steam power plant operates on a theoretical reheat cycle. Steam at boiler at 150 bar, C expands through the high pressure turbine. It Is reheated at a constant pressure of 40 bar to C and expands through the low pressure turbine to a condenser at 0.1 bar. Draw T-S and H-S diagram, find: i) Quality of steam at turbine exhaust ii) Cycle efficiency iii) Steam rate in kg/kwh. (20) (Dec.-08, KUK) Q12 (a) In a rankine cycle the steam at inlet to turbine is saturated at a pressure of 35 bar and the exhaust pressure is 0.2 bar. Determine: (i) The pump work (ii) The turbine work (iii) Rankine efficiency (iv) The condenser heat flow (v) The dryness at the end of expansion. Assume flow rate of 9.5 kg/s (10) (b) What do you understand by binary vapour cycle? (10)(Sep. 11, Kuk) Q13(a) A simple rankine cycle works between pressure 28 bar and 0.06 bar, the condition of the steam being dry saturated. Calculate the cycle efficiency, work ratio and specific steam consumption. (14) (b).describe the following terms used in relation to a steam turbine: (i) Reheat factor (ii) Regeneratively cycle (6)Dec.-12 Kuk.

7 UNIT-4 Q14 (a) Estimate the mass flow rate of steam in a nozzle with the following data:inlet temperature and pressure C and 13 bar resp., back pressure = 1.0 bar, throat diameter = 12mm. (10) (b) What is the physical significance of critical pressure of a nozzle? (10) (Dec.-08, KUK) Q15 (a) Derive an expression for mass flow rate of steam discharged through a nozzle? (10) (b) with the help of mathematical equation discuss the shape of nozzle for different value of match number (different inlet velocities) at inlet of the nozzle. (10)(Dec.-08, KUK) Q16. A steam nozzle supplied at 7 bar and C discharges steam at 1 bar. If the delivering portion of nozzle is 50 mm long and throat diameter is 4.5 mm, determine the cone angle of the divergent portion. Assume the 10% of the total available enthalpy drop to be lost in the friction in the divergent part. Also determine temperature and velocity of steam at the throat. (20) (DEC. 05 MDU) Q17. 5kg of steam per minute pass through a convergent nozzle.the pressure and temp.of steam supplied to the nozzle box is 12 bar and C respectively. The discharge pressure is 0.1 bar. The expansion is super saturated up to throat and in thermal equilibrium afterwards. Calculate (i) Area of nozzle at exit (ii) Max. Degree of super saturation (iii) Degree of under cooling at throat PV 1.3 =C forsuper saturation, P/T 1.3/0.3 =C for super saturated. (20) (May-05 MDU) Q18 (a). Show by analytical method that for isotropic flow of steam through a convergent divergent nozzle, the throat velocity is local acoustic velocity. (10) (Sep. 11, Kuk) (b). Estimate the mass flow rate of steam in a nozzle with the following data: inlet pressure and temperature 10 bar and 200 o C, back pressure = 0.5 bar, throat diameter = 12mm. (10) (Sep. 11, Kuk) UNIT-5 Q19 In a single stage impulse turbine rotor has a diameter of 1.2 m running at 3000r.p.m. the nozzle angle is Blade speed ratio is The ratio of relative velocity at outlet to relative velocity at inlet is 0.9. The outlet angle of blade is 3 0 smaller than the inlet angle. The steam flow rate is 5kg/sec. Draw velocity dia. And find the following. (i) Velocity of whirl (ii) Axial thrust on the bearing (iii) Blade angle (iv) Power developed (20) May-05, MDU

8 Q20 (a).what is degree of reaction? Explain the working of single stage reaction turbine. Also explain pressure and velocity variations along the axis of turbine. (10) (b).explain the difference between impulse and reaction turbine? (10) (Dec.-05, MDU) Q21 In an impulse turbine, the steam velocity at inlet is 500 m/s, the blade speed is 150 m/s. the nozzle angle is Determine the inlet blade angle, if there is a frictional drop of 8 % in the relative velocity at outlet and the outlet blade angle is 2 0 more than the angle at inlet determine the power developed and the axial thrust for the flow rate of 10 kg/min. (20) (Dec.-06, MDU) Q22. In an impulse turbine steam the mean diameter of the blades is 1.05 m and speed is 3000 rpm. The nozzle angle is 20 0, the ratio of blade speed to steam speed is 0.42 and the ratio of relative velocity at outlet from the blades to that at inlet is the outlet angle of blade is to be made 3 0 less than inlet. The mass of steam flowing through the turbine per second is 10.0kg.Calculate: (i) blade angles (ii) relative velocity of steam entering the blades (iii) power developed and blade efficiency (iv) Tangential force on the blades. (20) (Dec.-11, KUK) Q23 (a) What do you understand by governing of steam turbine? Explain throttle governing. (10) (b) Discuss the features of parsons turbine. What is its working principle? (10) (Dec.-11, KUK) Q24. Steam is supplied to a turbine at 30 bar and 350 o C. The turbine exhaust pressure is 0.08 bar. The main condensate is heated regeneratively in two stages by steam bled from the turbine at 5 bar and 1 bar respectively. Calculate masses of steam bled off at each pressure per kg of steam entering the turbine and the theoretical thermal efficiency of the cycle. (20) (Dec.-11, KUK)

9 UNIT-6 Q25 (a).what are sources of air leakage into the condenser? How its pressure is detrimental. (10) (b) With the help of neat sketch explain the working of low level jet condenser. (10) Q26. In a steam condenser, the average temperature is 34 0 C. The vacuum is 680 mm Hg when the barometer reads 762 mm hg. The water enters at 25 0 C and leaves at 32 0 C. Determine the condenser efficiency. Also determine vacuum efficiency. (20) (Dec. 06 MDU) Q27 (a).with the help of neat sketch explain the working of surface condenser. (10) (b)a condenser has 5 cm Hg absolute pressure. The air vapour mixture has been cooled to 25 0 C in an air cooler section of condenser. Determine the capacity of ejector to handle m 3 /min of free air leakage in the condenser free air conditions are bar and 15 0 C. (10)(Dec.06MDU) Q28. A surface condenser deals with kg of steam per hour at a pressure of 0.09 bar. The steam enters at 0.85dry and the temperature at the condensate and air extraction pipe is 36 0 C. The air leakage amounts to 7.26 kg/hr determine: (i) The surface required if the average heat transmission rate is 3.97 KJ/cm 2 per second (ii) The cylinder diameter for the dry air pump, if it is to be single acting at 60 r.p.m. with a stroke to bore ratio of 1.25 and volumetric efficiency of 0.85 (20)(Sep. 11, KUK) UNIT-7 Q29. A single stage single acting air compressor 30 cm bore and 40 cm stroke runs at 200 r.p.m. the succession pressure is 1 bar at 15 0 C and the delivery pressure 5 bar determine the mean effective pressure and the ideal power required to run it when (a) compression is isothermal, (b) compression follows the law PV 1.25 =C, (c) compression is reversible adiabatic ɤ=1.4 and (d) Compression is reversible adiabatic n=1.5 neglect clearance. Determine the isothermal efficiency for (b), (c) and (d). Also find a adiabatic efficiency for (d) assume isentropic and reversible adiabatic index as ɤ=1.4 and R=0.287 Kj/Kg 0 K (20) (Dec. 08, Kuk) Q30. Determine the size of a cylinder for a double acting air compressor of 37 KW, in which air is drawn at 1 bar and 15 0 C and compressed, according to the law PV 1.2 = C to 6 bar the compressor runs at 100 r.p.m. with average piston speed of m/min. Neglect clearance. (20) (Dec. 06 MDU) Q31. Define volumetric efficiency of reciprocating air compressor and derive expression for it. (20)(Dec. 06 MDU)

10 Q32. An air compressor takes in air at 1 bar 100 (KPa) and 20 0 C and compresses it according to the law PV 1.2 =C, it is then delivered to a receiver at a constant pressure of 10 bar determine: (i) The temperature at the end of compression and (ii) The heat transferred and work done during the compression process per kg of air (iii) The work done during delivery take R= 287 J/Kg 0 K and ɤ = 1.4 (20) (Dec 06, MDU)