SHRI SANT GADGE BABA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHUSAWAL DEPARTMENT OF MECHANICAL ENGINEERING
SUBJECT: APPLIED THERMODYNAMICS Class SE (A, B &C)
Assignment no.1
01)
The Following data were obtained during the boiler trial. Mass of steam is 700kg/h, 0 temperature of feed water is 60 C, steam pressure is 10 bar, oil consumption is 55kg/h, C.V. of oil is 44,000 kJ/kg, Dryness fraction of steam is 0.98, temperature of flue gases leaving the 0 0 boiler is 350 C, boiler room temperature is 25 C, specific heat of flue gases is 1.02 kJ/kg-k, partial pressure of steam is 0.08 bar, heating surface area is 21.4 m 2.Percentage composition of oil by mass is C=85%, H2 = 14%, Ash = 1%. Analysis of dry flue gases by volume CO2 = 12.5%, O2 = 4.5%, N2 = 83%. 0 Find i) Equivalent evaporation per kg of fuel from and at 100 C. ii) Equivalent evaporation per sq.m of heating area. iii) Thermal efficiency of boiler. iv) Heat balance sheet on the basis of 1 kg of fuel and on the percentage basis.
02)
In a boiler trial of one hour duration, the following observations were made. Steam generated is 5250kg, fuel burnt is 695kg, calorific value of fuel is 30200kj/kg, 0 steam condition is 0.94, boiler pressure is 11 bars, temperature of hot well is 47 C, 0 temperature of steam leaving super heater is 240 C. Calculate i) Equivalent evaporation per kg of coal without and with super heater. ii) Boiler efficiency with and without superheater.Assume atmospheric pressure as 100 kpa.
03)
The following readings were obtained during a boiler trial of 6 hours duration. Mean steam pressure = 12 bar; mass of steam generated = 40000kg; mean dryness fraction 0 = 0.85; mean feed water temperature = 30 C, coal used = 4000 kg. Calorific value of coal is 33400kJ/kg. 0 Calculate: i) Factor of equivalent evaporation; ii) Equivalent evaporation from and at 100 C; iii) Efficiency of the boiler.
04)
A boiler generates 7.5 kg of steam per kg of coal burnt at a pressure of 11 bars; from feed 0 water having a temperature of 70 C. The efficiency of boiler is 75% and factor of evaporation is 1.15, specific heat of steam at constant pressure is 2 .3. Calculate; i) Degree of superheat and temperature of steam generated; ii) Calorific value of coal in kJ/kg; iii) Equivalent evaporation in kg of steam per kg of coal.
05)
The following data refers to a boiler plant consisting of an economizer, a boiler and a super heater. Mass of water evaporated per hour = 5940 kg, mass of coal burnt per hour = 675 kg, L.C.V. of coal= 31600kJ/kg, pressure of steam at boiler stop valve = 14 bar, temperature of feed 0 water entering the economizer = 32 C, temperature of fees water leaving the 0 economizer= 115 C, dryness fraction of steam leaving the boiler and entering 0 super heater= 0.96, temperature of steam leaving the super heater = 260 C, specific heat of superheated steam = 2.33. Determine: i) Percentage of heat in coal utilized in economizer, boiler, super heater, ii) Overall efficiency of boiler plant.
SHRI SANT GADGE BABA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHUSAWAL DEPARTMENT OF MECHANICAL ENGINEERING
SUBJECT: APPLIED THERMODYNAMICS Class SE (A, B &C) 01
Assignment no.2 3
A 4 – cylinder double acting compressor is required to compress 30 m of air per min. at 1 bar and 27 C to a pressure of 16bar.Determine the size of the motor required and cylinder dimension if following data are given Speed of compressor = 320 r.p.m. Clearance Ratio = 4% Stroke to bore ratio = 1.2 Mechanical efficiency = 82 % Value of index = 1.32 Assume no pressure change in suction valve and air gets heated by 12 C during Suction stroke.
02
A single stage, double-acting compressor has a free air delivery (F.A.D.) of 14 m 3 / min. measured at 1.013 bar. & 15 0C. The pressure and temperature in the cylinder during induction are 0.69 bar 320C. The delivery pressure is 7 bar and index of compression and expansion n = 1.3. The clearance volume is 5% of the swept volume. Calculate i) Indicated power required, ii) Volumetric efficiency.
03
A single-stage double-acting air compressor delivers air at 7.5 bar. The pressure and temperature at the end of suction stroke are 1 bar and 25 0C. It delivers 2.2 m3 of free air per minute when the compressor is running at 310 r.p.m. The clearance volume is 5% if stroke 0 volume. The pressure and temperature of ambient air are 1.03 bar and 20 C. Determine i) Volumetric efficiency of the compressor, ii) Diameter and stroke of the cylinder if both are equal , iii) I.P. of the compressor and B.P. if the mechanical efficiency is 85%. Take: Index of compression is 1.25, and Index of expansion is 1.3.
04
A two- stage single-acting reciprocating compressor takes in air at the rate of 0.2m 3 /s. The 0 intake pressure and temperature of air are 0.1 MPa and 16 C. The air is compressed to a final pressure of 0.7 MPa. The intermediate pressure is ideal and intercooling is perfect. The compression index in both the stages is 1.25 and the compressor runs at 600 r.p.m. Neglecting clearance. Determine : i) The intermediate pressure, ii) The total volume of each cylinder, iii) The power required to drive the compressor, iv) The rate of heat rejection in the intercooler Take Cp = 1.005 KJ/kg K and R = 0.287 KJ/ kg K
05
A single- acting two stage air compressor delivers air at 18 bar. The temperature and pressure of the air before the compression in L.P. cylinder are 25 0C and 1 bar. The discharge pressure of L.P. cylinder is 4.2 bar. The pressure of air leaving the intercooler is 4 bar and the air is 0 cooled to 25 C. The diameter and stroke of L.P. cylinder are 40 cm and 50 cm respectively. The Clearance volume is 5% stroke in both cylinders. The speed of the compressor is 200 r.p.m. Assuming the index of compression and re-expansion in both cylinders as 1.25, C p for air is 1.004 KJ/kg K, Determine: i) Power required to run the c ompressor ii) Heat rejected in intercooler per minute.
