[N Scheme] Diploma Thermal Engineering 1 Important Questions All Units PDF Download Direct Link

Diploma Thermal Engineering 1 Important Questions

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UNIT-I Basics of Thermodynamic and Thermodynamic Processes of Perfect Gases
Three Marks Questions
1. What are intensive and extensive properties? Give examples for each. [October 2019, 2005]
2. Define the term system, boundary and surroundings [April 2019]
3. State and explain the Kelvin Planck statement of the second law of thermodynamics. [April 2019, 2004, October 2010, 2007]
4. State and explain the Clausius statement of the second law of thermodynamics. [October 2018,2016, 2010, April 2007]
5. What is the universal gas constant? What is its relation with characteristic gas constant? [October 2018]
6. What are the types of thermodynamics systems? Give one examples for each system. [April2018, 2013, 2012, 2008, 2005, 1996, 1995, 1994, October 2014, 2003. 2009, 2003, 1994, 1993]
7. State and Explain the Zeroth law of thermodynamics.[October 2002, April 2018, 1996]
8. Distinguish between point function and path function. [April 2017, 2006]
9. What are intrinsic and extrinsic properties? Give examples for each. [April 2016]
10. Define the relationship between Cp, Cv & R. (Or) Derive the relation Cp-Cv=R [October 2015,2008, April 2004]

7 Marks and 10 Marks and 14 Marks Questions
1. 2.5 kg of gas with an initial volume 1.2m3 is cooled at constant pressure of 700 KN/m2 . The temperature at the end of cooling is 287°C. Determine: (i)The change in internal energy (ii)The change in enthalpy (iii)Heat transferred (iv)Work done and (v)Change in enthalpy Take R=0.32kJ/kgK and Cp =1.16 kJ/kgK.[October 2020]
2. 035 m3 of air at 22°C and under atmospheric pressure is heated under constant volume to a temperature of 100°C. Determine mass of air, the final pressure, heat transfer, change in internal energy, work done, change in enthalpy and change in entropy. Assume Cp = 1 kJ/kgK and Cv = 0.71 kJ/kgK. (Answer: m = 0.41454 kg, p2 = 128.116 kN/m2 , Q = 22.957 kJ, ∆U = 22.957 kJ, W = 0, ∆H = 32.334 kJ, ∆S = 0.069 kJ/K) [ April 2019, 2016, October 2010]
3. 0.25 kg of air at a pressure of 1 bar occupies a volume of 0.3 m3 . If this air expands isothermally, to a volume of 0.9 m3
. Determine the initial temperature, the final temperature, external work done, change in internal energy, heat transfer and change in entropy. Assume R = 0.29 kJ/kgK. (Answer: T1 = 413.79K, T2 = 413.79K, W = 32.9583 Kj, ∆U = 0, Q = 32.9583 kJ, ds = 0.07965
kJ/K) [October 2019, 2014, 1998, April 2010, 1998]
4. 0.5 kg of air at a pressure of one bar occupies a volume of 0.4 m2 . If this air expands isothermally to a volume of 0.8 m3
, find the initial temperature, external wok done and change in internal energy. Assume R = 0.29 kJ/kgK. (Answer:T1 = 275.962K, W = 27.726 kNm, ∆U = 0) [April 2021, 2007]
5. A gas expands adiabatically from a pressure and volume of 700kN/m2 and 0.015m3 respectively to a pressure of 140kN/m2 . Determine (i) The final volume (ii) Work done by the gas. (iii) Heat transfer and (iv) Change in internal energy. Take Cv = 0.752 J/kgK and, γ = 1.4. [April 2021] 6. 2 kg of a gas at 8 x 105 N/m2 expands adiabatically till the pressure falls to 4 x 105 N/m2 . During the process 120000 Nm of work is done by the system and the temperature falls from 377°C to 257°C. Calculate the value of index of expansion and characteristic gas constant. (Answer: γ = 1.4172, R = 0.2086 kJ/kgK) [October 2019, 2003]

7. 0.5 kg of a gas occupies 0.3 m3 at 20ºC and 140 kN/m2 and after adiabatic compression to 0.15
m3 , the pressure is 370 kN/m2 . Find the values of two specific heats and the value of a gas constant. (Answer: R = 0.2867 kJ/kgK; Cp = 1.001 kJ/kgK; Cv = 0.714 kJ/kgK) [April 2018, 2016, 2010, October 2004, 1996, 1987]
8. 0.5kg of air at 180oC expands adiabatically to 3 times its original volume. During the expansion, the temperature is decreased to 20oC. Work done during expansion is 53kNm. Fine the Cp,Cv and R.(Answer: Cp = 0.9252 kJ/kgK, Cv = 0.6625 kJ/kgK, R = 0.2627 kJ/kgK) [April 2019, 2014, 2007, 2004, 1999, October 2001, 2000, 1999, 1998, 1991]
9. 2 kg of an ideal gas is compressed from a pressure of 1.5 bar and at 16ºC to a pressure of 7.5 bar according to the law PV1.3 = C. determine (i) the initial volume (ii) final temperature (iii) work done (iv) change in internal energy (v) heat transferred (vi) change in entropy. Assume R = 0.28 kJ/kgK and Cp = 1.0 kJ/kgK. (Answer: V1 = 1.0789m3 ; T2 = 418.98K; W = -242.55kJ; ΔU = 187.178kJ; Q = -55.3716kJ; ΔH = 259.97kJ; dS = -0.1585kJ/K.) [April 2017, 2013, 2011]
10.0.25 kg of air at a pressure of 140 kN/m2 occupies 0.15 m3 and from this condition it is compressed to 1.4 MN/m2 according to the law PV1.25 = C. determine (i) the change in internal energy of air (ii) the work done during this process. (iii) The heat transferred. Take Cp = 1.005 kJ/kgK and Cv = 0.718 kJ/kgK. (Answer: ΔU = 30.728kJ; W = – 49.112kJ; Q = – 18.383kJ) [October 2018, 2014, 2008, 2004, 1995, April 2005, 1997]

Diploma Thermal Engineering 1 Important Questions
Diploma Thermal Engineering 1 Important Questions

UNIT-II Thermodynamic Air cycles
Three Marks Questions
1. Distinguish between reversible and irreversible processes. [October 2019, 2007]
2. Compare Otto and diesel cycles.[October 2018, 2008, April 2007]
3. Draw the actual P-V diagram of Otto cycle and indicate the various sketches. [April 2019,October 2015, 2009]
4. No engine can work on Carnot cycle. Why? [April 2018, October 2004]
5. A Carnot cycle working between 377°C and 37°C produces 150kJ of work. Find (i) thermal efficiency and (ii) Head added during the process. [April 2017, 2015, 2011, 2004]
6. What are the assumptions made in the analysis of steady flow energy equation? [October 2019, 2008, 2007, 2005, April 2010]
7. Mention the applications of steady flow energy equation. [April 2014, 2010, October 2005]
8. Define Fourier’s law.
9. Define conduction, convection and Radiation.
10. Define LMTD.

7 Marks and 10 Marks and 14 Marks Questions
1. A perfect heat engine working on a Carnot cycle converts 1/6th of the heat input into work. When the temperature of the sink is reduced by 62°C, the efficiency is doubled. Determine the
temperature of the sink and the source. [October 2016, 2003, April 2021, 2019]
2. An engine working on Otto cycle has a compression ratio of 7. The temperature of the air at the start of compression stroke is 40oC and the maximum temperature is 1250oC. Determine the work done per kg of working fluid and efficiency of the cycle. Assume Cp=1.005 kJ/kgk and Cv=0.717 kJ/kgk. (Answer: ηotto = 54.24%, W = 326.31 kJ/kg) [April 2018] 3. In an ideal constant volume cycle the pressure and temperature at beginning of compression are 97 kN/m2 and 500C respectively. The ratio compression is 5:1. The heat supplied during the cycle is 970KJ/kg of working fluid. Determine (i) maximum temperature of the cycle (ii) thermal efficiency of the cycle and (iii) work done during the cycle per kg of working fluid Assume γ=1.4 and Cv=0.717
kJ/kgK. (Answer: T3 = 1967.74 K, ηotto = 47.47%, W = 460.459 kJ/kg) [April 2017, 1993, October 2009]
4. Calculate the air standard efficiency of an engine working on Otto cycle, if the pressure at the beginning and end of compression are 103.5 kN/m2 and 827.5 kN/m2 respectively. Take γ=1.4.(Answer: ηotto = 44.79 %)[April 2014, 1997, 1995, 1993, October 2016, 2013, 2011]
5. Find the air standard efficiency of a diesel cycle engine if the cutoff is 6% of the stroke and the clearance is 1/13th of the stroke. Take γ=1.4 (Answer: ηdiesel = 60.43%) [April 2013, 2006, 2004, October 2020, 2014, 2011, 2000]
6. Find the power output of a diesel engine working on a standard diesel cycle with a compression ratio of 16 and an air flow rate of 0.25kg/s. the initial conditions are pressure 1 bar and 27oC. If the heat added per cycle is 2500 kJ/kg. Assume Cp=1.005 kJ/kgk and Cv=0.71 kJ/kgk.(Answer: P = 337.8125 kW) [April 2016, 2014, 2012, October 2017, 2005, 1985]
7. Describe the working of a parallel flow heat exchanger with a line sketch. [October 2013]
8. Describe the working of a counter flow heat exchanger with a line sketch. [October 2014, 2013]
9. Discuss about the conduction heat transfer through a plane wall and composite wall.
10.Discuss about the conduction heat transfer through a hollow cylinder.
11.Explain heat transfer by conduction.
12.Explain heat transfer by convention.
13.Explain heat transfer by Radiation.
14.Explain with diagram the steady flow energy equation for steam Boiler, steam Nozzle and Air compressor. (Or) State and explain steady flow energy equation [April 2015, 2008, 2007, 2006, 2005, 2004, October 2017,2007]

UNIT-III Internal Combustion Engines
Three Marks Questions
1. Write down the difference between four stroke and two stroke petrol engines. (Or) Compare four stroke engines with two stroke engines. [October 2019, April 2008]
2. List the important components of an IC engine. [October 2019]
3. Draw a connecting rod and explain its salient features. [April 2019]
4. Compare wet liners with dry liners. [October 2018, 2016, 2013, 2012, April 2016]
5. State the function of flywheel. [October 2019, 2018, 2017]
6. List a few material sued for construction of cylinder block and connecting rod. [October 2019]
7. Sketch the valve of an IC engine and name the parts. (Or) Sketch the valve of an IC engine and Name its important features. [October 2017, April 2019]
8. Give the purpose of different types of piston rings. [October 2017]
9. Draw a typical valve timing diagram for a four stroke cycle diesel engine and indicate the various processes. [October 2016]
10. List out any two troubles and causes in lubrication system. (October 2019, 2007, 2006)
11. State the function of fuel filters and air cleaners. [October 2019]
12. Explain the diesel fuel feed system with a layout. [April 2017]
13. Draw the layout of a fuel feed system of a petrol engine and lists the salient parts. [October 2017]
14. What are the elements of fuel feed system in a petrol engine? [October 2018]
15. Give a detailed classification of carburetors. [April 2018, October 2013]
16. What is the petroil lubricating system (Or) explain the petroil lubricating system? [April 2019,2016, 2004]
17. State the main parts of a simple carburetor. [April 2019]

7 Marks and 8 Marks and 14 Marks Questions
1. Explain the working of A.C mechanical fuel pump, with necessary sketches. (April 2017, 2015, 2014, 2013, 2009, 2001, October 2020 CAT2, 2018, 2017, 2014, 2010, 2007, 2006)
2. Explain the construction and working of overhead valve operating mechanism with a neat sketch. (October 2018, 2016, 2013, April 2021, 2019, 2013, 2009, 2007, 2002)
3. Explain the working of a four stroke cycle petrol engine with a neat sketch.[October 2020 CATS,2017, 1998, April 2000]
4. Explain the working of a simple carburetor and point out its short coming for use in car engines. [October 2020 CAT2, April 2015, 2004]
5. Explain with a neat sketch the working of in line (CAV) fuel injection pump used in diesel engine. [October 2015, 2011, 2009, 2008, 1995, April 2010, 2005, 1993]
6. Explain the battery coil ignition system used in spark ignition engines with a line diagram. State its applications. [October 2018, 2017, 2015, 2014, 2013, 2011, 2007, 2006, 1994, April 2019, 2018,2016, 2010, 1997, 1995]
7. Explain with neat sketch, the working of a full pressure lubrication system in an I.C engine. (October 2019, 2018, 2016, 2015, 2013, 2012, 2009, 2008, 2005, April 2021, 2016, 2015, 2014,2012, 2011, 2010, 2001)
8. Explain the working of pump assisted water cooling system. (Or) Briefly explain with neat sketch, the construction and operation of water pump circulating cooling system. (April 2019, 2018, 2016,2013, 2012, 2009, 2005, 2004, October 2020, 2017, 2012, 2011, 2010, 2009, 2008, 2005, 2001)

UNIT-IV
Three Marks Questions
1. Explain the various efficiencies of an IC engine. [October 2000, 1999, 1993, April 1997]
2. List out various methods of determining the brake power of an IC engine and explain any one method. [October 2008, 2007, 19995, 1993]
3. Write the formula for calculate the following (i) brake thermal efficiency (ii) Indicated thermal efficiency (iii) Mechanical efficiency (iv) Relative efficiency [October 2015, 2006, 2004, April 2006]
4. Explain how Morse test is conducted. [April 2012]
5. Explain the high calorific value and lower calorific valve? [October 2009, April 2007]
6. How fuels are are classified? State the merits and demerits of each. [April 2008, October 2007]
7. What is indicated power and how it is measured? [April 2008]
8. What is meant by Heat balance sheet of an IC engine? [April 2007]
9. What is meant excess air? [October 2006, April 2006, 2004]
10.What are the requirements of a good fuel? [April2017, 2010, October 2013, 2008. 2005, 2003]

7 Marks and 10 Marks and 14 Marks Questions
1. Explain how the calorific value of a fuel is determined using Bomb calorimeter. [October 2014,2011, 2008, April 1996]
2. Describe with neat sketch the method of determine HCV and LCV of a gases fuel using Junker’s gas calorimeter. [April 2012, 1993, October 2009, 1995]
3. Explain with neat sketch. The analysis of flue gases using an Orsat apparatus. [October 2010,April 2014, 1995]
4. Explain the Morse test for finding out the indicated power of a multi cylinder engine. (Or) Describe the procedure for conducting Morse test. [April 2015, 2012, 2005, 2004, 1995, October 2019,2000, 1998, 1994]
5. A six cylinder four stroke engine has a bore to stroke ratio of 360:500 mm, During the trial, following results were obtained; Mean area of indicator diagram – 0.00075 m3 ; Length of indicator diagram – 0.075 m; Spring number – 70000 kN/m2 per m of compression; Brake torque – 14 kNm; Speed – 500 rpm; Fuel Consumption – 240 kg/hr. calculate (i) total indicated power developed (ii) brake power (iii) mechanical efficiency and (iv) specific fuel consumption. (Answer IP = 890.75 kW,
BP = 733.04 kW, ηm = 82.3%, BSFC = 0.3274 kg/kW-hr) [October 2018, 2006, 1992, April 2018, 2014, 2006, 2004]
6. The following particulars refer to a two stroke oil engine: Bore = 200mm, stroke = 300mm, speed = 350 rpm, Indicated Mean effective Pressure = 2.75 bar, net brake load = 610N, diameter of brake drum = 1m, oil consumption = 4.25 kg/hr, Calorific value of fuel = 44000 kJ/kg. Determine (a) Mechanical efficiency (b) Indicated thermal efficiency (c) Brake thermal efficiency. [April 2021, October 2016]
7. The following readings were taken during a test on a single cylinder four stroke oil engine, Stroke volume – 0.00924 m3
; mean effective pressure – 712 kN/m2 ; Engine speed – 250 rpm; Brake torque – 440 Nm; Fuel used per hour – 3.5 kg. Gross calorific value of oil = 46050 kJ/kg. Calculate Indicated power, Brake power, Indicated thermal efficiency ,brake thermal efficiency and mechanical efficiency. (Answer IP = 14.721 kW, BP = 11.52 kW, ηIT = 32.88%, ηBT = 25.73%, ηm = 78.26% ) [October 2020 CATS, 2013]
8. The following results were obtained during a Morse test on a four stroke petrol engine; BP with all
cylinders working = 11.92 kW; BP with cylinder 1 cut out = 8.46 kW; BP with cylinder 2 cut out = 8.60 kW; BP with cylinder 3 cut out = 8.54 kW; BP with cylinder 4 cut out = 8.50 kW. Calculate the mechanical efficiency of the engine. If the fule consumption is 3.5 kg/hour, find the indicated thermal efficiency. Calorific value of fuel is 42000 kJ/kg. (Answer: ηm = 87.78%, ηIT= 33.26%) [April 1999, 1994, October 2015, 2014, 2010, 2005, 1999]
9. During a trial of four stroke single cylinder oil engine the following observations were recorded. Duration of trial 1 hour, fuel consumption 7.05kg, calorific value of fuel 44000kJ/kg, engine speed 210 Rpm, Net load on brakes 1350N, Brake drum diameter 1600mm, mass of cooling water 495kg, temperature rise of cooling water 38oC, temperature of exhaust gases 300oC, air consumption 311kg, room temperature 20oC, specific heat of exhaust gases 1.004 kJ/kgK, specific heat of water 4.1868 kJ/kgK. Draw up a heat balance sheet per minute of the trial. (Answer: QBP = 27.56%, Qw = 25.39%, Qg = 28.82%, Qua = 18.23%) [April 2014, 2013, 2010, October 2020, 1994]

UNIT-V Refrigeration and Air conditioning
Three Marks Questions
1. State the desirable properties of refrigerants (April 2021, 2016, 2011, 2001, 2000, 1994, October 2015, 2011, 2005, 2001, 2000, 1993)
2. Draw the reversed Carnot cycle and derive an expression for COP for refrigeration. [April 2008]
3. Explain the terms: (i) Specific Humidity (ii) Relative Humidity. [April 2008]
4. Distinguish between Specific Humidity and Relative Humidity. [October 2007]
5. Define the term air conditioning. Mention any three important applications of air conditioning. [October 2016, 2011, April 2007]
6. Distinguish between a refrigerator and a heat pump. [October 2006]
7. What are the factors to be considered in air-conditioning? [April 2014, 2006]
8. Define the following terms: (i) COP (ii) TOR. [October 2005]
9. State the desirable properties of refrigerants. [April 2016, 2011, October 2015, 2011, 2008, 2005]
10.What is psychometric chart? [October 2005]
11.State the applications of the Refrigeration. [October 2008, April 2005]
12.Distinguish between vapour absorption and vapour compression refrigeration systems.[April 2015, 2009, 2005]
13.Explain any one psychometric process with sketches. [October 2015]
14.State the merits and demerits of a central air conditioning system. [October 2014]
15.Explain the processes sensible heating and sensible cooling. [October 2013, 2008, April 2012, 2011,
16.Define (i) Wet bulb temperature and (ii) Dry bulb temperature. [April 2009]

7 Marks and 10 Marks and 14 Marks Questions
1. Explain the refrigeration system on Bell-Coleman cycle with a neat sketch. [April 2007]
2. Explain the working of a vapour compression refrigeration system with a neat sketch. (April 2015, 2014, 2011, 2008, 2001, 1994, 1992, 1990, 1989, October 2020 CAT2, 2019, 2018, 2016, 2010, 2009, 2008, 2007, 2001, 1991)
3. With a simple sketch, briefly explain the working of vapour absorption system (April 2019, 2018, 2015, 2013, 2006, 1994, October 2017, 2016, 2005, 2003, 1999, 1997)
4. Explain the central air conditioning system. (April 2017, 2015, 2014, 2012, 2006, 2001, 1998, 1995, 1991, October 2011, 2010, 2006, 2003, 1996, 1992)
5. Briefly explain the principles of working of a room air conditioner with a neat sketch. (April 2016, 1992, 1997, 1998, 2000, 2001, 2008, 2007, October 1991, 1994,1999, 2003, 2006, 2013)
6. Enumerate the various load encountered in air-conditioning system. (April 1997, 2009,2015, October 1995, 2000, 2001, 2004, 2009, 2012, 2014)
7. What are the various psychrometric processes? Explain sensible heating and sensible cooling by indicating them in a psychrometric chart. (April 1996, October 1996, 1999, 2004, 2007, 2011,2013)

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