Solved question paper for EME May-2018 (B-TECH 1st-2nd)

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Solved Question Paper

Elements of mechanical engineering May-2018

PTU • B-TECH • Information Technology • 1st-2nd • May-2018

elements of mechanical engineering previous year question papers on BRpaper are organized for students of Punjab Technical University’s Bachelor of Technology program, 1st-2nd semester. This section makes it easier to browse subject-wise old question papers for elements of mechanical engineering, so students can review how questions are typically framed in past exams and get a sense of the exam pattern. Many students search for elements of mechanical engineering question bank while preparing for exams, and this page is built to support exactly that kind of subject-wise browsing and revision. BRpaper is not the official website of Punjab Technical University or any institution, and it does not publish official notices or academic updates.

PART-A

1. Basic Concepts of Thermodynamics (08)

Definition of thermodynamic: Need to study thermodynamics; Application areas of thermodynamic; Difference between Microscopic (or, Statistical) thermodynamics and Macroscopic(or, Classical) thermodynamics; Brief concept of continuum; Thermodynamic System : definition, types (Open, Closed and Isolated) and their examples; Thermodynamic System Boundary : definition, types and their examples; Surroundings; Control(fixed) mass and Control Volume concept and their example ; Thermodynamic State; Thermodynamic Property: definition, types citing their examples; condition for any quantity to be a property; State postulate; Thermodynamic equilibrium (which includes Thermal, Mechanical and Chemical equilibrium etc.); Thermodynamic path; Thermodynamic process: definition, concept of reversible process, quasi-static (or, quasi-equilibrium) process, irreversible process, conditions for reversibility and how these are met with, non-flow processes and flow processes, method of representation of reversible and irreversible process on property diagrams; Cyclic process; Thermodynamic Cycle: definition and its concept; Energy and its forms (microscopic and macroscopic); Physical insight to internal energy; Energy transfer across system boundary i.e. transient energies (heat and work); Difference between heat and work; Sign conventions for heat and work interactions; heat and work as path functions; Equality of Temperature and Zeroth law of Thermodynamics.

2. First Law of Thermodynamics and its applications (12)

Definition, essence and corollaries or consequences of first law of Thermodynamics; Expressions for First law of Thermodynamics for a control mass undergoing a Cycle and for process (i.e., a change in state of a control mass) ; Concept of Enthalpy and total energy and differentiation between the two - a thermodynamic property; Compressible and incompressible substances, Specific heats, Difference between Internal Energy and Enthalpy of compressible and incompressible substances; Representation of first law of thermodynamics as rate equation; Analysis of non-flow/ flow process for a control mass undergoing constant volume, constant pressure, constant temperature, adiabatic and polytropic processes; Free Expansion Process and its examples, its representation on Property diagram; Review of concepts of control volume; Expressions of first law of thermodynamics for a control volume (i.e. open system) ; Steady State Steady Flow process and its examples; First law analysis of Steady State Flow process e.g. isochoric, isobaric, isothermal, isentropic and polytropic process; Throttling process and its applications; Flow energy or inertial energy of flowing fluids or, Energy transport by mass; Application of Steady State Flow Energy Equation to various engineering devices.

3. Second Law of Thermodynamics (16)

Limitations of first law of thermodynamics; and how 2nd law is fully able to explain away and thus overcome those shortcomings of Ist law; Thermal Reservoirs, source and sink (Low temperature and high temperatures); Heat Engine, Heat Pump and Refrigerator: definitions, working, efficiency/performance and their real life examples. Justification as to why the actual efficiency of Heat Pump and Refrigerator shall also be ≤ 100% though on the face of it seems to be more than 100%; Various statements of Second Law of Thermodynamics and their equivalence; Philosophy of Carnot cycle and its consequences viz. how each of the individual four processes constituting the cycle contribute in optimizing the output and efficiency of the cycle; Carnot Engine, Carnot Refrigerator and Carnot Heat Pump: definitions, working, efficiency/performance and Limitations of the cycle; Carnot theorem for heat engines, refrigerators and heat pumps; derivation of Carnot efficiency/COP (which seems to be more than 100%); Thermodynamic Temperature Scale; Clausius theorem and Inequality; Philosophy and concept of entropy; Entropy changes during various processes; Temperature - Entropy Chart and representation of various processes on it; Principle of Increase of Entropy; Applications of Entropy Principle; Quality of Energy viz. high and low grade energies; Degradation of Energy; Third Law of Thermodynamics.

PART-B

4. Gas Power Cycles (12)

Introduction; Concept and philosophy of Air Standard Cycle alongwith associated assumptions and advantages; Air Standard Efficiency; Nomenclature of reciprocating piston-cylinder arrangement with basic definitions such as swept volume, clearance volume, compression ratio, mean effective pressure etc; Otto Cycle (or constant volume heat addition cycle), Diesel cycle (or constant pressure heat addition cycle) and Dual cycle (Mixed or Composite or Limited Pressure cycle) with their representation on P-V and T-S charts, their Air-standard (thermal) Efficiencies; Brayton Cycle, Comparison of Otto, Diesel and Dual cycle under some defined similar parametric conditions; Introduction to heat engines; Merits of I.C. Engines and their important applications, Classification and constructional features of I.C. Engines; working of two stroke and four stroke Petrol and Diesel engines and their comparison.

5. Engineering Materials (05)

Materials and Civilization, Materials and Engineering, Classification of Engineering Materials, Mechanical Properties of Materials: elasticity, plasticity, strength, ductility, brittleness, melleability, toughness, resilience, hardness, machinability, formability, weldability. Properties, Composition, and Industrial Applications of materials: metals (ferrous- cast iron, tool steels, stainless steels and non ferrous- Aluminum, brass, bronze ), polymers (natural and synthetic , thermoplastic and thermosetting), ceramics (glass, optical fibre glass, cements), composites ( fibre reinforced, metal matrix), smart materials (piezoelectric, shape memory, thermochromic, photochromic, magnetorheological), Conductors, Semiconductors and insulators, Organic and Inorganic materials. Selection of materials for engineering applications.

6. Centroid, Centre of Gravity and Moment of Inertia: (08)

Difference between centre of gravity and centroid. Determination of position of centroid of plane geometric figures of I, U, H, L, T, C, Circular and Triangular Sections. Centroid of Composite Areas. Determination of position of Centre of Gravity (CG) of regular solids viz. Right Circular Cone, Solid Hemisphere, thin Hollow Hemisphere. Area moment of inertia & mass moment of inertia, Polar moment of inertia, Parallel axes Theorem (or transfer formula), Perpendicular axes Theorem, Radius of gyration, determination of area Moment of Inertia of I, U, H, L, T, C, Circular and Triangular Sections along various axes. Mass moment of Inertia of Circular Ring, Disc, Cylinder, Sphere and Cone about their axis of symmetry and other axes.

Question papers (year-wise) Solutions

Solved Questions

Solved

Define a quasistatic process and state its salient characteristics.

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2019 Define quasistatic process and list its salient characteristics.

Dec 2014 Define a quasistatic process and state its salient characteristics.
What is meant by fixed points of a thermometric scale?

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2014 What is meant by fixed points of a thermometric scale?
How is polytropic exponent determined and within what limits it can range?

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2014 How is polytropic exponent determined and within what limits can it range?

May 2013 How is polytropic exponent determined and within what limits can it change?
State the Carnot Theorem in the context of a heat pump / refrigerator.

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2016 State Carnot theorem for an engine and a refrigerator.

Dec 2014 State the Carnot Theorem in the context of a heat pump/refrigerator.
State the requirements of a process to be isentropic.

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2017 Write the governing equation for isentropic process.

Dec 2014 State the requirements of a process to be isentropic.
For the same compression ratio and heat input, which cycle is more efficient: Otto, Diesel or Dual? Explain with T - s diagram.

Short Answer 2 Marks May-2018 • PTU B-TECH

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May 2016 For the same compression ratio and heat rejection, which cycle is most efficient: Otto, Diesel or Dual? Explain with p-v and T-s diagrams.

Dec 2014 For the same compression ratio and heat input, which cycle is more efficient: Otto, Diesel, or Dual? Explain with T–s diagram.
Mention the relative merits and demerits of two stroke engines when compared with four stroke engines.

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2017 Identify any 2 merits of two stroke engine over four stroke engine.

Dec 2014 Mention the relative merits and demerits of two stroke engines when compared with four stroke engines.
Compare and contrast elastic and plastic deformation of metals.

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2014 Compare and contrast elastic and plastic deformation of metals.

Explain the working of piezoelectric ceramics.

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2014 Explain the working of piezoelectric ceramics.
Write the position of centre of gravity for cylinder, hemisphere, sphere and right circular cone.

Short Answer 2 Marks May-2018 • PTU B-TECH

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Dec 2014 Write the position of centre of gravity for cylinder, hemisphere, sphere, and right circular cone.
Differentiate between temperature, heat and internal energy.

Short Answer 3 Marks May-2018 • PTU B-TECH

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May 2019 Distinguish between internal energy and enthalpy.

Dec 2016 Explain the difference between temperature, heat and internal energy.

Dec 2014 Differentiate between temperature, heat and internal energy.

Dec 2012 Differentiate between temperature, heat and internal energy.

May 2010 Differentiate between temperature, heat and internal energy.
A cylinder of volume 0.1 m3 contains nitrogen gas at 1.01 bar and 20°C. If 0.5 kg of nitrogen is now pumped into the cylinder, calculate the new pressure when the cylinder has returned to initial temperature. The molar mass of nitrogen is 28 kg/mol. Assume nitrogen to be perfect gas.

Long Answer 5 Marks May-2018 • PTU B-TECH

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Dec 2012 A cylinder of volume 0.1 m3 contains nitrogen gas at 1.01 bar and 20°C. If 0.5 kg of nitrogen is now pumped into cylinder, calculate the new pressure when the cylinder has returned to initial temperature. The molar mass of nitrogen is 28 kg/mol. Assume nitrogen to be perfect gas.
A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the mass of gas.

Long Answer May-2018 • PTU B-TECH

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May 2018 A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the change in internal energy.

May 2018 A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the heat transfer during compression.
A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the polytropic index n.

Long Answer May-2018 • PTU B-TECH

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Dec 2014 A cylinder contains 0.45 m3 of a gas at 1 bar and 253 K. The gas is compressed to a volume of 0.13 m3; the final pressure is 5 bar. Find: (a) the mass of gas, (b) polytropic index n, (c) change in internal energy, (d) heat transfer during compression. Take γ = 1.4, R = 294.2 J/kg-K.
A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the change in internal energy.

Long Answer May-2018 • PTU B-TECH

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May 2018 A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the mass of gas.

May 2018 A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the heat transfer during compression.
A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the heat transfer during compression.

Long Answer May-2018 • PTU B-TECH

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May 2018 A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the mass of gas.

May 2018 A cylinder contains 0.45 m3 of a gas at 1 bar and 353 K. The gas is compressed to a volume of 0.13 m3 and the final pressure is 5 bar. Find the change in internal energy.

Make an energy analysis of a centrifugal pump.

Short Answer 2 Marks May-2018 • PTU B-TECH

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May 2018 Make an energy analysis of a centrifugal pump.

Dec 2014 Make an energy analysis of a centrifugal pump.
A pump is used to raise the pressure of water from 1 bar to 25 bar and delivers 2000 kg/hr of water. Neglect changes in volume, elevation and changes in velocity. The specific volume of water is 0.00145 m3/kg. Calculate the power required to drive the pump.

Long Answer 6 Marks May-2018 • PTU B-TECH

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Dec 2017 Determine the power required to drive a pump which raises the water pressure from 1 bar to 25 bar at exit and delivers 2000 kg/hr of water. Neglect changes in volume, elevation and velocity. Assume specific volume of water to be 0.001045 m3/kg.

Dec 2014 A pump is used to raise the pressure of water from 1 bar to 25 bar and delivers 2000 kg/hr of water. Neglect changes in volume, elevation and changes in velocity. The specific volume of water is 0.00145 m3/kg. Calculate the power required to drive the pump.
Demonstrate using second law that free expansion is irreversible.

Short Answer 3 Marks May-2018 • PTU B-TECH

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Dec 2014 Demonstrate using second law that free expansion is irreversible.
A domestic food refrigerator maintains a temperature of –10°C while ambient temperature is –30°C. The heat leakage into the freezer is estimated to be at a continuous rate of 2 kJ/s. Determine the least power required to pump out this heat continuously.

Long Answer 5 Marks May-2018 • PTU B-TECH

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Dec 2014 A domestic food refrigerator maintains a temperature of –10°C while ambient temperature is –30°C. The heat leakage into the freezer is estimated to be at a continuous rate of 2 kJ/s. Determine the least power required to pump out this heat continuously.
In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.

Long Answer 8 Marks May-2018 • PTU B-TECH

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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.

May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.

Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4

Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.

Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.

Long Answer 8 Marks May-2018 • PTU B-TECH

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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.

May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.

Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4

Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.

Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.

Long Answer 8 Marks May-2018 • PTU B-TECH

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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.

May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.

Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4

Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.

Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.

Long Answer 8 Marks May-2018 • PTU B-TECH

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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.

May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.

May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.

May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.

Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.

May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4

Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.

May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.

Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
A mass m of the fluid at temperature T1 is mixed with an equal mass of the same fluid at temperature T2. Find the expression for resultant change in entropy of the universe and comment whether it is positive or negative.

Long Answer 5 Marks May-2018 • PTU B-TECH

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Dec 2014 A mass m of the fluid at temperature T1 is mixed with an equal mass of the same fluid at temperature T2. Find the expression for resultant change in entropy of the universe and comment whether it is positive or negative.
Find an expression for entropy change for an open system.

Short Answer 3 Marks May-2018 • PTU B-TECH

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Dec 2014 Find an expression for entropy change for an open system.
A solid right circular cylinder has its base scooped out so that the hollow is a right circular cone on the same base and having the same height as the cylinder. Find the centre of gravity of the remainder.

Long Answer 4 Marks May-2018 • PTU B-TECH

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Dec 2014 A solid right circular cylinder has its base scooped out so that the hollow is a right circular cone on the same base and having the same height as the cylinder. Find the centre of gravity of the remainder.
A hemisphere and cone have their bases joined together, the two bases being of the same size. Find the ratio of height of cone to the radius of the base, so that their common centre of gravity may be at the centre of common base.

Long Answer 4 Marks May-2018 • PTU B-TECH

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Dec 2014 A hemisphere and cone have their bases joined together, the two bases being of the same size. Find the ratio of height of cone to the radius of the base, so that their common centre of gravity may be at the centre of the common base.
Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Petrol engine. Describe briefly the factors which account for deviations between these plots.

Long Answer 4 Marks May-2018 • PTU B-TECH

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May 2018 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Diesel engine. Describe briefly the factors which account for deviations between these plots.

May 2014 Discuss the difference between theoretical and actual p–V diagrams for four stroke S.I. and C.I. engines.

Dec 2014 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke petrol engine. Describe briefly the factors which account for deviations between these plots.

May 2013 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Petrol engine. Describe briefly the factors which account for deviations between these plots.

Dec 2012 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Diesel engine. Describe briefly the factors which account for deviations between these plots.

Dec 2012 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Petrol engine. Describe briefly the factors which account for deviations between these plots.

Dec 2011 Discuss the difference between theoretical and actual p–V diagrams for two stroke S.I. and C.I. engines.
Explain briefly, particle reinforced, fiber reinforced and structural composites.

Short Answer 4 Marks May-2018 • PTU B-TECH

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Dec 2016 Explain briefly particle-reinforced, fibre-reinforced and structural composite.

Dec 2014 Explain briefly particle reinforced, fiber reinforced and structural composites.

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