Basic Mechanical Engineering (3110006)

BME-3110006

Summer-2019

BE | Semester 1

Summer - 2019|04-06-2023

Total Marks 70

Q1 (a) Define Melting point, Boiling point and Triple point of water using p-v diagram.

Unit : Introduction

Q1 (b)
Derive an expression for internal energy for a closed system.

Unit : Properties of gases | Topic : Various non-flow processes like constant volume process

Q1 (c) Define specific heat at constant volume, constant pressure and adiabatic index. Also derive relationship between specific heats in form of Characteristic gas constant.

Q2 (a) Discuss the factors responsible for global warming and ozone depletion

Unit : Energy | Topic : Environmental issues like Global warming and Ozone depletion.

Q2 (b) Explain Equivalent evaporation and factor of evaporation

Unit : Steam Boilers

Q2 (c)
Determine the value of final dryness fraction of steam.

After losing $125 kJ$ from the steam at constant pressure.

After expansion to $3 bar$ pressure in a turbine stage and work equivalent of $20 kJ / kg$ done. Initially steam is available at $7 bar$ pressure and $0.9$ dryness fraction.

OR

Q2 (c)
Three kg of steam at a pressure of $10 bar$ exists in the following conditions. Calculate its enthalpy and internal energy in each of the cases.

Steam with $x = 0.91$

Steam at temperature $200 ° C$ .

Unit : Properties of Steam

Q3 (a) Explain the construction and function of Steam Trap with neat sketch. Also mention its specific location in the system.

Unit : Steam Boilers | Topic : Functioning of different mountings and accessories.

Q3 (b) Derive the equation for efficiency of Carnot cycle.

Unit : Heat Engines | Topic : Description and thermal efficiency of Carnot; Rankine; Otto cycle and Diesel cycles

Q3 (c) A double acting reciprocating pump has piston diameter of $150 mm$ and stroke length of $225 mm$ . the suction and delivery heads are $4 m$ and $12 m$ respectively. If the speed of the pump is $80 rpm$ and the actual quantity of water discharged is $0.61 \frac{m^{3}}{\min}$ . find the percentage slip, the coefficient of discharge and the power required to drive the pump if the efficiency of the pump is $80 %$ .

Unit : Pumps | Topic : Types and operation of Reciprocating

OR

Q3 (a) Explain the construction and function of Steam separator with neat sketch. Also mention its specific location in the system.

Unit : Steam Boilers | Topic : Functioning of different mountings and accessories.

Q3 (b) Prove that the efficiency of Otto cycle is greater than that of Diesel cycle for the same compression ratio.

Unit : Heat Engines

Q3 (c) Air is to be compressed in a single stage reciprocating compressor from $1.013 bar$ and $15 ° C$ to $7 bar$ . Calculate the indicated power required for free air delivery of $0.3 \frac{m^{3}}{\min}$ when the compression process is 1. Isentropic 2. Reversible isothermal 3. Polytropic with $n = 1.25$ .

Unit : Air Compressors

Q4 (a) Draw a neat sketch of p-v diagram for single stage compressor with clearance.

Unit : Air Compressors | Topic : Types and operation of Reciprocating and Rotary air compressors

Q4 (b) It is required to produce ice from $36 ° C$ water. The capacity of the ice plan is $6 ton$ and specific heat of the water is $4.18 \frac{kJ}{Kg K}$ . Determine the amount of ice produced in 3 hours.

Unit : Refrigeration & Air Conditioning

Q4 (c) In an ideal Otto cycle the air at the beginning of isentropic compression is at 1 bar and 15oC. The ratio of compression is 8. If the heat added during the constant volume process is 1000 kJ/kg, determine (a) the maximum temperature in the cycle, (b) the air standards efficiency (C) work done per kg of air.

Unit : Heat Engines | Topic : Description and thermal efficiency of Carnot; Rankine; Otto cycle and Diesel cycles

OR

Q4 (a) Draw a neat sketch of p-v diagram showing Free Air Delivery for air compressor.

Unit : Air Compressors

Q4 (b) Calculate the energy consumed in one month for following conditions: COP of air-conditioning unit: 5; Capacity of air conditioner: 2 TR; No of air conditioners: 8; All air conditioners run for 4 hours/day.

Unit : Refrigeration & Air Conditioning | Topic : Window and split air conditioners

Q4 (c) A petrol engine with a stroke length of 200 mm and diameter of $150 mm$ has a clearance volume of $7 \times 10^{5} {mm}^{3}$ . If the indicted thermal efficiency is $0.30$ , find the relation efficiency. If the effective pressure is $5 bar$ and engine runs at $1000 rpm$ . Find the IP of the engine. Take $γ = 1.4$ $η_{rel} = \frac{0.30}{0.51} \times 100 %$ $η_{rel} = 58.82 %$ .

Unit : Internal Combustion Engines | Topic : Four-stroke/ two-stroke cycle Petrol/Diesel engines

Q5 (a) Discuss the operational difference between Vapour compression and Vapour absorption refrigeration cycle

Unit : Refrigeration & Air Conditioning

Basic Mechanical Engineering (3110006)

Q1 (a) Define Melting point, Boiling point and Triple point of water using p-v diagram.

Q1 (b) Derive an expression for internal energy for a closed system.

Q1 (c) Define specific heat at constant volume, constant pressure and adiabatic index. Also derive relationship between specific heats in form of Characteristic gas constant.

Q2 (a) Discuss the factors responsible for global warming and ozone depletion

Q2 (b) Explain Equivalent evaporation and factor of evaporation

Q2 (c) Determine the value of final dryness fraction of steam. After losing 125 kJ from the steam at constant pressure. After expansion to 3 bar pressure in a turbine stage and work equivalent of 20 kJ/kg done. Initially steam is available at 7 bar pressure and 0.9 dryness fraction.

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Q2 (c) Three kg of steam at a pressure of 10 bar exists in the following conditions. Calculate its enthalpy and internal energy in each of the cases. Steam with x = 0.91 Steam at temperature 200° C.

Q3 (a) Explain the construction and function of Steam Trap with neat sketch. Also mention its specific location in the system.

Q3 (b) Derive the equation for efficiency of Carnot cycle.

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Q3 (a) Explain the construction and function of Steam separator with neat sketch. Also mention its specific location in the system.

Q3 (b) Prove that the efficiency of Otto cycle is greater than that of Diesel cycle for the same compression ratio.

Q3 (c) Air is to be compressed in a single stage reciprocating compressor from 1.013 bar and 15° C to 7 bar. Calculate the indicated power required for free air delivery of 0.3 m3min when the compression process is 1. Isentropic 2. Reversible isothermal 3. Polytropic with n = 1.25.

Q4 (a) Draw a neat sketch of p-v diagram for single stage compressor with clearance.

Q4 (b) It is required to produce ice from 36° C water. The capacity of the ice plan is 6 ton and specific heat of the water is 4.18 kJKg K. Determine the amount of ice produced in 3 hours.

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Q4 (a) Draw a neat sketch of p-v diagram showing Free Air Delivery for air compressor.

Q4 (b) Calculate the energy consumed in one month for following conditions: COP of air-conditioning unit: 5; Capacity of air conditioner: 2 TR; No of air conditioners: 8; All air conditioners run for 4 hours/day.

Q5 (a) Discuss the operational difference between Vapour compression and Vapour absorption refrigeration cycle

Q1 (b)
Derive an expression for internal energy for a closed system.

Q2 (c)
Determine the value of final dryness fraction of steam.

After losing $125 kJ$ from the steam at constant pressure.

After expansion to $3 bar$ pressure in a turbine stage and work equivalent of $20 kJ / kg$ done. Initially steam is available at $7 bar$ pressure and $0.9$ dryness fraction.

OR

Q2 (c)
Three kg of steam at a pressure of $10 bar$ exists in the following conditions. Calculate its enthalpy and internal energy in each of the cases.

Steam with $x = 0.91$

Steam at temperature $200 ° C$ .

OR

Q4 (b) It is required to produce ice from $36 ° C$ water. The capacity of the ice plan is $6 ton$ and specific heat of the water is $4.18 \frac{kJ}{Kg K}$ . Determine the amount of ice produced in 3 hours.

OR