Download GTU BE/B.Tech 2019 Winter 4th Sem Old 141903 Engineering Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER- IV (Old) EXAMINATION - WINTER 2019

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Subject Code: 141903 Date: 10/12/2019

Subject Name: Engineering Thermodynamics

Time: 10:30 AM TO 01:00 PM Total Marks: 70

Instructions:

1. Attempt all questions.

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2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Differentiate between the following:

1. Statistical and classical thermodynamics
2. Open system and closed system

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3. Intensive properties and extensive properties

(b) Explain first law of thermodynamics for closed system undergoing a cycle.

Q.2 (a) What is difference between heat and work? Show that heat is a path function and not a property.

(b) Derive the steady flow energy equation for a single stream entering and a single stream leaving a control volume and reduce it for turbine.

OR

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(b) An engine manufacturer claims to have developed a heat engine with following conditions: Power developed = 75 kW, fuel burnt = 5 kg/hour, heating value of fuel = 73000 kJ/kg, temperature limits = 1000 and 400 K. is the claim of manufacturer is true or false? Justify your answer.

Q.3 (a) Define COP. Prove that COP_HP = COP_R+1

(b) Prove equivalence of Kelvin-Planck’s and Clausius’ statements.

OR

Q.3 (a) Show that the efficiency of a reversible engine operating between two given constant temperatures is the maximum.

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(b) A lump of steel of mass 10 kg at 627°C is dropped in 100 kg of oil at 30°C. the specific heats of steel and oil are 0.5 kJ/kgK and 3.5 kJ/kgK respectively. Calculate entropy change for steel, oil and the universe.

Q.4 (a) Derive expressions for availability of steady flow open system.

(b) With the help of schematic diagram, derive an expression for Rankine cycle. Also represent it on p-v, T-s and h-s diagram

OR

Q.4 (a) Derive Maxwell’s equations.

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(b) Derive equation for air standard efficiency of Brayton cycle.

Q.5 (a) Write down the first and second TdS equations, and derive the expression for the difference in heat capacities, Cp and Cv.

(b) What is Joule Thomson coefficient? Explain it’s significance.

OR

Q.5 (a) Describe the method of determination of heating value of solid fuel using Bomb calorimeter.

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(b) A 1.5 kg mixture of two gases in 40% and 60% proportion is stored at 20° C in a closed vessel of 5 m³ capacity. If the gas constant for the constituent gases is 287 kJ/kgK and 294 kJ/kgK, calculate partial pressure, total pressure and gas constant pressure for the mixture.