JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II Year THERMODYNAMICS Previous Question Paper (May/June - 2019 - R15)

Discuss the similarities and dissimilarities between heat and work.

What are intensive and extensive properties?

What is PMM-I. Justify with reason whether it is feasible or not?

A heat pump takes up heat from cold outdoors and transfers it to warmer indoor space. Is this a violation of second law of thermodynamics? Explain.

What is the difference between critical point and triple point?

What is pure substance? Draw PV diagram for a pure substance.

Define the degree of saturation. What are its limiting values?

List the six psychrometric processes?

State the four processes of Diesel Cycle?

What are cyclic and noncyclic heat engines? Give examples.

Explain Joules experiment and state the first law of thermodynamics applied to a closed system undergone by a cyclic process.

A mass of gas is compressed in a quasi-static process from 80 kPa, 0.1 m3 to 0.4 MPa, 0.03 m3. Assuming that the pressures volume are related by PVn=constant, find network done by gas system.

Show that internal energy is a property of the system.

Calculate the amount of heat required to convert 100 kg of ice at -10oC into steam at 100oC at normal pressure. Specific heat capacity of ice=2100 J/Kg K, latent heat of fusion of ice =3.36 × 105 J/Kg, specific heat capacity of water=4.2 kJ/kg-K and latent heat of vaporization of water = 2.25 × 106 J/kg.

Write the steady flow energy equation for a single stream entering and a single stream leaving a control volume and explain the various terms in it.

Define Claussius inequality and prove it.

Show that the enthalpy of a fluid before throttling is equal to that after throttling.

A room for four persons has two fans, each consuming 0.18 kW power, and three 100W lamps. Ventilation air at the rate of 80 kg/h enters with an enthalpy of 84kJ/kg and leaves with an enthalpy of 59 kJ/kg. If each person puts out heat at the rate of 630 kJ/hr. Determine the rate at which heat is to be removed by a room cooler, so that a steady state is maintained in the room.

Discuss about dryness fraction of steam.

Steam at 0.8 MPa, 250oC and flowing at a rate of 1 kg/s passes into a pipe carrying wet steam at 0.8 MPa, 0.9 dry. After adiabatic mixing the flow rate is 2.3 kg/s. Determine the condition of steam after mixing. The mixture is now extended in a frictionless nozzle isentropically to a pressure of 0.4 MPa. Determine the velocity of steam leaving the nozzle. Neglect the velocity of steam in the pipe.

Explain the working of throttling calorimeter.

Steam initially at 0.3 MPa, 250oC is cooled at constant volume.

1. At what temperature will steam become superheated vapour?
2. What is the quality of steam at 80oC?
3. What is the heat transferred per kg of steam in cooling from 250oC to 80oC.

Derive the expression for change of enthalpy of an ideal gas in a reversible adiabatic process in terms of pressure ratio.

Two streams of air 25oC, 50% RH and 25oC, 60% RH are mixed adiabatically to obtain 0.3 kg/s of dry air at 30oC. Calculate the amount of air drawn from both the streams and the humidity ratio of mixed air.

Express the changes in internal energy and enthalpy of an ideal gas in a reversible adiabatic process in terms of the pressure ratio.

Atmospheric air at 1 bar and is at 25oC DBT and 15oC WBT. Calculate (i) relative humidity (ii) specific humidity (iii) vapour density in air (iv) DPT(v) enthalpy of mixture.

Mention the merits and demerits of the Stirling and Ericsson cycles.

With the help of p-v and T-s diagrams, show that for the same maximum pressure and temperature of the cycle and the same heat rejection, ηDiesel > η Dual > η Otto