B.Tech Il Year lst Semester Supplementary Exams June 2016 (Thermodynamics)

(a) What is a pure substance?

(b) What is an irreversible process? Give examples.

(c) What is PPM1?

(d) write difference between non-flow process and steady flow process.

(e) State Kelvin-Planck statement.

(f) What do you mean by irreversibility of the process?

(g) Write clausius Clapeyron equation and its significance

(h) Define p-v-T surface and state its significance.

(i) State Gibb’s Dalton law,

(j) What is an air-standard efficiency and relative efficiency of gas power cycle?

2. (a) Explain briefly Zeroth law of thermodynamics.

(b) A fluid at a pressure of 3 bar and with specific volume of 0.18 m3/kg, contained in a cylinder constant. piston a according to a law, p=(C/v2) where C is constant Calculate the work done by the fluid on the piston.

3 (a) compare macroscopic and microscopic approach in thermodynamic studies.

(b) Explain about point function and path function with examples.

4. Write down the general equation for steady flow systems and simplify when applied for the following systems:
(a) Steam turbine.
(b) Steam nozzle.
(c) Centrifugal compressor.
(d) condenser.

5. At the inlet to a certain nozzle the enthalpy of fluid passing is 2800 kJ/kg and velocity is 50 m/s. At the discharge end the enthalpy is 2600 kJ/kg. The nozzle is horizontal and there is negligible heat loss from

(i) Find the velocity at exit of the nozzle.

(ii) If the inlet area is 900 cm’ and specific volume at inlet is o.187 m3/kg, find mass flow rate.

(iii) If the specific volume at the nozzle exit is 0.498 m3/kg, find the exit area of the nozzle.

6 (a) Explain in detail about Clausius inequality
(b) 1 kg of air initially at 8 bar pressure and 380 K expands polytropically (pv1.2= constant) until the pressure is reduced to one-fifth value, calculate: (i) Final specific volume and temperature. (ii) Change of entropy, work done and heat interaction. (iii) Change in entropy.

7 (a) Prove that entropy is a property of a system.

(b) 5 kg of air at 550 K and 4 bar is enclosed in a closed system.
(i) Determine the availability of the system if the surrounding pressure and temperature are 1 bar and 290 K respectively.
(ii) If the air is cooled at constant pressure to the atmospheric temperature, determine the availability.

8. Derive the Maxwell relations.

9 (a) Explain about compressibility charts.
(b) A pressure cooker contains 1.5 kg of saturated steam at 5 bar. Find the quantity of heat which must be rejected so as to reduce the quality to 60% dry. Determine the pressure and temperature of the steam at the new state.

10. (a) Explain about adiabatic mixing of perfect gases.
(b) A mixture of hydrogen (Hz) and oxygen (Oz) is to be made so that ratio of H2 to O2 is 2:1 by volume. If the pressure and temperature are 1 bar and 25 C respectively, calculate: (i) The mass of O2 required
(ii)The volume of the container

11 (a) Derive expression for air standard efficiency of Otto cycle.
(b) The stroke and cylinder diameter of a compressor ignition engine are 250 mm and 150 mm respectively. If the clearance volume is 0.0004 m and fuel injection takes place at constant pressure for 5 percent of the stroke, determine the efficiency of the engine. Assume engine is working on diesel cycle.