Applied Thermodynamics

Define the following with respect to a compressor :
i)  Isothermal efficiency ii) Adiabatic efficiency  iii) Mechanical efficiency iv) Overall efficiency v) Volumetric efficiency.

The dry and wet bulb temperatures of atmospheric air at 1 atm pressure are measured with a sling psychrometer and found to be respectively. Determine
i) Specific humidity ii) Relative humidity    iii) Enthalpy of air.
Use the table to find property values. Do not use psychrometric chart.

Derive an expression for the following :
i) Specific humidity (w)       ii) Degree of saturation 

A vapour compression refrigeration of 10 tonnes capacity using Freon - 12 as the refrigerant has an evaporator temperature of  and a condenser temperature of  Assuming simple saturation cycle, determine i) Mass flow rate of refrigerant in kg/min
ii) Power input   iii) Cop. Cpv = 0.72 kJ/kg.K. (Obtain properties of Freon - 12 From Data Handbook).

Give four comparisons between vapour compression refrigeration and vapour absorption refrigeration.

Define the following: 1) Refrigerating effect   ii) Ton of refrigeration  iii) Ice making capacity   iv) Relative Cop.

A gas turbine plant works between the temperature limits of 300K and 1000K and a pressure of 1 bar and 16 bar. The compression is carried out in two stages with perfect inter cooling inbetween. Calculate the net power of the plant, per kg of air circulation :
 Cp - 1 kJ/kg. K    ;  y = 1.4 for air.

With neat sketches, explain the working of the following:
1) Turbojet engine ii) Liquid propulsion rocket.

An air compressor takes in air at 1 bar and 20'C and compresses the same according to the law . It is then delivered to a receiver at a constant pressure of 10 bar. Determine
i) Temperature at the end of compression   ii) Work done and heat transferred during compression, per kg of air. R = 0.287 kJ/kg.K.

Explain the following:
 i) A - F Ratio         ii) Calorific value of fuels         iii) Adiabatic flame temperature   
iv) Internal energy of combustion    v) Combustion efficiency. 

In a Rankine cycle, the steam inlet to turbine is saturated at a pressure of 35 bar and the exhaust pressure is 0.2bar. Calculate 1) Turbine work ii) Pump work iii) Rankine efficiency iv) Condenser heat flow V) Dryness fraction at the end of expansion. Assume the mass flow rate of steam as 9.5kg/sec.

With a superimposed T-S diagram, compare Carnot and Rankine vapour cycles operating between the same boiler and condenser temperatures.

A test on a 2S IC engine gave the following results at full load. Speed = 350 rpm ; Net brake load = 630N; Indicated m.e.p - 3 bar; Fuel consumption = ; Jacket cooling water flow rate = 0.138kg/s : Jacket water temperature at inlet = 20°C ; Jacket water temperature at outlet = 40°C ; Room temperature = 20°C : Exhaust gas temperature = 400°C ; Air used per kg of fuel = 32kg; Cylinder diameter = 22cms; Brake drum circumference = 314cms ; Calorific value of fuel = 43 MJ/kg ; Specific heat of exhaust gases = 1kJ/kg.K. Determine i) Mechanical efficiency ii) Brake mean ch e pressure. Draw the heat balance sheet including heat equivalent of BP, heat loss due to friction, heat carried away by cooling water, heat carried away by exhaust gases and unaccounted heat loss.

Explain the following in detail:
1) Morse test method ii) Willan's Line method.

The compression ratio of a Diesel engine working on an ideal diesel cycle is 16. The temperature of air at the beginning of compression is 300K and the temperature of air at the end of expansion is 900K. Determine i) Cut-off ratio ii) Expansion ratio iii) Cycle efficiency.

With the help of T - S and P - V diagrams, derive an expression for me.p of otto cycle in terms of compression ratio, pressure ratio, showing all the processes involved.

Coal with the following mass analysis is burnt with 100% excess air, C= 74%, H2 = 4.3%,
S = 2.7%,  = 1.5%, = 5.5% ,  = 5%, ash= 7%. Find the moles of gases produced, if 100kg of fuel is burnt.