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If there is no exchange of heat between system and surrounding where system comprises of a compressible fluid but the heat is generated due to friction, the process is an adiabatic process.
Explanation: For process to be adiabatic, there is no heat exchange and no heat generation within fluid.
For a compressible fluid, if there is no change in specific volume at constant temperature, what type of process it is?
Explanation: As, specific volume remains constant, density remains constant. Therefore for given temperature there is no change in volume. hence, the process is isothermal.
If the fluid is incompressible, do thermodynamic properties play an important role in its behaviour at varying temperature and pressure?
Explanation: If fluid is incompressible there is not much change in observed properties with variation in temperature and pressure. Hence, no perceivable change.
If for same temperature and pressure change, the value of bulk modulus is compared for isothermal process and adiabatic process, which one would be higher?
Explanation: For isothermal process
For adiabatic process
where K=Bulk modulus
The value of gas constant is same for all the gases
Explanation: The value of gas constant depends on molecular weight. As the molecular weight is different, gas constant will be different.
Calculate the pressure exerted by 9 kg of air at a temperature of 20℃ if the volume is 0.8m3. Assuming ideal gas laws are applicable.
Explanation: Ideal gas Law: PV=nRT
A gas weighs 16 N/m3 at 30℃ and at an absolute pressure of 0.35 N/mm2. Determine the gas constant.
A cylinder of 0.8 m3 in volume contains superheated steam at 70℃ and .4 N/m2 absolute pressure. The superheated steam is compressed to .3 m3 . Find pressure and temperature.
Explanation: For polytropic process,
=(0.8/0.3)1.3 * 0.4 ……..(for superheated stream n=1.3)
Determine the compressibility of an incompressible fluid, if the pressure of the fluid is changed from 70 N/m2 to 130 N/m2. The volume of the liquid changes by 0.15 percent.
Explanation: Compressibility=1/Bulk Modulus
What is the variation of cp, cv and k in case of gases when the temperature increases?
Explanation: cp is molar heat capacity at constant pressure. As temperature is increased, enthalpy increases, heat capacity increases.
Same is for cv, cp is molar heat capacity at constant volume.
However cp-cv=R and cp/cv = R
Hence, as cp, cv increases R decreases.