Important concepts in Thermal Engineering for GATE 2019 Mechanical

The present post (Part-1) contains important basic concepts in Thermal Engineering in Mechanical Engineering. Note down each concept that might help in GATE 2021Mechanical.

• The pressure of the gas in terms of its mean kinetic energy per unit volume E is equal to 2E/3 and Kinetic Energy is always proportional to temperature.
• The superheated vapor acts as perfect gas and obeys all gas laws
• Absolute zero pressure will occur when there is no molecular momentum
• No liquid can exists at absolute zero pressure and absolute pressure can be attained at 0 Kelvin
• The behavior of gas can be fully determined by four gas laws
• For air ratio of specific heats is 1.4

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Mono-atomic gas has the highest ratio of specific heat = 1.66

As per Joule’s law, internal energy is a function of temperature.

The same volume of all gases would represent their molecular weights

Gases have two value of specific heat. One is at constant pressure and one is at constant volume

The molecular weights of all the perfect gases occupy the same volume under same conditions of pressure and temperature.

Work done in free expansion process is always zero

Work done for a rigid container having gas is zero

Heat and work are not properties of the system

The absolute value of internal energy cannot be found but only change in internal energy can be found

On weight, basis air contains 23 parts of oxygen

Heat and work are path functions