Gases Properties

Overview

Engineering reference data for Gases Properties in combustion engineering.

Key Formulas

Heat Release

$Q = \dot{m} \cdot HV$

Fuel energy release rate.

Air-Fuel Ratio

$AF = \frac{m_{air}}{m_{fuel}}$

Mass of air per mass of fuel.

Excess Air

$EA = \frac{O_2}{21 - O_2} \times 100\%$

From flue gas oxygen measurement.

Variables

Symbol	Description	Unit
$Q$	Heat release rate	W
$\dot{m}$	Mass flow rate	kg/s
$HV$	Heating value	J/kg
$AF$	Air-fuel ratio	—

Key Gas Laws

The fundamental relationships governing gas behavior under varying conditions of pressure, volume, and temperature.

Boyle's Law (Constant Temperature)

The pressure of a fixed amount of gas is inversely proportional to its volume. $P \propto \frac{1}{V} \quad \text{or} \quad PV = k$

Charles's Law (Constant Pressure)

The volume of a fixed amount of gas is directly proportional to its absolute temperature. $V \propto T \quad \text{or} \quad \frac{V}{T} = k$

Ideal Gas Law

Relates the pressure, volume, temperature, and amount of an ideal gas. $PV = nRT$

Note: For comprehensive, tabulated physical and chemical properties of specific industrial and pure gases, consult a dedicated engineering database. A useful resource is the Air Liquide Gas Encyclopedia.

References

• Original Source