Air Density Calculator, Formula, Air Density Calculation

Air Density Calculator:

Enter the values of dry air pressure, p_d(Pa), dry air gas constant, R_d(J/kg.K), temperature, T_(K), vapour pressure, p_v(Pa) and water vapour gas constant, R_v(J/kg.K) to determine the value of Air density, ρ_(kg/m3).

Air Density Formula:

Air density is the mass per unit volume of Earth’s atmosphere and is commonly measured in kilograms per cubic meter.

Air density is influenced by factors such as temperature, pressure, and humidity. Higher pressure and lower temperature generally increase air density, while higher humidity can decrease it.

Dry Air and Water Vapour: Air is a mixture of dry air (mostly nitrogen and oxygen) and water vapour. Both components contribute to the overall air density.

Pressure and Temperature: Both pressure and temperature affect the density. Higher pressure and lower temperature lead to denser air.

Gas Constants (Rd and Rv): These constants are specific values for dry air and water vapour, respectively. They act like conversion factors to relate pressure, volume, and temperature for each component.

Air density, ρ_(kg/m3) in kilograms per cubic metres is equal to the dry air pressure, p_d(Pa) in Pascals divided by the product of the dry air gas constant, R_d(J/kg.K) in joules per kilogram Kelvin and the temperature, T_(K) in Kelvin plus the vapour pressure, p_v(Pa) in Pascals divided by the product of the water vapour gas constant, R_v(J/kg.K) joules per kilogram Kelvin and the temperature, T_(K).

Air density, ρ_(kg/m3) = p_d(Pa) / R_d(J/kg.K) * T_(K) + p_v(Pa) / R_v(J/kg.K) * T_(K)

ρ_(kg/m3) = air density in kilograms per cubic metres, kg/m³.

p_d(Pa) = dry air pressure in Pascals, Pa.

R_d(J/kg.K) = dry air gas constant in joules per kilogram Kelvin, (287.05 J/kg.K).

T_(K) = temperature in Klevin, K.

p_v(Pa) = vapour pressure in Pascals, Pa.

R_v(J/kg.K) = water vapour gas constant in joules per kilogram Kelvin, (461.5 J/kg.K).

Air Density Calculation:

1. Finding Air Density:

Given: p_d(Pa) = 100000Pa, T_(K) = 300K, p_v(Pa) = 2000Pa, R_d(J/kg.K) = 287.05 J/kg.K,

R_v(J/kg.K) = 461.5 J/kg.K.

Air density, ρ_(kg/m3) = p_d(Pa) / R_d(J/kg.K) * T_(K) + p_v(Pa) / R_v(J/kg.K) * T_(K)

ρ_(kg/m3) = 100000 / 287.05 * 300 + 2000 / 461.5 * 300

ρ_(kg/m3) = 100000 / 86115 + 2000 / 138450

ρ_(kg/m3) = 1.161 + 0.0144

ρ_(kg/m3) = 1.1754kg/m³.

2. Finding Temperature:

Given: p_d(Pa) = 95000Pa, ρ_(kg/m3) = 1.2kg/m³, p_v(Pa) = 1500Pa, R_d(J/kg.K) = 287.05 J/kg.K,

R_v(J/kg.K) = 461.5 J/kg.K.

Air density, ρ_(kg/m3) = p_d(Pa) / R_d(J/kg.K) * T_(K) + p_v(Pa) / R_v(J/kg.K) * T_(K)

1.2 = 95000 / 287.05 * T_(K) + 1500 / 461.5 * T_(K)

1.2 = (95000 / 287.05 + 1500 / 461.5) * 1 / T_(K)

1.2 = (330.99 + 3.25) * 1 / T_(K)

1.2 = 334.24 * 1 / T_(K)

T_(K) = 334.24 / 1.2

T_(K) = 278.53K.

How To Calculate Density – With Examples