D = diffusion coefficient [m 2 /s]
dφ = change in concentration of substance [mass or mol/m 3 ]
dx = change in length [m]
For simple one-dimensional transport, the diffusion coefficient describes the time–rate of change of concentration . The diffusion coefficient varies from substance to substance and with temperature and pressure.
Figure and table below shows the diffusion coefficients, D 12 , for binary gas mixtures where air is in large excess.
See also Air Composition and molecular weight , Density at varying pressure, Density and specific weight at varying temperature , Diffusion coefficients for gases in air , Dynamic (absolute) and kinematic viscosity , Prandtl Number , Specific heat at varying temperature and Specific heat at varying pressure , Thermal conductivity , Thermal diffusivity , Properties at gas-liquid equilibrium conditions and Air properties , for other properties of air, as well as Diffusion coefficients of gases in water and Carbon dioxide concentrations in rooms with people
|Gases in large excess of air|| Diffusion coefficient, D 12 , [cm 2 /s] |
at atmospheric pressure and given temperatures
|0 °C||20 °C||100 °C||200 °C||300 °C||400 °C|
|Name||Formula||32 °F||68 °F||212 °F||392 °F||572 °F||752 °F|
Moist and humid air - psychrometric charts, Mollier diagrams, air-condition temperatures and absolute and relative humidity and moisture content.
The study of fluids - liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.
Air, LNG, LPG and other common gas properties, pipeline capacities, sizing of relief valves.
Material properties of gases, fluids and solids - densities, specific heats, viscosities and more.
Dry air is a mechanical mixture of nitrogen, oxygen, argon and several other gases in minor amounts.
Air density at pressure ranging 1 to 10 000 bara (14.5 - 145000 psi) and constant selected temperatures.
Online calculator, figures and tables showing density, specific weight and thermal expansion coefficients of air at temperatures ranging -100 to 1600 °C (-140 to 2900 °F) at atmospheric and higher pressure - Imperial and SI Units.
Online calculator, figures and tables with dynamic (absolute) and kinematic viscosity for air at temperatures ranging -100 to 1600°C (-150 to 2900°F) and at pressures ranging 1 to 10 000 bara (14.5 - 145000 psia) - SI and Imperial Units.
The mass of water vapor present in moist air - to the mass of dry air.
The moisture holding capacity of air increases with temperature.
Dry air is a mixture of gases where the average molecular weight (or molar mass) can be calculated by adding the weight of each component.
Prandtl number for air vs. temperature and pressure.
Properties of air change along the boiling and condensation curves (temperature and pressure between triple point and critical point conditions). An air phase diagram included.
Figures and tables with isobaric (Cp) and isochoric (Cv) specific heat of air at constant temperature and pressure ranging 0.01 to 10000 bara.
Online calculator with figures and tables showing specific heat (Cp and Cv) of dry air vs. temperature and pressure. SI and imperial units.
Speed of sound in air at standard atmospheric pressure with temperatures ranging -40 to 1000 °C (-40 to 1500 °F) - Imperial and SI Units.
Online calculator with figures and tables showing air thermal conductivity vs. temperature and pressure. SI and imperial units.
Figures and tables withdry air thermal diffusivity vs. temperarure and pressure. SI and Imperial units.
Thermal properties of air at different temperatures - density, viscosity, critical temperature and pressure, triple point, enthalpi and entropi, thermal conductivity and diffusivity and more.
Water may condensate when air is cooled in air conditioning systems.
Carbon dioxide concentration in a room may indicate air quality and ventilation system efficiency.
Pressure loss in compressed air pipe lines.
Thermodynamic properties of dry air - specific heat, ratio of specific heats, dynamic viscosity, thermal conductivity, Prandtl number, density and kinematic viscosity at temperatures ranging 175 - 1900 K.
Diffusion flux [kg/m2s] tells how fast a substanse solved in another substance flows due to concentration gradients. Diffusion constants [m2/s] for several gases in water.
Specific volume of moist air is defined as the total volume of humid air per mass unit of dry air
Weight of water vapor in air
The amount of air that can be dissolved in water decreases with temperature and increases with pressure.
Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!
We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.
Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.