Air Density Formula: Find w/ Temp & Pressure-Altitude

AI Thread Summary
The discussion focuses on deriving the air density formula based on temperature and pressure-altitude. The ideal gas law is highlighted, stating that air density (ρ) is proportional to pressure (P) and inversely proportional to temperature (T), expressed as ρ = (P / RT). To incorporate pressure-altitude, the International Standard Atmosphere (ISA) model is used to convert pressure to altitude. The combined formula for air density at a specific altitude and temperature is provided as ρ = (P / RT) * [1 - (P / P0)^0.190284] * 145366.45. This comprehensive approach aids in calculating air density effectively.
wutang
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I'm looking for a formula that will find the air density based on a relationship between air temperature and pressure-altitude. Any help would be greately appreciated!
 
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Sure, I would be happy to help you find the air density formula you are looking for. The relationship between air temperature and pressure-altitude is described by the ideal gas law, which states that the density of a gas is directly proportional to its temperature and inversely proportional to its pressure. This can be expressed mathematically as:

ρ = (P / RT)

Where ρ is the air density, P is the pressure, R is the gas constant, and T is the temperature in Kelvin.

To incorporate pressure-altitude into this formula, you will need to convert the pressure into its corresponding altitude. This can be done using the International Standard Atmosphere (ISA) model, which assumes a standard lapse rate for temperature and pressure changes with altitude.

The formula for converting pressure into altitude using the ISA model is:

h = [1 - (P / P0)^0.190284] * 145366.45

Where h is the altitude in feet, P is the pressure in pounds per square inch (psi), and P0 is the pressure at sea level, which is 14.696 psi.

Combining these formulas, we can find the air density at a specific altitude and temperature using the following equation:

ρ = (P / RT) * [1 - (P / P0)^0.190284] * 145366.45

I hope this helps you find the air density formula you were looking for. Let me know if you have any further questions or need clarification on anything. Best of luck!
 
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