Temperature Pressure and Density Danielle Hettmann and Chris
- Slides: 6
Temperature, Pressure, and Density Danielle Hettmann and Chris Saleh SYST 460 – Fall 2011
Ambient temperature: measure of the temperature of the air in the region surrounding the aircraft Static temperature: measure of the tempe rature at the surface of the ai rcraft
Ambient temperature varies with altitude: Below 36, 089 feet: ambient temperature (˚R) = -3. 566˚ * (altitude/1000) Above 36, 089 feet: ambient temperature (˚R) = 389. 988˚ θ = (Tamb Delta ISA + ∆ISA) / (TSea. Level + ∆ISA) rule of thumb: ambient temperature drops 1˚ C for every 1000 feet increase in altitude Temperature Ratio Below 36, 089 feet, Tamb/TSea. Level = θ = 1 – (6. 8753 X 10^-6) * pressure altitude Above 36, 089 feet, Tamb/TSea. Level = θ = 0. 7519
Ambient Pressure: Measure of the pressure of the air in the region surrounding the aircraft Static Pressure: Measure of the pressu re at the surface of the airc raft
Pressure Ratio : =Pamb / PSea. Level Below 36, 089 feet, the Ambient Pressure (lb/ft 2) = (1 - ˚ * 6. 88 X 10 -6 * Pressure Altitude)5. 26 Above 36, 089 feet, the Ambient Pressure (lb/ft 2) = 0. 223360 e ( (36. 089 – Pressure Altitude)/20. 8057)
Ambient Density: Measure of the density of the air in the region surrounding the aircraft Density Ratio: = (Slugs/ft 3) = amb / Sea. Level Boyles Law: Density ( ), pressure ( ), temperature (θ) = / θ
