Ready to Participate?
Ready to Participate?
Get Started!
Log In

What is the formula PV = nk Delta T
The formulation relates to air conditioning and pressurisation in aircraft that I need for an assignment
asked in aircraft

mathpath answers:

The ideal gas law has the formula
n=number of moles
R=gas constant
T=temperature in degrees Kelvin
See, for example

However, the formula you presented has the last part (delta T) instead of simply T, so I am not sure if we are talking about the same formula. Perhaps it is a variation that you can check out from your course notes or textbook.

/ reply

themadorange451 answers:

As far as I know, the formula relates the pressure and volume of a gas to (a change in) its temperature. If you heat a gas either its pressure or its volume goes up. I think the 'delta' bit means 'change of.' Looked at another way, reducing the pressure or the volume of a gas causes its temperature to fall. I think 'k' is the 'constant of proportionality' knowns as Boltzmann's constant. Boltzmann's constant in turn relates temperature to energy (the kinetic energy of the gas molecules.)
It sezz 'ere (something I'm reading) its value is 1.38 * 10^-23 joules per kelvin, in other words the amount of energy increase for an increase in temperature by one degree, in SI units.
If you're doing something on pressurizing an aircraft, this would seem to fit. Much like if you use a bike pump to compress air, it gets hot.
Beyond that I know nothing...

/ reply

TomYeo answers:

You may find a reasonable answer here. This is slightly out of my area, I work in a different pressurized envronment. Starting from basics, you have Boyle's law, which relates to flexible cotainers (pressure and volume) and Charles' law, which realtes to rigid containers (pressure and temperature). The two then have to be taken together in the Combined Gas Law Equation and hence the Ideal Gas Law Equation which Mathpath has explained. Both of the original laws are rather over simplistic for a real world application. Delta must be a constant specific to aircraft, maybe something related to expansion of the aircraft of thermal properties of the gases being pumped in.

/ reply


No Comments