This model describes the one-directional pressure driven air flow through a crack-like opening, using the equation
V̇ = C Δp^{m},
where V̇ is the volume flow rate, C is a flow coefficient and m is the flow exponent. The flow coefficient is
C = L C_{D,Rat} Δp_{Rat}^{(0.5-m)} (2/ρ_{0})^{0.5},
where L is the effective air leakage area, C_{D,Rat} is the discharge coefficient at the reference condition, Δp_{Rat} is the pressure drop at the rating condition, and ρ_{0} is the mass density at the medium default pressure, temperature and humidity.
The effective air leakage area L can be obtained, for example, from the ASHRAE fundamentals (ASHRAE, 1997, p. 25.18). In the ASHRAE fundamentals, the effective air leakage area is based on a reference pressure difference of Δp_{Rat} = 4 Pa and a discharge coefficient of C_{D,Rat} = 1. A similar model is also used in the CONTAM software (Dols and Walton, 2002). Dols and Walton (2002) recommend to use for the flow exponent m=0.6 to m=0.7 if the flow exponent is not reported with the test results.
lWet
as it is only used to compute
the Reynolds number, and the Reynolds number is not used by this model.
Also removed the variable Re
for the Reynolds number.A
and CD
which are not used by this model.A
which was
A=CD/CDRat * L * dpRat^(0.5-m)
rather than
A=CDRat/CD * L * dpRat^(0.5-m)
.useConstantDensity
to
useDefaultProperties
to use consistent names within this package.
A conversion script can be used to update this parameter.