61 plz Find the infiltration rate from stack and wind throug

6.1
plz

Find the infiltration rate from stack and wind through a curtain wall of area 300 ft^3 (27.58 m^2) if the indoor-outdoor pressure difference is 0.2 inWC (49.8 Pa)

Solution

The infiltration rate could be found by the principle of conservation of mass or simply,

rho A V = constant

assuming the density of the fluid to be constant, the eqn for two states of the flow is given by,

rho x A1 x v1 = rho x A2 x v2 -------eqn 1

siince the pressure difference is given by ,

Pout - Pin = 49.8 -----eqn2

using bernoulli\'s simplified eqn,

static Pressure difference = dynamic pressure difference

P out - Pin = 0.5 x rho x V2² - V1²

assuming external velocity to be zero V1=0

V2 = sqrt [(Pout - Pin) / 0.5 x rho]

The infiltration rate is given by,

Q = rho x A x V2 or,

Q = rho A sqrt[24.9] = 4.98 x sqrt(rho) x 27.88 = 139.12 sqrt(rho)