(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

1. A fly ash (ρ =1.8 g/mL) aerosol consists of particles averaging 13 μm in diameter and with a concentration of 800μg/m3. Use the average diameter to calculate the settling velocity (cm/s) and settling rate (μg/m/s) of the particles in air.

The Stokes-Cunningham slip correction factor is 1.015.

2. Relevant equations

vt = (pp - pa)C*g*dp^2/ 18n

vt = settling velocity in m/s

pp = particle density g/m3

pa = air density g/m3

C = stokes-cunningham slip correction factor (given in question)

g = acceleration due to gravity

dp = particle diameter in m

n = viscosity of air

3. The attempt at a solution

So first I had to figure out what each part of equation is since I was not given all of it.

pp was given in question as 1.8 g/mL converted to 1.8E6 g/m3 (is that correct conversion?)

pa I found online air density to be 1.184E3 g/m3 at 25 Celsius (note no textbook for this class)

g = 9/8 m/s2

n = 1.86E-2 g/m*s I also found this online

After this I plugged it all into equation.

vt = [(1.8E6 g/m3 - 1.184E3 g/m3)(1.015)(9.8 m/s2)(13E-5 m)]/[18(1.86E-2 g/m*s)]

= 2403.654 g/m / 0.3348 g/m*s

= 7179 = 7.2E3 s

my units don't make sense. everything cancels out but seconds. How go I get this in m(cm) a second. I don't know how to make it so m doesn't cancel?

Also I do not know how to do settling rate. We have never talked about rate in class. Any suggestions?

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Stokes law - Settling velocity and rate

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