Mass Flow Rate 2

[envirodude]

I am taking a Thermodynamics course on-line to complete my BS in Environmental Engineering. The following problem relates to mass flow rate:<br>
<br>
Air flows steadily through an adiabatic turbine, entering at 150 psia, 900 F and 350 ft/s and leaving at 20 psia, 300 F and 700 ft/s. The inlet area of the turbine is .1 sf. What is the mass flow rate of air?<br>
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If I understand mass flow rate, it is the amount of mass flowing through a cross section per unit time. They are looking for an answer in lbm/s. How do you arrive at the answer?

 

[mbeychok]

<br>
You are given the inlet flow rate in ft/s and the inlet area in square feet. Thus, you can easily calculate the the inlet volumetric flow rate in cubic feet per second. With the inlet volumetric flow rate, inlet temperature, inlet pressure, molecular weight of air, and the universal gas constant ... you can readily calculate the mass flow rate.<br>
<br>
Milt Beychok<br>
(Visit me at <A HREF="

http://www.air-dispersion.com"

TARGET="_new">

http://www.air-dispersion.com</A>)<br>

 

[kmuhsen]

First you need to find the inlet density for air, you can get this from ideal gas low : Pv = M x R x T<br>
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then you can get the mass flow rate staight away from :<br>
<br>
Mass flowrate = Area x velocity x density<br>
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i hope this helpful<br>
<br>
Khaled Muhsen