PROBLEM 2

Problem 13.7. Atmospheric air, with a temperature of 300 K, flows through a 80 μm- thick porous

membrane. The membrane's porosity (total volume fraction of pores) is 25%. The accommodation

coefficients have been measured to be a = 0.79 and ath = 0.24. The superficial velocity of air through

the membrane (velocity calculated based on the total membrane area) is 3.0 m/s. Assume that the

pores can be idealized as smooth-walled circular flow passages 5 μm in diameter.

a) Calculate the total pressure drop across the membrane.

b) Neglecting heat transfer from the front and back surfaces of the membrane, calculate the

thermal load that can be removed by air, in watts per square meter of the membrane, assuming

that the air mean temperature reaches 301 K. Estimate the membrane temperature, assuming

that the membrane remains isothermal.