A 1.5 mm thick plate is to be cooled by gas flow through microchannels with square cross sections. Assuming gas mean temperature and pressure of 300 K and 100 kPa, respectively, estimate the...

A 1.5 mm thick plate is to be cooled by gas flow through microchannels with square cross sections. Assuming gas mean temperature and pressure of 300 K and 100 kPa, respectively, estimate the microchannel cross-section size for the following thresholds:

a. Continuum with negligible slip at walls

 b. Continuum, with slip at walls

c. Free molecular flow

Perform these calculations for air and helium.