A cooling tower, $2 \mathrm{~m}$ in diameter, packed with $75-\mathrm{mm}$ ceramic Hiflow rings, is fed with water at $316 \mathrm{~K}$ at a rate of $25 \mathrm{~kg} / \mathrm{m}^{2} \cdot \mathrm{s}$. The water is contacted with air, at 300 \mathrm{~K}$ and $101.3 \mathrm{kPa}$ essentially dry, drawn upward countercurrently to the water flow. Neglecting evaporation of the water and changes in the air temperature, estimate the volumetric rate of airflow, in $\mathrm{m}^{3} / \mathrm{s}$, which would flood the tower.