Question

A gravity settling chamber of height ‘H' and length ‘L' is designed to control particulate air pollution. In the chamber, the horizontal velocity of air flow is $'V_h'$ and terminal settling velocity of the target particle is $'V_ť$. Which one of the following expressions is the correct concept used to calculate the minimum size of the target particle that will be removed with 100% efficiency?

• A. \(\frac{V_t}{L} = \frac{V_h}{H} \)
• B. \({V_h}\times {V_t} = L \times H\)
• C. \({V_h} = V_t \times L \times H\)
• D. \(\frac{V_t}{H} = \frac{V_h}{L}\)

Answer 1

The Correct Option is D

For a particle to be removed with 100\% efficiency in a settling chamber, it must settle to the bottom of the chamber before it can exit horizontally. This condition is satisfied when the particle’s settling time through the height of the chamber is equal to the air's travel time through the length of the chamber, mathematically represented as: \[ \frac{V_t}{H} = \frac{V_h}{L} \] This balance ensures that particles have sufficient time to settle out of the airflow before exiting the chamber.