Q1: Drift in a cooling tower is

ANS:A - the water entrained by the circulating air.

The water entrained by the circulating air in a cooling tower refers to the process by which small droplets of water are carried away by the air as it passes through the tower. This phenomenon occurs due to the interaction between the air and the water within the cooling tower. In a cooling tower, warm water from an industrial process is circulated through the tower and distributed over a fill material, which increases the contact surface area between the water and the air. As the warm water flows over the fill material, it is exposed to a flow of air that is usually induced by fans at the base or top of the tower. The air, being cooler than the water, causes some of the water to evaporate into the air stream. This evaporation process helps to remove heat from the water, cooling it down. However, along with the evaporated water vapor, small droplets of liquid water are also entrained by the air stream as it passes through the tower. These entrained water droplets become part of the exhaust air leaving the cooling tower. While the majority of the water droplets are collected and returned to the cooling system, a fraction of them, known as drift, may escape the tower and be lost to the environment. Controlling drift is important in cooling tower operation to minimize water loss and potential environmental impact. Various methods such as the use of drift eliminators and proper tower design can help reduce the amount of water entrained by the circulating air.