Download Aptitude Crack
img not found img not found

Mass Transfer - Engineering

Q1:

The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the __________ temperature.

A dew point

B wet bulb

C dry bulb

D none of these

ANS:D - none of these

Certainly! Let's explain each term:

  1. Dew Point Temperature:
    • The dew point temperature is the temperature to which a vapor gas mixture must be cooled at constant pressure to become saturated, meaning that the air holds the maximum amount of moisture it can at that temperature.
    • At the dew point temperature, the relative humidity is 100%, and any further decrease in temperature will result in condensation (formation of dew).
    • The dew point temperature is an important parameter in weather forecasting, HVAC (heating, ventilation, and air conditioning) systems, and industrial processes where controlling humidity levels is critical.
  2. Wet Bulb Temperature:
    • The wet bulb temperature is the lowest temperature that can be reached by evaporating water into the air at constant pressure.
    • It is typically measured using a thermometer with its bulb covered in a wet wick or fabric. As water evaporates from the wet bulb, it cools the thermometer, and the temperature indicated is the wet bulb temperature.
    • The wet bulb temperature is lower than the dry bulb temperature due to the cooling effect of evaporation and provides a measure of the cooling potential through evaporative cooling.
  3. Dry Bulb Temperature:
    • The dry bulb temperature is simply the air temperature as measured by a standard thermometer, without any consideration for humidity or moisture content.
    • It is the most commonly reported temperature in weather reports and represents the actual temperature of the air.
    • Unlike the wet bulb temperature, the dry bulb temperature does not account for the cooling effect of evaporation and remains constant when moisture is added or removed from the air.
In summary:
  • Dew point temperature: Temperature at which a vapor gas mixture becomes saturated, with 100% relative humidity.
  • Wet bulb temperature: Lowest temperature reached by evaporating water into the air, indicating the cooling potential through evaporative cooling.
  • Dry bulb temperature: Actual air temperature as measured by a standard thermometer, without accounting for humidity or moisture content.