# Evaporation rate of water with forced convection

A steel pot (diameter 200 mm) is fully filled with water (2 kg of water) and the water is maintained at a constant temperature of 40°C by supplying heat from an electrical tabletop burner.

Assume the heat supplied from the burner is 0.20 kWh (kW per hour). Let us neglect the heat losses.

The pot is kept open to the surrounding (room). Hot air with a temperature of 60°C and a velocity of 1.5 m/s is blown across the water surface of the pot to assist the evaporation process.

How can the amount (mass) of water evaporated from the pot after 1 hour be calculated? What are the formulae to be considered to calculate the evaporated amount of water under forced convection?

• If heat loses are neglected, you can link the energy given to the vaporization molar enthalpy. – user1420303 Nov 23 '18 at 19:52
• Could you tell me how to calculate the amount of evaporated water by linking the heat supplied and the vaporization molar enthalpy? – Rabin Nov 23 '18 at 20:52
• In 1 hour the system gets 0.20 kW, divide this value by the molar enthalpy of vaporization and multiply it with 18g/mol – user1420303 Nov 23 '18 at 21:02
• What is your understanding of the physical mechanisms involved in determining the mass transfer rate between the liquid water and the air? – Chet Miller Nov 23 '18 at 22:12
• The method described by @user1420303 does not guarantee that the temperature of the liquid will be maintained at 40 C. – Chet Miller Nov 23 '18 at 22:20