Answer to Question #255945 in Mechanical Engineering for Gani

Question

Compute the drying power Ea and the relative evaporation Er of an area covered with grass of Z. = 2 cm, and that of an adjacent area covered with trees of Z, = 70cm. Given that wind velocity U = 2.5 m/sec, Tair = 8°C, relative humidity = 0.3, Pair = 1.3 kg/m”, pw = 1000 kg/m”, Patm = 1013mb, Z = 2m, and net radiation Q = 90 W/m². Why the Ed of trees is higher than that of grass?

Answer 1

Evaporation occurs when water is converted into water vapor at the evaporating surface, the contact between water body and overlapping air. At the evaporative surface, there is a continuous exchange of liquid water molecule into water vapor & vice versa. The two main factors influencing evaporation from an open water surface are the supply of energy to provide the latent heat of vaporization, and the ability to transport the vapor away from the evaporative surface. The latent heat of vaporization lv is the amount of heat absorbed by a unit mass of a substance. Solar radiation is the main source of heat energy.