A stream of atmospheric air is used to dry a series of biological samples on plates that are each of length L_i = 0.25 m in the direction of the airflow. The air is dry and at a temperature equal to that of the plates (T_∞ = T_s = 50°C). The air speed is u_∞ = 9.1 m/s.

(a) Sketch the variation of the local convection mass transfer coefficient h_m,x with distance x from the leading edge. Indicate the specific nature of the x dependence.

(b) Which of the plates will dry the fastest? Calculate the drying rate per meter of width for this plate (kg/s ∙ m).

(c) At what rate would heat have to be supplied to the fastest drying plate to maintain it at T_s = 50^o during the drying process?

Transcribed Image Text:

Air т. LT,=T Lex