OCR Text |
Show The heat balance equation then reads Q + B + Mprs - XL(& o - & L)- 0' e23rWXL( Eo - eL) = 0 ( 15) pcp from which tL = r° + 0 ^ 2 3 ^ * 0/ 0 6 2 T r ^ r L + « , / 0.623 ' rw a~ L ( 16) / In a diagram with • v£ +( Q+ B//< 3L^ as abscissa and e, as ordinate, Equation ( 16) describes a group of straight lines with M/< Z, as group parameter. These lines are plotted in the right- hand part of Fig. 2 with a spacing of 0.01 mm h~* 7 meal cm"' min" 1 deg" , the associated values of M/&. appearing along the upper edge. Even though relationships are the same for M or M/ a", in the entire domain of a melting surface, three separate parts of the domain already illustrated in Fig. 1 can be distinguished. Evaporation and Melt. This domain encompasses the lower right part of the Figures. It is bounded on the left by the dividing line for the domain of a non-melting surface and above by V = 0 or E - e = 0, that is, by the straight line e = EQ = 4,58 torr, parallel to the abscissa. Condensation and Melt is the next domain above. This is bounded below by the already- mentioned line e, = 4.58 torr. To the left it is bounded by the group line M/ « £, = 0, which joins the other domain boundaries at the point ( Q+ B)// X'L = 0 C and e^ = 4.58 torr. Between these lines and the dividing line for the domain of a non- melting surface lies a small domain, Condensation and Freezing, in which the water vapor flux from the atmosphere appears not only as water but also partly as ice. In this case the heat of |