抄録
The present investigation was undertaken to apply theoretical methods to the ventilation of polluted air in room where carbondioxide was not homogeneously diffused. In the case of one dimensional diffusion, C is the concentration of carbondioxide at time nδT, and subscripts m, m+1 and m-1 denote space mδX, (m+1) δX and (m-1) δX, respectively, and superscript+denotes time (n+1) δT. Assuming that the concentration of carbondioxide depends on time and space as described in the previous paper, a following equation can be obtained : [numerical formula] where X is a distance from a source of evolution of carbondioxide, and D is a constant (not equal to 0). According to a Implicit difference analogue for the above equation, Taylor's expansion theorem, and Crank-Nicolson's method, a following equation can be obtained : [numerical formula] In the case of two dimensional diffusion, a following equation can be obtained as in the case of one dimensional : [numerical formula] where subscripts j, k ; j, k-1 ; j, k+1 ; j-1, k ; j+1, k denote space x=jh, y=kh ; x=jh, y=(k-1) h ; x=jh, y=(k+1) h ; x=(j-1) h, y=kh ; x=(j+1) h, y=kh, respectively. It was found that Crank-Nicolson's method is available for the theoretical study of natural ventilation of polluted air diffused heterogeneously in room as well as Schmidt's and Dusinberre's methods.
