Editing the code needed

I am trying to calculate the scaled surface area of a spherical flame in cylindrical tube. I have the code for planar plane surface area if you wanna look at it: file=fopen("[login to view URL]", "a"); fprintf(file, "%.15le\n", dat->Time*dat->Flame_velocity/(dat->Radius_of_tube*dat->Flame_thick)); printf("Front length: %.15le\n", dat->FrontLength); printf("Front velocity: %.15le\n\n", dat->FrontLength/dat->Y_grid[dat->NJ-1][0]*dat->Flame_velocity); fprintf(file, "%.15le\n", dat->FrontLength/(dat->Radius_of_tube*dat->Flame_thick)); fclose(file);