Конспект лекций по термодинамике. Коренблит С.Э. - 45 стр.

                                                                         |45|
3        ¢­®¢¥á¨¥ ¢ ¤¢ãåä §­®© á¨á⥬¥. ” §®¢ë¥
        ¯¥à¥å®¤ë
     áᬮâਬ ¨§®«¨à®¢ ­­ãî á¨á⥬ã, á®áâ®ïéãî ¨§ ¤¢ãå à ¢­®¢¥á­ëå
ä §, j = 1; 2, ®¤­®£® ¨ ⮣® ¦¥ ¢¥é¥á⢠(¢®¤ ¨ ¯ à), á ¯ à ¬¥âà ¬¨,
ᮮ⢥âá⢥­­®: Uj ; Vj ; Nj ; Sj ; Tj ; Pj ; j . ˆå ¢§ ¨¬­®¥ à ¢­®¢¥á¨¥, ¯®¬¨¬®
U + U = const, V + V = const, N + N = const, ®§­ ç ¥â â ª¦¥, çâ®
    1    2                   1               2                                   1           2

S + S = const. ®í⮬ã, ¤«ï ¬ «ëå ¢¨àâã «ì­ëå ®âª«®­¥­¨©:
 1       2



     U = U ; V = V ; N = N ; ¯à¨ç¥¬:
         2           1           2                   1                   2   (4.31)          1


   ¤«ï ª ¦¤®© ä §ë: Tj Sj = Uj + Pj Vj j Nj ; ®âªã¤ :
   0 = S = S + S = U + P V  N + U + P V  N ;
                                                     1               1       1           1       1           2       2       2   2   2
                     1

                     !
                                     2
                                         T!                  !    T          1                                               2



   â.¥.: T1 T1 U + PT PT V             1
                                                        N = 0;
                                                      T T
                                                         1               2
                                                                                     1
                                                                                                     1       2
                                                                                                                     1
             1           2                               1               2                           1       2

   ®âªã¤ : T = T ; P = P ;  =  :
                 1           2               1           2               1   (4.32)  2



à¨ j (T; P; Nj ) = Nj j (T; P ) í⨠ãá«®¢¨ï ®¯à¥¤¥«ïîâ ­ ¯«®áª®áâ¨
(T; P ) ãà ¢­¥­¨¥ ªà¨¢®© à ¢­®¢¥á¨ï ¤¢ãå ä §:
                  @  !   (T; P ) =  (T; P )  @  ! ;
                             1
                                                                             (4.33)                              2


                  @N T;P     1
                                                     1
                                                            @N T;P                   2
                                                                                                                 2



«¥¦ 饥 ¢ ®á­®¢¥ ¢á¥© ⥮ਨ ä §®¢ëå ¯¥à¥å®¤®¢. „«ï ¯à¨à 饭¨© ¯®«-
­®£® ¯®â¥­æ¨ « ƒ¨¡¡á ¢á¥© á¨áâ¥¬ë ¢ ¯à®æ¥áá å ¢ëà ¢­¨¢ ­¨ï, ¯à¨
䨪á¨à®¢ ­­ëå T , P ¨ N + N = const, ãç¨âë¢ ï (4.7) ¨ (4.31), ¨¬¥¥¬:
                                                 1               2



      (T; P ; N ; N ) =  +  ; (d)T;P =  dN +  dN ;
                     1       2               1               2               (4.34)                  1   1       2       2


      (d)T;P =) (  )dN  0; â.¥., dN  0; ¥á«¨  >  ; (4.35)
                                 1           2           1                                       1                           1   2



â.¥., ¯®â®ª ç áâ¨æ ¢á¥£¤ ­ ¯à ¢«¥­ ®â ä §ë á ¡®«ì訬 娬¯®â¥­æ¨ «®¬
ª ä §¥ á ¬¥­ì訬 娬¯®â¥­æ¨ «®¬. ‚ á®áâ®ï­¨¨ â¥à¬®¤¨­ ¬¨ç¥áª®£®
à ¢­®¢¥á¨ï  ¨¬¥¥â ¬¨­¨¬ã¬, d = 0, â.¥. 娬¯®â¥­æ¨ « ®áâ ¥âáï ­¥¯à¥-
à뢥­ ¯à¨ ä §®¢®¬ ¯à¥¢à 饭¨¨,  =  . Ž¤­ ª® ¥£® ¢ëá訥 ç áâ­ë¥                 1           2

¯à®¨§¢®¤­ë¥, ¢®®¡é¥ £®¢®àï, ¤®«¦­ë ¨¬¥âì à §àë¢. ᫨ ᪠祪 â¥à¯ïâ
¯¥à¢ë¥ ¯à®¨§¢®¤­ë¥, â® £®¢®àïâ, çâ® íâ® ä §®¢ë© ¯¥à¥å®¤ 1-£® த , ¨, ¢
ᨫã ãà ¢­¥­¨ï ƒ¨¡¡á - „¬ (3.36):
             dj (T; P ) = sj dT + v j dP; £¤¥, ¯à¨ j = 1; 2 :               (4.36)