.


:




:

































 

 

 

 


.

.

=0, Pe → Re→ . .

- :

+Pe = +Po

- 3 ( - ):

( =- -=>Nu()=-

ρ[ + ]=- ρg+[ +.] - -

β=-1 - 1/[].

ρ t,:

β=-1

=-β =>ρ= - β (t- )

ρ[ + ]=- + β (t- )g+μ[ + ], =+ gx- .

ρ[ + ]=- + g+ +]

= -

:

ρ[ + +]=- + + [ +.]

ρ= ,:

[ + ]=- + + [ +.]

1/Pe + = + + [ .], Gr= - ( ), - .

( )

Nu=f(Re,Gr,Pe,Fo)

, , Pe=Re*Pr

Nu=f(Re,Pr,Gr)- , .. Nu=

2 : ( ) ( , ). :

. .

+ = - .

+ =0

= =0; ..

= <

= a =>

= => = = = => = , ..

= :

1) , ..

2)Pr<1,.. v<a, .

:

=a

Y=0, t= , y=

U=

Nu=0,377 =C , m=n=1/2.

Y y y

       
 
   
 


δ

δ

t x

:

= => =

:

= => =f(y)= y= y= , .. :

=> = y; ω=f(y). , .. ωy=const=0 ,

, :

= a =>

= = = = => , ..

= .

:

1) =f(x) , =f(x), ..

2)Pr>1;v>, .

:

y =

t= ; = ; t= ;

u=

:

Nu=0,2224 = C , m=1/2, n =1/3.

( ).

.

F V , , , , . . . .

.

 

.

t

dF=Vgdρ=Vg dz=-Vgβ dz

.. β=- ; ρ0 .

dt/dz>0,dF<0-

<0,dF>0

.

=- + +1/Re

1. - ( ):

=0=>Gr= =>Re => β△ =>ω= .. ω f(ν)

2. - ( ):

=1=>Gr=Re = β△ , .. ω=f(ν)

:

, :

Nu= C Re Gr.

 

c --

Nu= c --

< c - -

c - -

Nu =c , n=1/4 .

:

Nu=0,55 , 2* <GrPr<

:

Nu=0,41 , GrPr>

:


r r

t

t

 



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