131.13330.2012 .
:
1) . --;
2) ;
3) .
1 d=10;
2 d=200;
3 ѻ ( d=d);
4 d=8 ( ).
1.2
ѻg3=35 /3, l3=0,036 |
g1=800 /3, l1=0,19 |
g2=600 /3, l2=0,14 |
1.2-
:
- t = + 18C;
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- , - 24 .
:
1) 131.13330.2012 :
- .
2) .1 131.13330.2012 :
- .
.2 131.13330.2012 .
:
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1 (d1=10, g1=800/3, l1=0,19 );
2 (d2=200, g2=600/3, l2=0,14 );
3 ѻ(d3=d,g3=35/3, l3=0,036 ).
zht191.; tht= -1.90; text= 230; tint= 180; Dtn=4,50; aint=8,7 ; aext=23 ; n=1.
.
Ro, 20/, - Dd, C*cym, Rred, 2 0/, 4 131.13330.2012.
Ro>Rreg (1.1)
- , *, :
Dd=(tint-tht)zht; (1.2)
tint - , ;tht - ≤8, . 131.13330.2012
Zht ≤8, . 131.13330.2012.
Dd=(tint- tht)* Zht =(18-(-1,9))*181 = 3741.5 (C *.)
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Rreg=aDd+b (1.3)
, b- , 4 131.13330.2012 .
Rred =0,0003*3741.5+1,2= 2,32 (20/) (1.4)
:
(1.5)
αint- , 7 131.13330.2012
Rk- ;
αext- ( ) .
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(1.6)
σ - , ;
λ - , /( )
131.13330.2012
Rk :
RK, = R1+R2+... + Rn+Ra1,
R1,, R2,, Rn - ;
2,32=0,115+0,053+1,428+ +0,043
= 0,024() 30
, . -- :
∑=10+200+50+8 = 266, 300
R0=2,47 ,
2,47>2,32
∆t0,, :
(1.7)
n - , 6,
131.13330.2012
tint - , ;
text - 0,92:
Ro - ;
αint- , 7 131.13330.2012
∆t0<∆tn
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td tint φint %, 131.13330.2012, td=7,44 C 50%.
τint,, , :
τint = tint -∆t0 =18-1,908 = 16,092C
, 16,092 C>7,44 C