XIV bob. NURLAN ISH U SU LID A ISSIQ LIK UZATILISH I
58-§. A so siy tushunchalar
Issiq lik n in g n u rla n ish y o 'li b ila n u zatilish i deb, jism n in g ichki
en e rg iy asin i e le k tro m a g n it to 'lq in la r o rq ali u z a tilish ig a aytiladi.
N u r la n is h to 'lq in u z u n lig i A(m) y o k i te b r a n is h
c h a sto ta -
si v =c/A b ila n ifo d a lan a d i, b u y e rd a ,
с =
2,9979 • 108 m /s - b u va-
k u u m d a g i e le k tro m a g n it to 'lq in la m i tarq a lish tezligidir.
Q attiq va s u y u q jism la rd a n u rla n ish u z lu k s iz d ir. G a z la rd a se-
lek tiv d ir, y a 'n i g a z la r kerakli t o iq in u z u n lig id a g i
n u rla m i chiqa-
rad i. N u rla n ish o q im i d e b vaq t b irlig id a g i n u rla n is h energ iy asig a
aytiladi:
Ф - n u rla n ish oqim i, [Vt];
6Q - n u rla n is h en e rg iy asi, [J];
T - v a q t , [s].
issiqlik oqim ini jism n in g y u z a sig a n isb a ti n u rla n ish deyiladi:
8Ф
о
£ =
Vt/m .
(261)
dF
Issiqlik n u rla rig a to 'lq in u z u n lig i A = 0,4 • 1 0 -3-*-0,8 m m
ga teng
b o 'lg a n to 'lq in la r k iradi. Jism lar tizim i n u rla n g a n d a , u la r h a r biri
b o sh q a jism larg a o 'z la rid a n q a y tg a n n u rla ri tu sh a d i.
Jism ga kelib tu sh g a n n u r yoki issiqlik sh u jism d a y u tila d i (Q
a
),
q a y ta d i (QR) v a o 'tib k e ta d i (Qp).
N u rla n is h d a g i issiqlik b a la n sin in g ifodasi:
Q = Q
a
+ Q
r
+ Q
p
yoki:
A + R + D =
1 100%
b u y erd a.
131
A =
-5 a _ y u tis h koeffitsiyenti;
R =
-
q a y tish koeffitsiyenti;
D =
-
o 'tis h koeffitsiyenti.
A g a r A = l;
R=D=0
b o 'lsa , jism m u tla q qo ra,
R=l,
A=D=0 b o 'lsa ,
jism m u tla q oq, D = l;
A=R=0
b o 'lsa , jism shaffof jism d ey ilad i. Ta-
b ia td a m u tla q oq, q o ra va shaffof jism b o 'lm a y d i.
59-§. N u r la n is h n in g
a so siy q o n u n la r i
1. S tefan-B olsm an qo n u n i.
N u rla n is h en e rg iy asi b ila n m u tla q q o ra jism n in g m u tla q h a ro -
ratin i to 'rtin c h i d a ra jasig a to 'g 'ri p ro p o rsio n al:
E
= a 0T4
(262)
a 0- B o lsm an d oim iysi; a 0=5,67 V t/m 2 K4.
A m aliy h iso b la sh la rd a b u q o m m q u y id a g ic h a ifodalanadi:
Q = c(77100)4 F
(263)
b u y e rd a ,
с -
k u lra n g jism n in g
n u rla n is h koeffitsiyenti, Vt/
m 2K4.
132
B ir-biridan shaffof m u h it b ila n ajratilgan, ikkita yassi, p a ra l
lel jo y lash g an , h a ro ra ti y u q o ri b o 'lg a n jism d a h a ro ra t p a s t b o 'lg a n
jism ga n u rla n ish y o 'li bilan o 'ta y o tg a n u m u m iy issiqlik oq im i
q u y id a g i ifo d a d a n topiladi:
Ql-2 =
ckel
F [(T, / 100)4 - (T2 / 100)4 ]
(265)
b u y e rd a , F - issiqlik a lm a sh in ish y u z a si, m 2;
Ckei -
keltirilg an
n u rla n ish koeffitsiyenti, V t/m 2 K.
ckel
= -J
1
T
Vt/m 2 К
(266)
C l
c 2
C0
b u y e rd a ,
T u T 2 -
n u rla n u v c h i jism va a tro f-m u h itn in g m u tla q
h a ro ra ti, °C;
Ci, c2 - k u lra n g jis m la m in g n u rla n is h koeffitsiyenti;
c0 =
5,67 V t/m 2 К - a b so ly u t qora jism n in g n u rla n is h koeffit
siyenti;
Сы=е-
c0
ifo d a s id a n an iq la n ad i, e - q o ralik darajasi.
H a r xil n u rla n u v c h i tiz im la rd a n u rla n ish y o 'li
b ila n issiqlik
a lm a sh ish n i k a m a y tirish u c h u n e k ra n la rd a n fo y d ala n ila d i (47-
rasm ).
1
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