Kev hloov pauv cua sov - teeb meem thiab kev daws teeb meem
1. Ob lub hlau muaj tib qhov loj tab sis txawv hom. Lub thermal conductivity ntawm P = 2 npaug ntawm thermal conductivity ntawm Q. Qhov kub ntawm ob lub hlau yog dab tsi, raws li qhia hauv daim duab hauv qab no.
Paub:
k Q = k
kP = 2k
Xav tau: Kub ntawm ob lub hlau
Tshuaj:
Kev sib piv ntawm cov cua sov conduction :
Q/t = Tus nqi ntawm kev coj cua sov, k = kev coj cua sov, A = thaj tsam ntawm qhov khoom, T 1 = kub siab, T 2 = kub qis, l = qhov ntev ntawm cov hlau.
Kub = 60 o C.
2. Hlau A thiab hlau B muaj tib lub sijhawm ntev thiab tib thaj chaw hla. Yog tias cov thermal conductivity ntawm hlau A = ¼ npaug ntawm cov thermal conductivity ntawm hlau B. Ob lub hlau raug cua sov ntawm nws qhov kawg thiab qhov hloov pauv ntawm qhov kub ntawm ob lub hlau yog tib yam. Qhov piv ntawm tus nqi ntawm cov cua sov conduction ntawm hlau A rau hlau B.
Paub:
Qhov seem ntawm A(A) = Qhov seem ntawm B(A)
Qhov ntev ntawm A (l) = qhov ntev ntawm B (l)
Lub thermal conductivity ntawm hlau B (kB ) = k
Lub thermal conductivity ntawm hlau A (kA ) = ¼ k
Qhov kev hloov pauv ntawm qhov kub ntawm cov hlau A (ΔT) = qhov kev hloov pauv ntawm qhov kub ntawm cov hlau B (ΔT)
Xav tau: Qhov piv ntawm tus nqi ntawm cov cua sov conduction
Tshuaj:
Kev sib npaug ntawm kev coj cua sov:
Q/t = tus nqi ntawm kev coj cua sov , k = kev coj cua sov , A = thaj tsam hla , T 2 = kub siab , T 1 = kub qis , l = ntev ntawm cov hlau
3. Ob lub hlau, A thiab B, muaj tib qhov loj. Lub thermal conductivity ntawm cov hlau A = 2k thiab lub thermal conductivity ntawm cov hlau B = k.
Raws li pom hauv daim duab hauv qab no, qhov kawg ntawm ob lub hlau muaj qhov kub sib txawv.
Qhov kub ntawm ob lub hlau yog dab tsi?
Paub:
Ob lub hlau, A thiab B, muaj tib qhov loj.
Lub thermal conductivity ntawm hlau A = 2k
Lub thermal conductivity ntawm hlau B = k
Qhov kub ntawm ib kawg ntawm cov hlau A = 210 o C
Qhov kub ntawm ib kawg ntawm cov hlau B = 30 o C
Xav tau: Kub ntawm cov hlau A thiab B
Tshuaj:
Tus qauv ntawm tus nqi ntawm cov cua sov conduction:
Q/t = tus nqi ntawm kev coj cua sov , k = kev coj cua sov , A = thaj tsam hla , T 1 -T 2 = kev hloov pauv ntawm qhov kub thiab txias , l = qhov ntev ntawm cov hlau
Qhov kub ntawm P thiab Q:
4. Ob lub hlau muaj tib qhov loj. Lub thermal conductivity ntawm hlau II = 2 npaug ntawm thermal conductivity ntawm hlau I. Yog tias ib kawg ntawm hlau I raug cua sov ces T 1 = 100 o C thiab ib kawg ntawm hlau II raug cua sov ces T 2 = 25 o C, ces qhov kub ntawm ob lub hlau yog dab tsi.
Paub:
Lub zog ua kom sov ntawm cov hlau I = k
Lub zog cua sov ntawm cov hlau II = 2k
Qhov kub ntawm ib kawg ntawm cov hlau I = 100 o C
Qhov kub ntawm ib kawg ntawm hlau II = 25 o C
Xav tau: Kub ntawm cov hlau I thiab II
Tshuaj:
Kev sib npaug ntawm kev coj cua sov:
Q/t = tus nqi ntawm kev coj cua sov , k = kev coj cua sov , A = thaj tsam hla , T 1 -T 2 = kev hloov pauv ntawm qhov kub thiab txias , l = qhov ntev ntawm cov hlau
Kub ntawm ob qho hlau:
Qhov kub ntawm cov hlau I thiab II yog 50 o C.
5. Cov pas hlau uas muaj tib qhov loj me, tab sis ua los ntawm cov hlau sib txawv raug muab sib xyaw ua ke raws li pom hauv daim duab hauv qab no. Yog tias qhov thermal conductivity ntawm hlau I = 4 npaug ntawm qhov conductivity ntawm hlau II, ces qhov kub ntawm qhov sib tshuam ntawm ob lub hlau yog ……
Paub:
Tlub thermal conductivity ntawm hlau kuv = 4k
Lub thermal conductivity ntawm hlau I = k
Qhov kub ntawm ib kawg ntawm cov hlau I = 50 o C
Qhov kub ntawm ib kawg ntawm cov hlau II = 0 o C
Xav tau: qhov kub ntawm qhov sib txuas ntawm ob lub hlau
Tshuaj:
Kev sib piv ntawm kev hloov pauv cua sov:
Q/t = tus nqi ntawm kev coj cua sov , k = kev coj cua sov , A = thaj tsam hla , T 2 = kub siab , T 1 = kub qis , T 1 -T 2 = Kev hloov pauv ntawm qhov kub, l = ntev ntawm cov hlau
Ob lub hlau muaj tib qhov loj me yog li A thiab kuv raug tshem tawm ntawm qhov sib npaug:
6. Daim duab hauv qab no qhia txog cov pas hlau A thiab B sib txawv txuas rau ib kawg.
Thaj chaw hla ntawm ob lub pas nrig yog tib yam, tab sis qhov ntev ntawm A yog ob npaug ntawm qhov ntev ntawm B thiab cov coefficient thermal conduction ntawm A yog 3 zaug B. Yog tias cov kawg dawb A thiab B raug rau qhov kub sib txawv, qhov kub ntawm qhov sib tshuam yog ...
Paub:
Tlub thermal conductivity ntawm cov hlau rau = 3k
Lub thermal conductivity ntawm hlau B = k
Qhov ntev ntawm cov hlau A = 2l
Qhov ntev ntawm cov hlau B = l
Qhov kub ntawm ib qho kawg hlau A = 100 o C
Qhov kub ntawm ib kawg hlau B = 40 o C
Xav tau: Qhov kub ntawm qhov sib tshuam
Tshuaj:
Kev sib piv ntawm kev hloov pauv cua sov:
Q/t = tus nqi ntawm kev coj cua sov , k = kev coj cua sov , A = thaj tsam hla , T 2 = kub siab , T 1 = kub qis , T 1 -T 2 = Kev hloov pauv ntawm qhov kub, l = ntev ntawm cov hlau
Ob lub pas nrig muaj qhov loj tib yam yog li A raug tshem tawm ntawm qhov sib npaug.
