C1_1_Mot So Khai Niem Co Ban
-
Upload
leanhtoan11a3 -
Category
Documents
-
view
223 -
download
3
Transcript of C1_1_Mot So Khai Niem Co Ban
-
NHIT NG LC HC
S tit hc: 42 tit ko di trong 8 tun
- Tun 1 4 : 5 chng u tin
- Tun 4 : KIM TRA gia hc k
- Tun 5 8 : 5 chng cui
- THI CUI HC K
20%20%
80%80%
B mn: Cng ngh Nhit Lnh Khoa C Kh
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.1p.1
-
Mc ch mn hcNm vng nhng qui lut v bin i nng lng (ch yu l
nhit nng v c nng) nng cao hiu qu s dng nng lng
l mn c s nghin cu v thit k cc loi my nhit ni ring v cc h thng nhit ng ni chung
VD: - Cc loi ng c nhit: C t trong, C phn lc- HTHKK, T lnh- Cc thit b sy, l hi- Bm, my nn- Cc h thng s dng nng lng mt tri, vv.
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.2p.2
-
Ni dung mn hcChng 1: M t s khai nim c ba n Phng trinh trang thai cua cht khi
Chng 2: nh lut Nhit ng th nht (Nguyn l bo ton nng lng)
Chng 3: nh lut Nhit ng th hai
Chng 4: Cht thun khit
Chng 5: Mt s qu trnh c bit ca kh v hi
Chng 6: Khng kh m
Chng 7: Qu trnh nn kh v hi
Chng 8: Chu trnh thit b ng lc hi nc
Chng 9: Chu trnh ng c t trong
Chng 10: Chu trnh my lnh
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.3p.3
-
Ti liu tham kho1. Hong nh Tn L ch Hip, Nhit ng lc hc kthut, NXB i hc quc gia Tp HCM, 2007.
2. Hong nh Tn Bi Hi: Bi tp Nhit ng lc hcKT & truyn nhit, NXB HQG TpHCM, 2008.
3. Hong nh Tn, Nhit cng nghip, NXB i hc quc gia Tp HCM, 2001.
4. Cengel, Y. A. Boles, M. A., Thermodynamics: An Engineering Approach, 5th Edition, McGraw-Hill publisher, 2006.
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.4p.4
-
CHNG 1 (Phn 1):
Mt s kha i ni m c ba n
1.1 Cc vn chung
1.2 Nhng khi nim c bn
1.3 Thng s trng thi ca mi cht
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.5p.5
-
1.1 Cc vn chungTt c cc bi ton v NHIT chung qui cng ch nhm:
Xc nh NNG LNG ca h thng cng nh S CHUYN HA NNG LNG trong h thng
VD1:
m
VD2: Bm xe p nng ln khi bm
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.6p.6
-
1.2 Nhng khi nim c bn
1.2.1 Nhit lng v cng
1.2.2 H nhit ng
1.2.3 My nhit
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.7p.7
-
1.2.1 Nhit lng v cngNhit lngNhit lng: l lng nng lng i xuyn qua b mt ranh gii khi gia cht mi gii v mi trng c s chnh lch nhit - Qui Qui cc: + Vt nhn nhit: Q (+)
+ Vt thi nhit: Q (-)
CngCng: l lng nng lng i qua b mt ranh gii c kh nng dch chuyn mt vt no .- Qui Qui cc: + Vt sinh ra cng: W (+)
+ Vt nhn cng: W (-)
n v on v o: - H SI: 1 J (jun) = 1N.m = 107 erg ; 1 cal (calo) = 4.18 J
- H khc: 1 Btu = 1055 J = 252 cal ; 1 Wh = 3.413 Btu
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.8p.8
-
Mechanical Equivalent of Heat
Joule demonstrated that water can be heated by doing (mechanical) work, and showed that for every 4186 J of work done, the temperature of water rose by 1C0 per kg.
p.9p.9
Ngi son: TS. H anh Tng HBK tp HCM
-
1.2.21.2.2 H H nhit ngnhit ng
- H nhit ng (HN) khong khng gian c cha mt lng nht nh cht mi gii ang c kho st bng cc bin php nhit ng.
V d minh ha
Khi xem xt mt
HN cn ch :
Cht mi gii ?? Ngun nng ?? Ngun lnh ??
Cng v nhit lng trao i khi cht mi gii bin i trng thi
B mt ranh gii ngn cch gia cht mi gii v mi trng ??
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.10p.10
-
Mt s v d v h nhit ngMt s v d v h nhit ng (1)(1)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.11p.11
-
Mt s v d v h nhit ngMt s v d v h nhit ng (2)(2)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.12p.12
-
Mt s v d v h nhit ngMt s v d v h nhit ng (3)(3)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.13p.13
-
Phn loi h nhit ngPhn loi h nhit ng
- HN kn: lng cht mi gii trong h thng c duy tr khng i, cht mi gii khng th i xuyn qua b mt ranh gii ngn cch gia h thng v mi trng. ( VD: my lnh)
- HN h: cht mi gii c th i vo v i ra khi h thng xuyn qua b mt ranh gii. ( VD: ng c t trong, tuabin kh, ng c phn lc, etc.)
- HN on nhit: trong h thng ny, cht mi gii khng c s trao i nhit vi mi trng trong qu trnh hot ng.
- HN c lp: trong h thng ny, cht mi gii v mi trng hon ton khng c bt k s trao i nng lng no trong qu trnh hot ng.
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.14p.14
-
V d v h nhit ng V d v h nhit ng knkn
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.15p.15
-
V d v h nhit ng V d v h nhit ng hh
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.16p.16
-
V d v h V d v h c lpc lp
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.17p.17
-
1.2.31.2.3 My nhitMy nhit
y l loi my dng nhit sinh cng. Trong loi my ny, cht mi gii s vn chuyn nhit lng theo chiu thun t ngun nng n ngun lnh v gin n sinh cng. ( VD: ng c t trong, ng c phn lc, tuabin, vv..)
Ngun nng
Ngun lnh
ng c nhit
Q1
Q2
W
Xt bo ton nng lng cho ng c nhit:
WQQ += 21
Hiu sut nhit:1
2
1
2
1
11qq
QQ
QW
===
A/ ng c nhit:
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.18p.18
-
V d v ng c nhitV d v ng c nhit
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.19p.19
-
B/ Bm nhit, my lm lnh:
y l loi my nhn cng t bn ngoi vn chuyn nhit lng theo chiu ngc t ngun lnh n ngun nng.
(VD: my lnh, bm nhit)
Ngun nng
Ngun lnh
Bm nhit,My lm lnh
Q1
Q2
W
Xt bo ton nng lng cho bm nhit hay my lm lnh: WQQ += 21
H s lm nng (cho bm nhit):21
1
21
11
qqq
QQQ
WQ
=
==
H s lm lnh (cho my lnh):21
2
21
22
qqq
QQQ
WQ
=
==
1>
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.20p.20
-
My iu ha nhit My iu ha nhit
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.21p.21
-
T lnh - Refrigeration Animation
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.22p.22
-
Bm nhit My HKK
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.23p.23
-
1.31.3 Thng s trng thiThng s trng thiTi mt iu kin bt k, trng thi ca cht mi gii c th c xc nh = 2 thng s trng thi c lp (V d)
Cc thng s trng thi thng dng l:
- Nhit T
- p sut p
- Th tch ring v
- Ni nng u
- Entanpi i
- Entropi s
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.24p.24
-
V d v thng s trng thiV d v thng s trng thi
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.25p.25
-
Nhit Nhit TT
Thng s trng thi th hin mc nng lnh ca vt
n v:
Dng c o: Nhit k
- NK thy ngn, NK ru: da trn s gin n ca cht lng
(NK) - NK in tr: da trn s thay i in tr- Thermocouple: da trn s thay i dng in
- bch phn (oC): ( )3295
= FC oo
- Fahrenheit (oF): 328.1 += CF oo
273+= CK oo- Kelvin (oK):
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.26p.26
-
Tng quan gia cc thang nhit Tng quan gia cc thang nhit
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.27p.27
-
Absolute Zero and the Kelvin Scale
The pressure-temperature relation leads to the design of a constant-volume gas thermometer. Extrapolation of measurements made using different gases leads to the concept of absolute zero, when the pressure (or volume) is zero.
t (oC)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.28p.28
-
p sutp sut ppLc tc dng ln mt n v din tch b mt ranh gii theo
phng php tuyn vi b mt . (V d)
Dng c o:
- Manometer (p k): dng o p sut d pd, phn p sut ca cht kh ln hn p sut kh tri- Parometer: o p sut kh tri pkt- Vacumeter (chn khng k): o p sut chn khng pck, phn p sut ca cht kh nh hn p sut kh tri
ppp ktck =
n v:1 Pa (Pascal) = 1 N/m21 bar = 105 Pa = 750 mmHg1 at = 9.81 x 104 Pa = 0.981 bar = 10 mH2O = 735.6 mmHg1 mmHg = 133.3 N/m21 mmH2O = 9.81 N/m2
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.29p.29
-
V d v p sutV d v p sut (1)(1)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.30p.30
-
V d v p sut V d v p sut (2)(2)
2
1
2
121 A
AFFpp ==
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.31p.31
-
V d v p sut V d v p sut (3)(3)
p s: 111.7 kPa
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.32p.32
-
V d v dng c o p sutV d v dng c o p sut
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.33p.33
-
Nguyn l hot ng ca Nguyn l hot ng ca ParometerParometer
VD: vi 1mm H2O
PamNxxghOmmH 81.9/81.9001.081.910001 22 ====
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.34p.34
-
Nguyn l hot ng caNguyn l hot ng ca ManometerManometer
VD: vi kPaPcmhmkg atm 96;55;/850 3 ===
kPaxxghPP atmGas 6.1001055.081.985096 3 =+=+=
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.35p.35
-
V d: dng Manometer o chnh p sut ca dng chy
( ) ghgaPhagP 21211 ++=++Ta c:( )ghPP 1221 =
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.36p.36
-
Th tch ringTh tch ring vvTh tch ng vi mt n v khi lng
GVv = (m3/kg)
hay:1
=v
trong : + G: khi lng ca khi cht mi gii ang kho st (kg)+ V: th tch chon ch ca khi cht mi gii (m3)
+ : khI lng ring ca khi cht mi gii ang kho st (kg/m3)
Lu : th tch ring v mi l thng s trng thi, cn th tch V khng phi l thng s trng thi
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.37p.37
-
V d v tnh th tch ringV d v tnh th tch ring
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.38p.38
-
Ni nngNi nng uuL loi thng s trng thi khng o trc tip c m phi
tnh ton Ni nng U ca mt h thng bao gm:
- ng nng Ud do chuyn ng tnh tin, chuyn ng quay ca cc phn t, v do cc dao ng trong ni b phn t bn trong h thng
- Th nng Ut do lc tng tc gia cc phn t trong h thng
td UUU +=Nu kho st 1kg khi lng cht mi gii:
td uuu +=
trong : ud l ni ng nng; ut l ni th nng ca 1 kg khi lng cht mi gii
(kJ/kg)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.39p.39
-
td uuu +=
Theo thuyt ng hc phn t:
- Ni ng nng ud ch ph thuc nhit - Ni th nng ut ph thuc khong cch trung bnh gia cc phn t, tc ph thuc vo th tch ring
),( vTfu =i vi kh l tng: lc tng tc gia cc phn t c xem bng
khng, do ni nng ca kh l tng ch ph thuc vo nhit .
n v: kJ, kcal, kWh (h SI) hoc BTU (British Thermal Unit)
Lu : trong cc bi ton v nhit ng, ni chung khng cn bit gi tr tuyt i ca ni nng m ch cn bit lng bin i ni nng
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.40p.40
-
Ni thm v ni nng UL nng lng bn trong, gy ra do chuyn ng v tng tc gia cc phn t trong vt th.
V d: - i vi vt rn
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.41p.41
-
V d: (i vi cht kh)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.42p.42
-
EntanpiEntanpi iiL loi thng s trng thi khng o trc tip c m phi
tnh ton
Entanpi ca 1 kg khi lng cht mi gii uc tnh theo cng thc:
pvui += (kJ/kg)
i vi kh l tng, do u v pv ch ph thuc vo nhit nn i cng ch ph thuc vo nhit
Lu : trong cc bi ton v nhit ng, ni chung khng cn bit gi tr tuyt i ca entanpi m ch cn bit lng bin i entanpi
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.43p.43
-
EntropiEntropi ssLng bin i entropi ds ca 1 kg khi lng cht mi gii
trong 1 qu trnh thun nghch uc tnh theo cng thc:
Tqds =
trong : - l nhit lng trao i gia cht mi gii v mi trng trong qu trnh thun nghch v cng b
- T l nhit tuyt i
hayTQdS = cho G kg cht mi gii
(dS = G ds)
n v: kJ/kg.K, kcal/kg.KLu : = 0ds- d chu trnh l thun nghch hay khng
0= TQ- nu chu trnh l thun nghch
0
-
---------------------------------------
HT CHNG 1(Phn 1)
Ngi son: TS. H anh Tng HBK tp HCM
1/2009
p.45p.45
NHIT NG LC HCMc ch mn hcNi dung mn hcTi liu tham khoCHNG 1 (Phn 1):1.1 Cc vn chung1.2 Nhng khi nim c bn 1.2.1 Nhit lng v cngMechanical Equivalent of Heat1.2.2 H nhit ngMt s v d v h nhit ng (1)Mt s v d v h nhit ng (2)Mt s v d v h nhit ng (3)Phn loi h nhit ngV d v h nhit ng kn V d v h nhit ng hV d v h c lp1.2.3 My nhitV d v ng c nhitMy iu ha nhit T lnh - Refrigeration Animation Bm nhit My HKK1.3 Thng s trng thiV d v thng s trng thiNhit TTng quan gia cc thang nhit Absolute Zero and the Kelvin Scalep sut pV d v p sut (1)V d v p sut (2)V d v p sut (3)V d v dng c o p sut Nguyn l hot ng ca ParometerNguyn l hot ng ca ManometerV d: dng Manometer o chnh p sut ca dng chyTh tch ring vV d v tnh th tch ringNi nng uNi thm v ni nng U Entanpi iEntropi s---------------------------------------