N G H I S N CLTU-TRAOeOi
MO HINH TOAN XAC DINH CHIEU DAY MANG LONG NGUlVG TRONG VI ONG d CHE DO HINH XUYEN
MATHEMATICAL MODEL FOR DETERMINATION OF CONDENSATION FILM THICKNESS IN MICRO TUBE IN ANNULAR REGIME
ThS. Hoang Anh Tnin', PGS,TS. Nguyin Nguyen An^
'Tmdng Cao ding nghd Cdng nghiep Thanh Hoa
^Tnrdng Dai hpc Bich khoa Hi Npi TOM TAT
Bdi bdo trinh bdy viec xdy dung mgt mo hinh todn giup xdc dinh chieu ddy mdng long ngung trong vi ong cr che do hinh xuyen. Mo hinh diroc xdy dung dua tren vi^c thiet lap he phinmg trinh viphdn bdo todn dgng lufrng, bdo todn khoi vd cdn bdng ndng Ittfmg trong Ap tog do trg hai chieu, CO ki den dg cong ciia mdng long ngimg cUng nhu hi^n tuong truot tgi be mat phdn pha long - hai.
Vifc tich phdn he phuong trinh viphdn ndy theo tiet dien ngang vi ong dd duoc thttc hifn, gidp xdy dung mgt mo hinh todn chi gom cdc phep tinh dgi so vd tich phdn xdc dinh, hodn todn co the gim duoc bdng cdc phuong phdp so thong dung hien nay. Bdy Id co so de xdy dung mgt phucmg phdp ly thuyet giup xae dinh chinh xdc hem chieu ddy mdng long ngung ciing nhu he so trao ddi nhtft doi luu Irong vi ong a che dg hinh xuyen.
Tir khoi: Mdng long ngtmg, ngung Ut, vi Sng.
ABSTRACT
This paper presents Ihe development of a mathematical model to determine the thickness of condensed liquid layer during condensation in micro tube in annular regime. The model was developed based on the establishment of the differential equations for momentum, mass and energy conservations in two - dimensional cylindrical coordinate system. Theses differential equations are took into account the effects of cultivation of the liquid layer as well as the slip phenomenon al Ihe liquid - vapor interface surface. The integrating the differential equations in the cross - section cf Ihe lube was performed that converted these differential equations to the algebraic form which can be solved easily by popular numerical methods. This is basic of development of a theoretical method for precisely determine the thickness of the liquid layer as well as the convective heat transfer
coefficient during condensation in micro tube in annular regime.
Kcyivords: Condensed liquid layer, condensation, micro Uibe.
ISSN 0866-7056
TAPCHlCaKHlVl6TNAM,Sd I0nam2016 www.cokhivietnam.vn
NGHIEN CU'U - TRAO 06l
l.DATVANDE
Qua trinh ngung ty cua ddng mdi chdt Uong vi dng (nhirng dng cd dudng ldnh trong nhd hon 2mm) dang rdt duoc quan tdm do khd nang tiet kipm nguyfin vdt lieu chl tgo thiet hi, cDng nhu gidm dupc ddng ke Iupng mdi chdt su dyng. Trong qud trinh ngung ty bfin trong dng, che dp hmh xuyen Iudn xdy ra vdi tdn suat cao hon cdc chfi dp Ididc. Doi vdi vi dng, do cd kich thudc nhd, che dp hinh xuyfin xdy ra Uong phan ldn cdc trudng hpp [1,2]. Do vay, nghien ciiu ve qud trinh ngimg ty Uong dng d che dp hinh xuyen ludn dupc quan tam, dac biet la ddi vdi vi dng.
Qud trinh ngung ty bfin Uong vi dng ndi chung, d che dp hinh xuyfin ndi rifing, dupc nghifin ciiu cd d phuong di^n Iy thuyet lan thyc nghifm. Cdc nghien cim thyc nghipm thudng dupc tifin hdnh cho mpt sd ttudng hpp cy the vfi kich cd vi dng, chung logi mdi chdt va dai nhipt dO, dp suat Idm viec [1-12]. Tuy khdng chi ra dupc bdn chdt ciia cdc qud trinh xdy ra ben trong nhirag ket qud nghien ciiu thyc nghifim tiiudng cho ket qua khd chinh xdc, ddp iing dupc nhu cdu tinh toan Uong thuc te. De md rpng phgm vi dp dyng ciia cdc kfit qud nghien Cliu thyc nghipm, mdt sd nghifin ciiu ly thuyfit da dupc din hanh. Trong dd, hudng nghien ciiu dau tien dupc thyc hipn Id su dyng cdc cdng thiic da dupc xdy dyng cho ong thudng [13-
17], dp dyng cho vi dng vd so sdnh vdi cdc ket qua thyc nghipm de ddnh gid dp chinh xdc cung nhu phgm vi dp dyng ciia cdc cdng thiic ndy. Theo dd, cdng thiic ciia Akers vd cpng sy [13] cho kit qud phu hpp nhdt khi dp dung de tinh hp sd trao ddi nhipt ddi luu trung binh cho todn bp dogn vi dng dang khdo sdt, vdi sai lech cao hon tii 10% den 20% so vdi sd lipu thuc nghifm. Tuy nhien, khi so sdnh vdi sd lipu thyc nghipm vfi hp sd trao ddi nhiet ddi Iim cue bp Uong vi dng, Baird va cpng sy nhdn thdy, tdt cd
cac cdng thiic hien cd dlu cho kit qua rdt sai lech [1]. Vi vdy, Baird vd cdng sy da tien hdnh xdy dung mdt md hmh ban thuc nghiem de xdc dinh he sd trao doi nhifit ddi luu cyc bd ttong vi dng cho chl dp hinh xuyln, cd ke den dnh hudng cua tdc dp khdi, dp khd mdi chdt, kich CO vi dng vd dp sudt cua qud trinh ngimg ty [1].
Cdc nghien ciiu ly thuyet vfi qua trinh ngung ty Uong vi dng, nhu vua trinh bay, cd ddc difim la dlu kl thira ly tiiuylt ogimg mdng Nusselts vdi chieu ddy mang ldng ngung dupc coi Id rdt nhd so vdi dudng kinh dng va dnh hudng cua lyc trpng trudng Ifin chuyen dpng cua mang ngung Id khdng the bd qua ttong mdt sd trudng hpp. Ddi vdi vi dng, do cd dudng kinh rdt nhd nfin nhimg ddc difim nay trong Iy thuylt ngung mdng Nusselts Ud nen khdng phu hpp. Vi vgy, bdi bao se Uinh bdy mpt md hinh todn giiip xdc dinh chifiu ddy mang ldng ngung trong vi dng d chfi dp hinh xuyen tuong ty nhu ly thuyet ngung mdng Nusselts vdi diem khac bidt Id cd ke den dp cong cua mdng Idng ngung vd bd qua tdc d^ng cua lyc ttpng trudng.
Ngodi ra, md hinh ciing ke den sy trupt giiia bl mgt phdn pha Idng - hoi, mpt dac diem rdt quan Upng, khdng the bd qua ttong qud trinh luu dpng cua ddng 2 pha bfin Uong vi dng. Day Id CO sd de hieu rd hon bdn chdt cung nhu xdc dinh chinh xdc hon chieu ddy mdng Idng ngung vd he sd trao ddi nhiet ddi luu cua qua trinh ngung ty bfin trong vi dng.
2. CO s d LY THUYET
2.1. Hfi phuong trinh vi phdn md ta qud trinh Qud trinh ngung ty ben Uong vi ong d che dp hinh xuyen dupc trinh bay ttfin hinh 1.
Theo do, ddng hoi mdi chdt d Ugng thdi bao hod khd di vdo mpt ddu cua doan vi dng dang khdo sdt Tai ddy, qud trinh ngung ty bdt ddu xay ra vdi chieu day vd tdc dp mdng long ngung dupc coi Id bdng 0. Qua trinh ngung hi ^
ISSN 0866 - 7056
TAP CHl CO KHl V I £ T NAM. Sd 10 ndm 2016
www.coldiivietnam.vn
NGHlfN CUU - TRAO D6\
ctia hoi mdi chdt dpc theo chieu chuyen dpng se lam cho chifiu ddy ciia mdng Idng ngung tang Ifin vd hmh tiidnh mot ldp mdng Idng ngung hmh xuyln bao quanh chu vi dng. Chilu day vd phdn bd tdc dp trong ldp mdng Idng ngung hinh xuyln nay, vl co bdn, se chiu dnh hudng cua Iyc ma sdt vdi thdnh dng, lyc keo bdi ddng hoi trong loi dng (loi hoi) vd tdc dp ngung hoi. Tat cd cdc qud trinh ndy se dupc the hifin trong he phuong trinh vi phdn md td qud trinh nhu trinh bdy d phdn tiep theo cua bdi bdo.
hoi mdi
chit °
r i-Iwigngirag
4W^ ^ ^ai
^ ^ ^ / / / / /
1L
j~ pfain td xem x£t
/ / y
—,
J
y / / i-il
T / r
t
1 u
Hmh 1. Qud trinh ngung hf ben trong vi ong ache dg hinh xuyen
2.1.1. Cdc gid thiet ban dau
De phu hop vdi die diem ciia vi dng cung nhu de don giin trong vi?c giii h?
phuong trinh vi phan, can chap nhan nhiing gii thiet sau diy:
- Bd qua inh hudng cua l\rc trpng trudng;
Bd qua phin bd tdc dp trong ldi hoi vi coi ldi hoi li ddng nhit vd trjng thii nhiet dpng;
- Mdi chat trong ming ldng ngimg hinh xuydn dupc xem li chit ldng Newton (Newtonian iiuid);
- Ldp ldng ngung mdi chit d sit bd mat vi dng dupe coi la khdng chuySn dpng, do ma sit vdi vich 6ng;
- Qui trinh dupc coi li cd hi$n tupng trupt tai mat phin pha ldng - hoi giua ming Idng ngung hinh xuydn vdi ldi hoi;
Bd qua thay ddi ip suit dpc theo chidu dai ong;
- Do vi dng cd dudng kinh nhd, khdng Idn hon nhidu so vdd chidu day ming ldng ngimg nen ming Idng ngung hinh xuydn d diy dupc coi li vich tru, sau khi bd qua sv khdng dong dJn vd chidu diy quanh chu vi ong.
Do tmh ddi xiing quanh trvic ciia vi dng, d day, ta xet hien tupng trong h$ toa dp h\i 2 chidu 1, r vdi true 1 dupc chpn triing vdi tryc dug vi cd gdc d diu vio dng. Vdi hp t09 dp t^i nhu vira md ti, hp phuong trinh viphinsaudiy se duoc xay dimg cho mpt phin td ldng ngung hinh xuydn cd kich thudc dr x dl, nhu trinh bay tren hinh 1.
Hinh 2. Cdn bdng luc trong phan td dang khdo sdt 2.1.2. Phittmg trinh viphdn dgng lltgrng
Phuong trtnh vi phin d$ng lupng bieu thi su can bang lire cho phan td dr x dl, nha trinh biy tren hinh 2. Theo dd, khi bd qua lire trpng trudng, cic thinh phan lire tham gia vio su can bang niy chi bao g6m cic ling suit tnrpt giy ra bdi su chdnh Ipch tdc dp giOa be mjt phan td dang xdt vdi cic phin tu ldng ngung xung quanh. Trong hp toa dp trvi, cin bing niy dupc bi^u dien qua bieu thirc (1), sau dd dupc bidn ddi thinh bieu thiic (2).
2ii(r + dr)dl(T+dT) = 2iirdk (1) n; + rdr + rdr+dtdr = rt (2) BChi bd qua vi phin bic 2, dr dr, bife thirc (2) cd thd dupc bidn ddi thinh djuig (3) vdi kdt qua, sau khi tich phin, dupc bi^u diln trong hidu thurc (5).
ISSN 0866-7056
TAP CHI CO KHI VIET NAM, Sd lOnim 2016 www.eokhivietnam.vn
NGHIEN CCrU - TRAO D O I
•ff
\ ~ hi(r) = hi(C/r) T = Clr
(3) (4) (5) Neugiithietiingsuit trupt tai mat phin pha long - hoi, T, - h, da biet, hing sd tich phan C se dupc xic dinh va bieu thuc (5) cd the dupc bien ddi sang dang (6).
cung l i cac bidu thiic (11,12), x, - hdupc coi la da bidt Tuy nhien, theo [18] cd thd xae dinh gii tri ciia dai lupng niy dua vao bieu thiic (13).
f )V
(13)Vdi ij - h li hp sd ma sit tai bd mat phin pha ldng - hoi, duoc xic djnh theo cac bieu thiic (14) - (17).
R-S (6)
Luu ^ ring, vdi chit long Newton, ung suit trupt ti lp vdi dp thay ddi tdc dp theo phuong vudng gdc, vdi hp sd ti le chinh li dp thilt d^ng l\rc hpc p,. Khi gii thidt (i, khdng phu thudc vio nhipt dp, cd the bidn ddi bieu thiic (6) sang dang (10).
R-S tlm, r dr da. (R-S)T,_, dr
f^i f (R-S)T,_, [dr
Ml
IT
o\=- ^J=4-to(C/r) Ml
0) (8)
(9) (10) Theo difiu ki^n bifin, co, = 0 tai r = R, hang sd tich phdn C cung se dupc xdc dinh vd bilu thuc (10) cd the viet Iai thdnh dang (11).
/ ^ = 16/Re^, Re,<2000 (14) f^= Re,"-3V1525.2000< Re,<4000 (15) f^= 0,079 Re,-"-", 4000<Re,<3000 (16)
^ = 0,046 Re,-"-^. 3000< Re,<10* (17) Su thay ddi cua img suat trupt T vd tdc dp mdi chat o)^ Uong ldp ldng ngung cd chifiu day 5, tiieo quan h$ (6) vd (11), cung dupc trinh bay tren hinh 2. Tifip theo, de thiet lgp cdc phuong hinh vi phan bdo todn khdi va can bang nang lupng, phdn td chieu ddi vi dng, dl, dupc lua chpn nhu trinh bdy ufin hinh 3.
It' s
-
s
I y
G..iJ.
ifj)
AQc- Al
^—2^?^^
GX/ + <JO lAog ngung
B
= 3 ^ ' i < ' - )
Hinh 3. Bdo todn khoi vd cdn bang ndng lugng trong phdn to ^ng khdo sdt
.{R-S)T,., Ml
]n(,R/r) (11)
Do dd, tdc dp ldng ngung tai mjt phin pha se dupc xic dinh theo (12).
< » i - . = («z£)i^lor^] (12)
Bekay dyngoupcbifiu ±uc (6) vd cudi
2.1.3. Phmmg trinh viphdn bdo todn khdi Phuong trinh vi phdn bdo todn kh6i se dupc xdy dyng cho rieng pha Idng vd cho todn bp ddng mdi chdt frong vi dng. D6i vdi phdn td Idng ngung cd chilu day 5 vd chilu dai dl, nhu the hien trfin hinh 3, cdn bdng nay dupc =s
ISSN 0866-7056
TAP CHl CO KHf V I £ T NAM, Sd 10 nam 2016 www.cokhivietnam.vn
N G H I E N CLfU-TRAOe6i
bilu difin qua bilu thiic (18). Theo do, lupng hoi ngung Ui di vdo phan td, Gc, se bdng su gia tang ciia lupng ldng khi di qua phan td.
G,(l+dl) = G,0)+Gc (18)
Ddi vdi todn bp ddng mdi chat trong vi dng, luu Iupng mdi chdt di qua tiet dirai dng bdt ky se phdi bdng tdng luu lupng cua pha ldng va pha hoi. Do dd, phuong trinh bdo todn khdi cho todn bd ddng mdi chat trong vi dng, tai tiet difin 1 vd I + dl, cd the dupc bieu dien qua bieu thiic (19), sau dd, dupc biln ddi thanh dang chung (20).
G = Gl(l) + G,(I) = G, (1+dI) + G,(l+dl) (19) G = p, j 2jrra),+p^7r{R-Sfo)^ (20)
R-S
2.1.4. Phugng trinh viphdn ndng lugng Tuong ty, phucmg trinh vi phdn ndng lupng cQng dupc xdy dyng cho rifing pha Idng vd cho todn bp ddng mdi chat frong vi dng.
Phuong trinh vi phdn nang Iupng bifiu dien cdn bang nang lupng cho phdn td long ngung 5 x dl, nhu thi hi^n fren hinh 3. Theo dd, can bdng ndy cd thfi dupc bieu dien qua bilu thiic (21).
de^+I,(l+dl)=G^i,,+I,(l) (21) Khi bd qua chenh Ipch Enthalpy vdo - ra phdn th, bilu tiiiic (21) cd till dupc biln ddi tiianh d^g (22).
<'S,= Gi„ (22)
Luu y ring, theo ly thuydt Nusselts, ddng nhipt do phin td huydn ra thinh vi dng, dfi,, dupc coi li do dan nhiet qua mang ldng ngung. Do vjy, vdi ming long ngung hinh xuydn, ciing cd thd biSu didn ddng nhipt niy qua bidu thuc (23).
d&- h-K
1 1 ^ In 2;r.^ R-S
-dl (23)
Ddi voi toin bp ddng mdi chit frong vi dng, tong Enthalpy cua pha ldng vi pha hoi mdi chit t^ii tidt dipn 1 va 1 + dl se tuan theo quy luat bio toan nang lupng nhu trmh biy trong bidu thiic (24).
I(l+dl) = I(l)-de, (24) Ddng thdi, tdng Enthalpy ciia pha ldng vi pha hoi t£ii tiet dien dng bit ky se dupc xic dinh theo bidu thiic (25).
I = p, J 2nrQ},C^,t,dr-\-p,n(,R-Sfo},C^t, (25)
RS
Luu y rang, d ddy, phdn bo lUiipt dO frong ldp ldng ngung (coi Id vdch try) cd the dupc xdc dinh theo bilu thiic (26).
(26) 2KXdl R-S
2.2. Dilu kifn biln
De tim nghipm rieng cho hp phuong trinh viia xdy d\mg, can ket hpp vdi cdc dilu kipn bifin. Trong trudng hpp nay, dieu kipn bien tai bfi mat phdn pha ldng - hoi vd tai thanh ong da dupc xem xet, tuong iing, frong cdc bifiu thiic (6) vd (11). Ngodi ra, cac bilu tiiiic (12)- (16) cung giiip tinh todn chi tilt cho dieu kipn bien tai bfi mat phan pha ldng - hoi. Do v$y, d day, chi can xem xet them dilu ki§n bien tgi ddu vdo dng nhu trinh bdy frong bilu tiiiic (27).
1=0,6=8, =0 (27)
ISSN 0866 - 7056
T ^ CHf CO KHI Vl£T NAM, Sd 10 nam 2016 www.cokhivietnam.vn
N G H I E N CCrU - TRAO B61
^
\ TirtiCiTa/nKf *do]
t l « / ' « l Ttnh tnifi{i*art
JTlBli W»tlh»»C20)v*(ll:
["Tlnli W i l»i (* * <*/) Oice (25) y* ( ^
WnA 4. Luu do thupt todn xdc dfnh chieu ddy mdng long ngung
3. PHXrOfNG PHAP XAC DJNH CHIEU DAY MANG L 6 N G N G I T N G
Cdc bieu thiic viia xdy dung cho phep xdc djnh chieu ddy mdng ldng ngung cGng nhu phdn bd toe dp, phdn b6 nhiet dd vd ung sudt trupt frong Idp ldng ngung t^ii tiet difin bdt ky cua vi dng. De Idm dupc dieu dd, hay gid thifit tgi tiet di$n vi ong dang dupc xem xet, chieu ddy mdng ldng ngung 5 khi vdo phdn td dl Id da bilt. Vdi phdn t6 d dau vdo vi dng, chieu day mang Idng ngung ndy dupc xdc djnh theo difiu kipn bifin (27). Vdi cdc phdn td cdn Iai, chilu ddy mdng long ngung dupc coi Id bdng vdi gia
tri ra khdi phdn td dl trudc dd. Dfi tim dupc thay ddi chilu day mdng Idng ngung dpc theo chieu ddi vi ong, cdn xdy dung phuong phdp xdc dinh gid tri cua chieu day mdng Idng ngimg khi ra khdi phan td dl dang xem xet.
Luu dd thudt todn xdc dinh chilu day mang long ngung ra khdi phan td dl, tiic tai vi tri 1 + dl, dupc trinh bay tren hinh 4. Theo dd, todn bd qua trinh tinh todn dupc thyc hien tfadng qua 3 vdng lap long nfaau, giiip xdc dinh bang phuong pfadp sd cac gid tri cua a j ^ , a)^^ vd 5. Vdng lap thu nhdt (Uong ciing) xdc dinh tdc dp ldng ngung tgi mat phan pha, ty,^, fren co sd ddm bdo "cdn bang" ung sudt trupt, Q}^ _ ^.
Vdng lap tfaii 2 (giiia) xdc djnfa tdc dp loi hoi,
£0^, trfin CO sd ddm bdo luu Iupng khdi lupng, G, cua todn bp tiet dipn vi dng. Vdng lap thii 3 (ngodi cung) giup xdc djnh chifiu ddy mang long ngung, 6, trfin co sd ddm bdo "cdn bdng"
Enthalpy, I, cua toan bp ddng mdi chdt. Luu y rang, cdc vdng lap ngodi ludn bao fadm t^t cd cac mdi quan he ciia vdng lap Uong. Do vdy, vipc xdc dinh chieu ddy mang ldng ngung, 5, d vdng lgp ngodi cung da bao ham tdt cd cdc mdi quan hp dupc xet den Uong todn bp luu dd thudt todn.
4. K E T L U ^
Bdi bdo da trinfa bay co sd ly thuylt cung nhu md hmh vd thugt toan giiip xdc djnfa chieu ddy mdng Idng ngung Uong vi dng d c h l dp fainh xuyen. Ben canfa dd, md fainfa cdn cd khd ndng xdc djnh phan b ^ tdc dp, phdn bd nfaipt dp vd ling sudt trupt frong ldp ldng ngung tai tifit dipn bat ky cua vi ong. Day Id co sd dh xdy dung mpt phucmg phdp ly thuylt giiip xdc dinfa cfainh xdc hon chieu day mdng ldng ngung ciing nhu hfi sd Uao ddi nfaifit d6i luu frong vi dng d chl dp hmh xuyln. Cac kit qud nghien Cliu tilp theo se dupc cfadng tdi cdng bd frong
thdi gian tdi. • <r
ISSN 0866-7056
TiM» CHf C O KHf VIETNAM. Sd 10 nam 2016 www.cokbivietnam.vn
NGHIEN cuu-TRAO D6I
Cdc ky hieu sir dung trong bai:
C: Nhipt dung rieng, J/kg.K;
f: Hp sd ma sat;
i: Entfaalpy rieng ciia mdi chat, J/kg;
I: Enthalpy cua ddng mdi chat, J;
G: Luu lupng khdi lupng, kg/s;
1: Tog dp tfaeo hudng cfaieu dai vi dng, m;
Q: Ddng nhiet truyin, W;
r: Toa dp theo faudng bdn kinfa vi dng, m;
R: Ban kinfa (trong) vi dng, m;
Re: Tifiu chuan Reynolds;
t: Nfaipt dp, "C;
5: Chilu ddy mdng Idng ngung, m;
X: H? sd ddn nhifit, W/mK;
fi: Dp nfadt ddng lyc fapc, Pa.s;
T: tfng sudt truprt, N/m^;
03: Toe dp cfauyfin dpng, m/s;
Cdc cfai sd dudi:
c: Qud frinh ngung ty;
\^. Dau vdo vi dng;
h: Pfaa faoi;
1: Pha Idng;
Ifa: Qud trinh chuyin pha;
1 - h: Tgi b l mgt phdn pha long - faoi;
pi: Ddng dp vdi pha Idng;
ph: Ddng dp vdi pha hoi;
w: Tgi b l mat (frong) vi ong.
Cdc chi s6 d u d i :
c: Qud trinh ngung tu;
i^; Ddu vdo vi dng;
h: Pha hoi;
1: Pha Idng;
Ih: Qud trinh chuyen pha;
I - fa: Tgi bfi mat pfadn pfaa ldng - faai;
pi: Ddng dp vdi pha ldng;
ph: Ddng dp vdi pha hoi;
w: Tgi b l mgt (frong) vi dng.
Ngay nhan bai: 05/8/2016 Ngdy phdn bien: 17/9/2016
Tai lieu tham khao:
[I]. J. R. Baird, D. F. Flrtcbcr, and B S Haynes. ioco/
condetaalion heal transfer in fine passages. InL J. Heat Mass Transfer, 46,4453 - 4466, 2003.
[2]. Y.-Y. Yan, and T.-F Lin. Condensation heal transfer and pressure drop of refiigerani R-I54a in a small pipe. Im. I.
Heal Mass Transfer, 42,697-708.1999.
[3], A. Cavallini, L. Doretti, M. Matkovic, and L, Rosscno Update on condensation heat transfer and pressure drop inside minichannels. Heat Transfer Eng., 27. 74-87,2006.
[4]. S. Garimella, and T. M. Bandhauer Measurement of condensation heal transfer coefficients in micmchannel lubes.
Pax. 2001IMECE, ASME, New York, 2001.
[5]. M. H. Kim, J. S. Shin, T. J. Kim. and K. W. Seo. A sludytf condensation heal transfer in a single mini-tube and review tf Korean micro- and mini-channd studies. Proc. 1st Int. Conf on Microchannels and Minichannels, Rochester, New Yoric, pp. 47-58,2003b.
[6]. M. H. Kim, J. P. Cho. J. O. Kim, and B. Youn. Condensaiion heat transfer of R-22 and R-4I0A in flat aluminum multi- channel tubes with of without micro-fins. InL J, Refiig., 26, 830 - 839.2003a.
[7]. S. Koyama, K. Kuwahara, K. Nakashita, S Kudo, and K.
Yamamoto. An experimental study on pressure drop and local heal transfer eharacleristics of refrigerant R-134a condensing in a mulli-port extruded tube. UF - IIR Commission Bl, Padcrbom, Germany, 2001.
[8]. S. Koyama, K. Kuwahara, and K. Nakashita. Condensation of refrigerant in a multi - port channel. Proc. Isi Int. Conf. on Micro- and Mini-channels, Rochester, New York, pp. 193 - 205,2003.
[9}. A. Vardhan, and E. E. Dunn. Heal transfer and pressure drop charactenslics of R-22. R-134a. and R-407C in micmchannel lubes. ACRC TR-133, University of Illinois at Urbaia - Champaign, 1997.
[10]. W. W. Wang. Condensation and single - phase heat transfer coefficient and flow regime visualization in micrachannel tubes for HCFC-I34a. PL D thesis, Ohio Stale UnivcTstly.
1999.
[11}, R. L. Webb, and K. Ermis. Effect of hydraulic diameter on condensation of R-I34a in fiat, extruded aluminum tiihes Enhanced Heat Transfer, 8, 77 - 90. 2001.
[12]. M. J. Wilson. T. A. Newell, T. A. Chaio. and C. A. Infante Ferrcira. Refrigerant charge, pressure drop, and condensailon heat transfer in flattened tubes. HF - IIR Commission Bl.
Padeibom, Gemany, 2001.
[13]. W. W. Akers, H. A. Deans, and O. K. Crosser. Condensalim heal transfer within horizontal lube. Chem. Eng. Prog. Syn^i.
Ser.,55,171-176,1959.
[14]. M. K. Dobson, and J. C. Chato. Conden.ialian in smooth horizontal lubes. J. Heal D-ansfer. 120, 193-213,1998.
[15]. R G. Kosky, and F. W. Stauh. Local condensation heal transfer coefficients in ihe annular flow regime. AlChE J„ 17, 1037-1043,1971.
[16]. K. W. Moscr, R. L. WeU), and B. Na. A new equivalcni Reynolds number model for condensation in smooth tubes. J Heal jyansfer, 120,410-417, 1998.
[17]. M. M. Shah. A general correlation far heal transfer during film condensation inside pipes. InL J. Heat Mass Transfer, 22,
547-556,1979.
[18]. S. J. Chen, J. G. Reed, C. L. Tien. Reflux condensation in a two-phase closed thermosyphon. Ini. J. Heat Mass Transfer.
27{9), 1587-1594. 1984.
ISSN 0866-7056
TAP CHf CO KHi VIETNAM. Sd lOndm 2016 www.cokhivietnam.vn
