Tuyen tap Cdng trinh Hdi nghi Khoa hpc
10 hpc Thiiy khi Todn qudc, Phan Thiit, 2008 163
jilot SO van de tmh toan xa lu thiet ke 6* cac ho chira thuy dien
Ha Ngoc Hicn, Doan Xuan Thuy, Le Thu Hoai
Vien Ca hoc, 264 Ddi Cdn, Hd Ndi
Tom tat: Viec tinh todn xd lu thiet ke cho cdc hd chira thiiy dien neu khdng tinh den thdi gian thirc te ddng md ciia cdc cua van cd the dan den cdc phuang dn thiit ki cira van, dap trdn khdng phii hgp dnh hudng den an todn ho chira. Cdc thi nghiem md hinh vat ly ve cira van, dap trdn thudng cdn dugc lien hdnh trong thai gian thiet ke ky thiigt va gdy nhieu tdn kem. Bdo cdo nay trinh bdy ket qud nghien ciru tinh todn xd lit thiet ke cho cdc hd chira thiiy dien cd tinh den thdi gian ddng md cira van vd khd ndng du bdo ddng lit den hd. Ket qud tinh todn chi ra rdng ddi vdi cdc liru vuc cd lii len nhanh, mirc nude ddng cua hd phu thugc nhieu vdo thdi gian ddng md cua van vd thai gian du hdo ddng den hd. Tu dd, cd the dua ra cdc phuong dn thiet ke cira van, dap trdn phit hgp. Ket qud nghien cuu cd the gdp phdn gidm chi phi thiit ke bdng viec dinh hudng vd gidm bdt quy mo thi nghiem tren md hinh vat ly
Abstract: Calculations of discharge release for designed flood of a resen'oir without taking account the opening time of gates could lead to Improper design of the weir or gate sizes. Normally, experiments of physical models should be conducted for the technical design phase. This paper presents an algorithm for calculation of discharge release for designed flood of a reservoir taking account the opening time between the gates and prediction of inflow. The results show that In some cases the water level in the reservoir could be sensitive to these parameters and they should be taken under consideration in design process. The results could also contribute to decrease the number of experiments of physical models.
1. Mo-dau
0 Viet Nam, gan day hang loat cac hd chira thuy dien tren thugng ngudn cac he thdng sdng da duac thiet ke va xay dung. Ngoai cac van de ve mdi trudng, kinh te-xa hdi, van de an loan xa lu cua cac hd chua la van de bet sire quan trgng can dugc nghien ciru than trgng va dua vao cac quy trinh van hanh hd chira. Van de an loan xa lu hd chua hen quan den bai toan thiet ke dap Iran, he thdng van xa lii va xac dinh myc nude gia cudng (MNGC).
Xac dinh muc nude gia cudng ciia mot hd chira - muc nude Idn nhat ma hd chiia van an loan la van de phuc tap, trude het phu thugc vao cac yeu td kinh te, xa hdi, mdi trudng (giai phdng mat bSng, di dan, hieu qua kinh te, anh hudng mdi trudng ...), va cudi ciing la tinh loan kiem tra xa lu vdi cac lii thiet ke. Theo cac phuang phap tinh loan thdng thudng, MNGC dugc xac dinh khdng phy thugc vao thdi gian ddng md cua van va kha nang du bao lii den (lii thilt kl dugc cho bilt trude). Tuy nhien, neu tinh den thdi gian ddng md giira cac cua van, kha nang dy bao luu lugng vao hd, cd the nhan dugc ket qua tinh toan la cac MNGC khac nhau. Tir dd cd thi thSy rSng, phuang phap tinh loan thong thudng cd the dan den cac phuang an thiet ke khdng phu hgp anh hudng den an loan hd chira.
Nhu vay, neu bd qua cac ylu to kinh te va mdi trudng, theo cac phuang phap tinh loan
thdng thudng, MNGC se phy thugc vao lii thilt kc (do Idn va hinh dang), kha nang xa tdi da
cua he thdng cira van va dap Iran (cao do, kich thudc va sd lugng). Bao cao nay se chi ra
164 A/<9/ sd van de tinh todn xd lu thiit ki a cdc hd chira ihiiv dien r^ng MNGC cdn phu thugc vao thdi gian thyc te ddng md cua cae cua van va kha nang du bao luu lugng vao hd.
Cac phan tiep ihco cua bao cao trinh bay md hinh dicu tiet hd chira cd tinh den thdi gian ddng md cira van va kha nang dy bao ddng lii den hd. Thuat loan va chuang trinh tinh toan da dugc xay dyng va dugc tinh loan Ibii- nghiem cho mot sd hd chua thuy dien. Tir ket qua tinh toan da thu dugc mot sd kel qua danh gia ve anh hudng cua thdi gian ddng md cira .van va thdi gian dy bao ddng chay lii den myc nude dang cua hd.
2. M o h i n h dicu tiet xa lu ho chira
2.1. Nguyen tdc van hdnh xd 111 thic't ke hd chira thiiy dien
Hd chua can dam nhan nhicm vu chdng lii cho cdng trinh vdi lu thict kc va lu kiem tra. Trong dd tan suat lu kicm tra dugc xac dinh thco cac cap cdng trinh: cdng trinh ciip I:
0.02%, d p II: 0.1%, cSp 111: 0,2%,
Ddi vdi cac hd khdng cd nhicm vy chdng lu cho ha du. nguyen tac dieu tiet xa lu ho
chira duac md la nhu sau: , - Khi luu lugng ve hd nhd ban kha nang xa cua cdng trinh (xa day, xa mat va'
turbine), lien hanh md cac cira van de dieu tiet sao cho Qra=Qvao, duy tri dugc • muc nude hd d cao trinh xap xi muc nude dang binh thudng (MNDBT).
- Khi cac cdng trinh xa Iii da dugc md hct ma muc nude hd van len (luu lugng IQ den Idn ban kha nang xa cua cong trinh), cdng trinh chuyen sang trang thai xa Iran ty do (cac cua xa md hoan loan), myc nude hd dugc phep diing cao ban MNDBT.
- Khi luu lugng ve hd giam va cd kha nang lam giam myc nude hd xudng dudi MNDBT, ticn hanh ddng dan cac cira van xa mat, xa day giii' muc nude hd d cao trinh MNDBT.
Hinh 1 minh hga qua trinh ddng chay den, luu lugng xa qua cdng trinh \ a myc nude hd theo nguyen tac xa Id thiet ke. Cd the nhan thay rang, tren hinh 1 qua trinh luu lugng xa ra mot each ly tudng, ludn ludn cd gia tri bang luu lumig vao hd khi luu lugng vao hd cdn nhd ban kha nang xa ciia cdng trinh khi lu len va khi muc nude ho trd ve MNDBT khi lii xudng. Day chinh la gia ihict dugc sir dung trong cac phuang phap tinh loan thdng thudng (luu lugng vao hd = luu luang xa ) va dd chinh la nhung ban che cua cac phuang phap nay.
Trong thyc te, do ban che ve mat ky thuat, viec ddng md cac cira van can cd mot khoang thai gian vi vay khdng phai bao gid ciing dam bao dugc mot each chinh xac luu lugng vao hd bang luu lugng xa qua cac cua van. Khi lu len nhanh, cd thi viec md cac cua van khdng kip va myc nude hd cd ihl vugt tren MNDBT khi cac cua van van chua dugc md hit. Dilu nay cd the dan den muc nude hd \argt MNGC lam anh hudng an toan cua hd chua. Ngugc lai,^ khi lu xudng nhanh, cac cua van cd thi ddng khdng kjp dan d i n muc nuac hd cd the xudng dudi MNDBT lam anh hudng din san lugng dien cua nha may.
'oNsoe Hien, Dodn Xudn Thuy. Le Thu Ilodi 165
< 1 500
£
Qua trinh I u I ng t I h
-qvao q«a zho
617
615
6 1 a
6 1 3 20 40 60 80 100 120 140 1 60 180
Th I gian (gl )
//(/)/( /,• Qud trinh ddng chdy den, liru Iwirng xd nguven tiic xd lii thiet ke
2.2. Phuong trinh ca bdn
Phuong trinh ca ban ciia qua trinh dieu tiet hd chiia la phuong phap bao loan khdi lugng dugc viet dudi dang sau:
dt V{0)=r,
(1) (2) Trong dd:
6 day:
V- thi tich khdi nude chira trong ho tai thdi diem t. V la ham phy thudc vao myc nude z cua hd: V = V(z).
Ql - luu lugng vao ho, la ham phy thugc vao thdi gian
Q i = Q i ( t ) ; Q 2 = Q : i + Q22
Vdi O21 la luu lugng xa tu' hd qua cac cua xa day, cua xa mat va luu lugng qua tuabin Q21 = nxd . Qxd + nxm . Qxni + Qlb
nxd- sd cua xa day dugc md, nxm- sd cua xa mat dugc md.
Qxd-luu luong qua 1 cua xa day, phu thugc vao myc nude hd va do md cira van.
Qxm-luu lugng qua 1 cira xa mat, phu thugc vao myc nude hd va do md cira van.
Qtb-luu lugng qua tuoc bin, phu thudc vao myc nude cua hd va cdng suat phat.
166 A/o/ sd vdn de tinh todn xd IQ thiit ki dr cdc hd chira thiiy dien Luu lugng xa mat dugc linh toan tu dgng theo cac trang thai cira xa khac nhau:
- Khi ddng chay qua tran dugc khdng che bang cua van, muc nude ho cao hon cao trinh tren cua Id md, ddng chay ra khdi tran tiep xuc vdi khdng khi thi day chinh la dang ddng chay cd ap qua Id. Dugc tinh theo cdng thirc:
2___ n ^ ^ . , , 3 / 2 , , 3 / 2 ,
Qxd = -m.B.^^^.{Hf' -Iir)
3 sin a •
vdi: m-he sd luu lugng, g-gia tdc trgng trudng, 5-chieu rdng khoang tran, ///-Dp sau cot nude tir day cua van, H^-Do sau cot nude tir dinh tran, a - Gdc nghieng cua cira van so vdi phuang ngang.
Khi ddng chay qua tran tach khdi cira van thi lai trd ve dang qua dap tran tu do, vdi cdng thirc tdng quat:
Qxm = E.m.B. Jl^.H^'^
vdi: m-he so Iran, g-g'\a tdc trgng trudng, £-he sd co hep, 5-chieu rdng khoang tran, H^-Do sau cot nude tir dinh tran.
- Q22 - luu lugng boc hoi : Q22 = K.F(t).Zn(t)
vdi: K - he so, F(t) - dien tich mat hd tai thai diem t, Zn(t) - lop bdc hai tren mat ho trong mot don vi thdi gian.
2.3 Phirang phdp gidi:
Tai thdi diem t, khi sd cira xa mat nxm va nxd xac dinh, vc phai cua phuong trinh (I) hoan toan xac djnh va la ham cua t va V. Phuang trinh (1) la phuong trinh vi phan dao ham thudng vdi dieu kien ban dau (2) dugc giai bSng phuang phap Runge - Kutta bac 4.
So cira xa mat nxm va nxd tai thdi diem t dugc xac dinh dua tren nguyen tac van hanh xa lu va du bao luu lugng din hd theo thuat loan dugc trinh bay d dudi day.
3. Thuat toan dong ma van xa theo quy trinh co tinh den dir bao
Theo nguyen tac van hanh xa lu, cac cira van se dugc ddng md dl duy tri muc nude ho d MNDBT cho den khi tat ca cac cua xa day va cua xa mat dugc md hit. Vi vay neu biet trude luu lugng vao ho trong khoang thdi gian nao dd, s6 cira van can ddng md sao cho dao dgng muc nude hd xung quanh muc nude dang binh thudng trong khoang thdi gian do la nhd nhat. Thuat toan xac djnh sd Lin ddng md cira van dugc trinh bay nhu sau.
Ky hieu:
- dt: budc thdi gian tinh toan
- tdb=ndb*dt: khoang thdi gian cd kha nang du bao chinh xac luu lugng vao ho; ndb la sd nguyen duong
- tvan=ntvan*dt: khoang thdi gian tdi thilu dl md 1 nac van; ntvan la mot sd nguyen duang
Tai budc thai gian thir n can xac dinh so cira van md d thdi dilm n*dt + tvan. Qua
trinh dugc tien hanh theo cac budc:
fId_Ngoc Hien. Dodn Xudn Thiiv, Le Thu Llodi 1_67
1. Xac dinh sd lan ddng md van trong khoang tir n *dt din n *dt+tdb
2. Duyet tat ca cac phuang an ddng md van trong khoang thdi gian tren (sd cira van sau mot khoang thdi gian it nhat la tvan chi thay ddi mot cira tiic la ddng bdt mot cua hoac md them mot cira)
3. Tim phuang an ddng md van sao cho myc nude hd duy tri d MNDBT, dilu dd tuong duang vdi tdng binh phuang do lech la nhd nhdt:
mlh
Y^iz^-MNDBTf -^min
1=1
Trong dd z, la muc nude hd tai thdi dicm thir /;+/.
4. Tinh toan dieu tiet hd den thai diem n+ntvan
5. Neu cac cira xa day va xa mat chua dugc md het lap lai tir budc I.
Cd the nhan thay rang, theo thuat loan da trinh bay, thdi gian du bao tdi thieu can thiet de van hanh ddng md cira van la tvan (khoang thdi gian tdi thieu de ddng md cac cua van).
Thdi gian du bao cang dai kha nang duy tri myc nude hd gan vdi MNDBT se tdt han va nguyen tac xa lu hd chiia dugc chap hanh tdt ban.
4. Mot so ket qua
Chuang trinh tinh loan da duac xay dyng bang ngon ngu FORTRAN, chay dn dinh tren cac may tinh ca nhan va dugc tinh loan thir nghiem cho mot sd hd chiia thuy dien Da M'Bri, Seo Chong Hd, Trung Hd ... Ket qua tinh toan cho hd chira thuy dien Da M'Bri, Seo Chong Hd dugc trinh bay dudi day.
4.1. Ho chiia Da M'bri:
4.1.1. Tdng quan hd chira thiiy dien Da M'Bri [1]:
Du an thuy dien Da M'Bri la cdng trinh nam d thugng ngudn sudi Da M'Bri. Sudi Da M'Bri la nhanh ben bd phai cua mot phu luu Da Huoai, dd vao sdng Ddng Nai ben bd Uai, bit nguon tir dinh nui B'Nom Potial. Suoi Da M'Bri chay theo hudng Ddng Bac xudng Tay Nam. Dy an thuy dien Da M'Bri thudc dja phan 3 huyen Bao Lam, Da Te va Da Huoai tinh Lam Ddng. Cae thdng sd chinh cua hd chua dugc trinh bay trong bang I.
168 Mdt sd vdn de tinh lodn xd lu thiit ke a cdc hd chira thuy dien
TT I
II
III
IV
Bdng I: Thdng sd chinh ciia cdng trinh thiiv dien
Cac thdng sd Don vi
Da M 'Bri Gia tri Thuy vim
Dien tich luu vuc
Luu lugng lu thiet kl: P = 0,5%i Luu lugng lii kicm Ira: P = 0 , 1 %
km"
m .'s 1 /
m'/'s
215 1612 2069 Hd chira
Myc nude dang binh thudng Myc nude diet
Dung lich loan bg hd
m m 10" 111^
614 590 56.3 Nha may.
Luu lugng hrn nhiil qua nha may Cdng siial lap may
Cdng suat dam bao (P=85%o) Dien lugng binh quan nhicu nam Tran xa lii
Loai trim
Cao trinh ngudng Iran Cbicu rdng Iran So khoang tran Chieu rdng I klioang
Nac md van | m'V's
MW MW lO^KWh
m m
m
111 1
22.7 75 17.1 338,2
Thuc dung cd cira van 604
27 3 9 0,5
Kel qua linh toan xa lu thiet ke 0.1% vdi luu lugng dinh lu la 2069mVs vdi thdi gian du bao khac nhau lOli va 3h duac trinh bay tren hinh 2 va 3 so sanh vdi kit qua tinh toan theo phuang phap thdng thudng (qvao=qxa). Cd thi nhan thSy iing, thdi gian du bao cang dai, dudng qua trinh luu lugng xa qua cac cua van cang bam sat Idi giai theo phuang phap thdng thudng ban. Qua irinh muc nude tai Ii6 cho trudng hgp tdb=3h dugc trinh bay so sanh vdi qua trinh myc nude tinh theo phuang phap thdng thudng, Cd thi nhan thay su dao dgng myc nude hd xung quanh MNDBT do anh hudng cua thao tac ddng md cua van. Mirc nude hd cao nhat nhan dugc Idn ban muc nude cao nhdt cua phuong phap thong thudng.
Kill lu xudng, cac cua van khdng dugc ddng kip thdi (tvan=0.3h) va muc nude ho dii xudng
thap dang ke so vdi MNDBT.
Nsoe Hien, Dodn Xudn Thiiv, Le Thu Ilodi 169
Qua trinh 1 u 1 ng t i h
< 15 00
e
• q v a o
- q ) ( 3 ( v a o = r a |
q x a 3 ( t d m = o . 3 , d b = i 0)
0 2 0 40 60 80 1 0 0 1 20 1 4 0 1 60 1 80
Fh I gian (gi )
Hinh 2: Ket qua tinh loan hni hiang xa qua cdc cua van vai thai gian dir bdo Id lOh, thai gian dong nia cua van Id 0.3h
Qua trinh J u l ng t i h
< 1 5 0 0 E
500
' qvao
- q x a ( v a o = r a )
q x a i ( t d m = o . 3 , d b = 3 )
2 0 dO 6 0 1 0 0 1 2 0 M O 1 6 0 1 80 Th I gian (gl )
Hinh 3: Ket qud tinh todn hru luang xd qua cdc cua van voi thai gian du bdo la 3h, thai gian dong ma cua van la 0.3h
170 Mdt sd vdn de tinh todn xd lii thiit ki a cdc hd chira thiiy dien ;
n Ihi6n m e n c h
£ 6M i
• n (tvan=o 3h, db=3h) - i ( v a o = ra)
I h I gian (gi )
Hinh 4: Ket qud tinh lodn bien thien muc nude hd vai thdi gian du bdo Id 3h, thdi gian i
ddng mdr cira van la 0.3h •, 4.1.2. Anh hudng cua thai gian ddng ma cira van vd thdi gian du bdo den mirc nuac ddng ;
ciia hd I Anh hudng cua thdi gian ddng md cira van den muc nude dang cua hd dugc trinh bay i
trong bang 2. Tai day bdn trudng hgp dugc so sanh: trudng hgp 1 tinh theo phuang phap i thdng thudng (qvao=qra), trudng hgp 2 vdi thdi gian ddng md cir van la 0.3h (18 phiit), ', trudng hgp 3 vdi thdi gian ddng md cir van la 0.2h (12 phiit), trudng hgp 4 vdi thdi gian ; ddng md cu van la O.lh (6 phut), thdi gian du bao cho cac trudng hgp tren la 3h. Ket qua ; tinh loan chi ra rang vdi thdi gian ddng md cira van cang nhanh {tvan cang nhd) thi myc j nude dang cua hd cang gan vdi myc nude dang cua hd theo phuang phap tinh thdng ^ thudng. Thdi gian ddng md I nac van d day dugc xem xet tir 6 phut den 18 phut la phii hgp '•'..
vdi thuc te va sai sd ve myc nude trong trudng hgp nay khdng Idn do dd cac thdng sd thiet ; ke theo phuang phap ti'nh thdng thudng cd the chap nhan dugc. Sai sd Idn hon cd the nhan : dugc kkhi kich thudc cua van va dap tran dugc thiet ke khdng phu hgp thudng xay ra doi ;
vdi nhirng luu vuc cd dac trung lu Icn xudng nhanh ban. \ Ket qua tinh toan cho 4 trudng hgp dugc trinh bay tren cac hinh 5, 6. •
TT I 2 3 4
Bdng 2: Anh hudng ciia thdi gian ddng md cira van hd Da M'Bri: __
Thdi gian ddng md cira van (thdi gian du bao la 3h)
Qvao^qra tvan = 0.3h tvan = 0.2h tvan = O.lh
Muc nude hd nhd nhat (m)
614.00 613.22 613.48 613.71
Muc nude hd Idn nhat (m)
615.18
615.35
615.20
615.19
'Hd Ngoc Hien, Dodn Xudn Thiiv, Le Tim Hoai 171
Bi n thien m e n c h
615,5
615
J . 6 1 4 5
• y
N-
r
613,5
S13
l ( v a o = r a )
- — n (tvan = o . 3 h , tdb = 3 h | - - I 2 ( t v a n = 0 - 2 h , t d b = 3 h |
— - z 3 l t v a n = o.i h , t d b = 3 h |
^ ,,'?.N
V7 - ^ ' - • '
^^
° JO 4 0 6 0 " 8 0 1 0 0 1 2 0 1 3 0 1 6 0 1 8 0
rh I gian (gl )
Hinh 5: Bien thien muc nude hd theo thdi gian ddng md cira van (vdi thai gian du bdo Id 3h)
Qua trinh I u I ng tai h
<
E
• A
% 1
V ^
' V ^ * ""e^
- - - q v a o a r a ( u : r a )
— — g r a l l t v a n = o . 3 h , d b = 3 h )
— - q r a 2 ( t v a n = o.2h,tdb=3h)
— - qra3(tva<)=0 1 h , t d b = 3 h }
^ 1 - . • T - «
1 2 0 1 4 0 1 6 0 1 8 0
Th I g i a n (gl )
Hinh 6: Kel qud tinh todn luu luong xd qua cdc cira van theo that gian ddng md cira van (vai thdi gian du bdo la 3h)
Anh hudng ciia thdi gian du bao hd Da M'Bri dugc trinh bay trong bang 3. Thdi gian du bao b^ng 3h, 6h, lOh va 15h dugc xem xet. Kit qua chi ra rang trong trudng hgp ho Da M'Bri thdi gian du bao khdng cd anh hudng Idn den ket qua xa lii thiet ke.
172
TT I 2 3 4 5
Mdt sd vdn de tinh todn xd lU thiit ki a cdc hd chira thiiy dien Bdng 3: Anh hudng ciia thdi gian du bdo hd Da M'Bri
Thdi gian du bao (thdi gian ddng md cira van la 0.2h)
Qvao=qra tdb = 3h tdb = 6h tdb= I Oh tdb= 15h
Muc nude hd nhd nhat (m)
614.00 613.48 613.63 613.80 613.80
Muc nude hd Idn nhat (m)
615.18 615.20 615,20 615.19 615.19 4.2. Ho chira Seo Chong Hd:
4.2.1. Tdng quan hd chira thuy dien Seo Chong Hd f2]:
Ngdi Bo la nhanh cap 1 eiia sdng Hdng, bat nguon tir dinh nui cao cua day Hoang Lien Son chay tdi Ban Hd thco hudng Tay Bac - Ddng Nam rdi chuyen hudng Tay Nam - Ddng Bac dd ra cira Hoa Lac thugc Cam Dudng. Thuy dien Seo Chong Hd dugc du kien dat tren sudi Seo Trung Hd thugc nhanh cap I cua Ngdi Bo tren dia phan huyen SaPa tinh Lao Cai. Vi tri luu vuc nam d hiru ngan sdng Hdng, phia Bac giap luu vuc Ngdi Dum, phia Tay giap luu vuc Nam Mu nhanh cap 1 ciia sdng Da, phia Nam giap luu vuc Ngdi Thia nhanh cap 1 cua sdng Hdng. Cae thdng so chinh cua hd chira dugc trinh bay trong bang 4.
TT I
II
III
Bdng 4: Thdng sd chinh cua cdng Cac thdng sd
trinh thiiy dien Seo Chong Hd
Ky hieu D/vj Gia trj Thuy van
Dien tich luu vuc
Luu lugng lu thilt kl: P = 1%
Luu lugng lu kilm tra: P = 0,2%
Hd chiia
Muc nude dang binh thudng Muc nude chit
Dung tich toan bg hd Nha may
Luu lugng thilt kl Cdng suat lap may
Cdng suat dam bao (P=85%) Dien lugng binh quan nhilu nam
Flv
^ m a x p^max
MNDBT MNC
Wtb
Q Nlm Ndb Eo
km^
mVs mVs
26 480 639
M M
\0'm'
mVs MW MW 10''K'Wh
1562 1550 7.6
3.2
22
4.91
99.42
Hd Ngoc Hien, Dodn Xudn Thiiv, Le Thu Hoai 173
IV Tran xa lii Loai Iran
Cao trinh ngudng Iran
Sd khoang, kich thudc cira van Nac md van
M M M
Thuc dung 1554 2 x 6 x 8
0.5 4.2.2. Anh hudng ciia thdn gian ddng md cira van vd thdi gian dir bdo din muc nuac ddng ciia hd
Hd chira thuy dien Seo Chong Hd nam tren luu vuc cd dac trung lii len xudng nhanh.
Trudng hgp nay cd the minh hga tdt cho viec anh hudng cua cac thdng sd tinh toan nhu thdi gian ddng md cira van, thdi gian dy bao den cac thdng sd thilt ke cua hd.
Anh hudng cua thdi gian ddng md cira van den muc nude dang cua hd dugc trinh bay trong bang 5. Tai day bdn trudng hgp dugc so sanh: trudng hgp 1 tinh theo phuang phap thdng thudng (qvao^qra), trudng hgp 2 vdi thdi gian ddng md cir van la 0.3h (18 phiit), tnrdng hgp 3 vdi thdi gian ddng md cua van la O.lh (6 phut), trudng hgp 4 vdi thdi gian ddng md cir van la 0.05h (3 phut), thdi gian dy bao cho cac trudng hgp tren la 3h. Ket qua tinh toan chi ra rang sai khac ve myc nude dang cua hd giiia cac trudng hgp khac nhau la dang ke. Muc nude Idn nhat cua hd trong trudng hgp thdi gian ddng md mot nac van la 3 phut so vdi muc nude Idn nhat nhan duac theo phuang phap thdng thudng la 58 cm, ddi vdi trudng hgp thdi gian ddng md cira van 18 phut la 1.25m. Sai sd nay la dang ke va can dugc xem xet. Trong trudng hgp lu xudng hd ciing mat kha nhieu nude (myc nude hd xudng dudi MNDBT) do cac cira van khdng ddng kip.
Ket qua tinh toan cho cac trudng hgp dugc trinh bay tren cac hinh 7, 8.
Bdng 5: Anh hirang cua thdi gian ddng md cua van cua hd Seo Chong Hd TT
I 2 3 4
Thdi gian ddng md ciia van (thdi gian dy bao la 3h)
Qvao-qra tvan = 0.3h tvan = O.lh tvan = 0.05h
Myc nude hd nhd nhat (m)
1562.00 1559.83 1560.29 1561.00
Myc nude hd Idn nhat (m)
1562.19 1563.44 1563.12 1562.77
174 Mdt sd vdn de tinh todn xd lii thiet ke a cdc hd chira thiiv dien
Qua trinh I u I ng t i h
•^ 4 0 0
- q x a ( v : : r a )
— - q r a 3 ( t v a n - o . 0 5 h , t d b = 3 h l
: <- ' r ' • J i .
Th I gian (gl )
Hinh 7: Kit qud tinh todn lini luang xd qua cdc cira van vai thdi gian du bdo Id 3h, thdi gian ddng ma cira van Id 0.05h
n t h i e n m e n c h 1564
156J
1562
1561
1 5 6 0
- ^ "^^ V. ^ - Q ^ ^ ^ ^ . " * « - * • "
—
—
— n (Tvan
- Z 2 ( t v a n :
- Z 3 | t v a n = - o . 3 h .
0 1 h.
0 , 0 5 h t d b
t d b =
t d b 3 h |
3hl
= 3 h |
Th I gian (gl )
Hinh 8: Ket qud tinh todn bien thien muc nuac hd theo thdi gian ddng ma cira van (vai thcri gian dir bdo la 3h)
Bang 6 chi ra anh hudng cua thdi gian dy bao luu lugng vao hd Seo Chong Hd din
myc nude hd trong qua trinh cSt IQ. Cd Ihl nhan thSy rSng khdng cd anh hudng manh din
muc nude Idn nhat (su thay ddi so vdi phuang an qvao=qxa chu ylu do thdi gian ddng md
cua van). Tuy nhien nd cd anh huong din muc nude nhd nh5t cua hd chira. Khi
C.CTIgian
Hd Ngoc Hien, Dodn Xudn Thiiv, Le Thu Hoai 175 dy bao cang dai cac cua van cd the dugc ddng sdm ban khi muc nude hd chua xudng tdi MNDBT va vi vay muc nude hd cd kha nang duy tri gSn vdi NTNDBT ban (hinh 9).
Nhu vay, ddi vdi cac luu vuc cd lu len xudng nhanh, viec thilt k l cira van khdng phii hgp cd the gay muc nude hd dang qua cao (mit an loan dap) khi lu len va ha qua thSp khi lu xudng (lam giam san lugng dicn). Dc ban chi anh hudng nay ma khdng thay ddi MNGC, ngudi ta cd the thay ddi kich thudc bl rdng dap Iran hay cua van. Anh hudng cua bl rdng khoang cira van dugc nghicn cim d phan tiip theo.
Bdng TT
1 2 3 4
6: Anh hudng cua thdi gian dir bdo liru lirang vdo hd Seo Chong Hd Thdi gian du bao (thdi gian
ddng md cua van tvan=0. lb) Qvao=qra
tdb = 3 tdb = 6 t d b = 10
Myc nude hd nhd nhat (m)
1562,00 1560.74 1561.19 1561.19
Myc nude hd Idn nhat (m)
1562.21 1563.12 1563.12 1563.12 4.2.3. Anh hucrng cua chieu rdng khoang eira van den muc nude ddng cua hd
Neu giii nguyen thdi gian ddng md tdi thilu giira cac nAc cira van. B I rdng khoang cira van cd anh hudng true tiep din dao dgng myc nude hd khi xa IQ. Doi vdi luu vuc cd d^c trung lu len xudng nhanh, be rgng khoang cang Idn kha nang giam dao dgng myc nude hd cang nhieu (neu giu: nguyen khau do md va thdi gian md). Kit qua tinh toan anh hudng cua be rdng khoang cua van den giao ddng myc nude ho cua hd Seo Chong Hd dugc trinh bay trong bang 7. Cd the nhan thay rang trong 2 trudng hgp thdi gian ddng md cua van 0.05h va O.lh, dao dgng muc nude hd giam trong trudng hop b=24m ban nhilu so vdi trudng hgp 12m. Ket qua bien thien myc nude hd khi cat lii thilt kl cho 2 trudng hap dugc trinh bay tren hinh 9.
Nhu vay ddi vdi luu vuc cd dac trung lii len xudng nhanh, viec chgn bl rdng khoang cua van rdng han se dam bao cho viec xa lu an loan va phat dien hieu qua ban.
Bdng 7: Anh hirang chieu rdng khoang cira van TT
1 2 3 4
Cbicu rdng khoang cira van b= 12m (vdi tvan=0.05h) b=24m (vdi tvan=0.05h) b=I2m (vdi tvan=0.1h) b=24m(vdi tvan=0.1h)
Myc nude hd nhd nhat (m)
1561.00 1561.44 1560.29 1560.77
Myc nude hd Idn nhat (m)
1562.77 1562.26 1563.12 1562.50
176 Mdt sd vdn de tinh todn xd lu thiet ki a cdc hd chira thuy dien
Bicn thicn mirc nurrc hn
1 5 6 3 , 5
1563.0
1 5 6 2 5
1 562 o
1 5 6 1 . 5
1561 0
1 5 6 0 . 5
z 2 ( t v a n - o . 0 5 h , t d b - 3 h , b : : l 2 m ) - i 3 ( t v 3 n = 0 . 0 5 h , t d b = 3 h , b = 2 4 n i |
3 0 4 0 Th I gian (gl )
Hinh 9: Bien thien muc nuac hd phu thudc chieu rdng khoang ciia van (vai thai gian ddng mdr cira van la 0.05h, thdi gian du bdo la 3h)
5. Ket luan
Chuong trinh tinh loan dieu tiet xa lii hd chua theo ddng md cua van va thdi gian du bao ddng chay lii den hd da dugc xay dung bang ngon ngir FORTRAN, chay dn dinh tren cac may tinh ca nhan va dugc tinh loan thir nghiem cho mot sd ho chira thuy dien. Ket qua tinh loan chi ra rang ddi vdi cac luu vuc cd lu len nhanh, muc nude dang ciia ho phu thugc nhieu vao thdi gian ddng md cua van va thdi gian dy bao ddng lu den ho, Tir ket qua tinh toan cua chuang trinh cd the dua ra cae phuang an thiet kl cua van, dap tran phii hgp. Ket qua nghien cim ed the gdp phan giam chi phi thiet ke bang viec dinh hudng va giam bdt quy md thi nghiem tren md hinh vat ly trong giai doan thilt kl ky thuat.
Chuang trinh tinh ciing cd the img dung tdt cho cac hd chira thuy dien trong giai doan van hanh.
Loi cam an: Bai bao dugc hoan thanh mot phan nhd su tai trg kinh phi cua Chuang trinh nghien cun Co ban nganh Co hge.
Tai lieu tham khao
[1] Dy an ho chira thiiy dien Da m'Bn, "Phu luc tinh todn thiiv ndng ". Cong ty CP Thiiy dien Miln Nam, 2008
[2] Dy an ho chira Thuy dien See Chong Ho, T3- "Thiiy ndng vd kinh ti ndng luang". Cong ty dien
luc 1, Tong cong ty dien lye Viet Nam. i
