9'uyen tap Cdng trinh Hdi nghi Khoa hpc
%^(rhpc Thuy khi Todn qudc, Phan Thiit, 2008 261
t..
Anh hirong cua so la canh z va mat do day canh 1/t cua banh cong tac toi dac tinh lam viec cua
bo-m hu-ong true co ns lan han 1000 v/ph
Lc Danh Lien', Pham Van Thu^
' Tnrdng DHBKHd Ndi ' Vien Khoa hoc Thiiy loi Qudc gia
Tom tdt: Trong bdi nciy gidi thieu cdc ket qud nghien cim thirc nghiem cua mdt sd loai mdu cdnh hdnh cdng tdc bam hudng true cd n, cao han 101)0 v/ph vdi so Id cdnh Z thay ddi tir 2 den 4 vd mat do ddy cdnh thay ddi trong pham vl ±(10 ^20)% so vdi cdc gid tri ciia md hinh mdu. Tir ket qud nghien ciiv thuc nghiem tim dugc md hinh bdnh cdng tdc cd hieu sudt cao vd pham vi thdng sd Idm vice rdng do Id mdu cd sd Id cdnh Z = 2 vd mat do ddy cdnh l/t gidm 10% so vdi mo hinh mdu.
Abstract: This paper presents our research results obtained by experimental investigation carried on impellers of an axial pumps with ;;,. > 1000 rpm when Z = 2.
3 and 4 and l/t varies ±(10 ^ 20)% with respect to it's model. The obtained results show that, when Z = 2 and l/t reduced by 10%, the impeller will have its best efficiency.
1. Xuat XU'cua bai toan
Hien tai hdu bet cdc tram bom Idn d Bac Bg va Bdc Khu Bdn cQ deu su dung cdc may bam hudng trye cot nude tir 3m den 9m. Cac loai may bom nay cd liru lugng lu 1000m /h din 25000m^/h vd tdi da bdng 36000 mVh.
Cdc loai mdy bom nay cd sd vdng quay dac tnmg Us tir 700 den 900 v,/ph. Theo ket qud dieu tra hien trang mdy bom vd tram bom d Vict Nam do Tmng tam Bom va Mdy Xay dyng, Vien Khoa hge Thuy lgi thuc hien, tinh den nam 2004 d 16 linh thanh Bac Bg va Bac Khu Bdn cu cd 4.964 tram bom vdi 13,305 may bom hudng true cot nude thdp va vira cac loai:
Trong thyc tc dc thoat nude chdng iing ngdp mgt cdch hicu qud cdn cdc bom cd cot nude lam vice thap ban vd luu lugng Idn ban so vdi cdc bom thdng thudng, cung cd nghTa la can cdc bam cd sd vdng quay ddc trung Us Idn ban so vdi cdc bom da cd. Cdc bam nay can cd n^ > lOOOv/pb.
D I cd thi tao dugc mau bom budng true vdi ns > 1000 v/ph cd hicu sudt cao tuang duong mau nude ngoai, chung tdi da ticn hanh nghicn ciru hang loat mdu cdnh bam vdi viec hieu chinh cac thdng sd kit cau cua bom nhu ty sd bdu cdnh db/D, mat do day canh l/t, sd cdnh Z...
Kit qud cua mdt sd cdng trinh nghien cim trude ddy ve bom hudng true (cua ThS. Dd Hdng Vinh) vd vl tua bin hudng trye (cua TS. Nguyen Vu Viet ) cho thdy, ty sd bau canh anh hudng khdng nhilu tdi ddc tinh cua bom va tua bin. Vi vay trong cdng trinh nay chung tdi nghien ciru chu ylu dnh hudng cua sd la cdnh Z vd mat do day cdnh l/t tdi ddc tinh lam viec cua bom vdi ns > 1000 v/ph.
262
Anh hudmg cua sd la cdnh z vd mat dd day cdnh l/t cua bdnh cdng tdc tdi ddc tinh lam viec cua bom hudng true cd ns Idn han 1000 v/ph 2. H u o n g nghien ciiu
D I dat dugc muc tieu tren, trude hct cluing toi lua chgn mgt mau canh da dugc ung dung trong thuc tl, cd so vdng quay ddc trung ns cao va cd hieu suat lam viec tot lam ca sd de dua vao cac hicu chinh vl mat ket cau va thay doi sd la cdnh cua banh cdng tac ciia bam dl tim dugc mgt mau mdi tdi uu. Day ciing la phuang phap thudng su dyng trong nghien cim thyc nghiem. Cdn khi khdng dua vao mot mdu nao dd thi viec may md nghien ciru se khd khan ban, keo dai ban va ton kem han,
Tren ca so nghien ciiu cac mau bom cd trong tai lieu va cac bom dang boat ddng tudi, tieu trong nude, cbiing loi chgn loai bom cd khd nang thodl Idn nhdt luc la bom cd sd vdng quay ns Idn nhdt trong cdc loai bom hicn cd vd cd hicu sudt cao dd la bam theo mdu 0116 cua Nga,
Bam md hinh OlTd cd cdc thdng so ket cau khong thir nguyen va thdng sd quy dan nhu sau:
- Duimg kinh bau canh: j = _!2_= 0,40;
^ D
- So cdnh:
Z = 3;Mat do ddy cdnh 1,/tj vd do day Idn nhat 5„nax/li cua mdi prdphin cdnh nhu sau:
Tiet dien r,/R
1,/t,
Oini^x' Ij
I 0,234 0,903 0,081
II 0,268 0,822 0,072
III 0,343 0,734 0,054
IV 0,417 0,685 0,039
V 0,451 0,668 0,033
VI 0,486 0,650 0,028 - Thdng sd quy dan:
Tai gdc ddt cdnh ip = 0": KQ = 0,46; K„=0,1; ii = 84%.
Trong dd cac he sd KQ vd Ku duac xac dinh bdng:
Q , , . H
KQ =
nD 3 '
K H- n^D-
(1) Vdi [Q] = mVs; [H] = m; [n] = v/s; [D] = m.
Bam md hinh OTIO cd vdng quay ddc trung ns ~ 900 v/ph.
Tren co sd mdu Ofld chung tdi tien hdnh hieu chinh hai thdng sd ca ban cua mau nhir da dat van de d tren Id so cdnh Z va mat do day canh l/t,. So cdnh se thay ddi tir 2 din 4, cdn mat do ddy cdnh se thay ddi trong pham vi ±( 10 - 20)%o.
3. Phu-oTig p h a p nghien cuu
Chiing tdi da lya chgn ra 13 phuong an dl tiln hanh tinh toan thilt kl, chi tao va
nghien cuu thir nghicm. Cac phuang an dd cd cdc thdng sd kit cdu nhu sau: ^
Mdu Z - 2, ip - 0", l/i vd 5/1 lay thco mdu OTId cho 5 tiet dien nhu sau:
jj_panh Lien, Pham Vdn Thu 263
Tiet dicn r,/R 1,/t,
Ojniax'h
I 0,20 0,97 0,100
II 0,275
0,80 0,071
III 0,35 0,73 0,052
IV 0,425
0,69 0,038
V 0,50 0,65 0,028 Mau 2: Z =
Tiet dien r,/R l/t,
2, (p = 0", l/l I 0,20 0,874
gidm 10% sc II 0,275 0,721
vdi mau OlTd, va S/l khdng thay doi.
Ill 0,35 0,652
IV 0,425 0,617
V 0,50 0,585 Mdu 3: Z =
Tiet dien r,/R 1,/t,
2, (p = 0'\ l/t I
0,20 0,777
gidm 20% so vdi mdu OlTf 11
0,275 0,641
III 0,35 0,580
, va 5/1 khdng thay ddi.
IV 0,425 0,548
V 0,50 0,520 Mau 4: Z = 3, cp = 0", l/l va 5/1 Idy thco mau OFIO cho 5 licl dicn nhu mdu I.
Mdu 5: Z = 3, ip = 0", l/t gidm 10% so vdi mau 0116, vd 5/1 khdng thay ddi.
Mdu 6: Z = 3, cp = 0", l/t gidm 20% so vdi mau 0116, vd 5/1 khdng thay ddi.
Mau 7: Z = 4, (p = 0", l/t vd 5,T Idy theo mdu 0 0 6 cho 5 tiet dien nhu mdu I.
Mau 8: Z = 4, (p = 0", l/t gidm 10% so vdi mau 0116, vd 5/1 khdng thay ddi.
Mau 9: Z = 4, cp = 0", l/t tdng 10% so vdi mau 0116, va 5/1 khdng thay ddi:
Tiet dicn r,/R 1,/t,
1 0,20 1.067
11 0,275 0,880
III 0,35 0,803
IV 0,425 0.759
V 0,50 0.715
Mau 10: Z = 2, cp = 0", l/t va 5/1 dugc hieu chinh lai dua theo mdu 0 0 6 theo quy luat sau:
Tiet dien r,/R 1,/t,
OinKi\/ ^1
I 0,20 0,92 0,076
II 0,275 0,733 0,055
III 0,35 0,64 0,041
IV 0,425
0,57 0,030
V 0,50 0.52 0,022
Mau 1 I: Z = 2, ip = 0", l/l dugc hicu chinh lai thco quy luai cho tren dd thi (1.9) [3]
(5/1 khdng thay ddi):
Tiet dicn r/R 1,/t,
1 0,20
1,02
11 0,275 0,815
III 0,35 0,705
IV 0,425 0,632
V 0,50 0,572 Mau 12: Z = 3, ip = 0°, l/t tdng 10% so vdi mau 0 0 6 , va 5/1 khdng thay ddi.
264
Anh hirdng cua sd la cdnh z vd mat do day cdnh l/t ciia bdnh cdng tdc tdi ddc tinh lain viec ciia bom hudng true cd ns lan hon 1000 v/ph
Till dicn
r,/R 1,/t,
I 0,20 1,067
11 0,275 0,880
111 0,35 0,803
IV 0,425 0,759
V 0,50 0,715 Mau 13: Z--
Tiet dien r,/R 1,/t,
= 4, (p = 0". l/t tang 20% so 1
0,20 1,164
11 0,275 0,960
vdi mau 0 0 6 , va 5/1 khdn III
0,35 0,876
IV 0,425 0,828
g thay ddi:
V 0,50 0,780
Banh cdng tdc cua cdc phuang dn nay dugc thiet ke theo phuang phuong phdp phan bd xoay tren cung mong ciia Vdznbcxcnski - Pckin, dd la phuong phdp thict ke rat hieu qua tinh tdi anh hudng cua cd gdc tdi va do cong ciia prdphin cdnh. Phuang phap dugc dimg rat phd bien lai Nga va Lien xd cd,
Cdc mdu bdnh cdng tdc dugc che tao chinh xac theo cdc bdn ve thiet ke. Cdc la cdnh dugc mai nhdn cd do bdng cao. Sau khi che tao cdc banh cdng lac dugc tien hdnh nghien ciru thyc nghiem treiT gid thi nghiem ciia Trung tdm Bom va May Xdy dyng, Vien Khoa bgc Thuy Igi. Ddy la gia thi nghicm hicn dai vd hoan chinh nhat hicn cd de thi nghiem bom o nude ta. Cac sd lieu thi nghicm duac do dac bang cdc ddng hd dicn lu va duac truyen ve trung tain xir ly sd lieu, vi vay dam bao do chinh xac cao,
Tir cac sd lieu do dac dugc chiing tdi xac dinh dugc cac thdng sd 1dm vice chinh cua bom dd Id: liru lugng, cot dp, vong quay, cong sudt, hicu suat va cot dp hiit chdn khong cua bom.
4. Ket qua nghien ciiu
Tir cdc ket qua thyc nghicm chiing toi nhdn dugc 4 mau cd hicu sudt cao dd la cac mdu:
Mau 1 (Z=2, l/t theo 0 0 6 ) : hieu suat dinh dat 80% d gdc ip = 0";
Mau 2 (Z=2, l/t gidm 10%): hicu suat dinh dat 8 1 % d tjdc cp - 0" va ip = +2° vd dat
82% d gdc cp = -2"; ^ r, Mau 4 (Z=3, l/t thco 0 0 6 ) : bieu sudt dinh dat 79% d gdc cp = ±2"; ;
Mau 11 (Z=2, l/t Idy theo dd thi hinh (1-9) [3]): hieu sudt dinh dat 79% d cp = 0". '' Cdc dudng dac tinh thuc nghiem cua cdc mau ndy dugc cho tren cdc hinh 1-4. Mgt so mdu chung tdi da ticn hdnh nghien ciru ddc tinh lam vice cua chung cd a cac gdc khdc vcji 0".
Cdc mdu cdn lai c6 hieu sudt dinh nhu sau :
Mdu 3 (Z=2, l/t gidm 20%) : hicu sudt dinh dat 76% d gdc cp = 0";
Mau 5 (Z=3, l/l gidm 10%) : hieu suat dinh dat 75% d gdc cp = 0"; '•
Mdu 6 (Z=3, l/t gidm 20%) : hieu sudt dinh dat 7 1 % d gdc cp = 0" va dat 7 3 % d gdc cp
= -2";
nanh Lien, Pham Vdn Thu 165
Mau 7 (Z=4, l/t theo 0 0 6 ) : hieu sudt dinh dat 74% d gdc cp = 0" va cp = ± 2";
Mdu 8 (Z=4, l/t gidm 10%) : hieu sudt dinh dat 72% d gdc 9 = 0" va cp = -2" va dat 140/0 a gdc cp = +2°;
Mau 9 (Z=4, l/t tang 10%) : hieu sudt dinh dat 76% d gdc cp = 0° vd gdc cp = +2";
Mau 10 (Z=2, l/t hieu chinh) : hicu sudt dinh dat 70% d gdc cp = 0*;
Mau 12 (Z=3, l/t tdng 10%) : hieu sudt dinh dat 7 1 % d gdc cp = 0°;
Mau 13 (Z=4, I/t tang 20%) : bicu sudt dinh dat 62% d gdc cp = 0".
Il/2.ni N . k W
r^ rrT^/c 0.00 0,10 0,20 0.30 0-40 0.50 0.60 0,70 U . U l ' S
Hinh 1. Dae tinh md hinh bam hir&ng true , mdu l,f- 0"
H/2,m
N,kW^°°
4.50 4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00
\
, n
^\1 —
K
i ^
fjrii
.^^^_j
--4^—
_J7^ T ^ ..L
1 —
1 i
1
. .- - -
]
- 1.00 - 0 90 - 0 80 - 0 70 - 0,60 [ 0.50 - 0.40 - 0.30 0.20 0.10 - 0.00
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Q.mVs
Hinh 2. Ddc tinh md hinh bam hudng true , mdu 2.f-0°
266
Anh hu'd'ng cua sd la cdnh z vd mat do ddy cdnh l/t cua bdnh cdng tdc tdi ddc linh lam viec cua bom huirng true ed ns Idn han 1000 v/ph
H/2,in N,k\V ,5.00
112.111 N.kW
0.00
0.00 0,10 0,20 0.30 0.40 0.50 0.60 Q.mV-^
Hinh 3. Dgc linh md hinh brrm hudmg true . mdu 4,f= -2"
4,00
0.00 0,10 0,20 0.30 0.40 Q.iii-Vs
Hinh 4. Ddc tinh md hinh bom hirdng true , mdu Iff - if
5. Nhan xet va ket luan
Qua cdc sd lieu thuc nghiem d tren ta cd the nil ra mgt sd nhdn xc:t sau :
1. Khi thay ddi l/t, phuang an Z =2 cho hieu sudt cao nhdt (x\ = 82%) d mau l/t gidm 10% (khi lay l/t theo mau 0 0 6 ) .
2. Klii tdng sd Id cdnh cho thdy, hieu sudt eye dai se gidm ddn tir mdu cd so la canh Z
= 2 (ri = 82%) tdi mau cd so Id cdnh Z = 4 (q = 76%).
3. Khi tang so la cdnh Z thi l/l toi uu tang dan. Vdi mau cd Z = 2, (l/t),6i ^u '- 0,9(l/t)on6; vdi mau cd Z = 3, (l/t)„,,„ = l,0(l/t)o,i6; vdi mau cd Z = 4, (l/t),6,^. = l,l(l/t)on6-
Id Danh Lien, Pham Vdn Thu 267
[ Tren ca sd cac sd lieu thyc nghicm chimg toi thiet lap dugc ni6i quan be giira mat do day canh tdi uu (1/t),^, d bien ngoai ciia cdnh vdi sd la canh Z cho bom budng true vdi ty tdc til- 1000 din 1200 v/ph nhu sau:
(lyt),„ = - 0,0325Z^ + 0,2925Z + 0,13,
4. Dudng ddc tinh cua mdu 2 la cdnh ddc ban so vdi ddc tinh ciia mau 3 va 4 la cdnh, cd nghia Id pham vi lam viec d vung hieu sudt cao cua mdu 2 Id canh hep han so vdi cac mdu 3 vd 4 Id cdnh.
5. Ddi vdi cdc mdu nghien cuu d tren, khi Idy L'i theo quy luat bien ddi cua mdu 0116 se cho hicu sudt cao hon so vdi mdu l/t khdng Idy theo quy luat cua mau 0 0 6 : Mdu 1 (l/t theo 0 0 6 ) , q = 80%, trong khi dd mau 10(1/1 khdng theo 0 0 6 ) , q = 70%,
6. Khi gidm ty sd bdu j =0,35 va giam mat do day canh l/t tren bien ngodi theo dudng cong (kbi ndng lugng tdn thdt Id nhd nhdt, hinh 168 [3]) khdng cho hieu suat cao ban khi van giii' ty sd bdu d^ = 0,4 vd gidm l/t xudng 10%: mdu 11, d^, = 0,35 vd l/t gidm theo do thi (hinhI68 [3]) cd hieu sudt q,^ax=79%, trong khi dd mau 2, d^, = 0,4 va I't gidm 10% cd r|,„a,x= 82%,
Nhu vay qua mgt loat cac tinh loan ly thuyet va nghien ciru thyc nghiem ta da tim dugc mdu sd 2 cd Z = 2 va I't gidm 10% so vdi mau 0 0 6 la mdu cd ddc tinh lam viec tdt nhdt,
Sd vdng quay ddc trung cua mdu 2 bdng :
3,65nVQ 3,65^997^/053 , , . , ^ , v
He = r-^— = r n = l l o 2 v.pn.
S ^3,'4 3^Q..4
Mau banh cdng tdc ndy khdng thua kem mau cua nude ngodi. la cd the sir dung cho cdc loai bom cdt nude thap, luu lugng Idn de thodl nude chdng iing lut lai cdc vimg ddng bang vd \'en bien Bac Bg vd Nam Bg.
Tai lieu tham khao
[1] Pham Van Thu, Vicn Khoa h(?c Thuy lgi. Bao cao du an "Diiu tra hien trang mdy bam tram bam ngudn cung ung vd glai phdp phdt tnen mdy bom d Viet Nam " 1997 - 2001,
[2] Pham Van Thu, Luan an TSKT "Nghien ciru bom hudng true cd nS Idn hon 1000 de phuc vu tudi tieu cho dieu kien cot nirdc thdp d Viet Nam ", Ha noi nam 2007,
[3] A, A. LOMAKIN, « Bo'm ly tdm vd hudng tn,ic ». Ban dich cua Le Phii, Le Duy Tiing, Dang Xuan Thi, Nha Xuat ban Khoa hoc Ky t h u a t - 1971.
[4] A, K. Muxau-rioB, B, B. Ma;iiouieHK0, JIonacrHacocbi, Teopiia, pacHcr ii KOHCTpyiipoBaHHe, MocKBa "MAlUIIlIOCTPOEHMF\ 1977
[5] JIonacTiibie Hacoeu, CnpaeoHHHK, O o j ooutefi peaaKuneii B. A, 3HMiiimKoro u B, A. VMOB.
JleHHHrpajl "MauiuHocmpoenue" 1986.
