KHOA HOC CONG NGHE
So 03/2020
Nghien CLTU che tao mo hinh vat ly mo phong dong tham
I TS. N G U Y I N H O A N G - Trudng Dgi hoc Hang hdi Viet Nam
TOM TAT: Trong bai bao, tac gia de xuat nghien cuu, che tao thi/ nghiem mo hinh vgt ly mo phdng dong tham Dong thoi, tac gia cung tien hanh v^n hanh thCt de danh gia do chi'nh xac khi mo phong dong tham khi qua mpt cong trinh cu the, qua do khang d|nh nSng lyc che tao san pham khoa hgc trong nuac.
TL/ KHOA: M6 hinh, vat ly, dong tham, dap dat, luu luong, muc nuoc
ABSTRACT: In this paper, the author proposes to researching and designing seepage. At the same time, the author also conducted trial operation to assess the accuracy when simulating the flow net and seepage Therefore confirmed the capacity of manufacturing scientific products in the country, KEYWORDS: Model, physic
water level.
seepage, nver, flow,
I.DATVANDE
Mo hinh vat ly mo phdng ddng tham qua eae edng trinh thuy Ipi, thuc chat la mpt bien the thu nho cua mo hinh vat ly thiiy lue. Nd dugc nghien cdu, san xuat va ehe tao de dap Ung cho cac cosd nghien cdu vda va nho, chii yeu la trong eae trUdng dai hoe, noi cd rat it quy dat de xay dung cac mo hinh vat ly Idn [3],
Md hinh vat ly thiiy lUc rat pho bien d nude ngoai do cdtiem lue kinh te. Viee nghien euli che tao mo hinh vat ly thuy luc mo phdng dong tham da den mdc hoan thien. Hp da sSn xuat nhieu md hinh, trong dd cd nhUng phan tif tao lUu lUOng thay doi theo thdi gian, qua trinh tuan hoan nUdc va tao mo hinh cac cong trinh de tinh toan, mo phdng lUdi tham, tinh toan van tdc tham va luu lUOng tham...
Bang mo hinh nay, ngUdi ta co the gi^i quyet cae bai toan sau:
- Mo phdng ddng tham eiia dat nen khi ed cif chong tham;
- Mo phong ddng tham qua dap dat;
- Mo phdng muong thoat nudc.
Cau tao eiia bg md hinh bao gom: Mot hop thi nghiem hinh ehCf nhat, khung gia dd dupe ehe tao tCf thep hop, may bom nude ed van ON/OFF dieu tiet lUu luong; thung chUa nUdc, ong dan nude.
2. Di XUAT GlAi PHAP KET CAu, P H A N T ( C H VA Ll/A CHON H £ T H O N G C A P NUdC CHO SA B A N
2.1. Tinh toan Ic^tcau bo mo hinh
Dua vao ket eau mo hinh nguyen ban dugc gidi thieu d phan 1, tac gi^ da nghien cifu, tfnh toan va phan tich ketcau dedi den lua chon loai b g m d hinh nhu sau:
Hinh 2.1: Phoi cinh khdng gian kit cau bp md hinh Kich thudc bp mo hinh duoc de xuat nhu sau: Gia dd hop thi nghiem (dai x rong x eao): I,2x0,6x1,0m dUOc che tao bang thep hop 50x50mm, trong do kich thude hop thi nghiem la (dai x rpng x eao): 1,2x0,6x0,6m dupe lam b^ng mica day 01 cm. De phan tich, tinh toan ket cau khi chiu tai trpng nguy hiem nhat la hop thi nghiem chUa day nUdc, tae gia ap dyng md-dun ANSYS Structural de tinh toan. Ket qu^ phan tich tong chuyen vj eua ket eau nhu sau:
Hinh 1.1: Bp md hinh vat ly md phdng dong tham eua Armfield
Can ciir vao ket qu^ phan tich tren Hmh 2.2, ehuyen vj Idn nhat ciia k^t eau la 0,000093m. Chuyen vj nay dupe xem la nhd va khong ^nh hUdng tdi do on dinh ciia ket cau.
2.2. Tinh toan lira chon cong suat bdm May bom dupe lUa ehgn cap nUdc cho bp md hinh duoc xae dinh theo cong thdc tinh cong suat sau [3]:
Trong dd:
P - Cong suat dpng lUc, kW;
Q -Tong lUu lUpng, mVs;
H-Chieu cao hut, m;
e - Hieu suat tong hop ciia may dien va may bOm, thudng la 70%.
Can cif vao dieu kien, yeu cau eung nhu kich cd cija san ban, vdi luu luong toi da dat 4.0001/h cung cap eho mo hinh, chieu cao hut toi da 02m. Ap dung vao cong thijfc (1) ta CO cong suat cua may bOm dat 42W.
2.3. LUa chon van dieu tiet mUc nUdc Van dieu tiet mUc nude cho bp mo hinh la loai van dien, CO dddng kinh ren 21 mm. Van duoc ket noi vdi bo di^u khien van thong qua phan mem dieu khien [1,2] ciia bpthietbj dieu khien.
Hinh 2.3: Bp thiet bi dieu khiin sau khi da lap xong Bp thiet bi nay duoc ket noi vdi may tinh thong qua eong giao tiep USB va dUoc dieu khien bang phan mem duoc viet bSng ngon ngu" lap trinh C.
Hinh 2.4: Phan mem dieu khien muc nudc
3. TI^N H A N H M 6 P H 6 N G , TINH T O A N , K I I M DINH DO CHfNH XAC CUA M 6 HINH
3.1. Ctf sd ly thuyet ki^m djnh bai toan mo ph6ng Nhiem vy cua bai toan mo phong dong tham qua dap dat do la xae djnh vj trf dudng bao hda de tinh on
KHOA HOC CONG NGHE So 03/2020 djnh ciia dap. De xac dinh vi tri dudng bao hoa cung nhu quy dao ciia dong tham, ngUdi ta sif dyng cac phuong phap sau [4]:
Phuang phap cO hpc chat long: Mdi giai dUOc mpt so bai toan don gi^n, do do bj han che it sCf dung.
Phuong phap thiiy lUc: Kem chfnh xac hOn nhung van d^m bcio ky thuat. L/u diem dOn gian, gon va dupe sirdung rdng rai.
Sd do thdm qua ddp ddt trin nen khong tham (theo phuang phdp thuy luc):
Xet khoi dat tham nUdc cd day nam ngang tren nen khdng tham,ddng chay bien doi cham.Xet bai toan ph^ng ta ed:Theo dinh luat D a c x y j = - ^ thl ?^i''^=Wa. = k(--^))' (d day: k - He so tham. Don vj: m/s, m/ngd.
1 y
1 h,
0
^ 1
T * - ^
dx L
1\
XHinh 3.1: Sa do tinh thim theo cdng thdc Duypuy TCf dd ta lan luot c6 cac phUOng trinh nhU sau:
qdx = -kydy (2) Do luu lupng q la hang so nen ed the gili phuong
trinh (2) va dupe phUPng trinh dudng bao hda (3) nhu sau:
l'„(ldx = -kj^ ydy=>x=^Y{'''~y')
y-f^^ (3)
Vdi x= L thi IL/U iLfang tham q theo cong thufc (4):
, = t t t (4) ' 2Z.
Trong tracing hop dong tham do vao vat thoat nudc fHin/li.2;thltac6:
Hinh 3.2: Sado tinh toin ddng tham do vao vit thoat nudc (h,= 0)
- Dong tham d nem ha luu:
Hinh 3.3: Sado ddng tham a nem ha luu dap dat
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KHOA HOC CONG NGHE
So 03/2020
Chpn he true xoz nhu hinh ve. Lay vi phan dz each goe 0 mot doan z. Khi do, lUu luong q dupe xae dinh theo dq - kjdz. Tfeh phan hai ve ta cd cdng thdc xae dinh luu luong q nhUsau:
ka.
- Dong tham d nem thupng lUu:
Hinh 3.4: So do ddng tham onem thupng luu dap dat Trong trUdng hpp nay, mien tham abc dugc bien doi tUOng duong la adec ed chieu rpng la AL. Dudng bao hda thuc af dupe xae djnh tU dudng bao hda tuong duong df.Trong do: AL dUOc xac dinh theo cdng thdc (6)
AL=Xh, (6) Trong do: A. phu thuoc vao he sd mai doc thUOng lUu,
duoc xac dinh theo edng thUe eiia Mikhailop, tinh theo (7):
k= ^— (7) 2m,+1 ^'^
- Tinh tham qua dap dat dong chat tren nen khdng th^m theo phuong phuong phap thuy lUe:
Xet dap dat tren nen khdngtham, cd ludltham nhU Hinh3.5.
Hinh 3.5: Sado ludi tham cua dap dat dang chit Dudng bao hoa AC di thang gde vdi mai thugng luu, nd ha thap kha nhanh trong doan AE. Sau mat eat EF dudng bao hda gan nhu nam ngang, rdi thoat ra 6 ha lUu tai diem C theo phuong tiep tuyen vdl mai dap.
Su phan bo J tham d cifa ra cda vao d tai mot so diem dae biet co tri sd sau:
J^ = cosa; Jg= 0; J^^, = sina; J|,= \i.
De giai bai toan xac djnh lUu lupng tham va dUdng bao hda ngUdi ta thay tam giac thuong luu dap bang mpt hinh chd nhat c6 chieu rpng DL vdi dieu kien van dam bao luu luong tham khong doi.
Hinh 3.6: Sa do tinh thim ciia dap dit dong chat tren nen khdng tham
Bai toan tinh tham qua dap, dat vdi mai thupng luu nghieng di chuyen thanh thang difng da giai quyet d
100
ben tren. Luu lupng tham qua phan than dap thUOng luu tacd:
g^k-2{L + AZ.-m;(fl„ + /i,)} (8) Khi ha lUu dap ed nudc, so bp phan ha luu dap thanh hinh sau:
Hinh 3.7: Sa do tinh toin nem ha luu LUu luong tham qua phan tam giae nSm phfa tren mUc nudc ha luu:
^' m,-1-0,5 "
Luu lugng tham qua phan hinh thang dudi mUc nudc ha luu:
?: = k-h,. —^ —7—
(m, + 0 , 5 ) a , - K - ^ ^ ^
Luu lupng tham tong cpng:
Trong do:
(10)
(12) 2(m,+0.5)
GiSi he phuong trinh (8), {12) x^c dinh dtroc q va a^
Phaong trinh dudng bao hda theo he true toa dd xoy:
2.?
(V-y')
(13)- Dap dong chat co t
1 -
met bi th
L+A_
Dat nudc
1.
1
0
1 -
X Vfir' y
»\ --M-
^
b)4 ^
a) - H? luu 3$p CO nudc. b) - H? luu dap khdng cd nudc Hinh 3.B: Sado tinh tham qua dip dat dong chit
ed vat thoit nudc
Khi ha luu dap khdng cd nudc, dUa vao ly luain cua bai toan tham co ban ta cd:
a, = 2l-4(L*&L)'*l^-{L*M)
(14) PhUdng trinh bao hda: y = la^x (i 5) Khi ha luu cd nUdc thi trye hoanh ox nam ngang
mUc ha luu. Luc do, de tinh a^ (hoac 1) van dung dang cong thUc (14) song phai thay h, bdi h, - h,.
Luu luong tham dUdc xac dmh:
1=—, rlW -iK+a.f]
(16)= 27 = = J ( i + A L ) ' + ( * , - / , j ) ' - ( i + a i ) Phuong trinh cua dudng bao hda:
(18)
" [L + M] "
3.2. Thuc nghiem va so sanh
Tien hanh md phong ddng tham qua mot cong trinh cu the nhu sau.
Hinh 3.9: Tao dung md hinh doan dap dat Cong trinh la dap dat, co chieu cao H = 30cm; be rpng dinh la b ^ 10cm; mai doc phfa thupng luu m, ^ 3; phfa ha luu m j = 2. MUC nude phia thupng lUu trong trudng hpp mo phdng nay ia H.^= 33cm. Ket qua mo phong nhu sau:
Hinh 3.10: Kit qua ma phdng dudng bao hda qua than dap Nhin tren Hinh 3.2 ta thay, dudng mau tfm la dudng bao hda qua than dap. Dudng bao hoa nay phu hpp vdi hinh dang dudng bao hoa thudng thay khi quan trac, tinh toan tham eho cac cong trinh thiiy loi: de, dap dupe xay dung theo ly thuyet da trinh bay 6 tren... [4].
4. K^T L U A N
Can cd vao viee phan tich eae ket qua tfnh toan ta
KHOA HOC CONG NGHE
So 03/2020 thay, viec sddyng bg md hinh mo phong dong tham vao viee nghien cdu tae dpng cua ddng tham len cac cong trinh thiiy loi nhude, dap..., khong ehi dem lai hieu qua cao trong edng tac thiet ke, ma eon dem lai lpi fch trong giang day, nghien cUu khoa hoc.
Tai lieu tham khao
[1]. Vu Duy Quang, Pham Ddc Thuan (2009), Gido trinh Ky thudt thuy khi, NXB. Khoa hpc va Ky thuat.
[2].Tran The Sang, Tran Thj Kim Lang (2009), Thuy/t/c vdBam, NXB. Khoa hoc va Ky thuat.
[3]. Luong Phuong Hau, Tran Dinh Hoi (2003), Ly thuyet thi nghiem mo hinh cong trinh thuy, NXB. Xay dUng.
[4]. Nguyen Hoang [2018). Cong trinh thCiy lgi, NXB.
Hang hai.
Ngay nhan bai: 05/01/2020 Ngay chSp nhan dang: 30/01/2020 Ngudi phdn bien: TS. Tran Ngoc An TS. Pham Van Sy
