Xác định các thông số hình học tối ưu cho buồng tạo áp của gối đỡ thuỷ tĩnh máy nghiền xi măng

528 Tuyin ttip cdng trinh Hdi nghi Cff hoc todn qudc Ky niem 30 mini Vien Cff hge vd 30 nam Tgp chi Cff hoc Hd Ndi, ngdy 8-9/4/2009 Xac dinh cac thong so hinh hoc toi uu cho buong tao ap cua goi do' thuy tmh may nghien xi mang Nguyen Quan Thang, Nguyen The Minh Bp tu linh Cdng binh Do Qudc Quang, Cao Van Mo Trung tdm Ca & Tu dpng hda, Vien Cdng Nghi, Bd Cdng Thuong Tom tat: Bdi bdo trinh bdy nhitng kit qud budc ddu nghien cieu ly thuyet qud trinh thuc hiin di tdi 'Nghien ciru tinh todn, thiit ki vd cdng nghi chi tgo goi da thiiy luc chiu tdi ndng din 80 tdn'' Kit qud nghien ciru da di xudt phuang phdp tinh cdc hi sd khdng thic nguyen eho goi da thiiy tTnh cd bien phuc tgp, ddng thdi sic dung thuat todn tdi uu (DE) trin ca sd md phdng Monte-Carlo di xdc dinh thdng so hinh hoc tdi uu cho mot segment goi da thiiy luc ciia mdy nghiin Mo dau Trong nhii'ng nam gan day, may nghien diing the he mdi da dugc iing dung rgng rai cae nganh cong nghiep san xuat vat lieu xay dung eiing nhu mot sd nganh cdng nghiep khac can den nguyen cdng nghien Cd duge thj trudng nhu vay vi may nghien dung ed nhieu uu diem ve ket cau, hieu suat cao, ed tinh kinh te cao khai thac thiet bj va giam thieu d nhiem moi trudng O Viet nam, hau het cae nha may xi mang mdi duge xay dung deu su dung may nghien dirng nghien lieu, nghien than, nghien clinker Trong may nghien dirng, bd phan goi da thuy lire dd ban nghien ddng vai trd het sire quan trgng vi cum chi tiet chju ap lire rat Idn cua toan bd he thdng gia tai thuy lire, eiia trgng lugng phan quay may nghien, trgng lugng vat lieu budng nghien va cac lire nhieu dgng phat sinh qua trinh nghien Nam 2005, Cdng ty TNHH Nha nude mdt vien Co Ha ndi (HAMECO) thuc hien de tai "Nghien ciiu thiet ke may nghien diing cho day chuyen xi mang Id quay cdng suat 2.500 tin elinker/ngay" thuge du an KHCN "Nghien eu'u thiit kl, chi tao cac thiit bj ehii yeu eho day ehuyin ddng bg san xuat xi mang Id quay cong suit 2.500 tin elinhker/ngay thay thi nhap ngoai thuc hien tien trinh ndi dja hda" Tuy nhien du an mot s i chi tiet quan trgng ed hop giam tdc tfch hgp goi dd thuy lire vin dugc nhap ngoai khdng nam noi dung nghien ciru Nam 2006, Vien Cdng nghe da thuc hien de tai cip Bd ma sd 20.06/RD-2006 "Nang cao chat lugng mam nghien nham can bang ap lire lam viec eua may nghien diing" Ket qua ciia de tai da xay dung duge gia thi nghiem gdi thiiy tTnh va thir nghiem dac md phdng cac dieu kien eiia gdi dd thuy lire may nghien dung Xdc dinh cdc thdng sd hinh hoc tdi tni cho buong tgo dp cua gdi dd thiiy tTnh mdy nghiin xi mdng 529 Trong ke hoaeh nghien cuu khoa bgc cip Nha Nude 2009-2010 da cho md dl tai ''Nghien cini tinh todn, thiit ki vd cdng nghi chi tgo gdi thiiy lire chiu tdi ndng din 80 tdn" Ndi dung bai bao se trinh bay mdt sd ket qua nghien cuu ly thuylt budc diu eiia de tai ddi vdi gdi dd thuy tTnh loai thudng duge tich hgp vdi hop giam toe dimg eho may nghiin dirng Mgi gdi dd thiiy tTnh deu lam viec theo nguyen tae cap ddng dau bdi tron cd ap lien tuc vao giua hai be mat chuyen ddng tuong ddi Chit lugng lam viec ciia loai gdi dd nhu vay phu thude chii yeu vao tin cay boat dgng cua he thong cip diu bdi tron Khi tiln hanh thiet ke thudng dua vao ba dai lugng khdng thir nguyen la a t - He sd tai trgng, qf- He so luu lugng va Hf- He sd cdng suat de chgn lira cae kich thude hinh hge hgp ly cho cdng suat day dau qua khe hep cd gia trj eirc tieu Gia trj ciia nhung dai lugng khdng phu thude vao kich thude tuyet doi ciia goi ma ehi phu thude ty le giiia chiing Chinh xac ban la ty sd dien tich ciia budng tao ap vdi tdng dien tich ciia gdi dd Do vay viec xac dinh cac he sd khdng thu nguyen cho mot dang hinh hge cu the ciia gdi dd thiiy tTnh ed y nghTa bet sue quan trgng He sd tai trgng ciia gdi dd thuy tTnh aidirgc xac djnh bang bieu thiic: aj=- W ; (1) W - Kha nang chju tai thuc ciia gdi (KG) Ap - Toan bd dien tich hinh chieu ciia be mat tua (cm') Pr - Ap lire budng cua gdi dd cd khe hd (KG/em") He sd luu lugng eiia gdi dd: O.A„.u Q - Luu lugng dau (eiV/sec) W Tai trgng tac dung len gdi dd (KG) h - Chieu day mang dau bdi tron (em) p - Do nhdt tuyet ddi eua dau bdi tron (KG.see/cm ) Cdng suit cin thiit eua bom d l diy diu qua khe hep gdi do, tfnh bing tich giua ap lire budng va luu lugng qua d H,-pM W ^ h^ = H,.{-j-f.-; (3a) d day Hj la he so cdng suit: //^=—; (3) 530 Nguyin Quan Thdng, Nguyin The Minh, Dd Qudc Quang, Cao Vdn Md Trong nhilu tai lieu da gidi thieu cdng thiic xac djnh cac he sd khdng thii' nguyen (af, q^ Hf) eho gli dd trdn budng trdn trung tam, gdi dd trdn budng vanh khan, gdi dd ehii' nhat buong chir nhat, hinh con, hinh ciu Nhung chua cd tai lieu nao trinh bay dii chi tiet co sd tfnh toan cho segment (gulc dd) phang ed hinh dang kliae Chu yeu cac sd lieu dimg cho thiet ke cac d dd thiiy tTnh CO dang hinh hge khac deu dua tren nhung ket qua thi nghiem Tren ca sd cac bieu thiic giai tfch CO ban da bilt va cdng cu tmh toan moi cd the xay dimg dugc phuong phap dii tin cay xac djnh ba he si kliong thiJ nguyen quan trgng ciia gdi nhieu segment dang quat cip diu vao budng trung tam, tham chf ca goi dd cd hinh dang phuc tap hon L M o t so tinh t o a n thiiy luc cho d o n g d a u co a p chay q u a k h e h e p [3,4] Klie hep phang song song la dang nhat cua eae gdi dd thuy tTnh Ddng dau ed ap dugc cap vao buong ciia gdi dd, ap lire Idn ban ap lire tach hai be mat, ddng dau bdi tron se chu)'en dgng tir tam budng ngoai bien Trong nhCrng trudng hgp kfch thude ciia khe hep rat nho nen ddng chay tir tam bien dugc coi la ddng chay tang Mat kliac cac gdi da thuy tTnh boat ddng, tdc chuyen ddng tuong ddi giiia phan tTnh va phan dgng nhd nen nhieu tfnh toan cho phep bd qua anh hudng cua tdc den cac thdng sd thuy luc ciia gdi Tren ca sd ly thuyet tfnh toan cac thdng sd thuy lire cho ddng dau ed ap chuyen dgng qua khe hep theo phuong hudng kfnh ta cd: Phuong trinh chuyen dgng va tdc ddng chay [2, tr293] U = ±-±.(^y.h-/)- (4) 2.// dr Tdc dat gia trj cue dai y = hll cd nghTa la: dp h~ h^ dp z.p dr 8/J dr fc^ Tdc trung binh ciia ddng chay tang khe hep: \ dp ^ = ~"n,ax= « - ^ ; """^ 12/^ dr ,.- (o) Phdn bd dp luc dp _ \2/j dq dr (7) h^ r.dcp' U^y:dpJ-^^; h'.dip (8) r Tir cong thiie (8) ta ed thi nhan xet ring: dgc phuang hudng kinh theo ehilu ddng chay, ap lire dau giam dan theo ham logarit Luu lugng ddng diu Xdc dinh cdc thdng sd hinh hoc tdi ini cho budng tgo dp cita gdi dd thiiy tTnh mdy nghiin xi mdng va dQ = h^.dcp 12// Ap 531 (9) In Neu tfnh eho toan bd ehu vi ta cd tdng luu lugng: Q= 7r.h' (10) 6./^ ln(%^ Cdng thirc (10) ehi dung tren toan bd chu vi r„ va rb la hang sd Xay dung phucng phap tinh cac he so cho goi d& thiiy tinh tru'ong hop tong quat 2.1 Xdc dinh khd ndng chiu tdi thuc cua goi dd thiiy tinh Til' cac cdng thiic (1), (2) ta thay rang de xac djnh duge cac he sd ciia gdi dd thiiy tTnh can xac djnh dugc kha nang chiu tai va luu lugng dau qua goi dd gdi lam viec dn dinh Bieu phan bd ap lire dau ed dang nhu hinh ve Trong vimg budng dau ap luc khdng ddi bang Pr, khoang tii' I'b den r,, ap luc thay ddi theo quy luat logarit Klia nang chju tai ciia gdi trudng hgp chung tfnh theo cdng thirc: W^W,,+ jPrdF • (11) ^ a Fn W,=F,.p/, Hinh Phan bd ap luc gdi dd thiiy tinh Neu chia vimg ngoai buong tao ap n phan vd ciing nhd thi bieu thuc (11) cd the viet lai nhu sau: w = Pr-F.+J^Prf,; 1=1 d day: pr - Ap luc dau buong KG/cm Fb - Dien tfch ciia budng tao ap, cm" F„ - Phin dien tfch ngoai budng n - Sd phin dien tfch ngoai budng dugc chia nhd fi - Dien tfch ciia phan thir i, cm^ Pi - Ap luc tai trgng tam eua phan dien tfch thii i, KG/cm^ (12) Nguyen Qudn Thdng, Nguyin Thi Minh, Dd Qudc Quang, Cao Vdn Md 532 p,{\n{x)-\n{rj) P,= (13) T-^ In ^ Su dung bilu thirc (13) ta cd the xac djnh dugc ap luc tai mdt diem bat ky ngoai buong va cho phep tfnh kha nang chiu tai thuc cua gdi dd theo cdng thirc (12) 2.2 Tinh luu lugng thong qua goi dd N I U ta chia toan bd chu vi k phan, moi phan cd sd gdc d tam la Acp, tuang irng phin chia cd ban kfnh buong la rbi va ban kfnh ngoai bien la r„i, thi cd the tfnh toan bg lugng diu qua gdi bang each sir dung cong thirc (10) dugc viet dudi dang mdi: Aip, 12// tr (14) r 2.3 Xdc dinh cdc he so khong thir nguyen cua goi thuy tinh He so chju tai: Bang each ket hgp cdng thirc (1) va (12), ta eo bieu thirc xac djnh he sd af: ^/ = A„.P PrF+TPrf, (15) Ap lire dau ngoai budng tai diem bat ky p: xac djnh theo bieu thirc (13) - He sd luu lugng: Ket hgp bieu thiic (2) vdi (1) ta cd: ^f Q.A,,p Q.A,,p W.h' aj A^,.p^.h'' (16) Thay gia trj Q til' (14) vao (16) va gian udc ta duge bieu thiie tinh q^ •s- ^^ 1f = \2.a / '=1 In A^,, i n ^ (17) - He sd cdng suat: Sau da cd hai he so af va qrthi Hfdugc tinh theo (3) Nhu vay bilt dang hinh hge cua budng, dang hinh hge eiia bien vdi ddng dau chay bien theo chieu hudng kfnh ta co thi cai dat chuong trinh tinh cae he sd vdi chfnh xac cho phep Tren co sd cac bilu thirc (15), (17) va (3) chiing tdi da tiln hanh lap trinh va tfnh toan nhim khang djnli su dung dan ciia cac suy luan toan hge va tin cay eua ciia phuong phap tinh bang sd Xdc dinh cdc thdng sd hinh hoc tdi mi cho budng tgo dp ciia gdi thuy tTnh mdy nghiin xi mdng 533 Hv tu titiCiiini; '- -• , , • • - ',,,,/ , / / / X a- Hinh So dd tinh gdi va budng trdn 'ã J,:,-*-'i-ô'' -4 , ,n, , Hinh Dd thj eiia he so tai trgng va he sd km lugng klii thay ddi ty sd rb/r„ Da tien hanli ti'nli toan cho gdi dd dang bien trdn vdi budng tao ap trdn chinh tain Kit qua triing vdi ket qua tfnh bang giai tfch da dugc cdng bd [1] Ty sd kfch thude tdi uu ddi vdi gdi dd dang la rb/r,, =0,55 Cac he so tuong ung af = 0,584; qf= 1,501; Hf= 2,57 Vdi gdi vudng budng vudng, cd nhieu dang cdng tliuc giai tfch kliac nhung khdng cho ket qua diing vdi sd lieu thuc nghiem Theo each tfnli eiia chung tdi, ty si a/b = 0,5 ta cd af = 0,5400 diing vdi sd lieu thuc nghiem (ar= 0,54) [1] Tinh cho mot segment cua goi d a may nghien Do kfch thude eua eae mam dd may nghien Idn nen nd thudng duge eau tao nhu hinh ve Toan bd be mat ciia vimg tao mang dau bdi tron dugc chia tiing mang nhd rdi segment Mdi mdt segment duge cap dau dgc lap va nhu the co the tinh toan rieng Kha nang mang tai, tdng luu lugng, tdng cdng suat day dau ciia toan bd gdi dd bang tdng cua tat ca cac segment Budng tao ap tren tiing segment cua gdi dd thiiy tTnh thudng ed hai dang la budng trdn (niia tren hinh 4) va budng ddng dang vdi bien ngoai (nira dudi hinh 4) Hinh So bd tri cac segment tren goi dd may nghien Hinh So dl tinh cho hai loai segment Nguyin Qudn Thdng, Nguyin Thi Minh, Dd Qudc Quang, Cao Vdn Md 534 Klii tfnh toan cac he so af, qf va Hf bing cac cdng thirc (15), (13), (17) va (3) dilu cin phai chii y la phuong trinh cua cac dudng bien gidi han cua segment cung nhu buong tao ap phai dugc vilt he tga co glc tai diem 02 Dong thdi xac djnh dung gdc gidi ban Phil, Phi2, Phi3 Vf du vdi segment ed buong tao ap hinh trdn gdc tinh toan thay ddi tir 0-^180° thi gia trj cua r„i se bj gidi ban bdi cung A-Al, dudng thing Al-Bl va cudi ciing la cung Bl-B (hinh 5) rbi la khong ddi Trudng hgp ciia segment vdi budng tao ap ddng dang vdi bien ngoai thi rbi cQng' se thay ddi lien tuc tuong tu nhu bien ngoai Tren co sd cac cdng thirc da biet va nhung ehii y neu tren chirng tdi da tien hanh lap trinh dl tfnh eho segment vdi hai loai buong khac Ket qua tinh toan cho segment vdi buing tao ap hinh tron eho tren hinh Gia trj cue tieu dat duge trudng hgp khoang Rb/Rsh = 0.58+0.65 Do thj ll? so tiii af Ciic he so qfvA Hf 10,0 9,0 1.0 rv;, 8,0 y 08 06 X 04 i:/, • :-,-^v;./;, , J •.;, .^| 7,0 ^ / \ - • , • \ 6.0 : \ \ • nfl '/ 5.0 4,0 V 3,0 2,0 - 0,2 ', "->• - ,., •, ,/ ; y \ ' • ' • - ^ ^ ,., ;;,-' • ^ , ^ ; ;;: , j '['-y- '"•rC ' il_-:——-^/.^f / 1.0 0.0 0,0 C.0 0,1 0,2 0,3 0,4 0,6 Rb/Rgh^ _ ,_ 0,7 0,8 0,9 1, ) C : > C 0 0 0 0 Rb/Rgh -, _, - Hinh Dd thj bieu dien gia trj cac he so af, qf va Hf eiia segment vdi budng trdn phu thude vao ty sd Rb/Rgh (Rb- Bdn kinh budng tgo dp; Rgh- Khodng cdch tie tdm budng din diedng thdng Al-Bl) Bai toan chon thong so hinh hoc t6i uu cho g6i dS thuy tinh dam bao cong suat day dau qua khe la eye tieu 4.1 Xdy dung bai todn Cong suat eiia he thdng cip diu eho mdt gdi dd thuy tTnh bao gdm nhieu phan cd cdng suat diy dau qua khe hep giua hai mat eo chuyin dgng tuong ddi va duge xac djnh bing tich giira ap luc buong tao ap va luu lugng diu (3a) Tir bilu thiic (3a) eho thiy, co the giam phin cdng suit bing each giam gia trj cua he so cdng suit Hf Do vay, qua trinh thiit kl gdi dd thiiy tTnh ngudi ta ludn mong mudn vdi kfch thude da cho eua goi dd (hoac mdt segment) cin tim kfch thude hinh hge ciia budng eho Hf dat gia trj cue tilu Xdc dinh cdc thdng sd hinh hoc tdi leu cho budng tgo dp cita gdi da thiiy tTnh mdy nghiin xi mdng ^^^ Tir nhung vi du tfnh toan d tren ed thi rut nhan xet ring: Khi hinh dang ngoai eiia gdi hoac mdt segment la cd dinh thi gia trj ciia eae he s6 af, qf va Hf ehi eon phii thuge vao kich thude hinh hge ciia budng tao ap Vdi goi dd cd buong tao ap tron thi af, qf va Hf ehi phu thude vao ban kfnh budng tao ap Rb (ham mot bien) Bing phuang phap sd viec xac djnh gia trj eiia Rb de Hf dat gia trj cue tieu la don gian nhu trinh bay d tren va cac dd thj Nhung vdi budng tao ap CO bien phiic tap ban vi du nhu trudng hgp segment co budng dong dang vdi bien thi khong dan gian Vdi trudng hgp eu the nhu tren hinh thi Hf se phu thuge vao ba biin co ban: Hr = f{r,„r,„„(p„); (18) d day: ^b - Ban kinh eua budng tao ap; rnb - Ban kfnh ngoai ciia budng tao ap; cpb - Nira gdc d tam (gdc quat) ciia budng tao ap Ham/(^r,6, r,,/,, (pi,) khd ed the bieu dien bang bieu thiic giai tfch tudng minh, bdi de tinh duge Hf phai thdng qua rat nhieu cac tfnh toan trung gian nhu da trinh bay d tren Nhung eo the khang djnh rang vdi mdi tap cac gia trj ciia (r,b, r„b, cpb) ta cd the xac dinh dugc mdt gia trj nhat eua Hf Viec xay dung hkmf(r,t„ r,,;,, tph) tudng minh eiing khdng thuc su can thiet cac thuat toan tdi uu mdi cho phep giai bai toan chi can gia trj eiia ham Trong he tga vdi gdc la diem nhu tren hinh 5, bai toan tdi uu co dang: Tim tap cac gia trj (r,h, r,,/,, cpb) cho ham: Hf = f{r,„r„„q),)-^Min; vdi cac dieu kien rang budc sau: 0>r,b>r, (19) < rnb < fn < cpb < cps d day: r, - Ban kinh ciia segment; r„- Ban kfnh ngoai eiia segment; (Pb - Nu'a gdc d tam eua segment Nhirng dilu kien rang budc tren chi dam bao budng tao ap khdng vugt ngoai gidi ban hinh hoc cho phep 4.2 Chgn phuang phdp gidi D I giai bai todn (19) ed mdt sd phuong phap sau: - Phuong phap bien hinh hoac phuong phap dung sai mem [6] Thuat toan gen (Genetic Algolrithm - GA) [7] Thuat toan md phdng luyen kim (Simulated Annealing - SA) [8] Thuat toan tiln hda vi phan (Differential Evolution - DE) [9], [10] 536 Nguyen Qudn Thdng, Nguyin Thi Minh, Dd Qudc Quang, Cao Vdn Mo Hai phuong phap diu la cac phuang phap truyin thdng, viec xir ly eae dieu kien han chi phiic tap, kit qua phu thuge vao diem xuat phat ban dau, khd dam bao cho chung ta nghiem toi uu toan cue Ba thuat toan sau la cac thuat toan thuge lap cae thuat toan dua tren co sd mo phdng Monte - Carlo Theo kinh nghiem lap trinh va tfnh toan thir nghiem mdt sd bai toan phiic tap ciia chiing toi eho thiy, thuat toan SA va DE ludn cho ket qua diing va on dinh, tieu chuin dirng xay dung dan gian va chinh xac hon Thdi gian tfnh tren may eiia thuat toan DE luon la nhd nhit so vdi cac thuat toan khac giai nhiing bai toan phuc tap De giai bai toan (19) chung tdi da chgn thuat toan DE Giong nhu thu^t toan GA, DE dira tren qua trinh tiln hoa vdi ba toan tii' ca ban la dot bien, lai ghep va lira chgn nhung ban chat mdi toan tir lai khac hin vdi thuat toan GA Doan chuo'iig trinh sau md ta nhirng budc co' ban nhat eiia thuat toan DE truyin thong //Bat ddu qud trinh tim kiim // Tgo qudn thi tine nghiin ban ddu vdi Np cd thi DO i=l,Np //Dpi biin vd lai ghep ro = floor(rand(0,l)*Np); while (ro = i); rj = floor(rand(0,l)*Np); while (ri= ro orrj = i); r2 =floor(rand(0,1) *Np); while (r2= rj or r2- ro or r2 = i); jranj = floor(D*rand(0,1)); j=l,D// Tgo vec to thie nghiem if (rand(0,l)