KHOA HOC CONG NGHE M O T S O K E T Q U A IVBHIEIV CIJLI T U A BIIM HUOIMG CHEO CAIVH CD DflMH P H U C V U T H U Y DIEIM IMHD V I E T IMAIVI Pham Phiic Yen\ Biii Qudc Thai^ TOM TAT Bai bao trinh bay ket qua nghien ciru loai tua bin moi, tua bin budng cheo canh co dinh pham \i cong suat nho, cot nuoc thap va trung binh Loai tua bin co ket cau banh cong tac don gian, hieu suat cao, co the thay the tua bin tam true va tua bin huong true canh co dinh pham vi tren va phii hgp nang luc che tao tai Viet Nam Thong so lam viec cita mo hinh tua bin la: liru lugng quy din Q'i= 9001050 1/s, van tdc quy din n'i=8595 v6ng/phut, hieu suat tdi da ri„,„= 83% Viing lam viec: cong suit tir 801000 kW; cot nuoc tir 2040 m Tir khoa: Tua bin hudng cheo, nha may thuy dien, cong suit nho LDATVANDE ' O nude ta hien nay, pham vi thity dien nhd va cue nhd, vung cot nude thip va tmng binh mdi nghien ciiu, img dyng hai loai tua bin hudng tryc canh cd dinh va tam true Tua bin hudng cheo canh xoay cd hieu suit cao hon, vung lim viec tdi uu rdng hon, dac biet hieu qua pham vi vdi ti tdc n,= 250 450 v/p, nhien ket ciu phirc tap nen thudng dugc ap dung cho c i c tram thity dien ldn Viec nghien ciiu ap dung dac tinh nang lugng tdt cua tua bin hudng cheo (TBHC) cho thity dien nhd v i cue nhd cd y nghia thuc te r i t ldn Tir lap luan tren, cho thay ring Nghien cuu ung dung tua bin hudng cheo canh cd dinh phirc vu thuy dien nho & Viet Nam l i rit can thiet Tua bin hudng cheo canh cd dinh se phu hgp vdi thuy dien nhd va cue nhd, vimg cdt nude thip va tmng binh Nd cd ket ciu don giin, sd canh it hon binh cdng tic tua bin tam true, dd che tao hon dd gia re hon, cd the thay thd cho loai tua bin hudng true canh cd dinh vi tam true, phii hpp cdng nghe che tao nude II HUONG NGHIEN CUU Qua nghien cim img dyng TBHC cinh xoay tren the gidi, rut cac nhan xet sau: TBHC cd ti tdc n, = 250 - 450 v/p (cot nudc thip v i tmng binh) lim viec hieu qua hon tua bin hudng true vi tam true: \aing lim viec tdi uu rdng hon, hieu suit 77^,^^ cao hon (88 92%) Cic ket qui nghien ciru cho thiy cac 'Vien Thuy dien \ a Nang luong Tai tao - Vien Khoa hoc Thiiy Igi Viet Niini - Xru-onc Dai lioc Bach khoa Ha Npi NC thdng sd eua he thdng din ddng (z, 1/t, dt Do, D,, Dj, 6) rit quan trpng inh hudng den dac tinh lim viec eua tua bin Vd ket ciu md hinh: TBHC canh xoay cd ket ciu true dimg, khe hd giiia vinh canh v i budng li khe hd ndn yeu ciu dp hd rit kbit khe, sd canh binh cdng tic (BCT) tir 12 cinh [5],[6] Tir cac ket q u i phan tich v i nhan xet tren, ta cd cac ket luan sau: Viec ap dung rap khudn cic nghien cuu cita TBHC canh xoay cho thity dien nhd va cyc nhd a Viet Nam khdng phu hpp vdi k h i nang che tao nude, gia thinh che tao rit cao Vi vay, xin de xuat hudng nghien cvru va pham vi nghien cuu li loai banh cdng tic (BCT): kieu cd dinh, cd vinh ngoii try, sd canh gidi han de giai quyet bii toin thyc tidn, phii hpp ve mat thuy lye ciia he thdng dan ddng - BCT cd vinh try ngoii: chuyen dugc khe hd mep cinh vdi budng tir hudng ndn sang hudng true, dd dd dang hon nhieu cho ehe tao va lip rap Tang tinh dn dinh cua BCT cd kich thude nhd, giim tdn thit diu miit canh - BCT cd sd la cinh gidi han, cd dinh phu hgp n h i may thuy dien nhd va cyc nhd khdng cd hd dieu tiet nam, cot nudc it thay ddi Kieu BCT lam tang k h i nang thoit, cd the md rdng vung lim viec v i dd che tao bing phuong phip due hen Pham vi i p dyng TBHC cinh ed dinh cdng suit nhd, eye nhd cdt nude thip v i tmng binh: cdng suit: 50 - 1000 KW, cdt nudc: 20 - 40 m, sd vdng quay dac trung: 250 - 450 vg/phut III PHUONG PHAP NGHIEN CUU Phuong phap nghien ciiu ke! hgp giiia nghien ciiu ly thuyet va thyc nghiem Nghien ciiu ly thuyet: i NGHIEP VA PHAT TRIEN NONG THON - KY - THANG /2011 27 KHOA HOC CONG NGHE Tinh toan thief ke cic miu cinh; tinh toin phan bd van tdc, phan bd ap suit, cac tdn thit BCT; tim sy lien quan giira cac thdng sd kdt ciu den dac tinh nang lugng, lya chgn miu canh tdt cho thuc nghiem Nghien cim thyc nghiem: Dung thyc nghiem de kiem chimg cac ket qui ly thuyet, thdng qua thyc nghiem da phat hien mdt sd khac giira cinh cd dinh va canh xoay, da xac dinh dugc miu canh tdt cho tua bin canh cd dinh De tinh toan thiet ke mat nghieng (profile) cinh BCT tua bin hudng cheo lya chgn phuong phap mdt tga dd- Phuong phap mdt tpa dp la phuong phap bidn hinh bio giac len mat ndn Dac diem cita phuong phap la coi cac thdng sd cua ddng chay chi thay ddi dpc theo dudng ddng vdi gii thiet, cd the xem ddng chay tren timg mat ddng khac va ddc lap vdi Cac thdng sd cua ddng chiy chi thay ddi dpc theo dudng ddng, cd nghia la nd chi phu thupc vao mpt toa - toa chay theo ddng chay [3],[2] Tinh toan thiet ke cac BCT tua bin mo hinh Tham khao mgt sd thdng sd chinh cita BCT canh xoay da cdng bd [5], tinh toan thiet ke mdt miu chuin, thay ddi mau ludi cinh de cd cac miu mdi, so sanh dac tinh lam viec cac miu, nhim chgn mlu canh tdi uu cho thii nghiem budc tinh toan ly thuydt de kiem tra dac tinh lim viec cita miu tmdc thir nghiem Thu nghiem tua bin mo hinh Dudng kinh BCJT tua bin md hinh theo tieu chuin la 250, 300, 460 mm Theo didu kien thyc td cita gia thi nghiem tai Vien Thuy dien va Nang lugng Tai tao, chpn dudng kinh BCTF thi nghiem la 300 mm Didu kien md hinh hoa dat tieu chuin Qudc te IEC 41 - 1991 - 11 ( he sd Raynol Re = 2,302.10'^ > 2.10'') Cho phep tidn hanh thu nghiem tua bin md hinh [11,[31 Thong so chon cua tua bin mo hinh Sd vdng quay quy dan: n, = 90 v/ph; luu lugng quy dan: Q, = 950 1/s ; sd vdng quay dac trung cita tua bin: n, = 303,75 vg/ph; ti sd biu: d^/D, = 0,5 dudng kinh danh nghia; BCT: Dj = 300 mm ; cot nude tua bin: H = m; luu lugng qua tua bin: Q = 160 1/s; cdng suit cua tua bin: N = 4,94 kw; chgn hieu suit tinh toan tua bin: T| = 90%; sd vdng quay ciia tua bin: n = 561 vg/ph Ban ve thiet ke chd tao canh BCT va phan din ddng cua tua bin mo hinh: / Mdu A: Chgn gdc dat canh cp = 0°; cac thong so khac tinh chgn theo tai lieu [5] Tinh toan ton that thiiy lye va ve dac tinh ly thuyet IW / ^'\'4ifc J S J '"' Mdu B: Gili nguyen gdc dat canh cp = 0° nhung tang ty sd 1/t 6% so vdi miu A Tinh toan tdn that thuy lye va ve dac tinh ly thuyet Mdu C: Giii nguyen gde dat canh cp = 0° nhung giam ty sd 1/t 6% so vdi miu A Tinh toan ton that thuy lye vi ve dac tinh ly thuyet lOien: C-C TOieti: B-B Wn: A-A Tinh todn cdc mau thir nghiem: Tu miu tinh toan tdi uu a tren, thay ddi gdc dat canh cp duge cic miu mdi de thir nghiem (03 miu) Mdu li Chgn gdc dat canh cp = 0", miu canh dugc chgn tir 03 miu A, B , C Mdu 2i Chgn gdc dat canh cp = 5° nhim nghidn ciiu tang kha nang thoat luu lugng qua BCT Tinh toan tdn thit thuy lye va ve dac tinh ly thuyet Mdu 3A Chgn gdc dat canh cp = 5°, giam dp mau ludi canh 1/t, tang dudng kinh D2 Nham cai thien cic inh hudng vanh ngoai cd dinh gay ra, chgn miu canh cd kdt ciu mdi tdi uu Thdng qua cac 28 lOifn: F-F lOien, C-[ TOifn: D-D Mat nghieng cdc ti^t diin cdnh tren mat non BHBG NONG NGHIEP VA PHAT TRIEN NONG THON - KY - THANG 1/2011 KHOA HOC CONG NGHE Dudng dac tinh tong hgp ly thuyet m^u B o;(i/s) Kit cau phin din ddng tua bin hudng cheo md hinh IV KET quA NGHIEN CUU Dudng dac tinh tong hgp ly thuyet miu C Ket qua tinh toan ly thuyet chpn mlu canh a) Dudng dac tinh tong hgp ly thuyet cac miu canh Dudng dac tinh tong hgp ly thuyet mau Dudng dac tinh tong hgply thuyet miu A (miu 1) o;(i/v) NC Duong dac tinh tong hgp ly thuyet mau b) Phan tich tinh toan chon miu canh toi uu: - Mlu B so vdi miu A, hieu suit ly thuyet ldn nhit q^jax = 83,5% thip hon miu A 2,5% Nhu vay dac tinh lim viec cita mlu B kem hon mlu A - Mlu C so vdi mlu A, diem lim viec tdi uu thip hon, n'i= 88 vg/ph vi Q'l = 885 1/s Nhu vay mau C cd dac tinh lam viec cd xu hudng thip hon mlu A Qua phan tich d tren mlu A cd dac tinh lam viec tdt hon miu tren, vay chpn mlu A cho tinh toan thu nghiem tua bin md hinh NGHIEP VA PHAT TRIEN NONG THON - KY - THANG 1/2011 29 KHOA HOC CdNG NGHl c) Phdn tich tinh todn chon cdc mdu cdnh thuc nghiem: Cac thdng sd chinh mlu A gdm: cac thdng sd quy din n, = 90 v/ph, Q,' = 950 1/s, gdc dat cinh: cp = 0°, hieu suit tai diem tdi uu: r\„^^ = 86,75% So sanh dac tinh lam viec ly thuyet 02 mlu canh thyc nghiem gdc dat canh cp = 0" ( miu 1) vi cp = 5" (miu 2): - Vimg lim viec cua mlu cd xu hucmg dich sang phii, luu lupng Q', tdi uu tang them 5% (997 1/s) Nhu vay kha nang thoat duge tang len, mat khac n'l cung tang Miu md rgng vung lam viec cita tua bin - Hieu suit 1cm nhat ri,„.^.< cua miu giim so vin miucp = 0"lal,5% - Dudng dac tinh tdng \\a\^ ly thuyet cua miu cho thiy vung lam viec tdi tm phii hcrp ly thuyet tinh toan, cd the dua vao thir nghiem Mau dugc tinh toan thiet kd tren co sd thi nghiem mlu va miu cho ket qui khdng dung tinh toan ly thuyet Cac thdng sd chinh cua mau nhu sau:Gdc dat canh cp = 5" ; giim mau lucii canh tmng binh 1/t tai cac tiet dien: tai tiet dien mdp ngoii 1/t giam tir 1,006 xudng 0,89, tai tiet dien sat biu 1/t tang tir 1,433 den 1,59; tang ducbng kinh mep D2 = 0,99 D, (D2 = 298mm) Dac tinh lam viec ly thuyet cua mau nhu sau: Tai diem lam viec tdi uu sd vdng quay quy din khdng ddi n'i= 90 vg/ph, Imi lugng quy dan tang len Q'j = 1000 1/s, hieu suit v^„,^^ = 86% khdng thay ddi Nhu vay man cd xu hucing lam viec tdt hon mau va (khi nang thoat tdt hon) Mlu cd k h i nang khic phuc ducjc tdn tai inh hucmg cua vanh ngoai try thir nghiem Kdt qua nghien oiu thyc nghiem a) Cdc du&ng ddc tinh thuc nghiem cdc mdu cdnh tua bin mdhinh: Dudng ddc tinh thuc nghiem mdu cdnh 2((p = 5°) Ducmg ddc tinh thuc nghiem mdu cdnh Sdp = 5P) b) Ket qud thay doi dp mau luoi cdnh l/t cua mdu so v&i mdu 2: 1: Ti sd l/t cua mdu 1-2; 2: Ti sd l/t cua mdu Bang So sanh k^t qua cua mlu vdi cac mlu Mlu canh Mlu cinh Mlu canh Mlu canh -t — rV ' -P& ,4 \4r •i-\-H