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NGHIEN CLTU ANH H U d N G S\S THAY DOI AP SUAT GIO EP ONG HAM DEN TAG DUNG CUA VAN HAM Str DUNG TREN TOA XE PGS TS VU DUY LQC KS TAO VAN CHIEN Bp mon Ddu may - Toa xe Khoa Cff khf Truoitg Dqi hgc Giao thong Van tdi Tom tdt: Bdi bdo gidi thieu cdc nhdn to ldm thay ddi dp sudt ong ham doan tau, phuang phdp xac dinh luang giam dp ong ham cdc nhdn to gdy tgi mat cdt khac tren dudng dng ham doan tau Summary: This article presents the factors causing air pressure variability and method ofdetarmining the amount ofpreassure reduction at certain cross section along pipe line \ DAT VAN DE Do nhay tac dung ham, nha ham ciia cac loai van ham phy thuoc sy thay doi tri so ap suat ong ham va toe tang, giam ap ong ham doan tau Trong qua trinh van hanh, hien tugng xi gio ep cac moi noi lien ket duong ong ham chinh, ong nhanh, xi hd lien ket giira hai ham noi gay nen thay doi ap suat gid ep ong ham doan tau lam anh huong den tac dyng ham, nha ham cac toa xe doan tau Do do, nghien cu'u toe thay doi ap suat ong ham theo chieu dai doan tau, mirc do ong ham doan tau nham xac djnh anh huong chat lugng ham doan tau van hanh la mgt viec lam can thief IL NOI DUNG Ket qua khao sat trang thai ky thuat dudng ong ham chinh dua toa xe vao xi nghiep su'a chua va tren cac tram kiem tra ky thuat xac djnh mirc hu hong lien ket cac bg phan nhu sau: - Chi tiet CO djnh ong ham chinh vdi xa dau long ro chiein 41 % - Chi tiet CO djnh ong ham voi be xe long chiem 28,5% - Ong mem lien ket long chiem 12,8% - Cac moi noi lien ket ong ham bang ren, xi trung binh chiem 35,5%, 6ng ham nhanh 21 % doi vo'i toa xe hang f: - Kilm tra thir ham tren ga lap tau phat hien tai vj tri lien kit ham n6i xi (50 H- 60)% doi vdi toa xe hang Xi moi noi lien ket duong ong ham toa xe khach tii' (12,5 H- 35)% Tap chi KHOA.HQC GIAO THONG VAN TAI So 28 - 12/2009 59 Xi ho' gio ep ong ham doan tau lam thay doi ap suat ong ham Xi gio ep a cac moi noi lien ket duong ong ham chinh lam thay ddi chuyen dgng gio ep duong ong ham Chuyen dgng gio ep ong ham doan xe phan hai hinh thirc: - Chuyen dgng on djnh - Chuyen dgng khong on djnh Chuyen dgng on djnh xay ap suat gio ep phan bo duong ong tuong doi on djnh Chuyen dgng gio ep duong ong ham co tinh chat qua lai ciia nhung qua trinh khong on djnh Tren ca sd nhung qua trinh chuyen dgng khong on djnh xac dinh mgt loat nhirng tham so ky thuat van ham: - Thai gian nap gio ep vao xilanh ham - Thai gian nap gid ep cho toan bg he thong ham - Xi gio ep ong ham doan tau Khi thay doi trj so ap suat gio ep nap vao ong ham, tri so xi gio ep ong ham thay doi, tang ap suat nap trj so xi tang va ngugc lai Phuang phap xac djnh xi hd gio ep ong ham thong qua trj so duang thong tiet luu tuang duong tren mgt met chieu dai ong hSm Duang sat Chau Au cho phep ap dyng mii'c xi hd ong ham tii' HI,4 lit/phut dieu kien ap lye nap tieu chuan a nhiet 10°C cho Im chieu dai duong ong ham voi dien tich xac djnh theo cong thO'c: g.R.T V 0,648.?^.I yf = m.^ (1-1) Trong do: m: Khoi lugng gio ep di qua duong thong tilt luu phii hgp voi m chieu dai 6ng ham PM: ap suat tuy$t doi nap gio ep vao ong ham dat gia trj tieu chuan: PM=6 10" KG/m^ 1: Chieu dai duong ong, = Im g: Gia toe trgng truong R: Hang so chat khi, R = 29,27 T: Nhiet dg tuyet doi, T = 273 + to to: Nhiet moi truong, to = 20°C Vai ap suat gio ep nap vao ong ham doan xe tieu chuan a nhiet to trung binh, dien tich dudng thong tilt luu pf nhu bang 1.1 Dien tich duong thon^ Mu'c xi ong ham Ghi ehii tuong duang (KG/mVphiit) 0,738.10" 0,1.10' ,09.10-' 0,15.10' Tuang ung duong kinh lo 1,475.10"' 0,20.10' d= l,32.10-'(m) 60 Tap chi KHOA HQC GIAO THONG V^N TAI S6 28 - 12/2009 ^ • r Xac dinh xi trung binh ong ham toa xe van hanh d Viet Nam - He so xi ong ham toa xe hang: kvi, He so xi hd moi noi bang ren ko, ko xac dinh bang tong he so xi dng ham chinh va ong ham nhanh ko= 35,5%+ % = 56,5% ko=0,56 Trong van dung ko xac dinh bang he so xi hd moi noi giii'a hai ham noi ong mem: ko=(50-60)% Vay ta lya chgn he so xi hd ko van dung la ko = 0,56 - He so xi hd ong ham toa xe khach, k^, = 0,35 Mii'c xi hd' van dung xac djnh theo cong thirc: V +V (1-2) Trong do: rio: He so xi hd ong ham cho phep xac dinh theo tieu chuan dudng sat lien van quoc te rio= 0,2.10'(KG/mVphiit) f(p): La ham so phu thuoc ap lye nap va toe ddng chay qua vj tri xi hd: ap suat nap 6ng ham chinh 5.10" (KG/m") thi f(p) = 0,9 Vol,: The tich ong ham (m ) VR: The tich thiing gio phu (m ) The tich dudng ong ham toa xe va thiiug gio phu c6 gia trj d bang 1.2 Bdng 1.2 Loai toa xe Khach Hang Chieu dai duang ong ham (m) 22,5 14.,6 The tic (m^) Ong ham Thiing gio phy 0,021 0,078 0,013 0,042 Thay cac gia trj vao cong thirc (1-2) xac djnh xi ong ham toa xe khach rivk, xe hang Tfvh- Tlvk= 0,297.10" (KG/m-/phut) Tivk= 0,426.10" (KG/m'/phut) So sanh mirc giam ap toa xe van dyng vdi mirc giam ap Ion nhat ong ham de van ham khong tac dung Xem bang 1.3 Tap chi KHOA %^C GIAO THONG V^iN TAI So 28 - 12/2009 61 Loai toa xe Khach Hang Muc xi gio ep Van dyng: rjvi 0,297 0,426 Cho phep: r|o 0,2 Bdng 1.3 Mirc giam ap 6ng ham lan nhat de van ham khong tac dyng KE,VE P,K 0,33 - 0,4 0,2 -^ 0,25 Mu'c dg xi ho gio ep toa xe hang van dung ldn hon miic giam ap lan nhat de van ham khong tac dyng, din den van ham co thi ty dgng phat sinh tac dyng ham ngoai y mudn ngudfi dieu khien Truang hgp ty dgng ham thuang xay doan tau van hanh qua doc dai, diing a ga tac nghifp ky thuat Muc giani ap ong ham doan tau ong mem lien ket bi no, dii1 Truang hgp doan tau van hanh bj no, diit 6ng mem lien ket duang ong ham giua hai toa xe, lugng gio ep ong ham xa ngoai trai giay xac djnh theo cong thiic: G = ^'^^'^;^°"'"^V[PM-K06(PM-PJ]-(PM-P3) • (1-3) \/R Trong do: Sol,: Dien tich mat cat ong mem (m^) Soi,= 8,038.10-" (m^) P(f): He so dien tich ong ham a vj tri no, diit gio ep di qua xa ngoai trai Gia tri trung binh p.(f)= 0,45 PM: Ap suat tuyet doi gio ep nap vao ong ham a che dinh ap, PM = 6.10" (KG/m^) Pa: Ap suat khong a moi truong Pa = 1.10" (KG/m") Thay cac gia tri vao cong thuc (1-3) xac djnh: G = 0,3228 (Kg) Khoi lugng gio ep tii' thiing gio chinh qua tay ham chung nap bo sung vao ong ham, ky hieu l^Gi G, = ^ ' ' ^ ^ ^ " ' ^ [ P - ^ ( P - P M ) ] - ( P - P M ) (1-4) Trong do: St! La di?n tich duang thong nap gio ep tii' thiing gio chinh qua tay ham chung vao ong ham do^n tau Prpi Ap suat tuy$t doi nap vao thiing gio chinh Tinh trung binh Prp = 8,5.104 (KG/m^) Thay cac gia tri vao cong thii'c (1-4) xac djnh Gi: G, = 0,088 (Kg/giay) Mtrc dg giam ap ong ham doan tau sau mgt giay va hoac du1 ong mim ky hieu Ar,„axG-G, -.RT (1-5) V„ Tap chi KHOA HQC GIAO THONG VAN TAI So 28 - 12/2Q§9 Vo: The tich duong ong ham chinh doan tau (m^) - Doan ^ u hang dai 25 toa, true: Voh= 0,325 - Doan tau khach chieu dai trung binh 13 toa xe, tryc: Vok= 0,325 Thay gia trj vao cong thu'c (1-5) xac djnh An„ax (doan tau hang Annaxi, , doan tau khach ^rmaxkj- A™axh = 0,6195.10" (KG/mVgiay) Annaxk = 0,7375.10"(KG/inVgiay) Ap suat gid ep ong ham doan tau tai mat cat nghien cuu Px (ap suat tuyet doi) xac djnh theo cong thuc: 2.RT I2,rid^' (21g.^ + l,74y A (1-6) + A.^.G=+-*^'^'^'^'-^'-'^' Lo.Z.d„ L„ Trong do: A, B: La he so phy thuoc vao duang kinh ong ham (do) Khi do= 0,032m; A = 8,2; B = 0,11 LB: Chieu dai dudng ong ham Toa xe hang: LB = 14,6m Toa xe khach: LB = 22,5in A": Do nham be mat ong ham A" = 2.10" Z: H e s ; Z = 28,l X: Khoang each tir sau tay ham dau may den mat cat nghien cii'u X = LB.U, (n,: La mat cat nghien cii'u tai toa xe thir i) Thay cac gia trj vao cong thirc (1-6), xac djnh ap suat gio ep tai mat cat nghien cii'u no hoac dut ong mem quan he vdi he so dien tich p(f) Xem bang 1.4 He so G (Kg/giay) l-kn (1) 0,2 0,25 0,30 0,4 0,45 0,5 0,6 0,7 ' (2) 0,14349 0,17936 0,21539 0,278 0,3228 0,359 0,43 0,503 Mirc giam ap ong ham Ari (at/giay) Xe hang: A,; Xe khach: Ar2 (3) (4) 0,146 0,206 0,24 0,338 0,336 0,47 0,526 0,65 0,62 0,74 1,07 0,716 1,06 1,27 1,29 1,54 Bdng 1.4 Ap suat tuyet doi tai mat cat nghien ciru ciia toa xe ni Pcx (at) ni= 13 ni = 25 ni = 30 (5) (6) (V) Tap chi imOA^HQC GIAQ THONG VAN TAI 5,8 5,46 4,79 3,6 2,54 5,6 4,9 3,03 So 28- 12/2009 4,13 63 Khi no, dut ong mem van ham ty dgng phat sinh tac dung ham Truang hgp dap ong mem h? so P(f, > 0,2, toe dg giam ap ong ham Ar tai mat cSt nghien cuu: D6i vai doan tku hang AH = 0,146 (at/giay), doan tku khach Ar2 = 0,206 (at/giay), lan han trj so toe giam ap 6ng ham toi thieu de van ham phat huy tac dyng ham (A,= 0,05-^0,4 at/giay) Vi vay tkt ca toa xe ty dgng phat sinh tac dyng ham gay bo ham, let banh xe Xac dinh mirc thay d6i ap suat ong ham d nhirng mat cat khac tren dytrng ong ham chinh doan tau Mirc thay doi ap suat ong ham tai mat cSt nghien ciiu tinh tii' sau tay ham dku may co chieu dai la U, ky hieu la rix (at/giay) AP 1.22, (1-7) ilx=—-".b^e Trong do: AP: La lugng giam ap sukt ong ham dilu khiln ham doan tau, MPa cotb: Toe chuyin dgng trung binh ciia gio ep qua duong ong ham chinh phii hgp voi mu'c dg giam ap ong ham AP L: Chieu dai duong ong ham doan tau nghien cii'u (m) Ix: Chilu dai duong 6ng ham tinh tir sau tay ham chung cua dau may din mat cat toa xe nghien cii'u Xac djnh ehieu ddi doan tau nghien edu: Theo kit qua khao sat doan tau hang, tau khach van hanh tren duong sat Viet Nam - Doan tau hang co so lugng toa xe trung binh tir 20 din 25 toa, doan tau dai nhit la 33 toa - Doan tau khach co so toa xe trung binh tii' 14 din 15 toa xe, doan tku dai nhat la 18 toa xe Chieu dai doan tau xem bang 1.5 Bdng 1.5 Chieu dai doan tau = So lugng toa xe x Ijx +1 Om (til' sau tay ham den moc ndi) 33 X 14,6+10 = 491,8 (m) 18x22,5+10 = 415,0(m) Doan tau Xe hang Xe khach CO,, U AP (1-8) 2fV Trong d6; g: Gia toe trgng truong - : P: Ap sudt gio ep nap vao 6ng ham doan tau a che djnh muc (MPa) Tinh theo ap suit 64 Tapchi KHOA HOC GIAO THONG VAN TAI S628-12/2G09 donghd: P = 5.10"(KG/m^) '" ' y: Ty trgng khong d nhiet 20°C, y = 1,15 Toe coib quan he voi miic giam ap ong ham Bdng 1.6 AP (Mpa) 0,5 1,0 1,4 2,5 co,b (m/giay) 65,26 87,30 109,26 145,91 Muc thay doi ap suat dudng ong ham chinh tai mat cat nghien cuu phii hgp vdi mirc giam ap ong ham doan tau dieu khien ham (bang 1.7) xac djnh theo cong thirc (1-7) Bdng 1.7 Vi tri mat cat nghien ciiu Chieu dai duang ong ham doan tau (m) 100 200 300 491,8 400 Khi mirc giam ap AP = 0,5 (MPa); co,b= 62,25(m/giay) ri, (at/giay) 0,094 0,064 0,035 0,028 0,0308 Khi mirc giam ap AP = (MPa); (0,5= 87,3(m/giay) rix (at/giay) 0,509 0,16 0,119 0,98 0,088 Khi mu'c giam ap AP = 1,4 (MPa); co,b= 109,26(m/giay) rix (at/giay) -r|(at/giay) 0,0 100 200 300 400 491,8 Hinh I Dudng cong thay ddi tdc giam dp sudt dng hdm theo chieu ddi doan tau Til' kit qua nghien ciru toe thay doi ap suat ong ham theo chilu dai doan tku (hinh 1), tinh nang tac dyng cac loai van ham, miic do hd ong ham doan tau, xac dinh anh hudrng chat lugng ham doan tau van hanh (Xem tiep trang 58) rap chi KHOA HQC GIAO THONG VAN TAI So 28 - 12/2009 65 dugc I^p dya tren phucmg phap phan ttr hihi han co the ap dung tinh toan, nghien ciru trang thai ung suat he thong mong va mat dudng Co the noi rSng phin m§m tinh uu viet, dieu ki^n sa hiru va khai thac nen dugc coi la phan mem quy tgc Chfnh vi vay de co the ap dyng phan m§m nay, doi hoi phai co sy dau tu Ion ve tri tu$ va tai chinh T^i lieu tham khao [1] NguyinXudn Luu - Phuong phdp phan tir httu han - Trudng Dai hoc GTVT, Ha ndi, 2000 [2] Highway Engineering - Wright and Radnor J.paqueUe Nha xudt ban: John Wiley and sons 1987 [3] Principles of Pavement Design E.J.Yoder M.W.Wdczak 'Nha xuSt ban: John Wiley and sons 1975 Planning and design of airports 1993 - chinh sira bd sung 2003 Robert Horonjeff and Francis X McKelvey [4], Cdc tai iifu tii- AASHTO [5] Thiet ke va cong nghe xay dyng mat dudng otd - PGS TS Phqm Huy Khang Nha xudt ban GTVT 2008 [6] Getting Stated with ABAQUS* NGHIEN CLTU ANH HU ONG SU THAY DOI (Tiep theo trang 65) III KET LUAN Tren day la ca sdr ly thuyet tinh toan miic thay doi ap suat ong ham a nhu'ng mat cSt kh^c tren duijng ong ham Khi toe dg giam ap ong ham Ar tai mat cat nghien ciin Icm han trj so toe dg giam ap ong ham toi thieu de van ham phat huy tac dung ham thi tSt ca toa xe ty dgng phat sinh tac dyng ham gay bo ham, let banh xe Do do, ket qua nghien cuu co thi ap dyng de tinh todn xkc djnh chit lugng ham doan tSu van hanh, dong thai co bien phap de gidm thieu mu'c dg ong ham Tai lieu tham khao []] TS Vu Duy Lgc, bai giang cao hgc: K^t clu tfnh todn hSm doan tSu - Ha noi 2002 [2], Tai li?u khao sat tr^ng thai kj^ thuSt ham doan tau van hanh (6/2009 - 9/2009) phuc vu dl tai nghien ciru khoa hpc Ma s6 094030 [3] B.Jl.KAPBAUKHHobiiiaa meopufl abmomopMozobMocKaba-1947 [4] B.M KAZAPHHOB B.P HHOZEMUEB Teopemuneckue OCHOBOI npoeKmupobawH 3Kcnjiyamauuy abmomopMozob TpaHcnopm - 1968* 58 Tap chi KHOA HOC GIAO THONG V^^^N TAI S6 28 - 12/20, ... trung binh tir 20 din 25 toa, doan tau dai nhit la 33 toa - Doan tau khach co so toa xe trung binh tii'' 14 din 15 toa xe, doan tku dai nhat la 18 toa xe Chieu dai doan tau xem bang 1.5 Bdng 1.5... ham toa xe khach rivk, xe hang Tfvh- Tlvk= 0,297.10" (KG/m-/phut) Tivk= 0,426.10" (KG/m''/phut) So sanh mirc giam ap toa xe van dyng vdi mirc giam ap Ion nhat ong ham de van ham khong tac dung Xem... GIAO THONG V^N TAI S6 28 - 12/2009 ^ • r Xac dinh xi trung binh ong ham toa xe van hanh d Viet Nam - He so xi ong ham toa xe hang: kvi, He so xi hd moi noi bang ren ko, ko xac dinh bang tong he
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