Cdng trinh Khoa hgc NGHIEN c u t ! ANH Hl/ONG CUA CHIEU DAI VA DUONG KINH N G HUT DEN HIEU SUAT LAM VIEC CUA BOM THUY LUC NGUYEN DINH TiJ Bp mon Mdy xiiy dung - Xep dd Khoa Ca Trudng Dgi hgc Giao thdng Van Idi Tdm tdt: Dudng dng hut Id mot bd phdn ciia he thdng truyen ddng thuy luc, cd anh huong lan den hiiu sudt ldm viic cua bom thiiy tuc ndi riing vd chdt luong ldm viec cua he thdng thuy luc ndi chung Ndi dung bdi bdo trinh bdy ldm tdt mgt sd kit qua nghiin ciru ciia di ldi NCKH cdp truong md sd T20I3-CK-29 ve dnh hudng ciia chieu ddi vd dudng kinh dng hut din hieu sudt ldm viic cua bam thuy luc Summary: The pipes are part of the hydraulic drive system, its have great influence on the performance of hydraulic pumps privately and the all hydraulic systems generally This paper presents a summary of results of my researches topic number T2013-CK-29 on the impact of the length and diameter ofpipes to the performance of the hydraulic pumps I DAT VAN DE Dudng dng hiit la bd phdn trung gian ket ndi giCra bam thiiy lire va thiing ddu, ddy Id mgt nhDng bg phdn khdng the thilu he thdng truyin dgng thiiy luc, cd anh hudng rdt ldn dfin hi?u sudt hut va hi6u suat the tich bam thuy luc Mdt khdc, chi lam viec ciia bam thiiy luc lien quan true tiep din hieu suat hut, hieu sudt the tich, din dao dgng, mai mdn bl mat cdc thiit bj thiiy lyc,., Do vdy, can phai nghien cuu anh hudng cua cac ylu td kit cdu din kha nang hilt ciia bam thuy luc, lam ca sd cho viec lua chgn chieu dai vd dudng kinh ctia dudng dng phii hgp vdi timg logi bam va he thdng thiiy luc khac nhau, Nd giiip cho ngudi thiit kl lya chgn phuang an bd tri dudng dng hut, bd tri bom thiiy lyc tuang quan vj tri vdi thiing ddu de bam thiiyyuc lam viec vdi hieu qua cao nhdt Id vdn de can thiet nghien cuu II GIAI QUYET VAN DE Trong he thdng truyen dgng thiiy luc, vj tri mieng hiit thiing ddu cd thi duac bd tri cao han hodc thdp han bam thiiy luc, Vdi viec bd tri thiing ddu d vj tri cao han so vdi bam thiiy luc cho phep tgo dp luc d mieng hiit, qua dd nang cao duoc hieu sudt hiit trdnh dugc hien tugng hinh Idc xody ciia ddng ddu nhung cd nhugc diSm Id lam tang dp tuc ddng ddu hdi, ldm gidm luc keo tren dgng ca thiiy luc va dan den tieu hao nhien lieu dgng ca din ddng va lam gidm hi?u sudt lam viec cua bom thuy luc, Ngoai ra, viec thay ddi hinh dgng mieng hiit, sd lugng chd ndi, viec bd tri van, loai ddu cdng tdc,.,, cung lam thay ddi ddng ke khd nang hiit cira bom thiiy lyc 78 Tap chi KHOA HQC GIAO THONG VAN TAI So 50 - 02/2016 Cdng trinh Khoa hgc Bk lam tang kha ndng hiit ciia bom thuy luc ngudi ta cd thi sir dung nhieu phuang an bd tri dudng dng hiit khdc nhau, cd the siir dung may nen mdng dan hdi hodc tan dung ddng ndng ddng dau hdi, Mgt sd sa dd bd tri dudng dng hut dugc md ta nhu hinh va hinh :^^^^¥=0 Hinh I Sa kit cdu cd sudung mdy nin I Thiing ddu: Mdt thodng: Dudng ddu hdi: Ong hut; Dudng dng ndi vdi mdy nen Thiit bi chia Hinh So dd kit can su dung ddng ndng cua ddng ddu hdi I Thiing ddu Bom thuy lire (%g hdi Ong phun: Van an todn: Loc ddu: Ong ddn Cac gia thiit xdy dung md hinh bai toan nghien ciru dnh hudng ciia chilu dai va dudng kinh dng hiit din hi?u sudt ldm viec ciia bam thiiy luc: Tdc dg quay tren tryc bam la khdng ddi; dng hilt Id cirng tuy?t ddi; dudng kinh dng hiit khdng ddi tren sudt chieu ddi dudng dng; bd qua tdn that ve the tich ciia ddu cdng tac dudng dng hiit; cao mieng hiit so vdi bam la khdng ddi; vgn tdc ddu cdng tac thiing Id nhd cd th6 coi bang khdng; mo duyn bien dang dan hdi cua ddu cdng tdc la khdng ddi So dd bd tri bom thiiy lyc nghien cim anh hudng ciia chilu ddi vd dudng kinh dng hut dugc md td nhu tren hinh va hinh —7 K> 111 i l l 11 ° K I \ > Hinh Sa dd bam thuy luc f^lnh So ham thuy luc dgt phia dudi thiing ddu 0, p/,/^ ^^ew ihung ddu 0-0: Mdt cat trin be mat thodng cua ddu cdng tdc irong ihiing I-1 Mat cdt o ddu vdo cua bom thiiy luc: p„ - Ap sudt quyin: PI - Ap sudt ddu a miing hut cua bom: h, - Dp cao mieng hut so vdi bom Tiip chi KHOA H Q C GIAO THONG V^N TAI S6 50 - 02/2016 79 Cdng trinh Khoa hgc Tir cac gia thiit tren, dp dyng djnh ludt bdo todn nang lugng vilt cho ddng chd\ tai mat cat (1 -1) sa dd Hinh dudi dang phucmg trinh Becnuli ta cd: h^+PiL = l L + i ^ + L i L + b y , H + k.ii^L pg P-8 2g- t ^d, ^'••J2g g dT (, Trong cdng thiic tren nhung dai lugng xdc djnh dugc gid trj la po g p, v^ K «( b, cdn cac dgi lugng h^, Ic, dc, T^^, xdc dinh theo cdc thdng sd kit cdu ciia dudng dng hut Ty trgng ciia ddu cdng tdc dugc tinh bdng ty sd giiJa khdi lugng vd the tich dau cdng tac xac djnh theo cdng thirc sau: Khi tang nhiet dp thi ty trpng cua dku cung tang len va dupe xac dinh theo cong thuc sau: P20 ' (3) l + |3,(t-20) T6C dp cua dku cong tac duong 6ng htit Vc duoc tinh theo cong thirc: V c = ^ (4, Luu lugng ciia bam thiiy luc dygc xac dinh theo cdng thirc: Qh=qb-nh-ri (5) Tl - Hifiu sudt the tich ciia bam, phu thugc vdo kit cdu ciia bam su hao mdn hay khe hd va quan trgng nhdt Id nhdt ciia ddu cdng tdc Hieu sudt the tich ciia bam thudng dugc xdc djnh bdng thyc nghiem Trj sd Reynolds ddi vdi ddng chdy dudng dng hut cd the dugc xdc djnh theo cdng thuc: Re = ^ i i u (6) (3 ch6 dp chay r6i Re > 2320 K = 0.3I64.Re""-"; ct chj dp chay ting Re < 2320 lihi A^ = — ' Re He so dp nhat dpng hpc dupe xac djnh theo cong thuc: —(?)• 80 Tap chi KHOA HOC GIAO THONG VAN TAI (7) So 50 - 02/2016 Cdng trinh Khoa hgc Trong dd: p(, - Ap sudt quyen (Pa): pi - Ap suat ddu a mieng hiit ciia bam (Pa): p - T\ trgng ciia ddu cdng tdc (kg/m'): p, - Ty ciia ddu cdng tac d nhiet dd t (kg/m"'); p:,, - T> trgng ciia ddu cdng tdc d 20"C; p, - He sd gian no nhiet ctia ddu cdng tdc ("C"'); t - nhiet ctia ddu cdng tdc ("C); g - Gia tdc trgng trudng (m/s"); h^- Chieu cao mi^ng hiit (m); It - Chieu ddi dudng dng hiit (m): d^ - Dudng kinh dirdng dng hut (m); v^ - Tdc ddng ddu cdng tac d cudi dudng dng hiit (m/s); /_^^, - Tdng he sd can cue bd tren dudng dng; ?^ - He sd ma sdt dgc dudng; a^ - He sd Koriolis tinh din anh hudng khdng diu ciia tdc ddng chdy dng trdn, Qe = ddi vdi chi chay rdi, a^ = ddi vdi che chay tang; x - Thai gian tinh toan (s); qb - Luu lugng rieng ciia bam thiiy luc (cmVvdng); nb - Tdc quay cua bam thiiy luc (vdng/phiit); b - He sd tdn that ke den dnh hudng nhdt ciia dau cdng tac d nhiJng cho ndi Tir (4) cd the xdc djnh dugc dudng kinh dng hiit theo cdng thirc sau: d,, = ^ (8) Trong tinh todn tdc cua ddu dudng dng dugc xac djnh theo day gid trj sau: Vc = 0,6; 0,7; 0,8; 0,9; 1,0; 1,1 1,2 m/s, Thay (4) vdo (1), qua bien ddi ta nhdn dugc cdng thirc xdc djnh dp suat d mieng hiit ciia bam thiiy lyc nhu sau: (9) Hieu suat hiit ciia bam thiiy luc duoc xac dinh theo cdng thirc sau %=-^ 0) p Hieu suat the tich ciia bom thu> luc duoc xac djnh theo cong thirc sau: n.,=#^ (M) Trong dd: p