MC CH TH NGHIM Xc nh ct p ton phn ca bm, cng sut, hiu sut cho bm ly tm bng vic o c cc thng s khi thay i lu lng ca bm. Kho st v xy dng cc ng c tuyn ca bm. S dng nh lut t l tin on cc thng s c trng ca bm. Kho st s nh hng ca vic thay i ct p ng ht i vi bm, ng thi kho st hin tng xm thc bng cch thay i p sut thay i p sut trong ng ht vi vic thay i van ht thay i lu lng. Xy dng ng c tuyn ca mng ng xc nh im lm vic ca bm.Kt qu th nghimTh nghim 1: Ch tc bm 70%STTLu lng Q (l/s)Tc bm n (rpm)p sut ht Ph ( kPa)p sut yPd (kPa)Nhit T (oC)Moment xon ng c t (N.n)

10.001050.002.3037.5035.400.45

20.191050.002.1035.7035.300.49

30.291050.001.9033.0035.10.50

40.461050.001.1030.4035.100.52

50.581050.000.4027.7035.400.53

60.651050.00-0.4025.0034.900.53

70.721050.00-1.1021.9034.900.55

80.821050.00-1.8018.2035.300.57

90.901050.00-2.6014.9035.100.57

100.941050.00-3.1012.6035.100.58

Ngy th nghim:Xc nhn:

Th nghim 2:STTLu lng Q (l/s)Tc bm n (rpm)p sut ht Ph (kPa)p sut y Pd(kPa)Nhit T (oC)Moment xon ng c t (N.m)

Kt qu kho st ch 50%

10.00750.002.5021.4035.200.45

20.09750.002.2019.4035.100.46

30.28750.001.9017.7035.500.46

40.37750.001.5016.0035.000.47

50.41750.001.3015.5035.600.48

60.46750.000.9014.0035.300.49

70.53750.000.4012.4035.000.49

80.58750.000.2011.0035.400.50

90.61750.00-0.309.1036.000.51

100.66750.00-0.508.2035.600.51

Kt qu kho st ch 60%

10.00900.002.4026.1035.400.46

20.21900.001.7024.4035.100.47

30.35900.001.6023.6035.000.48

40.43900.001.1021.5035.500.49

50.48900.000.7019.8035.600.49

60.56900.000.4019.0035.800.50

70.61900.000.2017.0035.500.50

80.64900.00-0.5015.3035.400.52

90.78900.00-1.6010.7035.300.52

100.81900.00-1.809.4035.500.53

STTLu lng Q (l/s)Tc bm n (rpm)p sut ht Ph (kPa)p sut y Pd(kPa)Nhit T (oC)Moment xon ng c t (N.m)

Kt qu kho st ch 80%

10.001200.002.5045.9035.100.48

20.171200.001.9043.1035.400.51

30.301200.001.7042.0035.500.52

40.351200.001.4040.7035.400.54

50.501200.000.6037.0035.300.56

60.561200.000.3035.7035.300.57

70.761200.00-1.5028.4035.100.59

80.851200.00-2.2024.6035.400.61

91.011200.00-4.1016.1035.100.62

101.101200.00-5.0013.6035.300.64

Kt qu kho st ch 90%

10.001350.002.1055.9034.700.54

20.201350.002.0052.3034.100.58

30.481350.000.5049.2034.500.60

40.541350.000.5047.6034.700.61

50.681350.00-0.3043.1034.600.63

60.741350.00-1.4039.1034.600.66

70.881350.00-2.8035.0034.300.68

80.981350.00-3.8029.0034.800.69

91.091350.00-4.7024.0034.600.71

101.201350.00-6.3016.6034.200.76

STTLu lng Q (l/s)Tc bm n (rpm)p sut ht Ph (kPa)p sut y Pd(kPa)Nhit T (oC)Moment xon ng c t (N.m)

Kt qu kho st ch 100%

10.001500.002.1066.4035.700.47

20.211500.001.5061.7034.900.55

30.481500.000.6056.1034.900.56

40.601500.000.2053.5034.800.64

50.661500.00-0.7052.5035.100.66

60.811500.00-2.1046.7035.100.66

70.881500.00-3.0043.1035.100.69

80.941500.00-3.6039.2034.900.70

90.981500.00-3.9038.1035.000.70

101.301500.00-8.8016.4035.000.77

Ngy th ngim:Xc nhn:

Th nghim 4STTLu lng Q (l/s)Tc bm n (rpm)p sut ht Ph (kPa)p sut y Pd(kPa)Nhit T (oC)Moment xon ng c t (N.m)

Kt qu kho st ch 20%

10.24300.001.601.4035.100.52

20.23300.001.301.5034.600.52

30.21300.001.201.2035.100.52

40.19300.000.701.1034.800.52

50.16300.000.401.0035.000.52

60.13300.000.300.9035.100.52

70.11300.000.201.0034.900.52

80.09300.00-0.100.7034.800.52

90.07300.00-0.200.8035.000.52

100.00300.00-0.600.5034.600.52

Kt qu kho st ch 60%

10.81900.00-2.207.3035.100.53

20.76900.00-5.606.2034.600.51

30.68900.00-9.404.8035.100.51

40.57900.00-13.004.7034.800.49

50.52900.00-16.504.2035.000.49

60.49900.00-17.702.4035.100.48

70.30900.00-21.101.3034.900.48

80.21900.00-21.301.0034.800.46

90.04900.00-22.001.2035.000.43

100.00900.00-24.201.0034.600.45

STTLu lng Q (l/s)Tc bm n (rpm)p sut ht Ph (kPa)p sut y Pd(kPa)Nhit T (oC)Moment xon ng c t (N.m)

Kt qu kho st ch 100%

11.281500.00-9.1015.2035.900.75

21.251500.00-16.2016.1035.800.74

31.091500.00-26.1010.6036.000.70

41.021500.00-36.008.2036.000.68

50.811500.00-45.306.7035.900.66

60.681500.00-50.604.3036.000.62

70.571500.00-54.902.5035.900.58

80.401500.00-58.001.8036.000.58

90.381500.00-59.300.6035.900.56

100.001500.00-61.300.0035.800.51

Ngy th nghim: Xc nhn:

Th nghim 5STTLu lng Q (l/s)Tc bm n (rpm)p sut ht Ph (kPa)p sut y Pd(kPa)Nhit T (oC)Moment xon ng c t (N.m)

Kt qu kho st theo m van ch tc bm khng i

10.931050.00-3.509.7036.400.57

20.891050.00-3.3011.2036.100.58

30.781050.00-2.1016.2036.900.58

40.631050.00-0.5023.1036.200.54

50.521050.000.0026.2036.100.52

60.331050.001.4030.5036.500.50

70.201050.002.0031.8036.100.48

80.111050.002.0033.8036.300.48

90.071050.002.1034.0036.100.47

100.001050.002.2034.7036.300.47

Kt qu kho st theo ch tc bm m van hon ton

11.091350.00-6.9013.9036.000.71

21.051200.00-5.5011.6036.900.64

30.931050.00-3.808.9036.300.59

40.77900.00-2.107.4037.000.55

50.64750.00-1.005.3037.800.52

60.50600.000.103.9036.100.50

70.37450.001.002.8036.400.51

80.23300.001.601.9036.000.53

90.00150.002.001.3036.300.45

100.000.002.101.2035.100.01

Ngy th nghim:Xc nhn:

X L S LIU:Cc cng thc tnh ton: Tnh ct p ton phn (H):Ct p ton phn ca bm c tnh nh sau:

Trong :

Ph : p sut ht, PaPd : p sut y, Pa

v1: vn tc ng ng ht ca dng lu cht, m/s

d1 l ng knh ng ht, d1= 0.0235mv2: vn tc ng ng y ca dng lu cht, m/s

d2 l ng knh ng y, d2= 0.0235m

Vi m hnh FM50 He = 0.075m Tnh cng sut thc ca bm Pm:

(W) < lu : Q tnh theo l/s >Vi: g: gia tc trng trng, m/s2khi lng ring ca nc, kg/m3Q: lu lng ca bm, m3/sH: ct p ton phn ca bm, m Cng sut l thuyt ca bm (Plt)

Vi:N: s vng quay ca bm, vng/phtM: momen xon ca ng c, N.m Tnh hiu sut ca bm (E):

X l s liu v kt qu tnh ton: Th nghim 1: Bng kt qu tnh ton s liu ( ch tc bm 70%)STTLu lng Q (l/s)H

HwHeHPhPmE

103.58820.00000.07503.66320.000049.45500.0000

20.193.42510.02200.07503.52216.564953.851012.1908

30.293.17020.05140.07503.29669.378554.950017.0673

40.462.98670.12920.07503.191014.399657.148025.1970

50.582.78290.20540.07503.063317.429658.247029.9236

60.652.58920.25800.07502.922218.633558.247031.9904

70.722.34450.31660.07502.736119.325860.445031.9725

80.822.03870.41060.07502.524420.306462.643032.4161

90.91.78390.49470.07502.353520.779462.643033.1712

100.941.60040.53960.07502.215020.425463.742032.0439

VD:

He=0.075m i vi m hnh FM50H=Hs+ Hv+ He= 3.5882+0+0.075=3.6632m

V th:

th biu din mi quan h cc i lng chiu cao ct p, cng sut bm v hiu sut bm theo s thay i lu lng Nhn xt v bn lun1) Nhn xt v kt qu th nghim Cc dng ng biu din Mi quan h gia cc i lng im c hiu sut cao nht2) So snh thS ging nhauS khc nhau Thc nghim L thuyt Th nghim 2: Bng kt qu tnh ton s liu V th: th biu din mi quan h gia chiu cao ct p v lu lng tng ng vi mi tc bm Nhn xt v bn lun1) M t v nhn xt hnh dng cc ng hiu sut v cng sut2) So snh kt qu th nghim vi l thuyt Th nghim 3: Bng kt qu tnh ton s liu: V th: th biu din mi quan h gia ct p v lu lng theo d on. Nhn xt v bn lun1) So snh kt qu d on vi kt qu o c2) S chnh xc ca nhng gi tr xc nh c nh nh lut t l nh sau:3) Thun li v kh khn ca k thut ny cho vic thit k h thng bm. Th nghim 4: Bng kt qu tnh ton s liu V th: th biu din chiu cao ht ca bm theo lu lng v hiu sut ca bm theo lu lng Nhn xt v bn lun1) Hin tng xm thcKhi nim: xm thc l hin tng thng xy ra trong cc loi my thy lc nh bm l qu trnh ph hy tnh dy c ca dng chy cht lng do sinh ra trong dng chy nhng khoang cha y kh v hi ca cht lng.Nguyn nhn: s si v bc hi ca cht lng trong qu trnh my bm lm vic s gy nn hin tng xm thc.Qu trnh: p sut trong dng chy bng p sut bc hi bo ha -> nc si -> xut hin nhiu bt nc. Bt nc ngng t li thnh git nhng c th tch nh hn th tch git nc -> khong chn khng cc b xut hin. Lc ngng t, s va p ca cc phn t cht lng rt ln, m bin dng ca chng rt nh -> p lc rt ln -> song p lc ngc -> p lc gim, lm cht lng si li. iu dn n va p thy lc rt ln.Tc hi: Bo mn kt cu kim loi, lm cho kim loi han g nhanh hn. Lm cho bnh gung v b phn khc ca bm b h hi. To ra rung ng v ting n. Cng sut, hiu sut v ct p ca bm b gimo nhanh chng. Khi xm thc mnh, bm c th b hng. Thng s lm vic b gim t ngt. Gy ra va p thy lc.Cch phng chng: Khi lp t v s dng: Tng p sut vo my bm: dng ng ng ngn, c ng knh ln, t thit b chn, chiu cao lp my bm thp m bo cho kh khng lt t ngoi vo trong: theo ng ng ht v khe nt. Khi thit k v ch to: Tng ng knh ca bnh cng tc v chiu rng ca rnh. S dng vt liu c cng cao, thp khng g, ng thau

2) Din t s nh hng ca vic thay i p sut ht ln qu trnh lm vic ca bm p sut ht ca bm c s nh hng rt ln n qu trnh lm vic ca bm. trnh hin tng xm thc, phi xc nh ng chiu cao ht hnh hc cho php. Chiu cao ht hnh hc thc t khng c vt qu chiu cao hnh hc cho php. Chiu di ng ht phi ngn n mc ti thiu, trnh lm nhiu ch i hng.3) Vic s dng biu NPSH trong vic thit k h thng v chn bm hp l. Vic s dng biu s gip khc phc hin tng xm thc. Gip kim tra bm d dng v thun tin hn. Vic kim tra xc nh NPSH s lin quan n vn hnh bm vi nc cc cng sut khc nhau, trong khi iu tit van ht. Gi tr ca NPSH s xc nh dc h thng c th ca bm s dng. Da vo NPSH ta c th iu chnh thng s cho hp l. l tang NPSH hn ch hin tng xm thc. Chng hn:Nu bm ht cht lng t 1 bnh kn cha p, ta tng lng cht lng trong bnh hoc tang p sut trn b mt cht lngGim nhit lm vic.Gim tn tht trn ng ng ht.4) iu kin hin tng xm thc xut hin. Do cht lng chuyn ng vo ming bm ly tm c p sut thp hn p sut kh quyn. Do s bc hi ca cht lng. Do trong cc my c p sut nh, nhit cao lm cho cht lng si,to nhiu bt kh. Do kh lt vo my bm t bn ngoi.

Th nghim 5: Bng kt qu tnh ton s liu: th th biu din im lm vic ca bm Nhn xt v bn lun1) So snh th v c vi th l thuyt2) So snh giao im ng c tuyn mng ng vi ng ct p bm theo lu lng vi ng hiu sut bm.3) nh hng ca kt qu khi s dng gi tr trung bnh i vi van y. chnh xc thp. Dn n sai s trong vic o c tnh ton. Sai lch trong v th. Cc thng s khi tnh ton b nh hng.4) Phng php thay th i vi vic xc nh ng c tuyn ca h thng. xy dng ng c tuyn tnh ton xy dng ng c tuyn lm vic (n= const)5) S ph hp ca bm i vi h thng. Bm c cc thng s v kt cu ph hp vi h thng. C dng chy lin tc v u, cung cp khi lng nc ln vi p lc u ra khng i v p lc thp. C im lm vic n nh. Khi ng bm nhanh v iu chnh n gin trong khong lu lng ln. C th bm nhiu loi cht lng khc nhau, hn hp cht lng v cht rn. Nn mng nh khng chim nhiu din tch. Hiu sut lm vic cao.