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Thc hnh KTTPNguyn Vn Tng LmBi 4: HP THU1. MC CH TH NGHIMKho st c tnh ng lc hc lu cht v kh nng hot ng ca ct chm bng cch xc nh:- nh hng ca vn tc dng kh v lng ln tn tht p sut ( gim p) khi i qua ct.- S bin i ca h s ma st ct kh fck theo chun s Reynolds (Re) ca dng kh v suy ra cc h thc thc nghim.- S bin i ca tha s lin h gia gim p ca dng kh qua ct kh v qua ct t theo vn tc dng lng.- Gin gii hn kh nng hot ng ca ct (gin ngp lt v gia trng).

2. C S L THUYT2.1. gim p ca dng kh gim p Pck ca dng kh qua ct ph thuc vo vn tc khi lng G ca dng kh qua ct kh (khng c dng chy ngc chiu). Khi dng kh chuyn ng trong cc khong trng gia cc vt chm tng dn vn tc th gim p cng tng theo. S gia tng ny theo ly tha t 1,8 n 2,0 ca vn tc dng kh.

(1)Vin = 1,8 2,0Khi c dng lng chy ngc chiu, cc khong trng gia nhng vt chm b thu hp li. Dng kh do di chuyn kh khn hn v mt phn th tch t do gia cc vt chm b lng cht lng chim c . Khi tng vn tc dng kh ln, nh hng cn tr ca dng lng tng u n cho n mt tr s ti hn ca vn tc kh, lc gim p ca dng kh tng vt ln. im ng vi tr s ti hn ca vn tc kh ny c gi l im gia trng. Nu tip tc tng vn tc kh qu tr s ti hn ny, nh hng cn tr h tng gia dng lng v dng kh rt ln, Pc tng mau chng khng theo phng trnh (1) na. Dng lng lc ny chy xung cng kh khn, ct im lt.ng biu din log(Pc/Z) ( gim p sut ca dng kh qua mt dn v chiu cao ca phn chm trong ct) d kin nh trnh by trn hnh 1.

Hnh 1: nh hng ca G v L i vi gim p ca ct Pc2.2. H s ma st fck theo Rec khi ct khTr lc thp kh:

Trong : h - chiu cao lp m, mwo- vn tc pha kha - b mt ring, m2/m3 - xp, m3/m3k khi lng ring ca khng kh, kg/m3fck - h s ma sat ca dng chy qua lp ht, ph thuc vo Rek

Khi Rek40: 2.3. gim p Pc khi ct tS lin h gia gim p ct kh Pck v ct t Pc c th biu din nh sau:Pc = Pck(6)Do c th d kin fc = .fck (7)Vi: h s ph thuc vo mc xi ti ca dng lng L, kg/m2s.Leva ngh nh hng ca L ln nh sau: = 10L(8)haylog = L(9)Gi tr ty thuc vo loi, kch thc, cch thc sp xp vt chm (xp ngu nhin hay theo th t) v ln ca lu lng lng L. Th d vi vt chm l vng s Raschig 12,7 mm, chm ngu nhin, xp = 0,586; gi tr ca L t 0,39 n 11,7 kg/m2s v ct hot ng trong vng di im gia trng. = 0,084

Mt s ti liu cn biu din s ph thuc gia t s vi h s xi ti nh sau:

Khi A < 0,3 cho vt chm bng s c d < 30 mm, ta c:

(10)

(11)2.4. im lt ca ct chmKhi ct chm b ngp lt, cht lng chim tn b khong trng trong phn chm, cc dng chy b xo trn mnh lit, hin tng ny rt bt li cho s hot ng ca ct chm. Gi gi tr ca GL tng ng vi trng thi ny l GL*. 12

Hnh 2: Gin lt ca ct chm

Zhavoronkov kt lun rng trng thi ngp lt xy ra khi hai nhm s sau c s lin h nht nh vi nhau cho mi ct.

(12)

v (13)Vifck: h s ma st ct kh.v: vn tc di ca dng kh ngay trc khi vo ct, m/s.

: nht tng i ca cht lng so vi nc. , nu cht lng l nc th .Do s lin h gia 1, 2 trn gin log1 log2 s xc nh mt gin lt ca ct chm, phn gii hn hot ng ca ct chm di ng ny.3. S NGUYN L THIT BI-My thi kh1,2-Van iu chnh lu lng dng khII-Lu lng k dng kh3-Van x nc ng trong ng khIII-Ct chm 4,6-Van iu chnh lu lng dng lngIV-Bn cha 5-Van to ct lng ngn khV-Bm7-Van iu chnh mc nc trong ct chmVI- Lu lng k dng lng8-Van x nhanh khi lt ct chmD-lp m vng s Raschig 9-Van x y bn cha

4. X L S LIUCt thy tinh: ng knh d = 0,1 m.Chiu cao phn chm Z = 0,72 m.b mt ring a = 24.656 m2/m3, rng ca ct = 0,5885.Bng ct kh: L = 0 (lit/pht)4.1. s liu th nghimHngV(fit3/p)PCK (cmH2O)

S lnS nh

12.037.837

22.53836.5

33.038.536

43.538.835.2

54.039.535

64.539.935

Ct t L=4 (lt/pht)HngV(fit3/p)PCK (cmH2O)

S lnS nh

12.038.236.5

22.538.636

33.03935.5

43.539.635

54.040.134.5

64.540.933.8

HngV(fit3/p)PC (cmH2O)

S lnS nh

12.038.436.5

22.538.636

33.039.135.5

43.539.735

54.040.534.2

64.541.533

Tng t vi L=5 (lt/pht)

L=6 (lt/pht)HngV(fit3/p)PC (cmH2O)

S lnS nh

12.038.536

22.53935.6

33.039.735

43.540.834

54.041.932.5

64.543.531


S lnS nh

12.038.935.9

22.539.635

33.040.634

43.542.132.5

54.043.631.2

64.545.229.5


S lnS nh

12.039.935

22.540.933.7

33.042.132.5

43.543.931

54.046.129

64.55025


S lnS nh

12.041.533.2

22.54431

33.046.428

43.547.826

54.05024.5

L=10 (lt/pht)HngV(fit3/p)PCK (cmH2O)

S lnS nh

1253.821

4.2 X l s liuTnh ct kh:Tnh GChn ct kh vn hnh nhit 500C : KK = 1,093 (kg/m3) =1,96.10-5 (kg/m.s) =0.585Tnh V

vi V=2 (fit3/p) S=d2/4=(x0.12x0.585/4=4.5922x10-3 (m2)

PCK = (s ln s nh)x10x9.81=(37.8 37)x10x9.81= 78.48 (N/m2)PCK/Z= 78.48/0.52=109 (N/m2.m)Tnh Re

Vi a= 24.656 (m2/m3)Tnh FCK

Tng t vi cc s sau ta c bng sauBng ct kh L=0 (lt/pht)

iVm3/sGPCKN/m2PCK/ZLog (PCK/Z)Log GRefCKLog fCKlogRe

10.0009430.22578.481092.037-0.6481593.9860.87-0.063.202

20.0011790.281147.15204.3752.31-0.5511990.7110.832-0.083.299

30.0014150.337245.25340.6252.532-0.4722387.4360.802-0.0963.378

40.0016510.393353.16490.52.691-0.4062784.1620.778-0.1093.445

50.0018870.449441.45613.1252.788-0.3483180.8870.757-0.1213.503

60.0021230.505480.69667.6252.825-0.2973577.6120.74-0.1313.554

Tnh ct tTa tnh cho bng L=4 (lt/pht) v cc bng sau ta tnh tng tChn ct t vn hnh 300CKK =1.165 (kg/m3) =1,86.10-5 (kg/m.s) =0.585Tnh V

V=2 (fit3/p)

V=2.5 (fit3/p)

V=3 (fit3/p)

V=3.5 (fit3/p)

V=4 (fit3/p)

V=4.5 (fit3/p)

Tnh GS=d2/4=(x0.12x0.585/4=4.5922x10-3 (m2)

Hng 1:

Hng 2:

Hng 3:

Hng 4:

Hng 5:

Hng 6:

Tnh PCHng 1 PC = (s ln s nh)x10x9.81=(38.2 36.5)x10x9.81= 166.77 (N/m2)Hng 2 PC = (s ln s nh)x10x9.81=(38.6 36.)x10x9.81= 255.06 (N/m2)Hng 3 PC = (s ln s nh)x10x9.81=(39 35.5)x10x9.81= 343.35 (N/m2)Hng 4 PC = (s ln s nh)x10x9.81=(39.6 35)x10x9.81= 451.26 (N/m2)Hng 5 PC = (s ln s nh)x10x9.81=(40.1 34.5)x10x9.81= 549.36 (N/m2)Hng 6 PC = (s ln s nh)x10x9.81=(40.9 33.8)x10x9.81= 696.51 (N/m2)

Tnh PC/ZHng 1 PC/Z= 166.77/0.52=231.625 (N/m2.m)Hng 2 PC/Z= 255.06 /0.52=354.25 (N/m2.m)Hng 3 PC/Z= 343.35/0.52=476.875 (N/m2.m)Hng 4 PC/Z= 451.26/0.52=626.75 (N/m2.m)Hng 5 PC/Z= 549.36/0.52=763 (N/m2.m)Hng 6 PC/Z= 696.51/0.52=967.375 (N/m2.m)

Tnh Re

Hng 1

Hng 2

Hng 3

Hng 4

Hng 5

Hng 6

Vi a= 24.656 (m2/m3)

Tnh FC

Hng 1

Hng 2

Hng 3

Hng 4

Hng 5

Hng 6

Hng 1

Hng 2

Hng 3

Hng 4

Hng 5

Hng 6

Ta c bng ct t L=4 (lt/pht)

iVm3/sGPCN/m2PC/ZLog(PC/Z)LogGRefCLog fClogRe

10.0009430.239166.77231.6252.365-0.6222084.5981.8490.2673.319

20.0011790.299255.06354.252.549-0.5242607.9281.4420.1593.416

30.0014150.359343.35476.8752.678-0.4453131.2581.1230.053.496

40.0016510.419451.26626.752.797-0.3783654.5880.994-0.0033.563

50.0018870.479549.367632.883-0.324177.9180.942-0.0263.621

60.0021230.539696.51967.3752.986-0.2684701.2481.0720.033.672

Tng t ta c bng L=5 (lt/pht)

iVm3/sGPCN/m2PC/ZLog(PC/Z)LogGRefCLog fClogRe

10.0009430.239186.39258.8752.413-0.6222084.5982.0660.3153.319

20.0011790.299255.06354.252.549-0.5242607.9281.4420.1593.416

30.0014150.359353.16490.52.691-0.4453131.2581.1550.0633.496

40.0016510.419461.07640.3752.806-0.3783654.5881.0160.0073.563

50.0018870.479618.03858.3752.934-0.324177.9181.060.0253.621

60.0021230.539833.851158.1253.064-0.2684701.2481.2840.1093.672

Tng t ta c bng L=6 (lt/pht)iVm3/sGPCN/m2PC/ZLog(PC/Z)LogGRefCLog fClogRe

10.0009430.239245.25340.6252.532-0.6222084.5982.7190.4343.319

20.0011790.299333.54463.252.666-0.5242607.9281.8860.2763.416

30.0014150.359461.07640.3752.806-0.4453131.2581.5080.1783.496

40.0016510.419667.08926.52.967-0.3783654.5881.470.1673.563

50.0018870.479922.141280.753.107-0.324177.9181.5810.1993.621

60.0021230.5391226.251703.1253.231-0.2684701.2481.8880.2763.672


10.0009430.239294.3408.752.611-0.6222084.5983.2630.5143.319

20.0011790.299451.26626.752.797-0.5242607.9282.5520.4073.416

30.0014150.359647.46899.252.954-0.4453131.2582.1170.3263.496

40.0016510.419941.7613083.117-0.3783654.5882.0750.3173.563

50.0018870.4791216.441689.53.228-0.324177.9182.0860.3193.621

60.0021230.5391540.172139.1253.33-0.2684701.2482.3710.3753.672


10.0009430.239480.69667.6252.825-0.6222084.5985.3290.7273.319

20.0011790.299706.329812.992-0.5242607.9283.9940.6013.416

30.0014150.359941.7613083.117-0.4453131.2583.080.4893.496

40.0016510.4191265.491757.6253.245-0.3783654.5882.7880.4453.563

50.0018870.4791677.512329.8753.367-0.324177.9182.8770.4593.621


10.0009430.239814.231130.8753.053-0.6222084.5989.0260.9553.319

20.0011790.2991275.31771.253.248-0.5242607.9287.2110.8583.416

30.0014150.3591805.0425073.399-0.4453131.2585.9030.7713.496

40.0016510.4192138.582970.253.473-0.3783654.5884.7120.6733.563

Tnh ton ct ngp ltL(lit/phut)Hang V(fit3/p)PC (cmH2O)

S lnS nh

864.55025

9545024,5

102253.821

Ct V trong bng ngp lt tnh ging ct t:Vy hng 1 V= 0.000943 m3/sThng s nhit ph thuc vo cuc ct kh v ct t va tnh trn:Vy ta c:KK = 1.093 (kg/m3)=0.585g= 9.81 m/s2Lng =995.7 (kg/m3)fCK = 0.87

(vn tc ca dng kh qua ct)

(tit din ngang ca ct)

Tnh chun s th nht 1

log1 = -4.06 Tnh chun s th 2 2lt bng L=10(lt/p)L=10(lt/pht)= 10x10-3/60 = 1/6000 (m3/s)V= 0.000943K = 1.165 (kg/m3)Lng =995.7 (kg/m3)

Log2 = -2.218Tng t ta coL(lit/phut)Hanglog2log1

86-2.668-3.429

95-2.565-3.521

102-2.218-4.06

5. TH

6. BN LUNCh chy ca ct kh v ct t l ch chy tng.Ch chy ca ct ngp lt l ch chy ngp lt.H s ma st ca ct kh nh hn h s ma st ca ct t.Ct kh: lu lng dng kh vo ct tng th p sut dng kh qua ct cng tng.Ct t: lu lng dng kh t l thun vi p sut dng kh qua ct. thi ct ngp luc khng c cong nh thi chun co th do sai s trong qua trinh o

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