Bai 4 Ghep Bom

7/28/2019 Bai 4 Ghep Bom

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BI 4: GHP BM 4.1. MC CH TH NGHIM:

Xc nh c t p ton ph n ca bm, cng sut v hi u su t cho bm ly tm

bng vi c o c cc thng s khi thay i lu lng bm ( th nghim 1) Xy d ng ng c tuy n ca m ng ng xc nh im lm vi c cabm.

Xy d ng ng c tuy n c a h 2 bm ghp ni tip. Xy d ng ng c tuy n c a h 2 bm ghp song song.

4.2. BO CO TH NGHIM

4.2.1. Kt qu th nghim

Th nghi m 1:

SttLu lng

Q (l/s)

Tc bm

n (rpm)

p sutht

P h (kPa)

p suty

P h (kPa)

Nhit (ToC)

Momentxon ng

c t (N.m)

1 0.076 1260 2.7 33.4 39.4 0.212 0.357 1260 2.6 32.1 39.5 0.293 0.641 1260 2.5 28.8 39.4 0.36

4 0.85 1260 2.3 25.3 39.3 0.425 0.961 1260 2.2 23.1 39.3 0.436 0.943 1260 2.2 23 39.3 0.427 1.018 1260 2.1 20.8 39.4 0.448 1.057 1260 2 19.7 39.4 0.469 1.094 1260 2 19.3 39.3 0.48

10 1.131 1260 2 18.5 39.4 0.78

Th nghi m 2:

sttlu lng

Q (l/s)

tc bm

n (rpm)

p sutht

P h (kPa)

p suty

P h (kPa)

nhit (ToC)

momentxon ng

c t (N.m)

Kt qu kho st theo m van ch tc bm khng i 1 1.113 1260 2 18.8 39.3 0.432 1.113 1260 2.1 18.9 39.6 0.45


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3 1.113 1260 1.9 19 39.3 0.54 1.094 1260 1.9 19.4 39.4 0.535 1.074 1260 2.2 19.8 39.5 0.526 1.018 1260 2 21.6 39.6 0.477 0.867 1260 2.2 24.8 39.5 0.45

8 0.604 1260 2.5 30.1 39.6 0.459 0.133 1260 2.6 33.7 39.6 0.37

10 0.037 1260 2.8 34.4 39.7 0.37Kt qu kho st theo ch tc bm m van hon ton

1 1.547 1800 1.4 34.9 39.3 0.622 1.414 1620 1.5 29 39.4 0.493 1.283 1440 1.7 23.8 39.4 0.54 1.113 1260 2 19.7 39.5 0.465 0.943 1080 2.2 15.8 40.1 0.416 0.773 900 2.3 12.1 3906 347 0.623 720 2.5 8.8 40 328 0.471 540 2.5 6.5 39.7 0.239 0.32 360 206 5.1 39.6 0.29

10 0.17 180 206 4.2 39.5 0.54

Th nghi m 3

SttLu

lngQ (l/s)

Tc bm

n (rpm)

p sutht

P h (kPa)

p suty

P h (kPa)Nhit (ToC)

Moment

xon ng c t (N.m)

1 1.357 1260 1.5 11.5 35.1 39.1 0.452 1.396 1260 1.7 11.6 36.1 38.9 0.473 1.357 1260 1.6 12 35.4 39 0.494 1.357 1260 1.8 12.2 36.2 39.3 0.475 1.34 1260 1.6 12 36.1 39.1 0.476 1.32 1260 1.8 13 38.3 39.2 0.49

7 1.32 1260 1.6 13.8 40.8 39.3 0.58 1.227 1260 1.7 15.5 45.3 39.3 0.519 1.15 1260 1.9 18.5 52.3 39.2 0.45

10 0.133 1260 2.7 33.5 51.4 39.4 0.31


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Th nghi m 4:

SttLu

lngQ (l/s)

Tc bm

n (rpm)

p sutht

P h (kPa)

p suty

P h (kPa)

Nhit (ToC)

Momentxonng c

t (N.m)

1 1.867 1260 0.9 26.3 39.4 38.6 0.242 1.848 1260 0.8 26.3 38.9 38.7 0.283 1.83 1260 0.8 26.5 39 38.7 0.34 1.791 1260 0.9 27.2 39.8 38.7 0.35 1.697 1260 1 28.3 40.7 38.8 0.36 1.451 1260 1.4 30.6 43.2 38.9 0.287 1.037 1260 201 33.1 45.6 38.8 0.258 0.584 1260 2.5 43.9 52.4 39 0.249 0.15 1260 2.7 51 57.3 38.9 0.25

10 0.057 1260 2.7 52.1 58.2 39.1 0.25

4.2.2. X l s liu:

Th nghim 1: = 993 (kg/m 3)

a. Cng th c tnh ton:- Ct p ton ph n:

H = H s + H w + H e (m)

Trong : : bin thin c t p th y tnh, m.

Hs = 1000 = 3,152 (m)

P 1 : p su t ht (o bng p k ), Pa.

P 2 : p su t y (o bng p k ), Pa.

Hw= : bin thin ng nng, m.

w1 : vn tc ng ng ht c a dng lu cht, m/s.

w1= = = 0,039 (m/s)


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d1 = 0.05m

w2 vn tc ng ng y ca dng lu cht, m/s.

w2= = = 0.079 (m/s)

d2 = 0.035m

Hw= = = 2.10 -4 (m)

He = z 2 z1 = 0.08m: bi n thin th nng

H = 0.08 + 2.10 -4 + 3,152 = 3.2322 (m)

- Cng su t thy lc truy n cho ng c

P h= Q.H..g = 0.076/1000 3.2322 993 9,81 = 2,393 (W)

Trong : Q : lu lng c a bm, m3/s.

H : c t p ton ph n ca bm, m.

: khi lng ring c a ch t lng, kg/cm 3.

G : gia t c tr ng trng, m/s 2.

- Cng su t cn cung c p cho ng c c th c tnh nh sau:

= = 27,695 (W)

Trong : n: s vng quay c a bm, vng/pht

t: moment xo n ca ng c, N.m

- Hiu su t ca bm

= = 8.641 (%)

- Tn th t ct p c a bm :H0 : tn th t ca c t p khi ch t lng chuy n ng trong ng, m.

H0 = C = K.Q 2 Vi:

= 1000 + 0.16 0.08 = 3.232 (m)

Trong : z1, z 2 - chi u cao c a mi ng ng ht v ng y so v i mt chu n, m


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P 1, P 2 p su t ti ming ng ht (n i t bn n ng ht) v mi ng ng y (ni t bn n ng y, Pa

b. B ng k t qu :

Hs (m) w1(m/s) w2

(m/s) Hw

(m) H (m) Ph

(m) Pm

(m) E Ho

3.152 0.039 0.079 0.0002 3.2322 2.393 27.695 8.641 3.2323.028 0.823 1.485 0.0779 3.1809 11.062 38.245 28.924 3.108

2.7 1.479 2.666 0.2508 3.0258 18.894 47.477 39.796 2.782.361 1.961 3.536 0.4413 2.8773 23.824 55.39 43.011 2.4412.145 2.217 3.997 0.5638 2.7838 26.06 56.708 45.955 2.2252.135 2.175 3.923 0.5433 2.7533 25.292 55.39 45.662 2.2151.92 2.348 4.234 0.6327 2.6277 26.058 58.027 44.907 2

1.817 2.438 4.397 0.6825 2.5745 26.509 60.665 43.697 1.8971.776 2.524 4.551 0.7309 2.5819 27.515 63.302 43.466 1.8561.694 2.609 4.705 0.7814 2.5504 28.099 102.866 27.316 1.774

c. th : c tuy n th c ca bm ly tm

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2.5

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3.5

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Ho (m)

Ho (m)


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Th nghim 2:

a. Cng th c tnh ton- Ct p ton ph n:

H = H s + H w + H e (m)

Trong : : bin thin c t p th y tnh, m.

Hs = 1000 = 1.725 (m)


0

20

40

60

80

100

120

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Pm (W)

Pm (W)

0

10

20

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40

50

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Hiu sut

E (%)

hiu sut

E (%)


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w1= = = 0,567 (m/s)


w2= = = 1,157 (m/s)

Hw= = = 0,0518 (m)


H = 0.08 + 0,0518 + 1,725 = 1,857 (m)

- Cng su t thy lc truy n cho ng c P h= Q.H..g = 1,113/1000 1,857 993 9,81 = 20.132 (W)

- Cng su t cn cung c p cho ng c cth c tnh nh sau:

= =56,708 (W)

- Hiu su t ca bm = = 35,5 (%)

- Tn th t ct p c a bm :H0 : tn th t ca c t p khi ch t lng chuy n ng trong ng, m.H0 = C = K.Q 2

[( )( )]

Ho = 323572,31 = 0.401 (m)

b. B ng k t qu :


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Hs (m)w1

(m/s)w2

(m/s)Hw(m) H

P h(m)

P m(m) E k

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

1.725 0.567 1.157 0.0518 1.8568 20.132 56.708 35.501 323572 0.4011.725 0.567 1.157 0.0518 1.8568 20.132 59.346 33.923 323572 0.4011.755 0.567 1.157 0.0518 1.8868 20.457 65.94 31.024 323572 0.4011.796 0.557 1.138 0.0502 1.9262 20.528 69.896 29.369 323572 0.3871.807 0.547 1.117 0.0483 1.9353 20.247 68.578 29.524 323572 0.3732.012 0.519 1.059 0.0434 2.1354 21.176 61.984 34.164 323572 0.3352.32 0.442 0.902 0.0315 2.4315 20.536 59.346 34.604 323572 0.243

2.833 0.308 0.628 0.0153 2.9283 17.229 59.346 29.031 323572 0.1183.193 0.068 0.138 0.0007 3.2737 4.241 48.796 8.691 323572 0.0063.244 0.019 0.038 0.0001 3.3241 1.198 48.796 2.455 323572 0.00044

kt qu kho st theo ch tc bm m van hon toan3.439 0.788 1.609 0.1003 3.6193 54.542 116.808 46.694 323572 0.7742.823 0.721 1.47 0.0836 2.9866 41.138 83.084 49.514 323572 0.6472.269 0.654 1.334 0.0689 2.4179 30.219 75.36 40.1 323572 0.5331.817 0.567 1.157 0.0518 1.9488 21.129 60.665 34.829 323572 0.4011.396 0.481 0.981 0.0373 1.5133 13.901 46.346 29.994 323572 0.2881.006 0.394 0.804 0.025 1.111 8.366 32.028 26.121 323572 0.1930.647 0.317 0.648 0.0163 0.7433 4.511 24.115 18.706 323572 0.1260.411 0.24 0.49 0.0093 0.5003 2.295 13 17.654 323572 0.0720.257 0.163 0.333 0.0043 0.3413 1.064 10.927 9.737 323572 0.0330.164 0.087 0.177 0.0012 0.2452 0.406 10.174 3.991 323572 0.009

Th nghim 3:

- Ct p ton ph n:

H = H s + H w + H e (m)

= *1000 =1,027 (m).

P 2 = p su t y ca bm 1



w1= = = 0,691 (m/s)


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w2= = = 1,411 (m/s)

Hw= = = 0,0771 (m)


H = 0.08 + 0,0771 +1,027 = 1,184 (m)

- Cng su t thy lc truy n cho ng c P h= Q.H..g = 1,357/1000 1,184 993 9,81 = 15,651 (W)

- Cng su t cn cung c p cho ng c c th c tnh nh sau:

= = 59,376 (W)- Hiu su t ca bm

= = 26,36 (%)

- Tn th t ct p c a bm :H0 : tn th t ca c t p khi ch t lng chuy n ng trong ng, m.

H0 = C = K.Q 2

Trong : z1, z 2 - chi u cao c a mi ng ng ht v ng y so v i mt chu n, m

P 1, P 2 p su t ti ming ng ht (n i t bn n ng ht) vming ng y (ni t bn n ng y, Pa

L1, L2 chi u di c a on ng ht v ng y,m

D1, D2 ng kng ng ht v ng y, m

h s ma st ng ht v ng y (l y b ng 0,025)

t ng tr lc cc b ng ht v ng y= 2.4 = 1,14


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= 210162.86

o = 210162,86.(1,357/1000)^2= 0,.387

= 0,5 = 1 = 0,3 = 0,4

= khng ng kkhi m hon ton = 2,1(khi m 1 ca)

= 1

b. B ng k t qu :

Hs (m)w1

(m/s)w2

(m/s)Hw(m) H

P h(m)

P m(m) E H o

1.027 0.691 1.411 0.077 1.184 15.65128 59.346 26.373 0.387

1.016 0.711 1.452 0.082 1.178 16.0195 61.984 25.845 0.41

1.068 0.691 1.411 0.077 1.225 16.19326 64.621 25.059 0.387

1.068 0.691 1.411 0.077 1.225 16.19326 61.984 26.125 0.387

1.068 0.683 1.393 0.075 1.223 15.96429 61.984 25.755 0.377

1.15 0.673 1.373 0.073 1.303 16.7547 64.621 25.928 0.366

1.252 0.673 1.373 0.073 1.405 18.06627 65.94 27.398 0.366

1.417 0.625 1.276 0.063 1.56 18.64607 67.259 27.723 0.316

1.704 0.586 1.196 0.055 1.839 20.60145 59.346 34.714 0.278

3.162 0.068 0.138 0.001 3.243 4.201621 40.883 10.277 0.004


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c. th :

Th nghim 4:a. Tng t th nghi m 3 nhng thay p sut y P = (P bm 1 + P bm 2)/2b. B ng k t qu :

P y (kPa) Hs (m) w 1 (m/s)

w2(m/s)

Hw(m) H

P h(m)

P m(m) E (%) H

32.85 3.29 0.951 1.942 0.146 3.516 63.946 31.651 202.035 1.182

32.6 3.264 0.942 1.922 0.1431 3.4871 62.775 36.926 170.002 1.15832.75 3.27 0.932 1.903 0.14 3.49 62.215 39.564 157.252 1.13533.5 3.336 0.913 1.862 0.134 3.55 61.936 39.564 156.546 1.08734.5 3.398 0.865 1.765 0.121 3.599 59.495 39.564 150.377 0.97636.9 3.572 0.739 1.509 0.088 3.74 52.864 36.926 143.162 0.714

39.35 3.783 0.528 1.078 0.045 3.908 39.478 32.97 119.739 0.36548.15 4.666 0.298 0.607 0.014 4.76 27.079 31.651 85.555 0.11654.15 5.282 0.076 0.156 0.001 5.363 7.836 32.97 23.767 0.00855.15 5.661 0.029 0.059 0.0001 5.7411 3.188 32.97 9.669 0.001

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Ho


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c. th :

4.3. Bn lun:

Th nghi m 1:

T th v b ng s liu ta th y: Khi ta tng lu lng bm th ct p ton ph n gim, hi u su t tng nhng

ti mt gi tr no gim d n.Hiu sut cao nh t at 46% tng ng v i Q = 0,961 (l/s)

V khi m van t n th t ct p s gim.

Nhn chung th v t thc nghi m v th trong sch gi ng nhau.

Th nghi m 3:

T th nghi m 1 v 3 ta th y khi ghp 2 bm lm vic n i tip khng nh ng c kh nng tng ct p m cn tng c lu lng ca h thng.

ng d ng trong th c t: khi c n a nc ln r t cao

Th nghi m 4:

T th ta th y lu lng tng c ng c a 2 bm ghp song song nh hn lu lng c achng khi lm vi c ring r do khi cc bm lm vic song song, lu lng trong ngng tng ln s lam tng tn th t ct p.

Ghp bm song song c dng khi c n tng lu lng Q.

-1

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Bai 4 Ghep Bom

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