micro design. system capacity d = gross application for what ever time period ( hrs, day or days) t=...
TRANSCRIPT
![Page 1: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/1.jpg)
Micro Design
![Page 2: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/2.jpg)
System Capacity
**100
*(1 )r
gR
ET TGross Application F
EU L
dayplantgalf
SSFF rpg
dgp //**
623.0)/(
100( )11.6 ( / )
( )ft tapeQ gpm
Application Rate in hrLateral spacing in
( ) ( )
( )
453 ( )in ac
hr
D ASystem Q gpm
T
![Page 3: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/3.jpg)
( ) ( )
( )
453 ( )in ac
hr
D ASystem Q gpm
T
D = gross application for what ever time period ( hrs, day or days)T= hours in time period used to decide “D” (max 22hrs/day)A= Acres irrigated
**100
*(1 )r
gR
ET TGross Application F
EU L
![Page 4: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/4.jpg)
Wetted Area vs Area
![Page 5: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/5.jpg)
Irrigated area vs. wetted areaET rates are computed and published
assuming that the depth comes from the whole area, not just the canopy area or the wetted area. ET rate, expressed as depth per unit of time, is largely governed by the amount of energy available to convert liquid water into vapor (i.e. ET), and therefore does not depend upon the tree size (once the canopy exceeds 65% of the surface area), or the wetted area (as long as there is sufficient root mass to absorb the required water).
![Page 6: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/6.jpg)
Crop Water Needs Example Calculate capacity required for a proposed 1 ac. Micro
irrigation system on Vegetables. Using drip tape with a flow of 0.45 gpm/100’ and 12” emitter spacing, 200 ft rows, 5 ft row spacing, and 10 zones of 0.1 ac each. Design EU of 90%
Q = 453*DA TD = .2” / system
efficiencyA = AreaT = 22 hrs
![Page 7: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/7.jpg)
Crop Water Needs Example Answer
Q = 453*DA T
= 453 x (.2”/.9) x 1 ac22 hrs
= 4.5 gpm
![Page 8: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/8.jpg)
Each field will have a capacity of 4.5 gpm.◦ 200 ft rows with a 0.45 gpm/100’ drip tape
flow will give you 0.9 gpm per row.◦ At 5 ft row spacing, 1 ac will have
approximately 10 zones, each of these zones will have 5 rows, 200 ft long.
◦ 5 rows times 0.9 gpm/row is 4.5 gpm per field.
Minimum water requirement is 4.5 gpm for 1 ac, we only need to run 1 field at a time to meet the crop water demand.
![Page 9: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/9.jpg)
Hours of irrigation per day to apply .2”(1 zone of 0.1 ac each)
T = 453*DA Q
= 453 x (.2”/.9) x 0.1 ac4.5 gpm
= 2 hrs and 15 minutes
![Page 10: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/10.jpg)
WELL
10:1
5 a
.m.
zon
e 2
8:0
0 a
.m.
zon
e 1
2:4
5 p
.m.
zon
e 4
5:1
5 p
.m.
zon
e 5
7:3
0 p
.m.
zon
e 6
12:3
0 p
.m.
zon
e 3
9:4
5 p
.m.
zon
e 7
12:0
0 a
.m.
zon
e 8
2:1
5 a
.m.
zon
e 9
4:3
0 a
.m.
zon
e 1
0
![Page 11: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/11.jpg)
Adjust flow rate or set time
If Ta is greater than 22 hr/day (even for a single-station system), increase the emitter discharge
If the increased discharge exceeds the recommended range or requires too much pressure, either larger emitters or more emitters per plant are required.
![Page 12: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/12.jpg)
Practice problem – Set time and Qs
![Page 13: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/13.jpg)
Pressure flow relationship (Pa)
1
xa
a
qP
K
Where:
qa= average emitter flow rate (gph)
Pa = average pressure (psi)
x = emitter exponentK = flow constant
![Page 14: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/14.jpg)
EU is related to Friction loss
x
a
n
a
n
x
a
n
a
n
q
q
P
P
P
P
q
q
1
![Page 15: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/15.jpg)
Emission Uniformity
1 1.27 100
1 1.27 100
n
a
x
n
a
qCVEU
qn
or
PCV
Pn
![Page 16: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/16.jpg)
Lateral Line DesignImportant lateral characteristics
◦Flow rate◦Location and spacing of manifolds◦Inlet pressure◦Pressure difference
![Page 17: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/17.jpg)
Design objectiveLimit the pressure differential to
maintain the desired EU and flow variation
The pressure differential is affected by◦Lateral length and diameter
Economics longer and Larger
◦Manifold location◦slope
![Page 18: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/18.jpg)
Four Cases
Effects of slope
![Page 19: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/19.jpg)
Allowable pressure loss (subunit)
This applies to both the lateral and subunit. Most of the friction loss occurs in the first 40% of the lateral or manifold
nas PPP 5.2 Ranges from 2 to 3 but generally considered to be 2.5
DPs =allowable pressure loss for subunit
Pa = average emitter pressure
Pn = minimum emitter pressure
![Page 20: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/20.jpg)
Example
Given: CV=0.03, 3 emitters per plant, qa = .43gph Pa=15 psi, EU=92, x=0.57
Find: qn, Pn, and P
![Page 21: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/21.jpg)
Solution
1 1 1
.57
0.031 1.27 100 92 1 1.27 100
0.433
92 0.430.404
.031 1.27 100
3
0.404 15 13.474
0.43
2.5 2.5 15 13.47 3
n n
a
n
x xn n n
n aa a a
a n
q qCVEU
qe
q
P q qP P
P q q
P P P
.83psi
![Page 22: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/22.jpg)
Practice problem - allowable loss
![Page 23: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/23.jpg)
Start with average lateral
![Page 24: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/24.jpg)
Flow rate
Where:l = Length of lateral, ft. (m).Se = spacing of emitters on the lateral, ft. (m).ne = number of emitters along the lateral.qa = average emitter flow rate, gph (L/h)
6060aea
el
qnq
S
lq
![Page 25: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/25.jpg)
Determine optimum lateral lengthEU SlopeBased on friction loss
◦ limited to ½ the allowable pressure difference (ΔPs)
![Page 26: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/26.jpg)
HydraulicsLimited lateral losses to 0.5DPs
Equation for estimating◦Darcy-Weisbach (best)◦Hazen-Williams◦Watters-Keller (easiest, used in NRCS
manuals)
![Page 27: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/27.jpg)
LDC
QFhf 87.4
852.1
5.10
C factor Pipe diameter (in)
130 ≤ 1
140 < 3
150 ≥ 3
130 Lay flat
Hazen-Williams equation
hf =friction loss (ft)
F = multiple outlet factor
Q = flow rate (gpm)
C = friction coefficient
D = inside diameter of the pipe (in)
L = pipe length (ft)
![Page 28: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/28.jpg)
Watters-Keller equation
75.4
75.1
D
QKFLh f
hf = friction loss (ft)
K = constant (.00133 for pipe < 5” .00100 for > 5”)
F = multiple outlet factor
L = pipe length (ft)
Q = flow rate (gpm)
D = inside pipe diameter (in)
![Page 29: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/29.jpg)
Multiple outlet factorChristiansen's equation for computing
the reduction coefficient (F) for pipes with multiple, equally spaced outlets where the first outlet is Sl from the mainline is:
F = Reduction factorN= number of outletsM= exponent depends on which friction equation is used
![Page 30: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/30.jpg)
Multiple outlet factors
Number of outlets
FNumber of
outlets
F
1.851 1.752 1.851 1.752
12345678
1.000.640.540.490.460.440.430.42
1.000.650.550.500.470.450.440.43
910-1112-1516-2021-3031-70>70
0.410.400.390.380.370.360.36
0.420.410.400.390.380.370.36
![Page 31: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/31.jpg)
Adjust length for barb and other minor losses
![Page 32: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/32.jpg)
86.1711.0 ie DBf
OrOr use
equation
Where Fe= equivalent length of lateral, ft)K = 0.711 for English units)B = Barb diameter, inD = Lateral diameter, in
![Page 33: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/33.jpg)
Adjusted length
e
ee
S
fSLL
L’ = adjusted lateral length (ft)
L = lateral length (ft)
Se = emitter spacing (ft)
fe = barb loss (ft)
![Page 34: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/34.jpg)
Barb lossMore companies are giving a Kd
factor now days
2
2f e d ft f f e
Vh K h h eh
g
![Page 35: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/35.jpg)
Example
Given: lateral 1 diameter 0.50”, qave=1.5gpm,
Barb diameter 0.10” lateral 2 diameter 0.50”,
qave=1.5gpm, kd=.10
Both laterals are 300’ long and emitter spacing is 4 ft
Find: equivalent length for lateral 1 and htotal for lateral 2
![Page 36: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/36.jpg)
Solution
1.86
1.75
4.75
0.711*.1 .5 0.258
4 .258300 319.4
4
1.519.4 .36 0.00133 0.51
.5
ef
L
hf ft
fth
fth
gV
fpsV
et
e
h
675.75*009.0
009.009.0*1.0
09.02
45.2
45.20.5
1.5409.0
2
2
Lateral 1 Lateral 2
![Page 37: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/37.jpg)
Procedure
Step 1 - Select a length calculate the friction loss
Step 2 – adjust length to achieve desired pressure difference ( 0.5DHs)
75.2
a
bab L
Lhfhf
36.0
af
bfab h
hLL
![Page 38: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/38.jpg)
Practice problem Lateral length
![Page 39: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/39.jpg)
Step 3 - adjust length to fit geometric conditions
Step 4 - Calculate final friction loss
Step 5 – Find inlet pressure
Step 6 – Find minimum pressure
![Page 40: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/40.jpg)
Next step is to determine Δh
Paired Lateral
Single Lateral – ◦ Slope conditions
S > 0
S = 0
◦ Slope Conditions S < 0 and –S > friction slope
75.211 zhzEh f
fhEh
fhElh
fhElh )(
![Page 41: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/41.jpg)
Last condition
57.157.057.1
36.00.1
ff
ff
ff h
EFh
h
EFEorh
h
E
h
Eh
S < 0 and –S < Friction slope
Which ever is greater
![Page 42: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/42.jpg)
Inlet pressureEstimate with the following equation
Single Lateral
Paired Lateral
Better to use computer program
30.433
4 2f
l a
h ElP h
3.753.750.75 1 2 1 0.4332l a fp
EP h h z z z
![Page 43: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/43.jpg)
Find minimum lateral pressure
Where S > 0 or S=0
Where S < 0 and –S < Friction slope
Where S < 0 and –S > friction slope
n lP P P
n lP P
n lP P P
![Page 44: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/44.jpg)
Calculate final EU
1 1.27 100
1 1.27 100
n
a
x
n
a
qCVEU
qn
or
PCV
Pn
![Page 45: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/45.jpg)
Practice problem pressure difference and EU
![Page 46: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/46.jpg)
Block HydraulicsAvg lateral inlet pressure
Becomes the avg outlet pressure for manifold
![Page 47: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/47.jpg)
Manifold hydraulics
![Page 48: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/48.jpg)
Allowable manifold lossAllowable pressure loss – lateral
lossesCalculate losses using Hazen-
Williams etc.Find minimum and maximum
outlet pressures for manifold use this to calculate maximum and minimum lateral flow rate
Calculate block EU and flow variation
![Page 49: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/49.jpg)
Block EU
![Page 50: Micro Design. System Capacity D = gross application for what ever time period ( hrs, day or days) T= hours in time period used to decide “D” (max](https://reader038.vdocuments.us/reader038/viewer/2022103005/56649dc95503460f94abfe24/html5/thumbnails/50.jpg)
Flow variation
𝑞𝑣𝑎𝑟=𝑞𝑚𝑎𝑥−𝑞𝑚𝑖𝑛
𝑞𝑚𝑎𝑥