UniSim Design Automation Example - Set Compressor Curve Data

Speed 2488 rpm Speed 3733 rpmFlow Head Efficiency Flow Head EfficiencyACT_m3/h m % ACT_m3/h m %

3373.9 665.1 81.84734 5060.9 1540.3 81.880693794.7 632.7 82.45015 5721.5 1473.0 82.803414215.4 596.5 82.64101 6382.1 1394.2 83.270624325.5 586.1 82.56824 6488.3 1380.1 83.279294636.2 555.0 82.13257 7042.8 1299.2 82.938875056.9 509.7 81.02223 7703.4 1192.0 81.96325477.7 459.1 78.97281 8364.0 1067.1 79.877735898.5 404.5 75.92351 9024.6 930.6 76.803146319.2 347.0 71.79539 9685.3 778.7 72.118376740.0 286.2 66.12071 10345.9 607.4 64.812687160.7 221.2 58.07434 11006.5 411.6 52.750647581.5 152.0 46.42816 11667.1 182.0 30.197218002.2 78.2 28.74136 12000.0 0.0 1.1

8400 0 1.1

Add Compressor to currently open UniSim Design case with the curves specified aboveIf a compressor with this name exists already then offer to replace the curves

To add more curves simply insert more columns to the right above and copy the format of one of the existing blocks of data.If the curve needs more/less rows of data simply add remove data above.

Compressor Name Stage 1Speed Units rpm

Flow Units ACT_m3/hHead Units m

Used in chapter 7 of training course 4528 - Dynamic Modeling using UniSim® Design

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UniSim Design Automation Example - Set Compressor Curve Data

Speed 4977 rpm Speed 6177 rpmFlow Head Efficiency Flow Head EfficiencyACT_m3/h m % ACT_m3/h m %

6913.7 2810.2 81.72469 8635.6 4461.0 80.971987542.2 2741.2 82.59232 9230.0 4404.0 81.758188170.7 2656.6 83.15491 9824.4 4335.1 82.423558642.1 2588.5 83.50111 10418.8 4253.2 82.95288799.3 2564.2 83.58434 11013.2 4159.1 83.350639427.8 2456.8 83.70161 11607.6 4059.9 83.7252

10056.3 2332.0 83.40768 12202.0 3943.8 83.9048910684.8 2186.0 82.58902 12336.6 3914.8 83.9142111313.3 2022.2 81.28169 12796.5 3805.9 83.8166911941.8 1841.7 79.47417 13390.9 3644.5 83.4377612570.4 1636.4 76.81559 13985.3 3448.8 82.5494213198.9 1392.9 72.59763 14579.7 3153.0 80.017313827.4 1039.0 63.15203 15174.1 2673.8 74.19353

14600 0 1.1 16000 0 1.1

Add Compressor to currently open UniSim Design case with the curves specified above

To add more curves simply insert more columns to the right above and copy the format of one of the existing blocks of data.

Used in chapter 7 of training course 4528 - Dynamic Modeling using UniSim® Design

Possible UnitsFrequencyAct. Gas FLengthHz ACT_m3/h mkHz ACT_m3/mcmMHz ACT_m3/s mmper sec ACFM micronrpm ft3/min ft1/min inper min milesper hr

Background

USD Anti-Surge Controller Surge curve takes the form:

Where Head (m) and Q (m3/s) are points on the surge curve and A,B,C and D are parameters specified by the userWe simplify this by making B and D zero, hence:

and find A and C by fitting a curve through the lowest flow points of each of the curves we haveA and C can be found by plotting Head vs Vol Flow Squared and determining the slope (C) and intercept (A)

Surge Points

Speed Head (m) Min Vol Flow (m3/h) Mon Vol Flow (m3/s) Vol Flow Squared (m6/s2)2488 rpm 665.14227 3373.9148 0.937198555555556 0.878341132535423733 rpm 1540.3053 5060.8722 1.40579783333333 1.976267548204694977 rpm 2810.1577 6913.6994 1.92047205555556 3.688212916169786177 rpm 4460.9873 8635.6414 2.39878927777778 5.75418999918163

C 774.92939A -13.18078

Calculate Surge Curve so that it can be plottedControl Line

1.1Flow(m3/h) Head(m) Head(m) Head(m)

2500 360.53131 360 27483000 524.96463 500 32233500 719.29492 610 35514000 943.52217 860 42044500 1197.6464 1110 47675000 1481.6676 1360 52715500 1795.5857 1610 5731

0 1 2 3 4 5 6 7

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

f(x) = 774.929389299493 x − 13.1807765919966

Head (m) vs Vol Flow Squared (m6/s2)

Vol Flow Squared (m6/s2)

He

ad

(m

)

Head=A+B⋅Q+C⋅Q2+D⋅Q3

6000 2139.4009 1860 61576500 2513.113 2110 65557000 2916.722 2360 69307500 3350.228 2610 72868000 3813.631 2860 76258500 4306.931 3110 79509000 4830.1279 3360 82629500 5383.2218 3610 8563

10000 5966.2127 3860 88534110 91344360 94074610 96724860 99305110 101825360 104275610 106675860 10902

Where Head (m) and Q (m3/s) are points on the surge curve and A,B,C and D are parameters specified by the user

and find A and C by fitting a curve through the lowest flow points of each of the curves we haveA and C can be found by plotting Head vs Vol Flow Squared and determining the slope (C) and intercept (A)

Vol Flow Squared (m6/s2)

Backup Line

1.05Head(m)

2623307633904012455150325471

0 1 2 3 4 5 6 7

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

f(x) = 774.929389299493 x − 13.1807765919966

Head (m) vs Vol Flow Squared (m6/s2)

Vol Flow Squared (m6/s2)

He

ad

(m

)

587762576615695572797589788681738451871989809233947997199954

1018210406

0.0 2000.0 4000.0 6000.0 8000.0 10000.0 12000.0 14000.0 16000.0 18000.00.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

3500.0

4000.0

4500.0

Compressor Surge Control

2488 rpm3733 rpm4977 rpm6177 rpmSurge LineControl lineBackup line

Flow (m3/h)

Hea

d (

m)

Surge Line

Backup Line

Control Line