Isolate each result after "For...Next"

[Vinhermes]

Dear Sir,

I have built-up an application in vb.net, framework 4, that calculates the pressure drop in a single piping system for a given speed. From here all is fine and results compare really well with published litterature.

The next step for me is to draw a graph of the pressure drops for each flow speed from 0 to 6m/s. A typical example can be found here:

Résultats Google Recherche d'images correspondant à http://www.gouldspumps.com/download_files/pump_fundamentals/sect_a9_01.gif

The code below shows the routine calculations performed prior to draw the graph where I get the pressure drops for each speed. I want to plot Flow speed on th X-axis and pressure drops on the Y-axis.

Once the loop is done and that the pressure drop for the 7 flow speeds is calculated (from 0 to 6m/s), how do I isolate the figure for each one of these so that I can plot them?

Drawing the graph will be the next issue but let's take it step by step...

Thanks by advance to show me how to get the pressure drop figures for each speed.

Plase feel free to ask if you have any questions. All the best. Vincent



Public Class Graph


Sub CodepourGraph()


Dim FlowSpeedGraph As Integer 'Flow speed
Dim ReynoldsGraph As Double 'Reynolds number
Dim FrictionFactorGraph As Double 'Friction factor
Dim AGraph As Double 'A for Serghide's equation
Dim BGraph As Double 'B for Serghide's equation
Dim CGraph As Double 'C for Serghide's equation


'Variables raccords


Dim PipeLossesGraph As Double
Dim Losses9015Graph As Double
Dim Losses4515Graph As Double
Dim LossesGateGraph As Double
Dim LossesGlobeGraph As Double
Dim LossesButtGraph As Double
Dim LossesBallGraph As Double
Dim LossesCheckGraph As Double
Dim LossesFilterGraph As Double
Dim LossesTeeThroughGraph As Double
Dim LossesTeesideGraph As Double
Dim LossesOutletGraph As Double
Dim LossesInletGraph As Double
Dim FittingLossesGraph As Double


Dim PressureDropGraph As Double 'Total pressure losses or pressure required


For FlowSpeedGraph = 0 To 6 Step 1
'Reynolds number calculation
ReynoldsGraph = ((Form1.Diameter * FlowSpeedGraph * Form1.MediaDensity) / (Form1.MediaDensity * Form1.MediaViscosity)) * 1000


'Frcition factor calculation
If ReynoldsGraph < 2300 Then
FrictionFactorGraph = 64 / ReynoldsGraph
Else
'Serghide’s Solution for Colebrook Equation
AGraph = -2 * Math.Log10((Form1.RelativeRoughness / 3.7) + (12 / ReynoldsGraph))
BGraph = -2 * Math.Log10((Form1.RelativeRoughness / 3.7) + (2.51 * AGraph / ReynoldsGraph))
CGraph = -2 * Math.Log10((Form1.RelativeRoughness / 3.7) + (2.51 * BGraph / ReynoldsGraph))
FrictionFactorGraph = ((AGraph - (BGraph - AGraph) ^ 2 / (CGraph - (2 * BGraph) + AGraph)) ^ -2)
End If


'Pipe friction losses
PipeLossesGraph = (FrictionFactorGraph * (Form1.TxtLength.Text / (Form1.Diameter / 1000)) * (FlowSpeedGraph ^ 2 / (2 * 9.81)))


'Fittings losses 90°1.5D
Losses9015Graph = ((Form1.K9015 * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.Num9015.Value


'Fittings losses 45°1.5D
Losses4515Graph = ((Form1.K4515 * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.Num4515.Value


'Fittings losses Gate valve
LossesGateGraph = ((Form1.KGate * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumGate.Value


'Fittings losses Globe valve
LossesGlobeGraph = ((Form1.KGlobe * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumGlobe.Value


'Fittings losses Butterfly valve
LossesButtGraph = ((Form1.KButt * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumButt.Value


'Fittings losses Ball valve
LossesBallGraph = ((Form1.KBall * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumBall.Value


'Fittings losses Check valve
LossesCheckGraph = ((Form1.KCheck * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumCheck.Value


'Fittings losses Y-strainer
LossesFilterGraph = ((Form1.KFilter * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumFilter.Value


'Fittings losses Tee through
LossesTeeThroughGraph = ((Form1.KTeeThrough * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumTeeStraight.Value


'Fittings losses Tee side
LossesTeesideGraph = ((Form1.KTeeSide * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumTeeSide.Value


'Fittings losses Pipe outlet
LossesOutletGraph = ((Form1.KOutlet * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumOutlet.Value


'Fittings losses Pipe inlet
LossesInletGraph = ((Form1.KInlet * (FlowSpeedGraph ^ 2)) / (2 * 9.81)) * Form2.NumInlet.Value


'Fittings losses due to fittings
FittingLossesGraph = Losses9015Graph + Losses4515Graph + LossesGateGraph + LossesGlobeGraph + LossesButtGraph + LossesBallGraph + LossesCheckGraph + LossesFilterGraph + LossesTeeThroughGraph + LossesTeesideGraph + LossesOutletGraph + LossesInletGraph


'Total Pressure drop or required
PressureDropGraph = PipeLossesGraph + Form1.Elevation + FittingLossesGraph + Form1.OutletPressureMLC


Next FlowSpeedGraph


'Here are the values I need to isolate to draw a graph
'FlowSpeedGraph 0 -> PressureDropGraph = ??
'FlowSpeedGraph 1 -> PressureDropGraph = ??
'FlowSpeedGraph 2 -> PressureDropGraph = ??
'FlowSpeedGraph 3 -> PressureDropGraph = ??
'FlowSpeedGraph 4 -> PressureDropGraph = ??
'FlowSpeedGraph 5 -> PressureDropGraph = ??
'FlowSpeedGraph 6 -> PressureDropGraph = ??


End Sub


End Class

 

[Dunfiddlin]

Dim PressureDropGraph(6) As Double


PressureDropGraph(FlowSpeedGraph) = PipeLossesGraph + Form1.Elevation + FittingLossesGraph + Form1.OutletPressureMLC

 

[Vinhermes]

Dim PressureDropGraph(6) As Double


PressureDropGraph(FlowSpeedGraph) = PipeLossesGraph + Form1.Elevation + FittingLossesGraph + Form1.OutletPressureMLC

Thank you but can you please expand your answer. Do I need to do this for each speed:

PressureDropGraph(1), (2), etc?

 

[Dunfiddlin]

Each value is referenced by the variable name and its index. So it's PressureDropGraph(0), PressureDropGraph(1), etc.

The advantage in this is that just as you looped through the creation of the values, you can loop through all the values for any other purpose.

 

[Vinhermes]

OK I'll try tomorrow and come back to you if I have any issue. Thanks again!

 

[Vinhermes]

This is perfect, thank you very much!