Calculators in InfoSurge Pro

When working in InfoSurge Pro, there are several calculator tools available for computing operational characteristics of various model elements.

From the Model Explorer, InfoSurge toolbar, expand the Auxiliary Calculator drop-down for options:

Note that the AV (TCV) calculator is separate from these options.

Wave Speed Calculator:

Select Wave Speed to open.

Helps determine propagation speed for pressure waves in pipes.

Note that the stiffer the pipe material used and the more the pipe is restrained, the higher the wave propagation speeds.

Liquid flowing through pipes is generally set to water, but properties such as pipe material, diameter, and thickness can vary within a model.

Resistance Calculator:

Click Resistance to open.

Calculates resistance from minor loss coefficients, flow coefficients, and other factors like orifice data.

Several types of resistance calculators available, each for specific situations.

Most surge protection devices (SPDs) require resistance value to function properly within model.

Pump Inertia/Pump File Calculator:

Click Pump Inertia to open.

Identifies which of eight standard pump files are most appropriate for specific pump.

Helps calculate most appropriate pump file that accounts for unexpected operating conditions.

Select Edit User Pump File to specify two different pump files, to customize an intermediate file based on pump speed—data in intermediate file is interpolated from two files chosen and saved to specified file.

Pump File Characteristics Calculator:

Click Pump File Characteristics.

Helps determine operating conditions for pumps described by pump file, based on rated conditions—as well as flow and speed—at which pump is operating.

Adjust pump data values, such as relative density of liquid and reference flow, as well as head-torque characteristics.

Valve Stroking Calculator (Flowrate):

Click Valve Stroking and use the Flowrate option to determine optimum 2-stage closure for a valve in a single pipeline.

Based on pipeline properties and initial conditions, it calculates optimal set of closing time and area ratio for first stage, as well as corresponding velocity and head.

First, ensure that measurement units are set to match the data.

Pay close attention to Total Time for Closure, as it is the most-edited value—adjust until value of Head after Stage-1 Closure reaches acceptable level.

Valve Stroking Calculator (Velocity):

Click Valve Stroking and select the Velocity option to assign Steady State Velocity instead of Steady State Flowrate.

Again, adjust Total Time For Closure until Head after Stage-1 Closure value is acceptable.

Once Stage-1 Closure Time and Cv Ratio For Stage-1 Closure are calculated, use options in the Active Valve Characteristics Curve Generator to choose appropriate valve type.

Use valve curve to estimate opening percentage for Cv ratio for stage-1 closure.

Valve Modulating Calculator.:

Click Valve Modulating to open the Valve Modulating Calculator.

Calculates data needed to use an active valve as a modulating regulating valve.

For normal applications, static active valves are assumed to maintain initial settings during transient analysis.

To use properly, first perform two steady state runs with different conditions outside of a surge analysis to identify upstream and downstream head and flowrates.

Air Slam Pressure Calculator:

Click Air Slam Pressure to open.

Helps estimate surge pressure potential due to air expulsion from air release or vacuum release valve.

Calculates pressure surge generated by water column impact following expulsion of air.

Bladder Tank Precharge Calculator:

Click Bladder Precharge to open.

Can use results obtained for a closed surge tank to size a bladder tank and determine required precharge pressure—this bladder tank will provide same results as closed surge tank.

Note that initial volume is input for closed surge tank, and then maximum volume is determined by volume plot for surge tank.

Make sure initial maximum volume has been reached.

Initial air pressure is computed by an initial steady state analysis.

Active Valve Characteristics Curve Generator:

Click AV Characteristics Curve Generator to open.

Calculates minor loss (or k-coefficient) for a valve based on input curve of open area ratio versus stem position.

Curve generator can be used to create a curve that describes minor loss versus percent open characteristics of a typical valve.

Refer to Autodesk InfoSurge Help topic, Surge Calculators for more information on surge calculators and their input and output fields.