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Help Create and edit objects on scheme

How to use Stokes


Create and delete objects
Types and parameters of objects
· Consumers
· Splitters
· Reductors and Pumps
· Sources
· Pipes
· Mass editing of objects
Scheme parameters


Create and delete objects


Look at the panel with buttons on left of the work field. By default, "Hand" is selected — in this mode, you can move and select existing objects.

For add new objects to the scheme, select the desired type and then left-click on the places where you want to create objects of the selected type.

For create a pipe, select the node to which first end of the pipe should be connected, and then click the middle mouse button (click on the wheel) on the second node. A pipe will be laid between them. You can select one or several objects at once — after clicking on the second node, as many pipes will be laid as objects have been selected.

If the mouse does not have a wheel (for example, it is not a mouse, but a laptop touchpad), instead of the middle button, right-click on node and select "Lay pipe here".

You can delete objects by selecting them and pressing the Delete button on the keyboard. You can also right-click on the selected objects and select "Delete".

For select one object, left-click on it. You can select several objects by dragging the mouse cursor with the left button pressed on the work field.


Types and parameters of objects


There are six types of objects in the Stokes: five types of nodes (consumers, splitters, reductors, pumps, sources) and pipes, which connects nodes.

To open the window for editing object parameters, double-click on it with the left mouse button.

All types of objects have parameters Name and Color. These parameters are used exclusively for display on the scheme and do not affect the calculations in any way.

In the upper part of the parameters window for all types of objects there is a drop-down list that allows you to quickly set some parameters with some typical values.

Consumers

The final consumer of gas/liquid, only one pipe can be connected to it.

  • Debit – gas/liquid consumption. For gases, it is indicated at atmospheric pressure.
  • Altitude – the altitude of the object above sea level. It is used to calculate the difference in hydrostatic pressure between the start and end of the pipe between a pair of objects.
  • Min. allowable input pressure
  • Max. allowable input pressure – when the calculated pressure on this object exceeds the specified limits, it is highlighted in red, signaling an error.

Splitters

The branching point of the pipeline.

  • Altitude
  • Min. allowable input pressure
  • Max. allowable input pressure
  • Pressure loss – fixed pressure loss value to simulate local resistance. It is highly not recommended to use this parameter.

Reductors and Pumps

Nodes that change the pressure to a given level. They differ only in the icon, otherwise they work the same way.

The calculation model assumes that reductors and pumps can provide unlimited gas/liquid flow and their outlet pressure remains fixed.

  • Output pressure – fixed pressure at the outlet of the reductor/pump.
  • Altitude
  • Max. allowable debit – when the debit through the node exceeds this value, the object is highlighted in red, signaling an error.
  • Min. allowable input pressure
  • Max. allowable input pressure

Sources

Source gas/liquid. This is usually the connection point to the main pipeline.

The calculation model assumes that sources can provide unlimited gas/liquid flow and their outlet pressure remains fixed.

  • Pressure
  • Altitude
  • Max. allowable debit – when the debit through the node exceeds this value, the object is highlighted in red, signaling an error.

Pipes

  • L – length – 100 m by default.
  • k – coeff. local losses – before using in the pressure drop calculation formulas, the length is multiplied by this coefficient. In SP 42-101-2003, it is recommended to increase the estimated length by 5-10% to account for local losses – for this, use a coefficient of 1.05-1.1.
  • D – diameter – inner diameter of the pipe. 50 mm by default.
  • n – roughness – for steel pipes usually used 0,1+ mm, for PE 0,007 mm (for gas).
  • Vmax – max. allowable speed – if the speed of the pumped fluid exceeds this value, the pipe is highlighted in red. Also, this parameter is used in the automatic selection of diameters: if, with a diameter selected according to hydraulic resistance, the speed is higher than the set one, the diameter is additionally increased to reduce the speed to the allowed one.

Mass editing of objects

In version 22.12, a form for mass editing of objects was added. You can edit either all the objects in the scheme at once, or only the selected ones. The parameters are set individually for each type of object.

You can open the mass editing form in the menu Edit → Mass editing of objects F2. If any objects were selected at the moment of opening the form, the "What to edit" switch will be set to "Selected objects only". But you can also choose the option "All objects".

Specificities of form fields

  • Parameters Name of objects will edit only if the corresponding fields were in focus. If you clicked there with the mouse or at least once entered them using the Tab button, then the names of the corresponding objects will be edited after clicking OK, even with an empty value.
  • The remaining text fields are applied to the corresponding objects if they are filled with something. If the field is left empty, the corresponding parameter of the objects will not be changed.

Scheme parameters


For configure the scheme parameters click the "Parameters" button on the left side of the window, under the object type buttons.

  • Density – for gases, the density at atmospheric pressure is used. If the density is greater than 50 kg/m3 (50000 g/m3), the pumped fluid is considered an incompressible liquid. If less – then an ideally compressible gas.
  • Viscosity – kinematic viscosity.

Attention! By default, the parameters for natural gas are used. If you are calculating not a gas pipelines, be sure to change the viscosity and density of the pumped fluid!

Work area size

By default, work area size is 2000x2800 pixels. You can change it by pressing Ctrl+R or click Project → Work area size in main menu.

If the checkbox "Move objects proportionally" is checked, then when changing the size of the scheme, all objects will move proportionally closer/away from each other. If there was a background image, it will also increase, so that the objects will remain in the same places relative to the background.

If the checkbox is not checked, the working field will be enlarged/reduced, but the objects will be at the same distance from each other as before.

If you started to make a scheme and at some point realized that it turns out too tightly, the labels of objects are crawling over each other, try to increase the size of the scheme 2-3 times with the checkbox pressed.

If you add a background image Ctrl+Shift+B, the resolution of which is greater than the current size of the scheme, the working field will be automatically enlarged to the size of the image.