Running calculation

The following types of calculations are provided in the Hydrosystem:

• isothermal flow calculation - hydraulic calculation of steady-state (stationary) flow with constant temperature in a pipeline with a fully known configuration. In this calculation thermal effects (heat exchange with the environment, various internal cooling/warming effects in the fluid, etc.) are not taken into account, the fluid temperature in the pipeline is taken to be equal to the values specified in the input data. To run this calculation, click the  button of the Main toolbar and select the "Calculate Isothermal Flow" sub-item  (or use the corresponding "Analysis" menu item);

• diameters calculation - hydraulic calculation of steady-state (stationary) flow for a pipeline with unknown or partially known diameters (and with the aim to determine them). In this calculation thermal effects (heat exchange with the environment, various internal cooling/warming effects in the fluid, etc.) are not taken into account, the fluid temperature in the pipeline is taken to be equal to the values specified in the input data. To run this calculation, click the  button of the Main toolbar and select the "Calculate Diameters" sub-item (or use the corresponding "Analysis" menu item). Please note that upon completion of the diameters calculation, if the diameters are successfully calculated, the following message will be displayed:

If you click "Yes" in this window, the selected values of the internal diameters will be saved in the input data for the branches. This is convenient in cases where other calculations are planned for this pipeline, for example, the control valves sizing or the calculation of waterhammer, since for these calculations the diameters must be specified in the initial data. However, this may be inconvenient in cases where it is necessary to repeat the diameters calculation for this pipeline (for example, with other initial data or other calculation settings) - if the diameter is specified in the initial data, it will be considered a known value during the calculation and its value will not be calculated. Therefore, for such cases, it is better to click "No" in the above window. The selected diameters in this case will be shown in the calculation results, but will not be stored in the initial data.

Note: If you accidentally saved the diameters in the input data by clicking "Yes" in this window, you can cancel this operation by clicking the  button of the Edit toolbar or using the corresponding "Edit" menu item. In addition, you can quickly "zero out" the selected diameters in all branches using group replacement operations (for more information, see here);

• heat and hydraulic calculation - thermal and hydraulic calculation of steady-state (stationary) flow in a pipeline with a fully known configuration. This calculation takes into account the thermal interaction of the pipeline with the environment, heat gain due to internal friction in the fluid, inversion and other thermal effects in the pumped fluid, as a result of which, in addition to the hydraulic calculation, the change in the fluid temperature along the flow is also calculated. To run this calculation, click  button of the Main toolbar and select the "Calculate Heat and Hydraulic" sub-item  (or use the corresponding "Analysis" menu item);

• waterhammer calculation - calculation of a transient (non-stationary) process in a pipeline caused by a change in the state of piping components (valves closing/opening and/or pumps switch on/off and/or any combinations of these events). To run this calculation, you must first perform one of the steady-state flow calculations (isothermal flow analysis, diameters calculation or heat and hydraulic calculation), then click the  button of the Waterhammer toolbar or use the corresponding menu item "Analysis - Calculate Waterhammer". The progress of the waterhammer calculation is displayed by the progress bar in the status line of the program window (in the lower right part). At any time, the waterhammer calculation can be "paused" by the  button of the Waterhammer toolbar, for example, to study the calculation results (pressure, velocities, etc.) at the current moment. The paused calculation can then be resumed by clicking the button again or reset (for example, to start it over with different parameters or settings) by clicking the  button of the Waterhammer toolbar (or using the corresponding menu item "Analysis - Calculate Waterhammer").

Please note that some calculations may be unavailable, for example, if you do not have licensed certain program modules or if the calculation is performed for a two-phase flow with mass transfer (with the "Undefined" fluid phase state) for which isothermal and diameters calculations are not provided. Calculations of steady-state flow (isothermal flow analysis, diameters calculation and heat and hydraulic calculation) can be performed either for each pipeline in the project separately (by selecting this pipeline or any of its elements in the project tree), or for all pipelines in the project (if there are several) simultaneously. In the latter case, you need to select the project in the tree before running the calculation.

If errors are detected in the input data or during the calculation process, they will be shown in the calculation log window. Error messages in the calculation log are synchronized with the project tree and the Object Properties Window. When you click a specific message, the object to which this message refers is selected in these windows - this way you can easily find out what caused the problem in the calculation, then change the input data and run the calculation again. In addition to the above-mentioned window, the isothermal flow calculation log is also saved in the 'hydro.log' file, which is written to the temporary files directory of the Windows user account. Additional information (maximum error in calculating flow rates and pressures and the number of iterations in the calculation) is also output to this file.

If any changes are made to the input data, the calculation results are immediately reset. Also, the results of the calculations performed are not saved together with the project file, so when opening a previously saved file to view the calculation results in it, it is necessary to repeat the calculation for pipelines.