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Problem with the centrifugal pump is calculated for the occurrence of cavitation

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Old   February 2, 2022, 09:55
Default Problem with the centrifugal pump is calculated for the occurrence of cavitation
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Rec
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I ask for help with the question below questions in 3 languages: English, German and Russian.
Grateful for any help.

The centrifugal pump is calculated for the occurrence of cavitation in the impeller.
The calculation consists of 2 stages:
Stage #1
Stationary calculation in a two-phase medium. We use the Rayleigh–Plesset model. At the beginning of the liquid -1, Gas - 0, set the pressure of saturated vapors, etc. The calculation proceeds normally, an acceptable result is obtained. Cavitation occurs where needed.
Stage #2
Non-stationary calculation. To start the non-stationary calculation, the previously obtained stationary growth is used.
The problem is that after about 20-30 iterations (20 minutes of calculation on a 32-core processor) an error occurs - OWERFLOW.
What is the possible reason for the error? How to eliminate it? What method of receipt calculation in a two-phase medium is acceptable for pumps?
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Die Kreiselpumpe wird auf das Auftreten von Kavitation im Laufrad berechnet.
Die Berechnung besteht aus 2 Stufen:
Stufe 1
Stationäre Berechnung in einem zweiphasigen Medium. Wir verwenden das Rayleigh-Plesset-Modell. Stellen Sie zu Beginn der Flüssigkeit - 1, Gas - 0 den Druck der gesättigten Dämpfe usw. ein. Die Berechnung läuft normal ab, es wird ein akzeptables Ergebnis erhalten. Wo es nötig ist, tritt Kavitation auf.
Stufe 2
Instationäre Berechnung. Um die instationäre Berechnung zu starten, wird die zuvor empfangene stationäre Berechnung verwendet.

Das Problem ist, dass nach etwa 20-30 Iterationen (20 Minuten Berechnung auf einem 32-Kern-Prozessor) ein Fehler auftritt - OWERFLOW.
Was ist die mögliche Ursache für den Fehler? Wie kann man es beseitigen? Welche Methode der Zugangsberechnung in einem zweiphasigen Medium ist für Pumpen akzeptabel?
---------------

Рассчитывается центробежный насос на возникновение кавитации в рабочем колесе.
Расчёт состоит из 2-х этапов:
Этап №1
Стационарный расчет в двухфазной среде. Используем модель Rayleigh–Plesset. В начале жидкости -1, Газ - 0, задаем давление насыщенных паров и т.д. Расчет идет нормально, получается приемлемый результат. Кавитация возникает там где нужно.
Этап №2
Нестационарный расчет. Для запуска нестационарного расчета используется ранее полученный стационарный растёт.
Проблема – примерно через 20-30 итераций (20 мин. расчета на 32 ядерном процессоре) возникает ошибка – OWERFLOW.
В чем возможна причина ошибки ? Как ее устранить? Какая методика проведения квитанционного расчёта в двухфазной среде приемлема для насосов?
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Old   February 2, 2022, 17:53
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Convergence on cavitation models can be challenging. I do not know of any problems specific to transient cavitation models.

All I can suggest is the normal stuff to improve convergence:
* Double precision numerics
* Better mesh quality
* Smaller time steps
* Tighter convergence criteria
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