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Hitachi

Hitachi Industrial Products, Ltd.Pump system

We build optimal systems for pump equipment using a range of simulation technologies.

Siphon flow simulation

We apply our own simulation technology to siphon piping such as discharge pipes for drainage pumps and propose quick siphon formation.

Siphon phenomenon

When the pump is started under the siphon piping, air is forced to be ejected, the air bubbles are then entrained out and finally the bubbles are diffused. The siphon will then be formed and the pump will operate normally. Quick siphon formation is important to fully bring out pump performance.

Image: Pump discharge and piping siphon formation
Pump discharge and piping siphon formation

Summary of the analysis

  • We use our own two-fluid model flow analysis technology to analyze the gas-liquid two-phase flow of the siphon phenomenon.
  • When we do case studies at the planning stage, we analyze the siphon phenomenon using a combination of the gas-liquid two-phase analysis and the law of similarity.
  • In a detailed analysis, we use the gas-liquid two-phase analysis to simulate processes directly from pump start-up to the siphon formation process.

Comparison between test and analysis results

We have compared the analysis and test results for the rectangular siphon piping, as shown below, and have confirmed that our test and analysis results match.

Image: Analysis using scaling
Analysis using scaling

Main applications

  • Pump equipment with siphon piping