Vibration, dynamics and noise

formerly BETA Machinery Analysis and SVT Engineering Consultants

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Helmholtz Calculator

How effective will your bottle be at reducing acoustical pulsations?

Applications:

  • Sizing pulsation filtration devices
  • Formulas and instructions: API standard 618, Fourth Edition, Appendix O

Instructions:

  • Enter the ID and length of all components
  • Enter the gas properties which are used to calculate the speed of sound
  • Press the "Calculate Helmholtz" button

Cautions/Tips:

  • The pressure drop through the choke tube should be kept below API 618 pressure drop guideline. Orifice plates may be required to assist in pulsation suppression.
  • The Helmholtz frequency for any system should avoid coincidence with an order of run speed. The Helmholtz frequency should ideally be about 70% of the minimum run speed. Alternately the Helmholtz frequency can be set between 1 and 2 times run speed.

Disclaimer: All calculations provided at the BETA Machinery Analysis web site are intended for educational use only.

Inputs

Geometry
ComponentID (inches)Length (inches)
Volume 1
Choke
Volume 2
Gas properties
K = Specific Heat Ratio
T = Temperature (°F)
Z = Compressibility Factor
Specific Gravity = Density of gas / Density of air at standard conditions

Results