Other Compressor Design Studies

 

Along with a standard pulsation/vibration study, here are three optional studies that may be required.

  • Dynamic and Static Stress Calculation on Pulsation Bottle Internals (formerly M.8)
  • Compressor Valve Dynamic Response Study (formerly M.9)
  • Pulsation Bottle Low Cycle Fatigue Analysis (formerly M.10) 
 

Dynamic and Static Stress Calculation on Pulsation Bottle Internals (formerly called M.8)
This analysis applies pulsation-induced shaking forces and pressure-induced static forces to the shell and vessel internals and computes stress levels to meet API 618 guidelines.

The primary dynamic load acting on the baffle is the unbalanced force resulting from the pressure pulsations. The overall unbalanced force is calculated by the acoustical simulation. The overall unbalanced force is applied, as a pressure, first to the concave and second to the convex side of the baffle to calculate the alternating stress. The vessel design pressure is also applied to the inside of the shell.

This loading is applied to an axisymmetric finite element model of the baffle and pulsation bottle shell. The model is created using the ANSYS 11.0 analysis software. The model uses 3D solid elements or 2D plane axisymmetric to simulate the baffle and shell deflection.

Compressor Valve Dynamic Response Study (formerly called M.9)
This analysis predicts compressor valve behavior and, if required, recommends modifications to the proposed valves or selects alternate valves.


Pulsation Bottle Low Cycle Fatigue Analysis (formerly called M.10)
When required by Division 2 of the ASME code, this analysis is used to predict the stresses from thermal gradients, thermal transients, and pressure cycles on the pulsation-suppression devices and internal components. The stresses are compared to ASME-code allowable.

 

 

 
Bottle Dynamic and Static Stress

Bottle - Dynamic and Static Stress