A pulsation analysis is only as accurate as the data that goes into the acoustic model. Engineers who have seen analysis results diverge from field measurements almost always find the same root cause: inaccurate or incomplete input data.
What Goes Into the Model
A complete acoustic model for a reciprocating compressor system includes compressor cylinder dimensions and valve timing data, gas composition and thermodynamic properties at suction and discharge conditions, complete piping geometry including all bends, tees, reducers, and lengths, pulsation suppression vessel geometry including internal baffles, all orifice plate locations and diameters, and operating speed range including any variable speed capability.
Each of these inputs affects the acoustic simulation in a specific way. Gas composition affects acoustic velocity, which shifts resonance frequencies. Piping geometry determines the acoustic mode shapes. Bottle geometry controls the suppression effectiveness at each harmonic.
The Most Common Input Errors
The single most common data problem is inaccurate piping geometry. Analysis is often performed on planned geometry from early P&IDs, but the as-built configuration differs. When this happens, the analysis results are technically correct but don’t represent the actual installation.
Gas composition errors are the second most common issue, particularly on projects where the gas stream changes over the production life of the field.
Tech Transfer’s Approach
Our analyses are built on actual equipment data provided by the compressor manufacturer and confirmed gas data from the operator. When as-built piping geometry differs from the design, we perform a field measurement campaign to update the model before making recommendations. The additional time this requires is always less than the cost of implementing the wrong corrective action.
