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For the last 50 years the natural gas industry has relied on acoustic analysis tools to determine piping system resonances for reciprocating compressor stations. This was initially accomplished using an analog electric circuit simulation where essential compression station elements were simulated using function generators, resistors, capacitors and inductors. Conveniently, the transient acoustic wave equation was simulated based on the functionally identical governing equations of electric circuitry. Later in the 1990s, this technique was improved upon by the application of digital computer simulations of the acoustic wave equation using numerical solver algorithms. However, both approaches did not solve the actual fluid dynamic equations of pulsating flow in pipes, but rather solved a linearized, acoustic (low pressure perturbation) equation. The classic wave equation solution is based on a number simplifying assumptions which include no mean through-flow, infinitely small pressure pulsations, equally small variations in acoustic density, no viscosity, and quasi-constant gas properties. Incorporation of linear attenuation terms will further distort the accuracy of the linear, acoustic model. These assumptions sufficiently simplify the equation to allow for superposition (simple summation of sources) and a fast solution for the resonant frequencies of complex piping systems. Unfortunately, these assumptions also severely limit the acoustic wave equation methodÂ’s ability to provide correct predictions of high pressure pulsation magnitudes. For variable-speed high-rpmmachines, where resonance will inevitably occur due to overlapping speed bands, accurate prediction of pulsation magnitudes is critical to the design process. Specifically, as pulsations in real piping systems tend to be large (>1% of mean pressure) and have a mean flow component, the inertial transport terms and the viscous terms of the governing equations must be included in the analysis to prediction t
Your Price $195.00
List Price $195.00