Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
A MODIFIED WINDKESSEL MODEL APPLIED IN A TUBULAR PULSATION DAMPENER ANALYSIS
Submission Author:
Michel de Oliveira dos Santos , ES
Co-Authors:
Michel de Oliveira dos Santos, Daniel Ribeiro, João Paulo Barbosa, Renato Siqueira
Presenter: Michel de Oliveira dos Santos
doi://10.26678/ABCM.COBEM2021.COB2021-1355
Abstract
In this work, the two-parameter Windkessel model, a model widely used in the area of hemodynamics, was used to determine the behavior of a tubular pulsation dampener, with deformable latex walls, installed in a hydraulic circuit powered by a positive displacement pump. Pulsation dampeners or accumulators are devices widely used in industrial pumping systems to reduce pressure and flow pulsations that generate excessive noise, undesirable mechanical vibrations and process instabilities. In conventional pulsation dampeners, compressed gases are used as a continuous deformable medium, with pure nitrogen and dry air being the most common gases. However, to achieve greater reliability, an accumulator can be designed to dispense the compressed gas, as long as it provides the same level of pressure and flow attenuation in a suitable frequency range. At first, the Windkessel model was modified to consider the variable flow resistance due to the turbulent regime, but keeping constant dampener compliance. In sequence, another modification was made to consider the pressure-dependent pulsation dampener compliance. To estimate compliance as a pressure function, by means of simulations using the finite element method a relationship between accumulator volume variation and an average internal pressure related to steady state flow Reynolds number was determined. The results of two modified models were compared in terms of attenuation (ratio between flow amplitude before and after the pulsation dampener) and dampener volume change. Non-linear ordinary differential equations resulting from modified models were solved for time averaged Reynolds number range from 16000 to 24000 and Strouhal number from 0.01 to 0.13. Results demonstrated that an increase in both Reynolds and Strouhal number resulted in greater attenuation of flow amplitude. Also greater attenuation was achieved in variable compliance model (maximum value of 4.72) than constant compliance model (maximum value of 3.07). Regarding dampener volume change, it was verified that it mainly decreases for a Strouhal number increase. In general, best theoretical behavior of the dampener (higher attenuations and lower volume changes) was found for higher values of both Reynolds and Strouhal number for evaluated ranges.
Keywords
Pulsation dampeners, Windkessel model, Intermittent flow, hydraulic systems modeling, Finite Element Method
