Vibrational characteristics of piping system in air conditioning outdoor unit

Abstract

The modal analysis of piping system in air conditioner (AC) outdoor unit is essential to investigate the vibration properties of the system. In view of the growing significance of numerical finite element (FE) model for vibration behaviour prediction, the AC piping elastic end support characterization has been explored. The axial and radial stiffness variables (k a , k r1 , k r2 ) of the compressor-piping mounting are obtained and represented by dynamic stiffness of compressor grommet. They are obtained from dynamic load deflection test based on compressor operating condition such as excitation frequency and amplitude. The unknown stiffness variables of the other tube end (chassis-piping mounting) are determined by parameter fine tuning. An experimental modal analysis using impact hammer test has also been employed to determine the vibration properties such as natural frequencies, mode shapes and damping ratio of the piping structures. The modal parameters acquisition using SCADAS mobile acquisition system and LMS Impact Testing software is compared with the corresponding simulated modal properties using Abaqus. Most of the simulated natural frequencies achieve good correlation with the measured frequencies and it is reasonably a good prediction model to predict vibration behaviour of AC piping structures. air conditioning outdoor unit, piping, modal analysis, vibration characteristics Citation:Loh S K, Faris W F, Hamdi M, et al. Vibrational characteristics of piping system in air conditioning outdoor unit.

Vibration cause analysis and elimination of reciprocating compressor inlet pipelines

“…Each piping element has a transfer matrix M. For example, to a straight pipe, the transfer matrix M is given by Eq. (2). For the total piping system, the governing equation of acoustic natural frequency of pipe is formulated by multiplying the transfer matrices of all the piping elements as Eq.…”

“…The studies concerning pipeline vibration and pressure pulsation mainly include theoretical research and engineering application. Theoretical research includes building mathematical modeling of pipelines, model parameters calculation, pressure pulsation simulation, fluid-structure interaction conveying fluid and a dynamic response of pipeline [1,2]. The acoustic wave theory, transfer matrix method, and finite element method have been proposed to analyze gas pulsation in the piping system [3,4].…”

Statistical Methods to Estimate Natural Frequency of Air Conditioner Piping

“…The number of degrees of freedom associated with a factor is equal to one less than the number of levels for that factor (Madhav Phadke, 1989). Therefore degrees of freedom (DOF) of factors are (A(2), La (2)…”

“…Statistical methods (DOE and Regression analysis) applied to cantilever beam in order to avoid resonance are demonstrated in [1]. Results from finite element methods and experimental methods for an air conditioning piping are compared in [2]. Design optimization techniques for an air conditioning piping system to reduce the cost of pipes are discussed in [3].…”

Vibration Failure Analysis and Countermeasures of the Inlet Pipelines at a Gas Compressor Station

“…Consequently, it is important to study and then analyze the vibration phenomena to avoid such possible problems. e researches concerning piping vibration and vibration control mainly include vibration theoretical studies and applications in engineering [1][2][3]. eoretical studies include building mathematical modeling of pipelines, vibration experiments, and investigation using numerical analysis, such as modal analysis, acoustic analysis, and fluid-structure interaction between pipe and fluid in pipe [4][5][6].…”