Conference Year

2014

Keywords

Reciprocating compressor, Gas pulsation attenuator, Pressure loss

Abstract

Gas pulsation produces excessive noise in the piping system of the reciprocating compressor and even causes damage in the piping and the machine. Therefore, it is very important for reasonable analysis and proper control of pressure pulsation. The perforated tube attenuator is widely applied in the compressor because of its favourable performance of acoustic attenuation. For the attenuator design, pressure loss and transmission loss are the two equally significant parameters characterizing its performance. Even if an attenuator can greatly reduce the compressor pressure pulsation, but cause large pressure loss, it will not be used yet. So it’s necessary to pursue the attenuator with low pressure loss as well as low pressure pulsation. The traditional method of calculating pressure loss of the attenuator is according to empirical formulas, which only fit for simple structures. But for the perforated tube attenuator, the flow is complex, and the empirical formulas are not available to calculate the pressure loss. Presently, CFD method is used to calculate pressure loss of the attenuator with complex structure. Most perforated attenuators could consist of hundreds of small holes distributed on the pipe, so three-dimensional flow models ensure the accurate solution. This paper predicts pressure loss of the perforated tube attenuator with various geometry parameters using CFD. A three-dimensional CFD model of the attenuator was established under the following assumptions: (1) The physical parameters of the solid and fluid domain of the attenuator are constant; (2) The flow is steady turbulent flow; (3) The influence of the gravity is ignored; (4) The inlet velocity of the attenuator is homogeneous without impulse effect. The standard - model is used in this paper. The flow through the attenuator follows the law of conservation of mass, law of conservation of momentum and the law of conservation of energy. The solution of the model was implemented with the FVM method of the commercial CFD code fluent. According to the CFD model, the following three aspects were analyzed: (1) The influence of the hole diameter on the pressure loss (2) The influence of porosities on the pressure loss (3) The influence of the inlet velocity on the pressure loss Based on analysis of the above three aspects, an attenuator with low pressure loss as well as low pressure pulsation was designed.

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