Passive pressure pulsation damping using shaped nozzles

Pressure pulsations in intake and outlet systems of positive-displacement compressors are one of the most important problems in compressed gas pipelines. This problem occurs not only in huge compressed systems, such as the natural gas piping in gas mines or national gas transport systems, but also in small refrigeration compressors in domestic applications. Nowadays systems require new approach since in all applications the variable rotational speed compressors are introduced. The mufflers designed in a conventional way on the basis of the Helmholtz theory are effective only for specific frequency range. In case of variable rotational speed the reaction of such damper may be insufficient. Therefore, any innovative ideas for pressure pulsating damping are welcomed by the compressor industry. One of the possible solutions to attenuate pressure pulsation over a wide range of frequencies is the introduction of shaped nozzles just after the compressor outlet chamber. It is obvious that the nozzle attenuates pressure pulsation, but simultaneously the requirement for the driving power of the compressor rises. The main subject of this paper is to show that using properly shaped nozzles one can achieve pressure pulsation damping, with insignificant influence on the compressor power consumption. The results of experimental investigations and some results of CFD analyses are shown in the paper, with indication for the best construction of the nozzle shape.

Full text (pdf)

1. Andersen K.S.: Analyzing muffler performance using the transfer matrix method, COMSOL Conf., Hannover 2008.
2. Cyklis P.: Experimental identification of the transmittance matrix for any element of the pulsating gaz manifold, J. Sound Vibration, 244 (2001) 859-870.
3. Cyklis P.: Transmittance estimation for any element of volumetric compressor manifold using CFD simulation, Arch. Mech. Eng., 56 (2009) 157-171.
4. Dowling J.F., Peat K.S.: An algorithm for the efficient acoustic analysis of silencers of any general geometry, Appl. Acoustics, 65 (2003) 211-227.
5. Georges S.N.Y., Jordan R., Thieme F.A., Bento Coelho J.L., Arenas J.P.: Muffler modeling by transfer matrix method and experimental verification, ABCM, XXVII (2005) 132-140.
6. Huang Z., Jian W.: Vibration analysis of pipelines with arbitrary branches by absorbing transfer matrix method, J. Sound Vibration, 306 (2007) 215-226.
7. Ma Y.-C. and Min O.-K..: Pressure calculation in a compressor cylinder by a modified new Helmholtz modeling, J. Sound Vibration, 243 (2001)775-796.
8. Mehidizadeh O.Z., Paraschivoiu.: A three-dimensional finite element approach for predicting the transmission loss in mufflers and silencers with no mean flow,
   Appl. Acoustics, 66 (2005) 902-918.
9. Sekavcnik M., Ogorevc T., Skerget L.: CFD analysis of the dynamic behaviour of a pipe system, Forsh Ingenieurwes, 70 (2006) 139-144.