Local natural gas companies in Iran employ turbine flow meters to measure natural gas which is delivered to Compressed Natural Gas (CNG) stations at low pressure. The stations, then, utilize reciprocating compressors to increase pressure to a very high level. The reciprocating compressor produces a flow pulsation which largely affects the accuracy of the measurement. The main aim of this article is to eliminate or decrease the compressor effects on measurement accuracy by utilizing a snubber between the turbine flow meter and the reciprocating compressors. To this aim, a numerical model has been built to simulate natural gas flow through a snubber. The effects of various snubber parameters on pressure pulsation at the station inlet have been investigated numerically. The parameters included are: snubber volume to the minimum volume ratio; the ratio of height to diameter; outlet pipe length; and the existence and non-existence a buffer. The ANSYS FLUENT package has been used for numerical modeling with transient analysis. The turbulence model applied in this study was k-ε/ high Reynolds number. Results show that with a height to diameter (H/D) value of 3, the maximum reduction in the percentage of pressure pulsation drop is about 47%; increasing the outlet pipe length to 10 times the initial length causes a decrease of about 83% in pressure pulsations. In addition, for the ratio of snubber volume to the minimum volume from 1 to 16.7, amplitude of pressure pulsations decreases from 4.1% to 0.25%.

Keywords