Translated Abstract
Reciprocating compressor, as an important device of conveying and compressing gas, is widely used in the modern chemical and petroleum industry. The vibration on reciprocating compressor obviously threaten the production safty, and the gas pulsation is the main reason that causes such pipe vibration. Orifice plate and buffer can reduce the gas pulsation effectively, but their design and production in industrial applications are usually empirical. In this thesis, the effects of different orifice plates and buffer on the gas pulsation of the piping system were investigated numerically and experimentally, thus providing a guideline for the design and application of orifice plate and buffer.
Based on the one-dimension acoustic equations, this thesis firstly studied the mechanism that orifice plate and buffer work to reduce gas pulsation in pipelines of reciprocating compressor. Next with the fluid simulation software CFX, the three-dimensional models of reciprocating compressor piping system were established for evaluating the pressure pulsation when orifice plates of different types and different aperture ratios are uesd alone or together with the buffer. Finally the test platform of reciprocating compressor outlet piping system was constructed to investigate the pressure pulsation with standard orifice plates of different aperture ratios used in the pipeline system.
The experiment and simulation results show that the standard orifice plate, multiple orifice plate and eccentric orifice plate are able to reduce the pressure pulsation after the orifice plates and in the main pipeline when the aperture ratio is 0.3. The reduction of gas pulsation by using both orifice plates and the buffer is better than all kinds of orifice plates uesd alone. In the main pipeline and the orifice to the buffer section, the reduction of gas pulsation decreases with increase of the aperture ratio, and the effect of the eccentric orifice plate is best in reducing the gas pulsation when the aperture ratio is 0.3. In the compressor outlet to the orifice section, the reduction of gas pulsation enhances with increase of the aperture ratio, and the effect of the multi-hole orifice plate is best in reducing the gas pulsation when the aperture ratio is 0.7. The orifice plates will generate a certain pressure drop across the orifice plates in the pipeline of reciprocating compressor. The pressure drop decreases with the increase of aperture ratio. The pressure drop after the orifice plates could reach 1%~8.5%, but the pressure will recover slightly again in the main pipeline. In general, the pressure drop in the whole pipeline is about 0.5%~8.1%. Utilizing the orifice plates alone have no influence on the spectrum distribution of gas pulsation in the pipelines of reciprocating compressor. The combined use of the orifice plates and the buffer lead to almost invariable spectrum distributions of gas pulsation in the pipelines at the aperture ratio of 0.3 and 0.4, whereas, the spectrums have peaks at the double frequency when the aperture ratios are 0.5, 0.6 and 0.7.
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