第一部分 翻译

1)Centrifugal compressors consist of a housing, an impeller mounted on a rotating shaft, bearings, and seals to prevent gas from escaping along the shaft.

2)Because natural gas is a mixture of several components with different physical properties, the properties of the mixture must be determined from a gas analysis for accurate calculation.

3)The typical design problem is not to determine the capacity of a compressor but to select a compressor to handle a given volume of a specific gas at the prescribed pressure conditions. 

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第三部分

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