实际气体喷管喉部尺寸的设计计算

NOZZLE THROAT DESIGN UNDER REAL GAS CONDITION

由于天然气输送中的压力通常较高,因此,天然气不能按理想气体处理。本文详细介绍了采用BWRS方程计算天然气在喷管内流动时喷管喉部临界参数的计算方法、过程以及计算程序编制步骤,计算了不同喷管入口压力下喷管喉部面积,并将之与理想气体状态方程的结果进行了比较。结果表明,在喷管入口压力比较低,设计精度要求不高时,可以采用基于理想气体状态方程的喷管喉部计算公式。但如果天然气压力大,设计精度要求较高时,就必须采用实际气体方程进行喷管设计计算。

Usually the pressure of natural gas in transportation system is very high, so it can＇t be treated as ideal gas in the process of design calculation. In this paper, the authors presented a method of nozzle throat design with BWRS state equation as the basic formula, and further the corresponding results at different inlet parameters were compared with those of the method under ideal gas condition. The analysis shows that natural gas can be treated as ideal gas when the pressure of the nozzle inlet is relatively low and the design accuracy is not strictly specified, or the method under real gas condition should be used in the process of design calculation of nozzle throat.