基于BWRS方程的压缩空气压缩因子计算

使用压缩空气作为介质进行流体计算时,为保证计算精度须考虑压缩因子的影响。为了精确得到压缩空气的压缩因子,对压缩因子的计算方法进行了研究。将空气简化为氮气与氧气的混合气体,通过3个真实气体状态方程计算压缩因子,并与已有数据进行比较,验证了将空气模型简化,再计算其压缩因子的方法是可行的。BWRS方程计算出的压缩因子精度较高,但在不同压力下的计算误差有较大差距。为进一步提高计算精度,考虑了偏心因子的影响,通过计算分析、经验修正,得到了精度较高的压缩因子计算算法,并进行了试验验证。结果表明：不同压力下改变偏心因子的数值对计算结果有不同程度的影响;改进后的BWRS方程计算精度得到了提高,从而验证了BWRS方程改进算法计算压缩因子的有效性和可行性。

Compressibility Factor Calculation Method of Compressed Air Based on BWRS Equation

When using compressed air as medium of flow calculation,compressibility factor should be considered to ensure the calculation accuracy. In order to obtain the precise compressibility factor of compressed air,the compressibility factor calcula.tion method was studied. The air was reduced to mixed gas of nitrogen and oxygen, three real gas equations of state were used to calculate the compressibility factor and the calculations were compared with the practical data, verify the feasibility of this calculation method. The calculation accuracy of BWRS equation is the highest of the three equations,but the calculation error of BWRS equation varies widely under different pressures. In order to improve the accuracy,the impact of acentric factor was considered. Empirical correction was made after calculation analysis, an improved calculation algorithm with higher precision was obtained, and the improved algorithm was then verified through experiment. The results show that changing the value of acentric factor has different impacts on the calculation results under different pressures and the calculation precision is improved after empirical correction, proides the improved BWRS equation calculation method is feasibility and validity.