图共 5个 表共 5
    • 图  1  BP神经网络训练误差

      Figure 1.  Training error of BP neural network

    • 图  2  压缩机第四段压比

      Figure 2.  Pressure ratio of the fourth section of the compressor

    • 图  3  压缩机第四段多变效率

      Figure 3.  Polytropic efficiency of the fourth section of the compressor

    • 图  4  裂解气四级压缩系统

      Figure 4.  Cracking gas four-stage compression system

    • 图  5  压缩机功耗、第四段多变效率与出口温度的关系

      Figure 5.  Relationship among power consumption, the fourth polytropic efficiency and the outlet temperature of compressor

    • ItemIterations timesStandard deviation
      BP algorithm1980.164 4
      LR-GA-BP algorithm200.011 5

      表 1  迭代次数与标准差

      Table 1.  Iterations times and standard deviation

    • SampleExpected valueBP output valueLR-GA-BP output value
      0,000.164 30.015 2
      0,110.947 70.999 6
      1,010.985 90.999 2
      1,100.225 80.013 2

      表 2  两种算法学习结果比较

      Table 2.  Comparison of learning results between two algorithms

    • Normalized flow$\varepsilon '$Normalized flow$\eta '$
      0000.510 6
      0.067 90.133 30.047 20.587 2
      0.071 70.177 80.098 70.668 1
      0.154 70.255 60.158 80.744 7
      0.166 00.322 20.231 80.838 3
      0.267 90.411 10.309 00.914 9
      0.290 60.444 40.390 60.974 5
      0.381 10.555 60.442 10.995 7
      0.422 60.577 80.510 71.000 0
      0.494 30.644 40.588 00.987 2
      0.535 90.722 20.652 40.957 4
      0.600 00.733 30.703 90.910 6
      0.649 10.766 70.746 80.846 8
      0.698 10.788 90.789 70.770 2
      0.762 30.788 90.828 30.676 6
      0.792 50.844 50.858 40.587 2
      0.864 20.911 10.884 10.489 4
      0.875 50.966 70.909 90.400 0
      0.947 21.000 00.931 30.314 9
      1.000 01.000 00.94850.251 1

      表 3  归一化样本数据

      Table 3.  Normalized sample data

    • ComponentPredicted value/%Actual value/%Relative error/%
      H27.0616.9731.26
      CH432.46232.503-0.13
      C2H440.55940.4760.21
      C2H65.6115.706-1.66
      C3H6 12.25612.320-0.52
      C3H81.0571.066-0.84

      表 4  压缩机第四段出口气体主要组分预测值与实测值比较

      Table 4.  Comparison between predicted values and actual values of main components in cracking gas from the fourth-stage outlet of the compressor

    • CompressorOutlet temperature/℃Relative error/%Outlet pressure/MPaRelative error/%
      Predicted valueActual valuePredicted valueActual value
      C100-1ST82.582.500.2710.2690.74
      C100-2ND82.983.4−0.600.4930.494−0.20
      C100-3RD84.384.20.120.9470.951−0.42
      C100-4TH101.1101.3−0.202.4152.4110.17

      表 5  压缩机各段出口温度/压力预测值与实测值比较

      Table 5.  Comparison between the predicted temperatures /pressures and actual values of each stage outlet of compressor