-
摘要:
开展了可压缩流体中热线探针校准方法的研究,以满足其在各种速度测量场合的使用需求。研究了对数校准数学模型,发现校准系数求解过程中存在矩阵奇异性过强的问题,导致在速度小扰动条件下方程求解稳定性差。对对数校准数学模型进行了参数无量纲化及添加正向偏置的改进,建立了无量纲化对数校准数学模型。在马赫数为0.3~0.5,引射压力为150~300 kPa范围内进行了校准实验,利用对数校准数学模型对实验数据进行拟合,拟合优度为0.997 61,拟合速度平均偏差为1.378 m/s,校准系数求解过程中系数矩阵条件数为1.595×108,矩阵奇异性过强,加入速度小扰动(1 m/s)后,拟合优度为0.379 74,拟合速度平均偏差为43.81 m/s,方程求解稳定性差。利用无量纲化对数校准数学模型对实验数据进行拟合,拟合优度为0.998 95,拟合速度平均偏差为1.203 m/s,校准系数求解过程中系数矩阵条件数为3.655×102,且无量纲化方法不受速度小扰动影响。对流体速度进行不确定度分析,速度平均不确定度为3.168 m/s,无量纲化拟合速度平均偏差明显小于速度平均不确定度。实验结果证明了无量纲化对数校准数学模型应用于可压缩流体热线探针校准的可行性。
Abstract:Research on calibration method of hot-wire probe in compressible fluid is carried out to meet usage requirements of various velocity measurements. The logarithmic calibration mathematical model is studied and it is discovered that there is a problem of matrix singularity in the process of solving calibration coefficients, which results in poor stability in solving linear equations with a small velocity perturbation. The mathematical model is improved by nondimensionalizing the parameters and adding a positive offset to build a dimensionless logarithmic calibration mathematical model. Calibration experiments are conducted with Mach number varying from 0.3 to 0.5 and ejection pressure varying from 150 kPa to 300 kPa. When using the original logarithmic calibration mathematical model, the results of data fitting show that correlation coefficient is 0.997 61 and deviation of fitting velocity in average is 1.378 m/s. Condition number of coefficient matrix in the process of solving calibration coefficients is 1.595×108, which means that the matrix has a strong singularity. After introducing a small velocity perturbation (1 m/s), correlation coefficient becomes 0.379 74 and deviation of fitting velocity in average becomes 43.81 m/s, which shows instability in solving linear equations. When using the dimensionless logarithmic calibration mathematical model, the results of data fitting show that correlation coefficient is 0.998 95 and deviation of fitting velocity in average is 1.203 m/s. Condition number of coefficient matrix in the process of solving calibration coefficients is 3.655×102, which indicates a weak singularity, and the improved mathematical model is not affected by a small velocity perturbation due to selection of dimensionless method. Uncertainty of fluid velocity is analyzed and velocity uncertainty in average is 3.168 m/s, which is obviously greater than the deviation of fitting velocity in average. The experimental results verify the feasibility of application of the dimensionless logarithmic calibration mathematical model to hot-wire probe calibration in compressible fluid.
-
Key words:
- hot-wire probe /
- compressible fluid /
- logarithm /
- calibration /
- mathematical model /
- nondimen-sionalization /
- uncertainty
-
表 1 热线探针校准实验数据
Table 1. Data of hot-wire probe calibration experiment
pe/kPa E/V u/(m·s-1) p0/kPa T0/K Ma p/kPa T/K 151.727 8 1.989 6 103.563 0 89.971 59 296.064 2 0.302 14 84.431 88 290.755 8 149.573 2 2.090 3 119.608 2 92.018 07 295.797 0 0.350 92 84.537 09 288.687 0 149.767 1 2.172 6 136.852 8 94.236 87 295.526 7 0.402 18 84.330 02 286.266 2 150.004 1 2.232 5 152.453 6 96.477 22 295.220 4 0.448 39 84.035 05 283.808 4 150.068 8 2.291 6 169.145 6 99.148 41 295.028 3 0.499 72 83.610 31 280.994 1 199.366 3 1.940 0 102.981 2 82.302 70 294.631 5 0.301 66 77.267 83 289.365 2 200.185 0 2.030 4 119.696 6 84.047 59 294.588 1 0.349 86 77.197 20 287.548 9 200.982 3 2.106 0 136.410 3 86.201 77 294.599 5 0.401 29 77.168 82 285.407 6 200.422 1 2.163 9 153.318 0 88.851 41 294.599 5 0.449 60 77.225 88 283.152 4 199.905 0 2.232 4 169.811 9 91.651 86 294.626 9 0.502 26 77.238 02 280.476 1 249.827 3 1.864 0 102.435 2 73.793 69 294.689 7 0.300 05 69.306 57 289.477 4 250.883 1 1.956 9 119.159 4 75.452 41 294.646 2 0.350 00 69.339 75 287.599 8 250.366 0 2.041 6 136.317 2 77.649 67 294.553 7 0.401 37 69.522 38 285.359 5 250.796 9 2.111 3 153.334 8 79.911 57 294.466 9 0.452 31 69.465 87 282.892 0 248.776 1 2.174 1 168.775 2 82.668 91 294.385 9 0.501 19 69.740 60 280.303 8 300.094 5 1.786 9 104.509 8 65.306 21 294.492 1 0.306 63 61.183 71 289.056 4 299.275 7 1.868 9 119.193 9 67.180 35 294.401 1 0.350 80 61.730 54 287.329 4 299.124 9 1.956 9 137.085 8 69.420 70 294.350 4 0.403 32 62.081 20 285.076 1 300.137 5 2.026 4 153.597 3 71.510 25 294.301 1 0.452 81 62.137 74 282.708 0 299.469 6 2.080 9 169.643 2 73.987 56 294.257 7 0.501 27 62.298 86 280.177 7 表 2 数学模型校准系数
Table 2. Calibration coefficients of mathematical model
校准系数 数值 c1 4 071.75 c2 -1 938.92 c3 -1 650.43 c4 -2 108.53 c5 785.941 c6 1 008.88 c7 854.547 c8 -408.857 表 3 真实速度与拟合速度偏差对比
Table 3. Comparison of real velocity and fitting velocity deviation
u/(m·s-1) Δu/(m·s-1) 103.563 0 0.492 1 119.608 2 -0.443 8 136.852 8 -1.867 8 152.453 6 -2.591 2 169.145 6 -2.016 8 102.981 2 -0.574 5 119.696 6 0.632 2 136.410 3 -0.135 6 153.318 0 -5.104 6 169.811 9 -4.954 2 102.435 2 0.461 4 119.159 4 0.280 0 136.317 2 0.713 4 153.334 8 0.901 3 168.775 2 2.710 0 104.509 8 0.220 0 119.193 9 0.162 0 137.085 8 0.489 4 153.597 3 0.785 0 169.643 2 -2.030 6 表 4 数学模型校准系数和相对变化量(加入速度小扰动)
Table 4. Calibration coefficients of mathematical model and relative change amount (small velocity perturbation added)
校准系数 数值 相对变化量/% c1 4 773.38 17.23 c2 -2 297.34 18.49 c3 -1 934.59 17.22 c4 -2 427.80 15.14 c5 931.113 18.47 c6 1 172.13 16.18 c7 983.852 15.13 c8 -474.975 16.17 表 5 真实速度与拟合速度偏差对比(加入速度小扰动)
Table 5. Comparison of real velocity and fitting velocity deviation (small velocity perturbation added)
u+ε/(m·s-1) Δu/(m·s-1) 104.563 0 -25.46 120.608 2 -33.28 137.852 8 -43.04 153.453 6 -53.48 170.145 6 -63.85 103.981 2 -33.50 120.696 6 -39.39 137.410 3 -46.44 154.318 0 -57.26 170.811 9 -64.61 103.435 2 -27.77 120.159 4 -33.78 137.317 2 -41.07 154.334 8 -49.21 169.775 2 -56.78 105.509 8 -27.63 120.193 9 -33.90 138.085 8 -40.76 154.597 3 -47.71 170.643 2 -57.32 表 6 数学模型校准系数(参数无量纲化)
Table 6. Calibration coefficients of mathematical model (parameters nondimensionalized)
校准系数 数值 c1 0.043 05 c2 0.307 9 c3 0.061 27 c4 0.404 8 c5 -0.200 2 c6 -0.739 0 c7 0.205 8 c8 -0.221 5 表 7 真实速度与拟合速度偏差对比(参数无量纲化)
Table 7. Comparison of real velocity and fitting velocity deviation (parameters nondimensionalized)
u/(m·s-1) Δu/(m·s-1) 103.563 0 0.286 1 119.608 2 -0.260 6 136.852 8 -0.904 5 152.453 6 -0.998 3 169.145 6 1.589 7 102.981 2 0.142 7 119.696 6 -0.527 6 136.410 3 -1.106 7 153.318 0 -5.074 4 169.811 9 -1.972 7 102.435 2 0.352 9 119.159 4 -0.032 5 136.317 2 0.505 6 153.334 8 1.292 8 168.775 2 4.826 3 104.509 8 -0.442 3 119.193 9 0.180 5 137.085 8 1.038 1 153.597 3 1.746 4 169.643 2 -0.783 9 表 8 真实速度与速度不确定度对比(参数无量纲化)
Table 8. Comparison of real velocity and velocity uncertainty (parameters nondimensionalized)
u/(m·s-1) Uu/(m·s-1) 103.563 0 3.652 0 119.608 2 3.137 2 136.852 8 2.756 6 152.453 6 2.496 2 169.145 6 2.261 4 102.981 2 3.979 6 119.696 6 3.457 8 136.410 3 3.014 0 153.318 0 2.716 2 169.811 9 2.430 8 102.435 2 4.459 6 119.159 4 3.827 6 136.317 2 3.339 8 153.334 8 2.981 4 168.775 2 2.683 0 104.509 8 4.936 6 119.193 9 4.280 0 137.085 8 3.724 2 153.597 3 3.329 0 169.643 2 3.015 6 -
[1] FREYMUTH P.On feedback control theory for constant temperature hot wire anemometers[J].Review of Scientific Instruments, 1969, 40(2):258-262. doi: 10.1063/1.1683914 [2] BRUUN H H.Hot-wire anemometry:Principles and signal analysis[M].Oxford:Oxford University Press, 1995:19-26. [3] KING L V.On the convection of heat from small cylinders in a stream of fluid:Determination of the convection constants of small platinum wires with application to hot-wire anemometry[J].Philosophical Transactions of the Royal Society A-Mathematical Physical and Engineering Science, 1914, 214:373-432. doi: 10.1098/rsta.1914.0023 [4] KOVASZNAY L S G.Turbulence in supersonic flow[J].Journal of the Aeronautical Sciences, 1953, 20(10):657-682. doi: 10.2514/8.2793 [5] KOVASZNAY L S G.The hot-wire anemometer in supersonic flow[J].Journal of the Aeronautical Sciences, 1950, 17(9):565-572. doi: 10.2514/8.1725 [6] STAINBACK P C, JOHNSON C B, BASNETT C B.Preliminary measurements of velocity, density and total temperature fluctuations in compressible subsonic flow:AIAA-1983-0384[R].Reston:AIAA, 1983. [7] JONES G S, STAINBACK P C, HARRIES C D, et al.Flow quality measurements for the langley 8-foot transonic pressure tunnel LFC experiment:AIAA-1989-0150[R].Reston:AIAA, 1989. [8] 李超, 黄淑娟.单丝热线速度和方向特性的校准方法[J].甘肃工业大学学报, 1997, 23(2):42-45. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=gsgy702.008&dbname=CJFD&dbcode=CJFQLI C, HUANG S J.The methods of the calibration of single hot-wire in the velocity and directional sensitivity[J].Journal of Gansu University of Technology, 1997, 23(2):42-45(in Chinese). http://kns.cnki.net/KCMS/detail/detail.aspx?filename=gsgy702.008&dbname=CJFD&dbcode=CJFQ [9] 姚惠元, 刘国政, 孙楠, 等.恒温热线风速仪的一种新型校准方法[J].现代电子技术, 2013, 36(23):110-112. doi: 10.3969/j.issn.1004-373X.2013.23.031YAO H Y, LIU G Z, SUN N, et al.A new calibration method of constant temperature hot wire anemometer[J].Modern Electronics Technique, 2013, 36(23):110-112(in Chinese). doi: 10.3969/j.issn.1004-373X.2013.23.031 [10] 盛森芝.热线热膜流速计[M].北京:中国科学技术出版社, 2003:9-22.SHENG S Z.Hot wire/film anemometer[M].Beijing:Science and Technology of China Press, 2003:9-22(in Chinese). [11] 庄永基, 盛森芝.预移相型恒温热线(膜)流速计的动态响应方程[J].气动实验与测量控制, 1992, 6(1):49-56.ZHUANG Y J, SHENG S Z.The dynamic equation of constant temperature hot wire(film)anemometer with main bridge prephase shift circuit[J].Aerodynamic Experiment and Measurement & Control, 1992, 6(1):49-56(in Chinese). [12] 庄永基, 盛森芝.主电桥预移相模型恒温热线(膜)流速计动态响应方程的解析解[J].气动实验与测量控制, 1992, 6(3):45-52.ZHUANG Y J, SHENG S Z.The analytic solution of dynamics equation of constant-temperature hot-wire (film) anemometer with main bridge prephasing circuit[J].Aerodynamic Experiment and Measurement & Control, 1992, 6(3):45-52(in Chinese). [13] 汪健生, 郑杰, 舒玮.用热线风速仪同时测量流场速度与温度[J].实验力学, 1998, 13(3):393-398. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=sylx803.017&dbname=CJFD&dbcode=CJFQWANG J S, ZHENG J, SHU W.Measuring the velocity and the temperature in a flow field at the same time with hot-wire anemometer[J].Journal of Experimental Mechanics, 1998, 13(3):393-398(in Chinese). http://kns.cnki.net/KCMS/detail/detail.aspx?filename=sylx803.017&dbname=CJFD&dbcode=CJFQ [14] 陈忠基.热线风速仪在紊流流场测量中的应用[J].宇航计测技术, 1990, 2:65-70. http://d.wanfangdata.com.cn/Conference/199049CHEN Z J.Application of the hot wire anemometer in measurement for turbulent flow field[J].Journal of Astronautic Metrology and Measurement, 1990, 2:65-70(in Chinese). http://d.wanfangdata.com.cn/Conference/199049 [15] 皇甫凯林, 徐璋, 张雪梅, 等.热线风速仪在测量电站风量中的实验研究[J].电站系统工程, 2009, 25(3):17-19. http://d.wanfangdata.com.cn/Periodical/dzxtgc200903006HUANGFU K L, XU Z, ZHANG X M, et al.Experimental study on hot wire anemometer for measurement of power plant airflow[J].Power System Engineering, 2009, 25(3):17-19(in Chinese). http://d.wanfangdata.com.cn/Periodical/dzxtgc200903006 [16] 吴志军, 尹程秋.运用热线风速仪研究内燃机的流动特性[J].吉林工业大学自然科学学报, 1999, 29(2):91-95. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=jlgy902.017&dbname=CJFD&dbcode=CJFQWU Z J, YIN C Q.Research of flow characteristics in internal combustion engine with hot wire anemometer[J].Journal of Jilin University of Technology (Natural Sciences), 1999, 29(2):91-95(in Chinese). http://kns.cnki.net/KCMS/detail/detail.aspx?filename=jlgy902.017&dbname=CJFD&dbcode=CJFQ [17] 王仑, 周远, 候宇葵.热线风速仪低温测速的初步研究[J].真空与低温, 2001, 7(2):89-91. http://d.wanfangdata.com.cn/Periodical/zkydw200102007WANG L, ZHOU Y, HOU Y K.Exploration of measuring velocity with constant temperature anemometer system under low temperature condition[J].Vacuum & Cryogenics, 2001, 7(2):89-91(in Chinese). http://d.wanfangdata.com.cn/Periodical/zkydw200102007 [18] 论立勇, 陈厚磊, 蔡京辉.高压交变流动下热线风速仪标定方法研究[J].实验流体力学, 2010, 24(3):87-91. http://d.wanfangdata.com.cn/Periodical/ltlxsyycl201003018LUN L Y, CHEN H L, CAI J H.Investigation on calibration method of hot-wire anemometer in high pressure reciprocating flow[J].Journal of Experiments in Fluid Mechanics, 2010, 24(3):87-91(in Chinese). http://d.wanfangdata.com.cn/Periodical/ltlxsyycl201003018 [19] 杜钰锋, 林俊, 马护生, 等.可压缩流体恒温热线风速仪校准方法研究[J].航空学报, 2017, 38(6):120600. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=hkxb201706001&dbname=CJFD&dbcode=CJFQDU Y F, LIN J, MA H S, et al.Research on calibration method of constant temperature hot-wire anemometer in compressible fluid[J].Acta Aeronautica et Astronautica Sinica, 2017, 38(6):120600(in Chinese). http://kns.cnki.net/KCMS/detail/detail.aspx?filename=hkxb201706001&dbname=CJFD&dbcode=CJFQ [20] LEON S J.Linear algebra with applications[M].New York:Pearson Education Inc., 2014:308-319.