涡轮流体介电常数对高压涡轮叶尖间隙测量影响计算分析

Calculation and Analysis of the Influence of the Turbine Fluid Dielectric Constant on the Tip Clearance Measurement of High Pressure Turbine

为了评价涡轮流体介电常数对电容式高压涡轮叶尖间隙测量精度的影响,通过理论分析获得航空发动机涡轮流体介质的成分,并计算各成分的体积分数。由于水蒸气的体积分数对涡轮流体介电常数影响较大,仿真计算了不同工况和不同水蒸气体积分数下涡轮流体介电常数的变化范围,在此基础上计算了涡轮流体介电常数对涡轮叶尖间隙测量误差的影响。计算结果表明:涡轮流体介电常数对涡轮叶尖间隙测量带来的误差最高为0.3%,在工程应用时可以忽略。

In order to evaluate the influence of the turbine fluid dielectric constant on the precision of the capacitive tip clearance measurement of high pressure turbine,the composition of the turbine fluid medium of aeroengine was obtained by theoretical analysis,and the volume fraction of each component was calculated.Because the volume fraction of water vapor had a great influence on the turbine fluid dielectric constant,the variation range of turbine fluid dielectric constant under different working conditions and different volume fraction of water vapor was calculated by simulation.On this basis,the influence of turbine fluid dielectric constant on the error of the tip clearance measurement of turbine was calculated.The calculation results show that the maximum error caused by the turbine fluid dielectric constant is 0.3%,which can be neglected in engineering application.