蒸汽湿度的测量对汽轮机安全、经济运行具有重要意义。为了能够实现直接对排汽湿度准确、快速在线监测, 以948 nm-DFB可调谐激光器为传感部件, 以单片机C8051F410为核心, 基于TDLAS-WMS技术开展了汽轮机末级湿度检测系统设计。其中讨论了TDLAS技术湿度检测原理, 推导了湿度与可调谐激光的理论公式, 并结合有关谐波信号检测、PID温度控制、锁相放大以及所需软件的设计, 完成了汽轮机湿度测量系统的开发。通过比测实验结果表明, 该湿度检测系统具有较好的实用性及可行性。其湿度测量误差在±1.2%以内, 能够满足对汽轮机湿度高动态、高精度测量的需要。

The measurement of steam wetness is of great significance to the safe and economical operation of the steam turbine. In order to realize the accurate and rapid online detection of the exhaust wetness, A steam turbine final-stage wetness detection system was designed based on TDLAS-WMS technology. Moreover, a 948 nm-DFB tunable laser was adopted as the sensor component while the SCM C8051F410 was used as the core part. The principle of detecting the wetness through TDLAS technology has been discussed. The theoretical formula for the wetness and tunable laser has been also derived. Based on the theories of the harmonic signal detection, PID temperature control, lock-in amplification as well as relevant software design, the development of the steam turbine wetness detection system has been completed. According to the comparison of experimental result, this wetness detection system has achieved the excellent practicability and feasibility. With the wetness measurement error falling between minus 1.2 percent and plus 1.2 percent, it can satisfy the requirement for the dynamic and high-precision measurement of the steam turbine wetness.