Novel gap inspection method for gas turbine with total fiber optic system

Based on the reflective principle, a new kind of laser and fiber optic sensor system was proposed and designed based on the formidable on-site operation conditions with the temperature over 700 degree(s)C, the abominable electromagnetic interference and the hard mounting problems. The optical fiber sensor is a total fiber fabric which has the high performance for high-temperature, very good insulating property. It is particularly suitable for those special accessions and conditions that conventional sensors are difficult to apply. Because of the superiorities of this kind of sensor such as simple structure, convenient to use, and the high measurement accuracy, there is an attractive application foreground on the turbine and other complex measurement problems. The measurement principle of the optical fiber sensor and its structure was described. The compensation technique for the thermal radiation and variation of the light power was proposed. The preliminary experimental results showed that the measurement range of the gap can reach 5 mm and the measurement resolution was better 0.01 mm. The operating temperature was about 700 - 10 degree(s)C, and rotational speed was 3,600 turn per minute.