Electroless Nickel-Plating Sealing in FBG Pressure Sensor for Thermoelectric Power Plant Engines Applications

In this paper, we proposed a sealing method of fiber Bragg grating (FBG) in pressure sensors using electroless nickel-plating. The sensor is designed to be used in harsh environments of thermoelectric power plant engines. In order to be applied in the engine injector nozzle, the FBG has just a single attached point in the pressure sensor and the combustion chamber pressure will freely compress the FBG. The fixation material used to seal the FBG in the pressure sensor is the key for the sensor performance considering the engine environment used in thermoelectric power plant. Typical level of pressure in the engine monitoring point is around 200 bar and the temperature exceeds 300 °C. We detailed the method of fabrication and the characteristics of this method. Next, the FBG pressure sensors using electroless nickel-plating sealing were studied and submitted to laboratorial and field trial evaluation. In addition, we evaluated the signal characteristics of the FBG pressure sensor and we compared it with a standard pressure sensor used in this application.