Experimental testing of additively manufactured embedded fiber optic smart devices for clean energy applications

Abstract An additively manufactured prototype smart part was created to investigate in-flow temperature distribution using embedded high-definition fiber optic sensors within a standard reactor component. The devices were created using Ultrasonic Additive Manufacturing (UAM) to create a unique embedded pathway for the high-definition fiber optic sensors within a flow conditioner. The high-definition fibers had a spatial resolution of 0.65 mm which allows measurements to be taken every 0.65mm along the whole length of the fiber. These high-resolution fiber devices were thermally calibrated which enabled the 2-D reconstruction of the temperature profile in the flow path of the structure. This is due to the temperature-related strain response of the material and strain measurements of the fibers. Hot airflow testing of these devices showed the devices were able to identify localized temperature differences. The structure of the flow device resulted in strain concentrations along the thicker portions that led to higher strain values within those regions. The higher strain portions in turn leads to higher uncertainties in the temperature responses. Further calibration is needed to improve the accuracy of the smart devices, specifically within the inner web structures of a flow straightening component. The investigations of the devices within flow showed the temperature sensing to be independent of the effects of flow velocity when compared to upstream and downstream thermocouples. The devices were able to distinguish temperature differences within single and two-phase flow and showed local sensitivity to the temperature changes with the identification of hot and cold spots. The presented results showed the viability of the smart device for obtaining detailed temperature distributions using common industrial components. Eventually, the goal for these sensors will be to withstand higher temperature environments such as those experienced in nuclear, fusion, and concentrated solar energy systems.