Mr. Mehdi Aslinezhad, Dr. Maryam Akhavan Hejazai,
Volume 15, Issue 4 (JIAEEE Vol.15 No.4 2019)
Abstract
Reliability of gas turbine power plant is related to the blade normal operation. In this paper, a new on-line condition monitoring method has been presented to evaluate two important factors affecting the turbine blades that are the tip clearance and tip deformation.
A K band’s microwave sensor has been simulated and optimized in CST Microwave Studio software. Scattering parameters of the near field sensor has been used as a finger print for the turbine blade. A set of measuring indices has been introduced to compare the amplitude and phase of the scattering parameters and received power. The simulation results show that the proposed indices can effectively detect deformation of the blade tip and tip clearance extent can also be estimated.
Dr. Mehdi Aslinezhad, Dr. Mehdi Khajavi, Dr. Meysam Bayat,
Volume 21, Issue 3 (JIAEEE Vol.21 No.3 2024)
Abstract
In this article, a refractive index absorber and sensor based on graphene metamaterials in the terahertz range is presented. In many studies, the dependence of the sensor on the radiation angle and polarization type has not been investigated, and usually complex structures have been used, the reason for this complexity is the lack of a systematic method and the reader is not convinced by the reasons of the geometry of the structure in the desired frequency band. In this article, advanced transmission line theory has been used to investigate the geometric structure and efficiency of terahertz sensors.The designed sensor has an alternating arrangement of graphene discs on a dielectric material and an integrated gold plate on the other side, which compared to other references has high accuracy in the selection of parameters and the geometry of its structure without the use of optimization algorithms has been calculated. The values maximum figure of merit (FOM) 24.5, the quality factor (Q-Factor) 80 and the sensitivity 1.57 THz⁄RIU have been obtained, which has improved significantly compared to previous works. Also, the simplicity of the structure, reduction of calculation time and memory, higher sensitivity and better stability are the advantages of this design compared to the previous methods.
