Analysis of Geothermal Fluid Pipe Behavior in Dry Steam Geothermal Power Plant under Dynamic Load

Abstract

This study investigates the dynamic behavior of a dry steam geothermal fluid piping system located in a seismically active region of West Java, Indonesia. Given the potential for resonance under earthquake-induced dynamic loads, modal analysis was conducted using ANSYS finite element software to determine the piping system's natural frequencies and mode shapes. The piping system, spanning 186 meters, was modeled with fixed and roller supports to reflect realistic boundary conditions. Analysis results revealed that while the first mode (10.31 Hz) falls within the critical earthquake frequency range, its low mass participation indicates minimal influence on system response. In contrast, the twenty-fifth mode (31.12 Hz) exhibits deformation patterns more aligned with expected seismic excitation, with its frequency exceeding the dominant earthquake spectrum. Thus, the system is not considered highly susceptible to resonance. This study underscores the importance of modal analysis in assessing seismic resilience and confirms the structural adequacy of the piping design under dynamic loads.