Session: 6.1.2 - Student Competition

Paper Number: 108802

108802 - A Design Study of an Elasto-Hydrodynamic Seal for Sco2 Power Cycle by Using Physics Informed Neural Network 

Supercritical carbon dioxide (sCO₂) is a promising alternative working fluid in power cycles. It offers several benefits, including improved efficiencies, lower power costs, lower water usage, and reduced equipment footprint. However, the technological readiness of the sCO2 power plants has yet to be demonstrated on a 10 -600 MWe scale with operating temperature and pressure ranges of 350 – 700 °C and 20 – 35 MPa, respectively. At the subcomponent level, there is a lack of suitable shaft end seals to minimize the sCO₂ leakage in the turbomachinery, which would otherwise penalize the efficiencies by up to 0.65 percent, for example, for a 500 MWe utility-scale power plant when existing sealing technologies are used such as labyrinth seals. For a potential solution, we propose a simple sleeve-like elastohydrodynamic (EHD) seal concept that provides low leakage, minimum wear, and no stress concentration. In this work, a numerical study has been performed to model the structural deformation of the EHD seal and fluid flow by using Lame's equation and simplified Reynold's equation, respectively. However, the analytical solutions for this type of modeling require a set of coupled differential and highly non-linear equations. Conventional approaches for optimizing the solution often end in convergence issues and require selecting specific flow rates. Therefore, the design equations used in this work have been solved by adopting the Physics Informed Neural Network (PINN) to mitigate these issues. It is a modern solution technique for physics-based analytical modeling, exhibiting better computational efficiency and accuracy than conventional methods. For the analysis, the seal geometry's fixed root condition was considered, and a parametric study has been performed to investigate the effects of pressure, seal gap, seal length, and seal thickness on the seal’s deformation and leakage rate. The pressure was varied from 101,325 Pa to 401,325 Pa; the seal gap was increased from 25 µm to  125 µm; the seal length was increased from 25 mm to 35 mm; and the seal thickness increased from 0.25 mm to 0.50 mm. In addition, the effect of material was also considered. For that, four different materials, including PEEK, Teflon, aluminum, and vespel, were taken into consideration under the same geometric parameters and operating conditions. Through using PINN analysis, the throttling behavior of the seal was successfully demonstrated. In addition, the effects of significant design parameters, including geometric, materials, and operating parameters, on the performance of the seal were discussed. The proposed analysis can be used to design EHD seals for specific cases when more comprehensive simulation models are not readily available or are deemed to be costly.

Presenting Author: Mohammad Towhidul Islam Rimon Georgia Southern University

Presenting Author Biography: Mr. Mohammad Towhidul Islam Rimon is a Graduate Assistant in the Mechanical Engineering Department at Georgia Southern University. Mr. Rimon is currently working on developing an elastohydrodynamic seal system that could potentially be used for supercritical carbon dioxide turbomachinery, which has been financially supported by the U.S. Department of Energy and the U.S. Department of Defense through STTR Phase I and II grants.