Session: 37-01 Radial Turbomachinery Experimental

Paper Number: 153737

Numerical Simulation and Validation of As-Manufactured NASA High-Efficiency Centrifugal Compressor Using Fully Coupled FSI Approach 

This study presents a numerical validation of the NASA High-Efficiency Centrifugal Compressor (HECC) using as-manufactured geometry under as-measured in situ testing conditions, employing a fully coupled Fluid-Structure Interaction (FSI) approach. The HECC, experimentally investigated at the NASA Glenn Research Center, serves as a challenging test case for CFD methods due to its small diameter, high total pressure ratio of 4.7, high work factor of 0.81 and complex flow physics. The HECC vaned diffusor configuration comprises of impeller with 15 main-splitter pairs, diffuser with 20 main-splitter pairs, and 60 exit guide vanes. Building on previous publications that systematically quantified iteration and discretization errors, this study focuses on the modeling errors by using the as-manufactured cold impeller geometry confirmed to accurately represent the physical High-Efficiency Centrifugal Compressor (HECC) from detailed scans. A fully coupled FSI approach is employed to integrate the flow and structural solvers, simulating engine hot conditions and accounting for impeller blade displacement within a unified simulation environment. Mapped contact interfaces are utilized between fluid and solid regions to facilitate the exchange of ambient temperature, heat transfer coefficient, pressure, wall shear stress, and solid displacement via mesh morphing. The fluid domain employs a coupled flow and energy solver, while the solid domain utilizes a finite element stress and energy solver. The methodology of the coupled approach is explained in detail.

To validate and ensure accurate thermal predictions for the impeller, which ultimately influence the hot condition geometry generated from the FSI analysis, the impeller aft cavity which provides cooling is added. Parametric studies on leakage flow through the cavity and labyrinth seal were conducted, and the resulting impeller temperature was compared with experimental data for verification, showing reasonable agreement. The final baseline model was used to assess the overall compressor characteristics, and the results demonstrated improved agreement with experimental data as compared with previous studies using design intent hot geometry. This validates the effectiveness of the coupled FSI approach and highlights the accuracy and benefits of using as-manufactured cold scanned geometry, which further minimized the modeling error part of the systematic error hierarchy, for the numerical simulations of this open test case.

Presenting Author: Qingyuan Zhuang Siemens Industry Software

Presenting Author Biography: Qingyuan Zhuang is a Technical Application Specialist at Siemens Industry Software Netherlands. He studied Mechanical Engineering at KTH Royal Institute of Technology in Stockholm, after which he joined ABB and Siemens Energy core engine R&D as staff engineer and aeromechanics specialist

Authors:

Qingyuan Zhuang Siemens Industry Software
Thorsten Hansen ISimQ GmbH
Erik Munktell Siemens Industry Software
Georg Scheuerer ISimQ GmbH
Kim Zwiener Siemens Industry Software