arXiv subjects

Gan Fu

Publications and source records attributed to Gan Fu.

3 recordsLinked to original sources

arXiv2026

Dielectric Barrier Corona Discharge Anomaly by Ionic Wind under Unipolar Voltage Excitation

An anomalous back discharge movement phenomenon is induced by a set of dielectric barrier corona discharges (DBCD) at unipolar half-sine voltage waveforms, where the back discharge has a time delay that relates to the applied voltage level. An ionic wind model is employed to analyze the physical behavior. Theoretical explanation and quantitative analysis are presented in this study based on abundant experimental results of 5 typical insulating materials and a FEP insulating cable. A numerical model is derived, which indicates that the back discharge can be activated under a relatively low potential voltage level in this study. The results highlight that the back discharge movement phenomenon behaves distinctly under half-sine voltage with negative polarity, yielding a significantly different partial discharge (PD) pattern with positive polarity. Besides, PD amplitude dependent on dielectric thickness is demonstrated by plotting in phase resolved partial discharge (PRPD) pattern. Furthermore, comparative experiments are conducted with respect to the variation of air gap length and dielectric geometry, manifesting different influences on PD amplitude.

physics.app-ph↗

arXiv2025

Fast Forward and Inverse Thermal Modeling for Parameter Estimation of Multi-Layer composites -- Part I: Forward Modeling

This study presents fast and accurate analytical methods for transient thermal modeling in multi-layer composites with an arbitrary number of layers. The proposed approach accounts for internal heat generation and non-homogeneities in the heat diffusion equation. The separation of variables (SOV) method is employed to decouple spatial and temporal components, enabling the determination of eigenvalues. The orthogonal expansion (OE) technique is then applied to compute Fourier coefficients using 'natural' orthogonality. An analytical solution for composites with constant heat sources is developed by combining the SOV method and OE technique. Additionally, a Green's function (GF) based approach is formulated to handle transient heat sources and other non-homogeneous conditions, including temperature-dependent thermal conductivity. The results demonstrate that the proposed method offers significantly faster computations compared to finite element (FE) methods, while maintaining high accuracy. This forward modeling approach serves as an efficient basis for inverse modeling, aimed at estimating unknown material properties and geometric deformations, which are explored in Part II of this study.

physics.app-ph↗

arXiv2025

Fast Forward and Inverse Thermal Modeling for Parameter Estimation of Multi-Layer Composites -- Part II: Inverse Modeling and Applications

A fast inverse heat conduction model (IHCM) is developed for estimating unknown properties of multi-layer composites considering internal heat generation. This work builds on the validated analytical forward models presented in Part I. Transient temperature at a single point is used as input, with the objective function minimized through an interior-point optimization algorithm. The IHCM accurately estimates thermal properties such as thermal conductivity, specific heat capacity, density, and heat transfer coefficient. It also identifies internal geometric variations and their locations, such as delamination caused by thermal expansion or mechanical motion. These predictions are validated through finite element (FE) simulations. Additionally, a sensorless strategy is introduced, providing a non-invasive inverse modeling approach. The feasibility, sensitivity and limitations of the proposed IHCM are evaluated across various scenarios. The results demonstrate strong potential for applications such as thermal performance monitoring, online defect detection, and real-time diagnostics in multi-layer composite systems.

physics.app-ph↗