arXiv Machine Learning

Aggregation of Published Non-Uniform Axial Power Data for Phase II of the OECD/NEA AI/ML Critical Heat Flux Benchmark

The paper compiles and digitizes a comprehensive dataset of critical heat flux (CHF) measurements for both uniform and non‑uniform axial heating conditions, preparing it for Phase II of the OECD/NEA AI/ML CHF benchmark. Heating profiles were extracted from technical reports, interpolated onto a consistent axial mesh, validated with energy‑balance checks, and encoded in machine‑readable formats. Baseline modeling results show that classical CHF correlations perform poorly, especially for non‑uniform profiles, and that neural networks trained only on uniform data fail to generalize to spatially varying scenarios, highlighting the need for models that explicitly incorporate axial power distributions.

arXiv Machine Learning
Sep 21

Assessment of Machine Learning-Based Critical Heat Flux Models in the CTF Subchannel Code for Square Rod Bundle Prediction

The paper evaluates machine learning (ML) models for predicting critical heat flux (CHF) in square rod bundles using the CTF subchannel code and the EPRI rod bundle CHF database. It compares pure and hybrid residual correction models in local and semilocal forms, finding that tube-trained ML models transfer well to rod bundle geometries and outperform traditional empirical correlations and lookup tables. The local hybrid LUT model shows the best overall performance, while the semilocal pure ML model remains highly competitive, indicating that significant improvements in rod bundle CHF prediction are achievable even with tube-only training data.

By Aidan Furlong, Vinicius de Melo Monteiro, Robert Salko, Juliana Pacheco Duarte, Xu Wu
arXiv Machine Learning
Aug 19

Open datasets and machine learning for two-phase heat transfer: a review following a spatial-temporal taxonomy

The review discusses how two‑phase heat transfer—critical for boiling, condensation, and thermal management—poses challenges for data reuse due to its complex interfacial physics. It surveys open datasets, machine‑learning techniques, and reusable software, organizing them with a spatial‑plus‑temporal dimensionality taxonomy (S+TD) that links data types to AI tasks such as regression, sequence learning, and image/video analysis. The paper proposes a roadmap for physics‑aware open data, including metadata standards, maturity labels, benchmark splits, and community databanks, emphasizing that progress in two‑phase AI relies as much on robust data infrastructure as on model design.

By Christy Dunlap, Ridwan Olabiyi, Firas Al-Hindawi, Hari Pandey, Stephen Pierson, Daniel Curl, Braden Stevens, Mohammad Ishraq Hossain, Annapurna Parjuli, Chinmaya Joshi, Ashif Iquebal, Han Hu
arXiv Machine Learning
Oct 28

Flow Mesh: A Velocity-Regularized Flow Matching Framework for Stable Distributional Modeling of Physical Fields on Unstructured Meshes

FlowMesh is a generative framework that produces full-field thermal‑fluid realizations directly on fixed unstructured meshes by combining permutation‑invariant mesh encoding, deterministic latent flow matching, and an l1 penalty on transport velocity. It achieves high probability‑density‑function coverage (91.7%–97.0%) and significant reductions in temperature‑field Kullback–Leibler divergence compared to latent diffusion models, while generating each realization in about 1.2 s—over 500‑fold faster than traditional computational fluid dynamics. The method enables large‑scale, data‑driven characterization of thermal‑fluid states on complex geometries without the need for grid interpolation or stochastic denoising chains.

By Siddharth Verma, Jaewan Park, Jay Phil Yoo, Kazuma Kobayashi, Souvik Chakraborty, Syed Bahauddin Alam
arXiv Machine Learning
Oct 8

NeuralBES: A Differentiable, Control-Aware Emulator for Scalable Building Energy Modeling

NeuralBES is a differentiable emulator that blends a physics‑based resistance–capacitance thermal model with a shared neural encoder to predict building energy use. By mapping building metadata to physically bounded model coefficients, it solves a scalar linear recurrence in log‑space and uses a predictor–corrector loop to handle thermostat nonlinearity while maintaining full‑horizon gradient flow. Trained on the ResStock dataset, NeuralBES accurately models heterogeneous buildings across climate zones, achieving physics‑valid predictions with fewer parameters than transformer and recurrent baselines and outperforming grey‑box RC models in mean absolute percentage error.

By Ting-Yu Dai, Takuya Kurihana, Wing Yee Au, Hon Yung Wong
arXiv AI
Oct 9

Virtual Smart Metering in District Heating Networks via Heterogeneous Spatial-Temporal Graph Neural Networks

The paper proposes a heterogeneous spatial‑temporal graph neural network (HSTGNN) to create virtual smart heat meters for district heating networks, addressing sparse instrumentation and sensor faults. It integrates network functional relationships and learns graph structures and temporal dynamics for flow, temperature, and pressure, enabling joint modeling of cross‑variable and spatial correlations. A new laboratory dataset from the Aalborg Smart Water Infrastructure Laboratory is introduced, and experiments show the HSTGNN outperforms existing baselines.

By Keivan Faghih Niresi, Christian M{\o}ller Jensen, Carsten Skovmose Kalles{\o}e, Rafael Wisniewski, Olga Fink