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Experimental research and measurement technology development

Reliable prediction of thermal-hydraulics phenomena requires rigorous validation of numerical models. We conduct dedicated experiments to generate high-quality data for code verification and validation. In parallel, we develop advanced measurement techniques to resolve complex, transient multiphase flow structures.

Rod bundle bubble flow visualization based on deep learning

Deep learning–based techniques are applied to visualize and analyze bubble dynamics within rod bundle geometries.

Thermal-hydraulics experiments in debris beds

Experimental studies provide data on heat transfer and flow behavior within particulate debris, contributing to the understanding of post-solidification molten material behavior.

Wire-mesh sensor for void fraction distribution measurement

Development of measurement techniques for time-resolved void fraction and velocity distributions in multiphase flows.

Development of the three-dimensional visualization method for a jet in liquid-liquid system

A technology base was built to experimentally obtain three-dimensional interfacial shape data.

Development of the three-dimensional image-based measurement method for a jet in liquid-liquid system

A technology base was built to measure the feature quantities of a jet from three-dimensional interfacial shape data.

Deepening understanding of phenomena and developing numerical models

Accurate prediction of complex thermal-hydraulics phenomena requires a sound understanding of the governing physical mechanisms. We investigate fundamental processes such as flow, heat transfer, and phase change through experiments and numerical simulations, and develop physics-based models to enhance predictive capability and reproducibility.

Development of the evaluation method for the atomization mechanisms of a wall-impinging jet

A technology base was built to evaluate the mechanisms of phenomena on the basis of three-dimensional interfacial shape data.

Evaluation of void fraction measurement accuracy using wire mesh sensors (WMS)

Combined electrical field analysis and CFD are used to clarify the sources of measurement error inherent in WMS-based void fraction measurements.

Development of a simplified boiling model for large-scale simulations

A simplified boiling model based on the VOF method is developed by introducing bubble generation as a boundary condition, enabling large-scale boiling flow simulations.

Conservative Ghost Fluid Method for compressible two-phase flows

A coupled VOF–Ghost Fluid Method is developed to achieve both conservation and sharp interface capturing in simulations of compressible two-phase flows such as steam explosions.

THINC/AWLIC method for sharp interface capturing

A VOF-based method that enables accurate and robust interface advection with simple implementation, allowing high-resolution simulation of complex multiphase flows.