BOILING SIMULATIONS AT NEAR CRITICAL THERMODYNAMIC CONDITIONS USING THE LATTICE BOLTZMANN METHOD

• Grant number: 25/11714-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: January 01, 2026
• End date: December 31, 2028
• Field of knowledge: Engineering - Mechanical Engineering - Transport Phenomena
• Principal Investigator: Luben Cabezas Gómez
• Grantee: Luiz Eduardo Czelusniak
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/15765-1 - Study of transport phenomena applied to emerging technologies of energy conversion and storage, AP.TEM

Abstract

This research project proposes a numerical study of boiling under thermodynamic conditions near the critical point using the Lattice Boltzmann Method (LBM) with a pseudopotential model, implemented on the open-source platform OpenLB. Understanding heat transfer mechanisms under near-critical thermodynamic conditions is essential for the development of emerging technologies such as Organic Rankine Cycles (ORC), CO2-based refrigeration and power systems, and small-scale modular nuclear reactors. Despite increasing interest, the literature still exhibits significant gaps, particularly regarding the representation of variable thermophysical properties, the modeling of the liquid-vapor interface, and the reliability of empirical correlations used for the onset of nucleate boiling (ONB), heat transfer coefficient (HTC), and critical heat flux (CHF). This project aims to investigate these limitations through three-dimensional simulations in microchannels, incorporating temperature- and density-dependent properties, with the goal of validating and improving existing models. The OpenLB framework will be extended to account for such effects with thermodynamic consistency and numerical stability. The project is expected to generate benchmark numerical datasets, assess the validity of classical correlations for ONB, HTC, and CHF, and propose new criteria tailored to near-critical conditions. The project is aligned with the FAPESP Thematic Project 2022/15765-1 and will benefit from computational support provided by KIT (Germany), as well as the candidate's previous experience with the OpenLB development group. In addition, the numerical data generated in this study will be compared with experimental results obtained within the scope of the FAPESP Thematic Project, particularly those derived from investigations involving organic fluids in microchannels conducted by the Heat Transfer Research Group (HTRG) at EESC-USP. This integration strengthens the reliability of the results and promotes cross-validation between modeling and experiments. (AU)