Name

 

LIU Wei

               
 

Email

w_liu@hust.edu.cn

               
 

Affiliation

Huazhong University of Science and Technology

         
 

Title

The problems of heat transfer and flow in the saturated and unsaturated porous media

 

Abstract

In this plenary speech, our research results were presented both in single phase and phase change heat transfer and flow in porous media by using saturated and unsaturated models respectively. For the former, a concept of heat transfer enhancement in the core flow was presented in a tube with partly filled porous insert by using saturated model, which was also verified by experiment data. It is then verified by several re-generator models of the Stirling engine based on conventional CFD calculation. Moreover, porous media model can be used for numeral simulation in complex heat exchanger, which is usually unavailable by using conventional CFD model. Meanwhile, a porous combined wall model was proposed for heat application of solar energy. For the latter, heat and mass transfer in the soil bed was numerically simulated by a seven-field model. And phase change heat transfer and flow in a capillary wick within the LHP evaporator was investigated by using unsaturated model to evaluate evaporator performance. In addition, heat and moisture migrations in a gas diffusive layer of PEMFC was studied by using unsaturated model to introduce a mechanism of phase-change in gas-liquid interface, rather than a mechanism of liquid droplet transport.

 

 
 

Short Bio

 

Liu Wei, Professor of School of Energy and Power Engineering at Huazhong University of Science and Technology. He is executive member of a council of the Chinese Society of Engineering Thermophysics and vice director of the Branch of Heat and Mass Transfer. He presided over more than 20 national projects, including key projects of the National Natural Science Foundation, national "973" projects, and national defense pre-research projects. He had published more than 330 SCI journal papers which were cited more than 10000 times by the Web of Science core collection. He had won second prize of National Natural Science (ranking 1), second prize of National Teaching Achievements (ranking 1), first prize of Science and Technology Progress of the Ministry of Education (ranking 1), first prize of Natural Science of Hubei Province (ranking 1), and 2 first prizes of Hubei Province Teaching Achievements (ranking 1). He was authorized 22 national invention patents, presided over the formulation of 1 national standard, published 2 academic monographs and 1 national planning textbook, and won 1 national excellent textbook. He had been listed in the Stanford World's Top 2% Scientists List from 2020 to 2023 and the Elsevier's China Highly Cited Scholars List from 2021 to 2023.

 

 

 

 

 

Name

 

Chakravarthy Balaji

               
 

Email

balaji@iitm.ac.in

               
 

Affiliation

Indian Institute of Technology Madras

               
 

Title

Optimizing Two-Phase Immersion Cooling in High-Performance Computing: A Confluence of Multi-fluid Systems and Machine Learning-Based Thermal Prediction Models

Advancing High-Performance Computing: A Dive into Multi-fluid Systems and Machine Learning for Two-Phase Immersion Cooling
Leveraging Multi-fluid Systems and Machine Learning for optimizing in Two-Phase Immersion Cooling
Multi-fluid Systems and Machine Learning for Superior Two-Phase Immersion Cooling Efficiency: Bridging the Best of Both Worlds
Authors: C.Balaji1 and Prateek Suresh2
Heat Transfer and Thermal Power Laboratory
Department of Mechanical Engineering
Indian Institute of Technology Madras, India

 

Abstract

In recent years, the ever-increasing power demands of electronic devices have posed significant challenges in terms of efficient heat dissipation and thermal management. The number of transistors that can be concomitantly active inside a processor is limited by the inability of the cooling solutions to take away heat. Consequently, the upper bound of computing performance is inherently determined by the efficiency of the cooling solutions. Two-phase immersion cooling has emerged as a promising solution in this context, particularly for high-performance computing applications. However, the poor thermal conductivity of the dielectric fluids and the effect of non-condensable gases in the system impede the efficiency of the two-phase immersion-cooled system. To address these challenges, a multi-fluid system approach is proposed. In this configuration, two immiscible fluids are used - a denser, more volatile boiling fluid in which the heat-generating processors are immersed and a less dense, less volatile condensing fluid where the vapours of the boiling fluid condense. These fluids are arranged in series without a solid interface separating them. Due to the differences in their densities, polarities and volatilities, the boiling and condensing fluids maintain an immiscible separation, ensuring the efficiency of the system. The effect of condensing fluid in the system is efficacious in improving heat transfer and coolant condensation with negligible effect of non-condensable gases. The experimental investigations reveal that multi-fluid systems demonstrate superior cooling performance compared to single-fluid systems, with an average increase of 33.3% in the overall heat transfer coefficient.
Transitioning to the next phase of thermal management, the focus shifts to ensuring reliable operations in data centre applications. This requires the development of a practical and proactive control framework for immersion cooling systems, which necessitates the prediction of server temperature. While deep learning-based temperature prediction models have shown effectiveness, further enhancement is needed to improve their prediction accuracy. In this context, Long Short-Term Memory (LSTM) Networks based on recursive encoder-decoder architecture and attention mechanisms have been explored to improve forecasting accuracy and prediction horizon.

 
 

About

the Authors

 

1.Dr. C. Balaji is currently the T.T. Narendran Institute Chair Professor in the Department of Mechanical Engineering at the Indian Institute of Technology (IIT) Madras. He graduated in Mechanical Engineering from Guindy Engineering College, Chennai, India, in 1990 (University Gold Medal) and obtained his M.Tech (1992) and Ph.D. (1995), both from IIT Madras. He has published over 220 international journals and has undertaken several sponsored research projects. He is a recipient of many awards that include the Humboldt Fellowship of Germany, the Swarnajayanthi Fellowship of the Govt. of India, the Marti Gurunath Teaching Award and the Mid-Career Research Award from IIT Madras.
2.Pratheek Suresh is an engineering graduate who is now pursing his doctoral research in immersion cooling at IIT Madras under the guidance of Prof.C.Balaji

 

 

 

 
 

 

Name

 

Wojciech Lipiński

               
 

Email

w.lipinski@cyi.ac.cy

               
 

Affiliation

The Cyprus Institute

               
 

Title

Heat transfer in dual-scale porous media

 

Abstract

Heat transfer in dual-scale porous media is encountered in numerous industrial applications, including energy conversion and storage, processing of materials, and separations. In this presentation, theoretical development of convective, conductive and radiative heat transfer in dual-scale porous media is presented, from fundamental principles to numerical model validation. The volume-averaging method is applied to obtain a continuum model to predict the energy transport phenomena in dual-scale porous structures. For convective and conductive heat transfer, closure problems are formulated to establish a two-equation model. The closure problems are numerically solved on three representative elementary volumes (REVs) of dual-porosity media consisting of three different arrangements of closely packed spheres of porous spherical particles to determine effective transport coefficients for the medium. Numerical experiments are performed to compare the convective–conductive heat transfer results obtained using the volume-averaged equations with effective coefficients to those of a pore-level simulation. For radiative transfer, the volume-averaging method is applied for the largest porosity scale at which laws of ray optics are valid. Radiative transport phenomena at smaller scales are captured by using effective radiative properties, which can be derived using methods of computational electromagnetics. Selected problems of concentrated solar energy collection and conversion are discussed as examples of practical applications of the effective heat transfer models.

 
 

Short Bio

 

Wojciech Lipiński is a professor at the Cyprus Institute. He obtained his Master of Science degree in Environmental Engineering from Warsaw University of Technology (2000), doctorate in Mechanical and Process Engineering from ETH Zurich (2004), and habilitation in Energy Technology from ETH Zurich (2009). He previously held academic positions at ETH Zurich (2004–2009), the University of Minnesota (2009–2013), and the Australian National University (2013–2021). Prof. Lipiński's research interests extend across optical, thermal and chemical engineering sciences applied to solar energy. His basic research focuses on advances in transport phenomena, reactive flows and energy materials, in particular for problems involving radiative transfer coupled to physical and chemical changes in matter. Prof. Lipiński's research primarily underpins developments in concentrated solar thermal energy for electricity generation, processing of fuels and materials, and environmental separations. Prof. Lipiński is the editor-in-chief of Thermopedia, and is serving on editorial boards of Solar Energy and the Journal of Quantitative Spectroscopy and Radiative Transfer. He is involved, among others, in the International Centre for Heat and Mass Transfer, the Eurotherm Committee, and the American Institute of Chemical Engineers. Prof. Lipiński is a recipient of the Elsevier/JQSRT Viskanta Award in Radiative Transfer (2013) and the ASME Yellot Award (2020). He is Fellow of the ASME (2021).

 

 

 

   
 

 

     
   
 

 

Name

 

Moran Wang

               
 

Email

mrwang@tsinghua.edu.cn

               
 

Affiliation

Tsinghua University

               
 

Title

Pore-scale modeling of heat and mass transfer in porous media: challenges and recent progress

 

Abstract

Porous media is ubiquitous in nature and engineering applications. Correct understanding of transport mechanisms and accurate prediction of transport behavior of heat and mass transfer in porous media become crucial for design and optimization of porous materials. Pore-scale modeling provides a powerful tool, yet have met several challenges because of the contradiction between description resolution and computational costs. In this talk, we will introduce some ideas of revisiting and reconsidering this issue and some new progresses in exploring such challenges based on the intrinsic characteristics of porous media.

 
 

Short Bio

 

Moran Wang is a Professor of Fluid Mechanics and Thermophysics at Tsinghua University. He obtained Bachelor and PhD degrees from Tsinghua University, and held postdoc positions in Johns Hopkins University and University of California of USA. He worked at Los Alamos National Laboratory as an Oppenheimer Fellow. He has been a full professor at Tsinghua University since 2011. He is working on microscale fluid mechanics, heat and mass transfer in porous media, multiscale modeling and interface science. He has authored over 200 peer-reviewed papers on international journals which gained over 13k citations based on Google Scholar Reports (H-index: 58). Prof. Wang has been serving as editorial board members for several international journals including “International Journal of Mechanical Sciences”, “Journal of Colloids and Interface Science”, “Transport in Porous Media”, “Journal of Porous Media” and so on. He has been invited to contribute comprehensive reviews on “Physics Reports”, “Material Science and Engineering R: Reports”, “Progress in Materials Science” and so on. He was awarded J.R. Oppenheimer Fellowship in 2008, Interpore P&G Award in 2019 and Fellow of IMMS in 2022.

 

 

 

 

 

 

Name

 

Bowen Ling

               
 

Email

lingbowen@imech.ac.cn

               
 

Affiliation

Institute of Mechanics, Chinese Academy of Sciences
School of Engineering Science, University of Chinese Academy of Sciences

               
 

Title

Professor/Research Scientist

 

Abstract

The development of new mineral phases in confined spaces, especially within porous media, plays a critical role in geological processes like mineralization and diagenesis. This process begins at the microscale through interactions between fluids and rocks, where primary phases dissolve, creating supersaturated conditions that facilitate the nucleation and growth of secondary minerals. As nuclei form on the surface of the media, mineral accumulation ensues, leading to precipitation and growth at larger scales. Past studies have typically focused on either precipitation or nucleation independently, rather than exploring their combined influence, particularly on the pore-scale reactive transport in fluid-rock interactions. Understanding the synergistic effects of these phenomena is essential for accurately predicting the evolution of porosity and permeability during reactions. Our research introduces a computational framework that integrates classical nucleation theory with the micro-continuum method. This approach enables the study of pore-scale reactive transport while incorporating nucleation dynamics. We examined how nucleation and precipitation interact and affect pore-scale flow and transport properties, such as permeability, within confined environments. Our findings indicate that adjusting surface nucleation rates can alter precipitation patterns from preferential to more uniform textures. Furthermore, our study highlights that traditional deterministic precipitation methods may underestimate the permeability of porous matrices in specific scenarios.

 
 

Short Bio

 

Bowen Ling completed his Ph.D. in Mechanical & Aerospace Engineering at the University of California, San Diego, specializing in Engineering Science. Following this, he conducted postdoctoral research at Stanford University in Energy Resources Engineering. Dr. Ling’s research is dedicated to investigating multiscale flow and transport processes within complex geometries found in both industrial and natural heterogeneous systems. His group employs a combination of theoretical, experimental, and computational analyses to model the dynamic behavior of these systems and explore the coupling of multiple physics in energy-related applications. His research findings have been primarily published in academic journals such as PNAS, GRL, JFM, IEEE TGRS, PoF, PRF, and others.

 

 

 

 

 

 

Name

 

Ruming PAN

               
 

Email

ruming.pan@hit.edu.cn

               
 

Affiliation

School of Energy Science and Engineering, Harbin Institute of Technology

               
 

Title

The role of porous media in solid waste treatment and valorization

 

Abstract

Porous media play an important role in solid waste treatment and valorization. We focus on the treatment of solid pollutants by smoldering, and the role of porous media in heat transfer enhancement during pyrolysis and gasification of biomass and waste plastics. We constructed a two-dimensional robust model of smoldering by introducing the thermally thick approximation. The heat generated from smoldering of solid pollutants is utilized to pyrolyze solid wastes. Further, the concept of smoldering-driven pyrolysis reactor is proposed. In addition, the emergence of ''hot spots'' was used as a criterion for determining the ignition of smoldering. We also introduced the porous skeleton structure with high thermal conductivity into the value-added treatment process of biomass and waste plastics, and established the numerical models. Finally, we proposed a novel direct-radiation solar reactor for solid waste valorization and developed numerical models considering different wavelengths.

 
 

Short Bio

 

Ruming PAN, Associate Professor of Harbin Institute of Technology (HIT), Doctor of Engineering. His research interests are Solar Thermal Utilization and Heat and Mass Transfer Enhancement in Porous Media. Dr. Ruming PAN has published more than 30 SCI papers in journals such as Nature Communications and Communications Chemistry, including 1 cover-page paper. He is currently serving as a Young Editorial Board Member of the SCI journal Rare Metals and a Guest Editor of Molecules. He received the Prix Jean Nougaro (Provincial Outstanding Young Scholar Award) in Engineering Physics from the Toulouse Academy of Sciences, France for the year 2024; and the Prix Léopold Escande (Outstanding PhD Thesis) from the Toulouse INP, France.

 

 

 

 

 

 

Name

 

Ke Xu (徐克)

               
 

Email

kexu1989@pku.edu.cn

               
 

Affiliation

Peking University (北京大学)

               
 

Title

Gas mobility at thermodynamic equilibrium in porous media

 

Abstract

After CO2 geological sequestration, minimum gas mobility is wanted to reduce leakage risk; in natural gas production and subsurface H2 storage, in contrast, high gas mobility is favored to enhance recovery. Unfortunately, although hydrodynamic history determines short-term gas morphology and mobility, subsequent relaxation process may reshape fluid spatial distribution in long-term, and the consequences have not been clarified.
We conduct microfluidic experiments to study static gas ganglia evolution in porous media, at large time-scale that quasi-equilibrium state can be achieved. Surprising phenomena are observed:  a slowly expanding gas ganglion is always of high continuity and thus high mobility; however, a slowly shrinking gas ganglion is fragmented by spontaneous formation of liquid bridges that break the ganglion into pieces, which reduce gas mobility.
This observation is theoretically rationalized with thermodynamic analysis. Forming liquid bridges increases free energy in high curvature (expanding) ganglia; in contrast, forming certain number of liquid bridges can significantly reduce the free energy of low curvature (shrinking) gas ganglia. The thermodynamically optimum morphology can be analytically resolved in a 2-D homogeneous medium. In addition, spontaneous ganglia fragmentation results in major enhancement in mass transfer efficiency.

This study provides support on evaluating CO2 sequestration and H2 storage economics。

 

 
 

Short Bio

 

Ke Xu, assistant professor of Peking University College of Engineering since 2020. He got bachelor and master degree in chemical engineering from Tsinghua University, and PhD degree in petroleum engineering  from UT-Austin. Before joining Peking University, he worked as a postdoctoral researcher in MIT CEE for two years. He is now serving as the deputy chair of Peking University department of energy & resources engineering, and the general secretary of InterPore China committee

His major research interests include physics of complex fluids in porous media, and relevant engineering problems in carbon dioxide geological storage, extraterrestrial resource development and hydrocarbon recovery. He has published more than 40 peer-reviewed papers on PNAS, PRL, GRL, JFM, SPE J, etc. He is now hosting a National Key R&D Program Young Scientist Project, a National Young Talent project, several NSFC Projects, and multiple industrial R&D projects.

 

 

 

 

 

 

 

Name

 

Xianglei Liu

               
 

Email

xliu@nuaa.edu.cn

               
 

Affiliation

Nanjing University of Aeronautics and Astronautics

               
 

Title

Solar-driven greenhouse conversion into syngas via biomimetic porous foam reactors

 

Abstract

The conversion of greenhouse gases to syngas using solar energy holds promises for addressing global energy and environmental challenges, but often suffers from low solar-fuel efficiency and coke-induced instability, severely hindering its scalable applications. Here, we propose a novel approach that synergizes plasmonic meta-nanoalloy catalysts with biomimetic butterfly wing-inspired reactors to achieve highly efficient and stable solar-driven upgrading of greenhouse gases into syngas. The developed NiCoZn/MgAlOx catalysts exhibit a high solar-fuel efficiency of 43.4%, an optimal H2/CO ratio of 0.97, and a conversion rate surpassing thermodynamic limitations. The underlying mechanism is attributed to plasmonic activation of the initial C-H bonding of CH4 and C-O bonding of CO2 , facilitated by hot electrons injection induced by the localized surface plasmon resonance of trimetallic nanoalloys. Further catalysts deposition on biomimetic dual-gradient foam reactors enables the system scalability, achieving the synergy of plasmonic catalysis with light transport, reactants flow, and fluid-solid energy exchange. A bench-scale solar-driven system, operating without external heating, demonstrates a remarkable solar-fuel efficiency of 40.44% and durable performance over 100 hrs.

 
 

Short Bio

 

Xianglei Liu is a full professor of School of Energy and Power Engineering in Nanjing University of Aeronautics and Astronautics. Prof. Liu mainly focuses on the researches of micro/nanoscale heat transfer, solar fuel production, and thermal energy storage. He has authored and coauthored 3 book chapters, more than 140 peer reviewed journal papers, and over 50 conference papers/presentations including 12 keynote presentations and 1 plenary report. He received Elsevier/JASRT Raymond Viskanta Awards, Wu Zhonghua Award for outstanding young scholars, Jiangsu Distinguished Young Scholars, and the Sigma Xi Best Ph.D. Thesis Award.

 

 

 

 

   
   
 

 

Name

 

Kentaro Yaji

               
 

Email

yaji@mech.eng.osaka-u.ac.jp

               
 

Affiliation

Osaka University

               
 

Title

Invitation to topology optimization for heat transfer problems

 

Abstract

Topology optimization is a method that optimizes the distribution of material within a given design space to maximize performance while efficiently using resources. This technique has broad applications across various fields, including structural, aerospace, and automotive engineering. In heat transfer devices, topology optimization can significantly enhance performance. This presentation will introduce the basic ideas and mathematical formulation for topology optimization in heat transfer problems.
A representative topology optimization method, the density-based approach, optimizes the local porosities of a target solid structure. For fluid problems, a design-dependent Brinkman-type equation is used to optimize local porosities. We will explore the relationship between topology optimization and porous media and the potential for extending these concepts to practical porous heat transfer systems.
As a leading challenge in the research community, we will also present recent research results on the design of lattice-type heatsinks and their applicability to 3D printing technology. This combination enables the creation of heatsinks with complex internal structures, improving performance beyond what traditional methods can achieve. This presentation will provide a detailed overview of these advancements and their practical applications.

 
 

Short Bio

 

Dr. Yaji is an Associate Professor in the Department of Mechanical Engineering at Osaka University, specializing in topology optimization and its applications to thermal-fluid devices and battery systems, as well as data-driven design using deep learning. He graduated from Kyoto University with a master’s degree in engineering in 2013 and received his Ph.D. in Engineering in 2016. Prior to joining Osaka University, he served as a Research Fellow for Young Scientists at the Japan Society for the Promotion of Science. He was also a visiting researcher at the Oden Institute for Computational Engineering and Sciences at the University of Texas at Austin from 2021 to 2022. Dr. Yaji has received numerous awards throughout his career, including the ASSMO Young Scientist Award and the JSME Design Engineering and Systems Division Award. As editor of journal papers, he worked as one of the guest editors of Structural and Multidisciplinary Optimization for a special issue on shape and topology optimization of flow-based multiphysics problems from 2021 to 2022. Additionally, he has been working as an editor of the Journal of Advanced Mechanical Design, Systems, and Manufacturing since 2023.

 

 

 

 

 

 

Name

 

Qian Fu

               
 

Email

fuqian@cqu.edu.cn

               
 

Affiliation

Chongqing University

               
 

Title

Microenvironment regulation strategies for enhanced electrochemical CO2 reduction

 

Abstract

Electrochemical CO2 reduction reaction (CO2 RR) integrated with renewable energy is an attractive approach for mitigating greenhouse gas emissions and converting CO2 to value-added chemicals. However, the electrode-electrolyte interface has significant impacts on electrochemical reactions that have been inadequately acknowledged. Meanwhile, low current densities (production rates) and low energy efficiency (EE) caused limited CO2 mass transfer in the catalyst layer (CL) prevent this technology from application. Herein, we firstly investigated the cation effects in the electrical double layer on the Faradaic efficiency (FE) of target products at the electrochemical interface. And the microenvironmental regulation strategies are proposed to enhance the selectivity of target products. Furthermore, we explored the mass transfer process of CO2 molecules at the reaction interface and within CL. By optimizing the pore-scale CL structure, the design achieved stable cell operation at high current densities and EE. This work highlights the importance of tailoring the CL microenvironment as a means of improving the overall performance in the CO2 RR, and offers a unique insight to drive industrial applications of current systems.

 
 

Short Bio

 

Prof. Fu obtained his Ph. D degree from the Department of Systems Innovation, The University of Tokyo, Japan in 2013, and then worked as a Research Fellow at the Institute of Industrial Science, The University of Tokyo, Japan. He joined School of Energy and Power Engineering, Chongqing University as a scholar of "Hundred Talents Program" of Chongqing in 2015. He won the young scholar of “Chang Jiang Scholars Program” of Ministry of Education, China in 2019. Prof. Fu’s research interests include fuel cells and electrochemical CO2 reduction. He has authored and co-authored more than 100 journal papers. He also acted as the guest editor of special issue of Electronics, academic editor of DeCarbon, and editorial board member of Energy and AI