Keynote Speaker I:
"Metamaterial-Structured Battery Pack Casings for Enhanced Vibration Isolation"
Abstract: Battery pack casings rated at 12.432 kWh were designed and assessed using two material systems: a conventional aluminum alloy and a lightweight carbon fiber reinforced polyphthalamide (PPA CF) filament (a high-performance, high-temperature nylon composite). Because battery packs experience continual “shaking” during vehicle operation—arising from road roughness, drivetrain excitation, and other sources—this work focuses on reducing random vibration, i.e., a broadband, irregular vibration environment that can contribute to noise, discomfort, and long-term fatigue damage. To improve vibration resistance, we investigated mechanical metamaterials integrated into the casing design. In simple terms, mechanical metamaterials are engineered internal geometries (rather than new chemical compositions) that change how a structure carries loads and transmits vibrations. Two concepts were evaluated: lattice structures (networks of repeating struts/cells that can act like a stiff but lightweight “skeleton”) and auxetic structures (geometries that deform in an unusual way—expanding laterally when stretched—which can alter stiffness, energy absorption, and vibration transmission). A numerical study was conducted to compare baseline casings and metamaterial-enhanced casings under random vibration loading, with vibration responses evaluated at key locations such as the top cover and the center of the front and back walls. For the aluminum casing, both lattice and auxetic designs showed outstanding performance, achieving approximately 97%–99% reduction in vibration levels. For the PPA CF casing, the improvements were more limited and depended on measurement location and direction; the metamaterial concepts reduced longitudinal vibration by about 63.8% at the top cover and 92.8% at the center of the front and back walls. Overall, the results indicate that aluminum alloy provides better vibration-mitigation capability than PPA CF, both with and without metamaterial-inspired structural modifications. The findings also suggest that while metamaterial geometries can be highly effective, their benefits are material- and location-specific, highlighting the need to co-design material selection and internal architecture for targeted vibration control in battery pack enclosures.
Bio-Sketch
Heow Pueh LEE is currently a Professor at the Department of Mechanical Engineering, National University of Singapore. He graduated with first class honours from Cambridge University and PhD in Mechanical Engineering from Stanford University. His more recent works focus on acoustics and vibration, metamaterials, and composite structures. He is a Deputy Editor-in-Chief for Applied Acoustics, and member of Editorial Board for the International Journal of Applied Mechanics, Acta Mechanical Sinica, and Scientific Reports. He has more than 500 journal publications with google scholar H index of 81 and citations of more than 28,000.
National University of Singapore, Singapore
Keynote Speaker II:
"Modelling and Optimisation of Condensers with Liquid-Vapor Separation
"
Abstract: This talk addresses the development of highly efficient and compact multi-pass parallel flow condensers (MPFCs). Condensers plays an important role in many thermal energy systems. Condensers and evaporators take 30-40% of air conditioners and heat pumps total cost. Liquid-vapour separation (LS) is an advanced technology recently developed to further enhance condensation heat transfer and is applied to multi-pass parallel flow condensers (MPFCs). The talk focuses on the modelling of MPFCs. A 2D distributed-parameter model, using the -NTU method, is developed to accurately predict local distributions of heat transfer and pressure drop. The positions of the onset and completion of condensation are accurately determined. The flow patterns of condensation in microfin tubes are predicted and relevant empirical correlations are selected for predicting heat transfer and frictional pressure drop in different flow regimes. The predictions of the model agree well with the experimental data within 20%. The talk clarifies the insight of liquid-vapour separation technology. The model is used to investigate the mechanisms of how liquid-vapour separation enhances condensation heat transfer in MPFCs. The local and averaged vapour quality, heat-transfer coefficient and pressure drop are compared for MPFCs with (MPFC-LS) and without liquid-vapour separation. The entropy analysis is performed to examine the contributions of entropy generation in tubes by heat transfer and pressure drop. The talk discusses the optimisation of MPFC-LS. The MPFC-LS with an optimised tube-pass arrangement reduces pressure drop by 84% - 98%, improves the overall heat transfer by 5% - 9%, and reduces the condenser size by about 30%. The talk highlights the prediction methods for refrigerant flow distribution in tube-passes. In MPFCs, refrigerant flow maldistribution deteriorates heat transfer. The generic algorithm is adopted to determine the refrigerant flow rates through microfin tubes in tube-passes. In addition, A robust algebraic method is further developed to determine refrigerant flow distribution in tube-passes. This algorithm can be directly integrated with the 2D distributed-parameter model and significantly reduces the computational time.
Bio-Sketch
Professor Wang has many years research and teaching experience in thermofluids engineering, building services in universities in China, Japan and the UK. His research interests are in the field of enhanced heat transfer, condensation heat transfer, flow boiling heat transfer, inverse method of heat transfer measurement, molecular dynamics simulations of condensation and boiling/evaporation, multiscale simulations, advanced refrigeration technologies, sustainable thermal energy systems e.g. solar assisted air source heat pump based heating systems and advanced intelligent control for building management systems.
Queen Mary University of London, UK