Marco Marengo

• Ph.D.
• Distinguished Professor at University of Pavia

This paper presents a feasibility study on a fully passive cooling system for electric vehicles using Loop Heat Pipes (LHP) to transfer the batteries excess heat to the underbody of the vehicle. Multiple LHPs are in contact with a battery module, on the evaporator side, while their condensers are embedded in the underbody of the vehicle, cooled via...

In the present study, the transient behavior of a diffusion-bonded ultra-thin LHP, specifically designed for the thermal management of smartphones, is predicted by means of a 1-D Lumped Parameter Model (LPM). The LPM approach was previously validated for larger LHPs with different working fluids and is one of the few highly reliable transient model...

Physical dealloying (PD) is explored in this work as a way of creating a porous layer on metallic surfaces to be used for the enhancement of Pulsating Heat Pipe (PHP) thermal performances. PD can be applied to metal alloys consisting of components with a high difference between their partial vapour pressure, such as copper and zinc. Commercially av...

This study introduces an innovative method aimed at achieving exceptional stability in emulsions. The primary focus is on re-emulsifying precisely controlled and uniform initial single emulsions, generated by microfluidic devices, to produce single-core double emulsions and core–shell microparticles. Departing from traditional approaches, our metho...

In Battery Thermal Management System (BTMS), Loop Heat Pipes (LHPs) may act as thermal vectors connecting the bottom of the battery pack with the remote chiller of the EV’s HVAC system, whilst graphite sheets allow to achieve satisfactory temperature homogenization of the cell surface, containing the added system weight and thermally isolating one...

This study includes an examination of the design, fabrication, and experimentation of a rudimentary droplet generator. The device has potential applications in on-demand double and higher-order emulsions as well as tailored emulsions with numerous cores. The phenomenon of a pendant double droplet creation is observed when an inner phase is transpor...

A significant amount of heat can be generated during the operation of rotary machinery, which degrades its working performance and lifetime. It has been proven that, under radial rotation conditions, pulsating heat pipes (PHPs) can operate with good thermal performance. PHPs have excellent potential for application in rotary machinery, owing to the...

Pulsating heat pipes are two-phase passive heat transfer devices partially filled with a working fluid in saturation conditions. During operation, supplying heat to one end of the system (named evaporator) results in a local increase in temperature and pressure, which drives the fluid through a transport section (named adiabatic section) towards th...

In this work, we present a dynamical theory of boiling based on fluctuating hydrodynamics and the diffuse interface approach. The model is able to describe boiling from the stochastic nucleation up to the macroscopic bubble dynamics. It covers, with a modest computational cost, the mesoscale area from nano to micrometers, where most of the controve...

Controllable patterning of bio‐compatible polymers in the presence of a cross‐linker in evaporating bi‐dispersed colloidal drops is of critical importance in functional coatings, bioprinting, and food packaging. This study investigates the effect of calcium chloride and sodium alginate concentration on the evaporative deposition and elemental distr...

Lunar missions’ data and samples led to new discoveries, but also raised new and fundamental questions that are difficult to address with currently available data. The lunar surface and shallow subsurface contain a diversity of materials, their investigation is crucial to improve our current knowledge of the Moon. The regolith covers the lunar surf...

Flow boiling within conventional, mini and micro-scale channels is encountered in a wide range of engineering applications such as nuclear reactors, steam engines and cooling of electronic devices. Due to the high complexity and importance of the boiling process, several numerical and experimental investigations have been conducted for the better u...

Building from previous successful results from the Authors, a Loop Heat Pipe (LHP) based Battery Thermal Management System (BTMS) is investigated over a range of different ambient temperatures (from 20°C to 50°C), using a state-of-the-art environmental chamber. LHPs act as thermal vector from the bottom of the battery pack to a remote chiller, whil...

Boiling has the peculiarity of being involved both in frontier technological applications, such as nano cooling, and in everyday life activities, such as food cooking. For that reason, everyone is very familiar with this kind of phase transition. Associated with the empirical knowledge of the process, despite tens of years of scientific exploration...

Droplet generation in microscale has gained enormous attention in recent years especially in the pharmaceutical industry due to their application in targeted drug delivery into droplets. In most of these applications, monodispersity and uniformity of droplets are essential. Microfluidic devices can generate droplets at high throughput, enabling tho...

Alginate-based hydrogels are frequently employed in biomedical fields, where their size and uniformity are important for applications such as encapsulating pharmaceuticals or biological agents. In this paper, we study alginate droplet formation in a flow-focusing microfluidic device with a rectangular orifice of 30×100\documentclass[12pt]{minimal}...

The authors previously proposed and successfully studied the feasibility of an innovative Battery Thermal Management System (BTMS) relying on Loop Heat Pipes (LHPs) and graphite sheets. LHPs act as thermal vector connecting the bottom of the battery pack and a remote chiller, whilst the graphite sheets allow to achieve satisfactory temperature homo...

Pulsating Heat Pipes (PHP) are promising and effective passive two-phase heat transfer devices in terms of high heat transfer capability, efficient thermal control, adaptability and low cost and therefore they have been extensively studied in the last years. Many authors have estimated the heat fluxes at the evaporator and at the condenser area onl...

Thermal management is important for rotating machinery, such as spindles, grinding wheels or drillers, etc. If the heat cannot be dissipated in time, high temperatures will be generated, and abnormal operations or even destruction of the machinery may occur. Oscillating heat pipes (OHP) have attracted attention in thermal management and also have a...

High efficiency grinding of difficult-to-machine materials can generate a good amount of heat in a short time. If the heat is not timely transferred, the accumulation of heat will cause a high grinding temperature and can be harmful to the machining quality. The oscillating heat pipes (OHP) are designed in the grinding wheel to directly transfer ou...

Electric Vehicles (EVs) are at the centre of the recent industrial sustainable revolution and are identified as a potential route to reduce GHG emissions and tackling global warming. In the development of EVs, battery thermal management is a crucial aspect in ensuring high performance, market competitiveness and environmental sustainability. It is...

Flow boiling within microchannel heat sinks constitute a promising solution for the cooling of high-performance electronic devices, dissipating high values of heat flux. Yet still, due to the complexity of flow boiling in small scales, the effect of important parameters is not clearly defined. In the present study a numerical investigation on the e...

The heat transfer performance of a flat-plate, flexible polypropylene pulsating heat pipe (PHP) is evaluated experimentally when the device is bent at different angles, and for different layouts of the evaporator and the condenser. Flexible pulsating heat pipes are a passive thermal management technology with important prospective applications in f...

The effect of Al2O3 monolayer coating on the performance of a flat-plate polymeric pulsating heat pipe (PHP) is investigated experimentally in comparison with an identical PHP without coating. The use of flexible PHPs built with polymer materials will significantly advantage the thermal management of foldable and deployable electronics and systems,...

Experimentalists are limited in the amount of information they can derive from drop impact experiments on porous surfaces because of the short timescales involved and the normally opaque nature of porous materials. Numerical simulations can supplement experiments and provide researchers with previously unattainable information such as velocity and...

Aiming to improve on fast charge timings, all-electric range and to reduce costs and complexity, a Battery Thermal Management System (BTMS) with Loop Heat Pipes (LHPs) and graphite sheets is proposed. The LHP placed at the bottom of a prismatic cell module will transfer heat from the cells to a chiller, already part of the HVAC system of the vehicl...

Passive two-phase heat transfer systems, such as pulsating heat pipes, are a promising thermal management solution for the rapidly growing space sector. The strong coupling between thermal and hydraulic phenomena complicated the development of reliable off-the-shelf components. This was due to the difficulties in establishing and maintaining the de...

Owing to their simple construction, cost effectiveness, and high thermal efficiency, pulsating heat pipes (PHPs) are growing in popularity as cooling devices for electronic equipment. While PHPs can be very resilient as passive cooling systems, their operation relies on the establishment and persistence of slug/plug flow as the dominant flow regime...

Oscillating heat pipes (OHP) have attracted much attention in thermal management due to its high heat transport capacity and simple structure. OHP also have the potential to transfer heat under rotational conditions, while research on OHP heat transfer performance under a system rotation is still insufficient. The thermal performance of a single cl...

The Surface Wettability Effect on Phase Change collects high level contributions from internationally recognised scientists in the field. It thoroughly explores surface wettability, with topics spanning from the physics of phase change, physics of nucleation, mesoscale modeling, analysis of phenomena such drop evaporation, boiling, local heat flux...

Machining processes can generate a good amount of heat in a short time due to friction. If the heat power is not properly dissipated, the temperature of the tool increases and can be harmful for the machining quality. It has been proven that an Oscillating Heat Pipe (OHP) has the potential to be used for the thermal management of the tool also in h...

The present investigation aims to devise a thermal management system (TMS) for electric vehicles able to improve on limitations like charging time and all-electric range, together with the safety and environmental impact of the chosen thermal medium. A research gap is identified, as focus is often on addressing system thermal performance without co...

In the present paper, a fundamental analysis on the effect of the channel aspect ratio on the bubble dynamics and heat transfer characteristics for the early transient stages of the bubble growth within confined microchannels of rectangular cross-section, under saturated flow boiling conditions, is conducted, utilising high resolution, 3D, transien...

Phase change heat transfer within microchannels is considered one of the most promising cooling methods for the efficient cooling of high-performance electronic devices. However, there are still fundamental parameters, such as the effect of channel hydraulic diameter Dh, whose effects on fluid flow and heat transfer characteristics are not clearly...

The thermal performance of flexible polypropylene pulsating heat pipes (PHPs) is characterized for different spatial orientations, different reciprocal positions of the evaporator and the condenser (configurations), and different bending angles (conformations). The dependence of PHPs performance on their geometric orientation, configuration and con...

An innovative Battery Thermal Management System for a 3-cell Electric Vehicle module is proposed, involving Loop Heat Pipes and graphite sheets, with the particular aim of fast charging and reacting to automotive requirements. The design feasibility is verified through a Lumped Parameter Model, which has been validated comparing the data from an ex...

This study is the first step towards a broader research intent: developing and optimising a Personal Comfort System for tertiary sector working environments. The entire industrial sector, and in particular offices, have seen changes in working habits, with a large increase in smart working to prevent COVID infection. The chance to partialise the HV...

Energy performance certificates (EPCs) are useful tools that not only provide an indication on the efficiency of buildings, but also help raising awareness on the importance of improving their performance. However, the current implementation of EPCs is affected by issues that prevent their full potential to be exploited: lack of standardization acr...

This study is part of a wider research aimed at creating building type databases for simplified dynamic thermal models of buildings. In particular, thermal inertia analysis is the focus of this paper, looking at its impact in terms of comfort and energy consumption in different climates and for different end uses. The impact of all factors influenc...

Encapsulation, i.e. the coating of tiny solid or liquid particles in a liquid film, has received a growing interest among scholars due to its practical applications, especially in food and pharmaceutical industries. Encapsulation technology is used in coating and controlling drug delivery by protecting the active agents from environmental pressures...

In the present paper the effect of solid surface thermophysical properties under saturated flow boiling conditions within a considered microchannel is numerically investigated. The simulations are performed by utilising a custom, enhanced VOF-based solver that has been developed in OpenFOAM CFD Toolbox and accounts for conjugate heat transfer betwe...

The process of flow boiling within micro-passages plays a very important role in many industrial applications. However, there is still a lack of understanding of the effect of an important controlling parameter: surface wettability. In this paper, an advanced numerical investigation on the effect of wettability characteristics on single and multipl...

Aiming to improve on key Electric Vehicles issues, such as maximum temperature during fast charging, parasitic power and cost reduction, an innovative thermal management system for a 3-cell battery module, including a flat plate Loop Heat Pipe and graphite sheet inserts, is presented. The proposed Loop Heat Pipe, located at the bottom of the module...

The advent of foldable and wearable devices, such as the Samsung Galaxy Fold (2019) and Huawei Mate X (2019), require increased battery size and processor performance to drive their larger flexible displays. There is a growing need to develop flexible thermal management solutions to cool these foldable electronic devices. This research presents a c...

A Pulsating Heat Pipe (PHP), specifically designed to be hosted on board the Heat Transfer Host of the International Space Station, is tested in microgravity conditions during the 67th Parabolic Flight Campaign promoted by the European Space Agency. The device consists in an aluminium tube (inner/outer diameter = 3/5 mm) closed in a 14 turns loop,...

The Joint 19th IHPC (International Heat Pipe Conference) and the 13th IHPS (International Heat Pipe Symposium) was held at the University of Pisa, June 10th-14th, 2018. The joint conference focuses on topics related to heat pipes, thermosyphons and other two-phase thermal devices. The conference is the most important and attended scientific and net...

In the present paper, an enhanced Volume of Fluid model is applied for the conduction of parametric numerical simulations, to investigate break-up phenomena of accelerating, elongated, vapour bubbles, within circular mini-channels. The effect of fundamental controlling parameters in the resulting break-up characteristics is investigated. Four diffe...

A parametric analysis of the thermal performance of flat polypropylene pulsating heat pipes (PHPs) is presented. In particular, the thermal performance was characterized for pulsating heat pipes with different number of turns of the serpentine channel, different orientations with respect to gravity, and containing different heat transfer fluids. Th...

Anumerical investigation on the effectof wettability characteristicson a single bubble growth duringsaturated flow boiling conditions within a microchannel,is conducted in the present paper.The numerical simulations are conducted with the open-source toolbox OpenFOAM, utilising auser-enhanced Volume OF Fluid (VOF)solver.The proposed solver enhancem...

The key concept in wound dressing design and development is the fact that keeping a wound moist accelerates healing. Therefore, the selection of the appropriate wound dressing type is vital. The absorption of wound exudate by wound dressings can be considered as a microfluidic phenomenon that can be investigated either by performing high resolution...

Using large scale molecular dynamics simulations, we study in detail the impact of nanometer droplets of low viscosity on flat substrates versus the wettability of the solid plate. The comparison between the molecular dynamics simulations and different macroscopic models reveals that most of these models do not correspond to the simulation results...

A pulsating heat pipe (PHP) with alternating hydrophilic/superhydrophobic channels was tested at vertical position, bottom heat mode and different heat power inputs. The device consists in a copper tube (internal/external diameters of 3.18/4.76 mm), bent into a planar serpentine of ten channels and five U-turns. The tube is partially functionalized...

Liquid penetration analysis in porous media is of great importance in a wide range of applications such as ink jet printing technology, painting and textile design. This article presents an investigation of droplet impingement onto metallic meshes, aiming to provide insights by identifying and quantifying impact characteristics that are difficult t...

An enhanced Volume Of Fluid (VOF) based numerical simulation framework that accounts for conjugate heat transfer between a solid region and a two-phase flow region with phase-change due to evaporation and/or condensation, is applied in order to investigate the effect of global flow oscillation frequency and amplitude on the liquid film evaporation...

An enhanced Volume Of Fluid (VOF) based numerical simulation framework that accounts for conjugate heat transfer between a solid region and a two-phase flow region with phase-change due to evaporation and/or condensation, is applied in order to investigate the effect of global flow oscillation frequency and amplitude in generated instabilities in t...

An ultra-large flat plate copper heat pipe (180 × 180 mm²) was constructed using a thermal spray technique, and it was then thermally characterized. A porous copper wick was fabricated by using a flame spray torch to deposit a mixture of copper and aluminum particles onto the target substrate. A stainless-steel wire mesh acts as a mask so that the...

When dealing with numerical simulations of boiling phenomena, the spontaneous appearance of vapor bubbles is one of the most critical feature to be addressed. Capturing bubble formation during the dynamics, instead of patching vapor regions as initial conditions, is crucial for the correct evaluation of nucleation rates and nucleation site density,...

In order to enhance heat transfer in the abrasive-milling processes to reduce thermal damage, the concept of employing oscillating heat pipes (OHPs) in an abrasive-milling tool is proposed. A single-loop OHP (SLOHP) is positioned on the plane parallel to the rotational axis of the tool. In this case, centrifugal accelerations do not segregate the f...

The paper presents a case study comparing the integration and coherence of available building occupancy data for use in early stage dynamic building performance simulation to support the an integrated building design process. Building upon previous work from the authors, a simplified dynamic simulation tool is used to quantify the impact of the use...

An ultra-large flat plate copper heat pipe (180 × 180 mm²) was constructed using a thermal spray technique, and it was then thermally characterized. A porous copper wick was fabricated by using a flame spray torch to deposit a mixture of copper and aluminum particles onto the target substrate. A stainless-steel wire mesh acts as a mask so that the...

Pulsating Heat Pipes are two phase passive heat transfer devices characterized by a thermally induced two phase oscillating flow. The correct detection of the dominant frequencies of such oscillations is fundamental to fully characterize the device thermofluidic operation but the studies available in the literature are very heterogenous and results...

A mesoscale approach to address vapor bubble nucleation in metastable liquid is presented. The modeling allows to capture the spontaneous bubble formation thanks to a proper description of thermal fluctuations, through Fluctuating Hydrodynamics Theory

An innovative type of engineered composite polymer sheet with enhanced thermal conductivity is described and tested. The concept is to sandwich a closed-loop serpentine channel, cut out in a polypropylene sheet and containing a self-propelled liquid-vapour mixture, between two sheets of the same material bonded by selective laser welding. Polymer m...

The prediction of flow pattern transitions is extremely important to understand the coupling of thermal and fluid dynamic phenomena in two phase systems and it contributes to the optimum design of heat exchangers. Two phase flow regimes have been extensively studied under controlled mass flow rate and velocity. On the other hand, less effort has be...

Oscillating heat pipes have the potential to combine with the grinding wheel to enhance heat transfer in grinding process to avoid thermal damage of workpiece and grinding wheel. Since the time of grinding process is short, it raises a requirement for a good start-up behavior of oscillating heat pipes inside grinding wheel. In order to understand t...

An experimental study of a flat plate pulsating heat pipe has been performed under various gravity conditions during ESA 69 th parabolic flight campaign. A molybdenum plate, with 14 milled rectangular channels with cross-section of 3×3 mm 2 , was covered with a sapphire window, and tested in vertical position with ethanol as working fluid. If opera...

Encapsulation of solid particles and liquid agents in a liquid shell is of exceptional interest in biotechnological, chemical and pharmaceutical fields such as personalized medicine, fluidized catalytic cracking, wire fabrication, catalytic reactions. Looking at the interaction between liquid drop and solid particles, we can study the special, idea...