Thermal management of a Formula E electric motor: Analysis and optimization

The thermal analysis of a high performance brushless synchronous electric motor with permanent magnets and water jacket cooling is presented. The analysis is carried out following a lumped parameter thermal network approach which allows to identify the most important thermal paths in the motor and the main parameters influencing them. Thanks to its simplicity, the solution of such a thermal network model is very fast, allowing a large number of what-if scenarios to be computed over a short amount of time. For this reason, the model is coupled with external tools for performing systematic sensitivity analyses and optimizations. Goal of the investigation is the reduction of the windings temperature being this temperature inversely proportional to the efficiency and the power delivered by the motor. The sensitivity analysis, performed over a series of material, geometric, and operational factors, leads to the identification of the most relevant parameters influencing the thermal behaviour of the motor. A series of optimizations, focusing on these parameters and including suitable constraints granting the well-posedness of the problem and the feasibility of the solution, bring to the definition of an optimum layout of the water jacket and of the stator geometries. The optimized geometry allows a significant reduction of the windings temperature to be achieved

Friction factor evaluation of compressible microflows using 1D Fanno flow-based numerical model

A numerical model based on the conventional Fanno flow theory for the friction factor evaluation of the gas flows inside microchannels has recently been developed by Cavazzuti et al. [1]. The current work aims to compare this numerical model with experimental results of microchannels. Pressure drop experiments are performed for a circular cross sectional microtube and a rectangular microchannel with Nitrogen gas as working fluid. The hydraulic diameters of microtube and microchannel are 100 \u3bcm and 69.4 \u3bcm respectively. Rectangular microchannel with an aspect ratio (height to width) of 0.036 is chosen for the comparison. This allows to treat the rectangular microchannel as parallel plate in the numerical Fanno model. During experiments stagnation pressure at the inlet is increased such that maximum Reynolds number is 3000 in the case of microchannel and 7600 for microtube. Results show that for the evaluation of average friction factor in both considered geometries, there exists a good match between Fanno-based 1D numerical model and experimental results in the laminar regime whereas comparison worsens as the flow approaches choking. Limitations as well as the potential reasons for the discrepancies between the developed model and experiments will be discussed

Development and calibration of a 1D thermo-fluid dynamic model of ventilation in tunnels

In complex, large civil infrastructures where ventilation has a crucial role for the safety of users in both normal operation and hazardous scenarios, the correct prediction of flow and heat transfer parameters is of fundamental importance. While full 3D simulation is applicable only to a limited extent, and the resort to 1D modeling is a common practice in both design and evaluation phases, the limitation of such models lies in the choice of transfer parameters, such as friction loss coefficients and heat transfer coefficients. In this work, we present an original approach based on the Finite Volume integration of the 1D flow and energy equations on a network of ducts, representing the ventilation system in the 11.6 km long Mont Blanc Tunnel with a spatial resolution of 10 m. The calibration of a set of friction loss coefficients against a rich experimental dataset collected throughout a dedicated set of in situ tests is of particular concern here, as it is carried out by means of genetic optimization algorithms. Predictions of the flow field are in remarkable agreement with the experimental data, with an overall RMS error of ± 0.42 m/s. Further refinements and possible parameter choices are also discussed

Structural optimization of automotive chassis: theory, set up, design

Improvements in structural components design are often achieved on a trial-and-error basis guided by the designer know-how. Despite the designer experience must remain a fundamental aspect in design, such an approach is likely to allow only marginal product enhancements. A different turn of mind that could boost structural design is needed and could be given by structural optimization methods linked with finite elements analyses. These methods are here briefly introduced, and some applications are presented and discussed with the aim of showing their potential. A particular focus is given to weight reduction in automotive chassis design applications following the experience matured at MilleChili Lab

P83 A pilot study to assess peak systolic velocity as a possible marker of atherosclerotic burden using ultrasound

Introduction: Ischemic heart disease (IHD) has been associated with lower peak systolic velocity (PSV) on penile Doppler measurements [1]. This study establishes whether carotid ultrasound (US) PSV was associated with computational fluid dynamics (CFD) outputs, which in turn may contribute to IHD pathogenesis. Methods: A sample of 57 subjects (with IHD: 27, without IHD: 30) had US velocity profiles (left- common carotid artery) determined between 10e12 equispaced points. Bezier curve fitting was used to fit the profile through the measured velocity points for a normalised diameter. PSV was correlated against CFD results such as wall shear stress (WSS) [2]. Difference in PSV between individuals with/without IHD was studied via t-test. Linear regression was carried out to see if peak systolic velocity was associated with CFD outputs. Any significant associations were analysed within stratified groups (with/without IHD). Results: PSV was significantly lower (p Z 0.042) in subjects with IHD (with IHD: 53.6 17.3 cm/s, without IHD: 62.8 16.1 cm/s). PSV was associated with carotid bulb average pressure drop (p < 0.001), area of average bulb WSS (<1 Pa: p Z 0.016, <2 Pa: p Z 0.006, <3 Pa: p Z 0.001). All the above associations remained significant in individuals with IHD (average bulb pressure drop: p Z 0.001, average bulb WSS (<1 Pa: p Z 0.013, <2 Pa: p Z 0.008, <3 Pa: p Z 0.003). In subjects without IHD, PSV was associated with only average bulb pressure drop (p Z 0.016). Conclusions: This study suggests that further work on PSV and its associations with CFD outputs is required in individuals with and without IHD in various vascular beds

Mobile elites at Frattesina: flows of people in a Late Bronze Age ‘port of trade’ in northern Italy

Following a mid twelfth-century BC demographic crisis, Frattesina, in northern Italy, arose as a prominent hub linking continental Europe and the Mediterranean, as evidenced by the remarkable variety of exotic materials and commodities discovered at the site. Debate persists, however, about the extent to which migrants influenced the foundation and development of Frattesina. The authors present the results of strontium isotope analyses, which suggest significant migration to the site, particularly of elites, mostly from within a 50km radius. Among these non-indigenous people, the authors identify a \u2018warrior-chief\u2019, whom they interpret as representing a new, more hierarchical society

A Heat Pump-Based Multi-source Renewable Energy System for the Building Air Conditioning: The IDEAS Project Experience

The current paper presents the state-of-the-art of the ongoing IDEAS research project, funded under the Horizon 2020 EU framework programme. The project involves fourteen partners from six European countries and proposes a multi-source cost-effective renewable energy system for the decarbonisation of the building envelope. The system features a radiant floor fed by a heat pump for the building thermal management. The heat pump can exploit sun, air, and/or ground as thermal sources through the use of photovoltaic/thermal solar panels, air heat exchangers, and shallow ground flat-panel heat exchangers. Thermal energy storage is achieved by means of phase change materials spread along several system components, such as: radiant floor to increase its thermal inertia, solar panels for cooling purposes, ground to enhance soil thermal capacity. Within the project framework, a small- scale building, featuring a plethora of sensors for test purposes, and two large-scale buildings are meant to be equipped with the renewable energy system proposed. The small- scale building is currently in operation, and the first results are discussed in the present work. Preliminary data suggest that while multi-source systems coupled with heat pumps are particularly effective, it is complex to obtain suitable thermal energy storages on urban scale

Assessment of cadmium levels in serum, toenails and diet: A cross sectional study in Modena, Northern Italy.

Assessment of cadmium levels in serum, toenails and diet: A cross sectional study in Modena, Northern Italy