Daniele Nocciolini

Energy and wear optimisation of train longitudinal dynamics and of traction and braking systems

Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components.

A Tool for the Simulation of Turbo-Machine Auxiliary Lubrication Plants

The reliability and safety of large turbo-machinery systems used in the oil and gas industries are heavily affected by the efficiency of the lubrication plant. In particular, hazard and operability (HAZOP) analyses are often performed using piping and instrumentation diagrams (P&ID; according to regulations in force, ISO 14617). Usually, these analyses are time-consuming and affected by potentially dangerous errors. In this work, a tool for the mono-dimensional simulation of thermal hydraulic plants is presented and applied to the analysis of safety-relevant components of compressor and pumping units, such as the lubrication circuits. Compared to known commercial products, the proposed tool is optimised for fixed step solvers in order to make real-time (RT) integration easier. The proposed tool defines a general approach, and can be used as a SimScape-Simulink library of thermal-hydraulic components (designed according to the P&ID definitions). Another interesting feature of the tool is the automatic scheme generation, where the Simulink model can be automatically generated by P&ID schemes.

Object oriented simulation of longitudinal trair dynamics efficient tools to optimize sustainability and efficiency of railway systems

As a partner of the Tesys Rail Project, the University of Florence has developed an innovative model of the longitudinal railway vehicle dynamics that can be easily adapted to different kind of applications and mission scenarios, ranging from tramways or freight to passenger or even high speed train. The aim of the model is the efficiency and energy optimization of railway systems. A particular attention has been paid to the modularity of the proposed approach and to the possibility of real time implementation on different application targets. The proposed modeling approach reaches a good compromise between the capability of the model to reproduce the behavior of the simulated physical systems and the simplification needed to make the model more general and suitable to represent different technological solutions. In this work, the proposed modeling approach is exposed and, in order to highlight its main features, some benchmark tests are shown.

Development of efficient models of Magnetic Braking Systems of railway vehicles

In modern railway vehicles, the use of Magnetic Braking Systems is continuously increasing, because they are characterized by high braking performances and low energy consumptions. Hence, the study and the accurate modelling of Magnetic Braking Systems is a very important issue, because they significantly affect the dynamics of vehicle and electrical supply circuit. Usually, the performances of Magnetic Braking Systems are evaluated on test-rigs in order to reduce times and costs of testing phases. For this reason, the authors focus on the development of a complete 3D model of Magnetic Brake System test-rig (built in COMSOL), including all the electromagnetic, circuital and mechanical parts. These parts are often studied separately in the literature; however, a combined analysis is crucial to correctly describe the behaviour of the whole system. The proposed model is highly modular (to describe different Magnetic Brake System test-rig layouts characterized by a different number of magnetic polar expansions) and aims at obtaining a compromise between accuracy and numerical efficiency. Subsequently, a second simplified lumped parameter model derived from the complete one and built in MATLAB is developed, to further reduce the computational load without decreasing the results accuracy. In this work, both the models have been developed and validated in collaboration Ferrovie dello Stato and compared with other simplified models present in the literature.

Development and validation of a model for the optimization of regenerative braking of high speed trains

The interest for the energetic optimization of railway systems is constantly increasing due to recent developments concerning Technological Standards and Regulations. A particular attention is usually paid to the coupling between the dynamical behaviour of railway vehicles and the electrical infrastructure, including all the subsystems related to energy distribution and storage. In this research work, the authors propose a newly developed modelling approach for the analysis of the railway vehicle-line system, based on the use of the object-oriented language Simscape that introduces significant advantages with respect to other conventional simulation tools in terms of computational efficiency and modularity. In order to validate the modelling approach, the Italian DC High Speed line, considering a high-speed train with distributed traction power based on the new ETR1000, has been used as a benchmark. The proposed model provides accurate results with a high computational efficiency, proving to be an important tool for the analysis of railway systems. This tool has then be used to perform a preliminary energetic optimization of the considered system).

Real-time modeling, control and optimization of turbo-machinery auxiliary plants

In the Oil & Gas industry, the testing of auxiliary lubrication plants represents a mandatory preliminary activity before the whole turbo-machinery train (including the auxiliary lubrication plant) can be put in operation. To this end, the employment of both efficient and accurate plant models becomes very important to synthesize satisfactory control strategies for both testing and normal operation purposes. This way, many benefits (e.g. in terms of safety, times and costs of execution) can be achieved. Therefore, this article focuses on the development of innovative and efficient real-time models and control architectures to describe and regulate the auxiliary lubrication systems. All the new strategies have been validated through accurate real experimental campaign and real-time hardware. According to the Bond-Graph modeling strategy, an efficient lumped parameter model of the lube oil console has been built to properly optimize the description of such system and the efficiency of the control strategies. The code has been compiled and uploaded on a commercial real-time platform that has been used to regulate the pressure control valve of the physical plant (to this aim, a new regulator has been developed). In particular, the control was designed according to a novel model-based methodology, including both identification and control optimization techniques (based on flexible simplex techniques). The comparison between the data obtained from the simulated system and the ones acquired from the physical plant shows the good agreement, reliability and efficiency of the proposed model and the control strategy. Both the modeling approach and the control strategy have been developed in collaboration with Baker and Hughes General Electric, while the experimental data were acquired in a plant located in Massa (Italy).

Control design, simulation and validation of a turbo-machinery auxiliary plant

In the oil and gas industry, the testing of auxiliary lubrication plants represents an important preliminary activity before the whole turbo machinery train (including the auxiliary lubrication plant) can be put in operation. Therefore, the employment of both efficient and accurate plant models becomes mandatory to synthesize satisfactory control strategies both for testing and normal operation purposes. For this reason, this paper focuses on the development of innovative real-time models and control architectures to describe and regulate auxiliary lubrication plants. In particular, according to the Bond-Graph modelling strategy, a novel lumped parameter model of the lube oil unit has been developed to properly optimize the behaviour of this unit if it is controlled. The code has been compiled and uploaded on a commercial real-time platform, employed to control the pressure control valve of the physical plant, for which a new controller has been developed. The comparison between the data obtained from the simulated system and acquired from the physical plant shows good agreement and the good performance and reliability of the proposed model and control strategy. The modelling approach and the control strategy have been developed in collaboration with GE Nuovo Pignone S.p.a. while the experimental data were acquired in a plant located in Ptuj (Slovenia).

Tilting Pad Journal Bearing TEHD Analysis: An Innovative Model

Tilting Pad Journal Bearings (TPJBs) are widely used in the turbomachinery field due to their superior dynamical performances, but their operation involves several different physical phenomena. In this research work the authors propose an innovative 3D ThermoElastoHydroDynamic (TEHD) model for the analysis of TPJBs behaviour developed and experimentally validated in cooperation with General Electric Nuovo Pignone: the model is able to perform a nonlinear transient coupled analysis taking into account fluid dynamical, thermal and elastic effects and reaches a good compromise between the accuracy of the results and the computational efficiency.

Braking Energy Recovery in High Speed Trains: An Innovative Model

Modern railway development trend is pushing towards a strong enhancement of the energy efficiency of lines and vehicles, with particular attention to braking energy recovery. In this research work the authors have developed an innovative and numerically efficient vehicle-line coupled model, using the object oriented Simscape language: the model has been validated considering a set of experimental measurements concerning the Italian High Speed train ETR 1000 and has then be used to analyze the feasibility of the application of energy storage systems in high speed application. This analysis has shown that the use of stationary energy storage devices can provide significant energy savings even in high speed applications.

An extended library of models of railway vehicles for fast simulation and optimization of regenerative braking and energy management

As a part of the Tesys Rail Project authors have developed a parametric and computationally affordable model of a railway DC line in order to analyze the complex energetic interactions arising between different travelling vehicles. In order to fully exploit the features of the proposed approach and its capability to investigate complex operating scenarios, the authors have further developed the model by including a wider variety of on-board functionalities and a more extended list of simulated vehicles. In this research work, the authors expose some improvements of a previously developed High Speed train model (based on the ETR 1000) and the development of additional models of older Italian High Speed Trains, such as the ETR 500, which are still in service on Italian High Speed lines.