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Cimac Congress | Shanghai 2013 trollable pitch propellers to the latest hybrid systems with dieselelectric drives. Different automation modes are available such as diesel, sailing and diesel-electric. The subsystem Marex AMC is a state-of-the-art alarm and monitoring system. Besides engine safety and ship alarm functions, subsystems like an exhaust gas deviation monitoring, navigation light control or integration of video can be realised. Marex ship control systems use a safe CAN-bus protocol for the communication between its main components, analogue or digital signals are standard, CAN SAE J1939, Modbus RTU, Modbus TCP or others can be implemented on request. Marex control systems are available for any type of vessel, low cost, standard or complex, from small pilot boats, workboats, yachts, mega yachts or oceangoing vessels. Their highquality components are well-proven and tested and meet the classification requirements. A service <strong>net</strong>work is supporting the partners worldwide. Rexroth puts special attention on manufacturing environmental compatible products. The Green Passport (in accordance with the IMO Guidelines on Ship Recycling) is already available on request for Marex systems. In cooperation with Bosch, Rexroth can now supply the full scope of products from diesel injection system up to the control lever. The newly developed marine platform from Bosch based on the electronic diesel control system (EDC) integrates seamlessly with Rexroth’s class-compliant engine safety and alarm system Marex AMC and the remote control system Marex OS II. This technical paper will describe the ship control system Marex with its subsystems Marex OS II and Marex AMC. A short technical introduction will be followed by functional information on two to three existing ship control systems. Machine test on fuzzy PID control strategy of diesel engine basing on Microautobox Guodong Liu, Shanghai Institute of Space Propulsion, China Enzhe Song, Harbin Engineering University, China Xiaohua Zhu, Shanghai Institute of Space Propulsion, China In order to develop and research the intelligent fuzzy self-tuning PID controller, the simulation can not fully show the ever-changing characteristics of diesels practical work in nonlinear time-varying. To further validate the design of the fuzzy self-tuning PID controller speed performance used in the electronic governor, the controller must use a real diesel engine. Therefore, with the D6114 diesel engine as the control target, the auto-adjusting load system of Shanghai Chuangxiang Power Supply Equipment Co Ltd was taken to adjust the load. Be eqiuipped with machine test on the D6114 diesel engine.Therefore, firstly in the paper design and debug the hardware board; then match the new-designed controller with the real diesel basing on microautobox in order to verify and improve the speed governing systems control strategy and performance. By no-load start, load mutation assay and steady speed test, being proved the new design of intelligent fuzzy self tuning PID controller is superior to conventional PID controller to the purpose of well meeting the diesel engine speed control requirement. Wednesday May 15th / 13:30 – 15:00 Fundamental Engineering – Simulation Room A Advances and challenges in simulating combustion and emission formation in large diesel engines Andreas Wimmer, Graz University of Technology - Large Engines Competence Center, Austria Gerhard Pirker, Graz University of Technology, Austria Michael Engelmayer, Graz University of Technology, Austria Martin Gufler, Graz University of Technology, Austria Franz Chmela, Graz University of Technology, Austria Gernot Hirschl, Kompetenzzentrum Das virtuelle Fahrzeug Forschungsgesellschaft mbH, Austria This paper gives an overview of current possibilities and challenges in precisely simulating the engine cycle of large diesel engines. Both the increasing demands of emission legislation and competition are forcing greater efforts to be made in the design phase to predict the emissions and efficiency of engine concepts for large diesel engines. In recent years, the development of simulation tools has allowed great progress to be made in prediction. However, due to the highly complex processes during combustion and emission formation in diesel operation, very high demands are placed on the employed tools. While 3D CFD simulation is used to optimise the details of the combustion and emission formation processes in the combustion chamber, the 0D and 1D engine cycle simulation are applied to select the concepts and to pre-optimise important engine parameters. One great advantage of 0D and 1D models is their short calculation time, which allows the investigation of a great amount of variations in parameters. This paper investigates, compares and evaluates several 0D, quasidimensional and 3D simulation models for calculating the burn rate and the formation of soot and NOx. The 0D combustion model evaluated (LEC-DCM) is based on a global description of the injection spray, while the quasi-dimensional model uses a multi-zone approach (MZCM). The assessment of the 3D combustion modelling comprises the extended coherent flame model (ECFM-3Z). Besides the combustion models one key factor is the injection rate history that provides the foundation for the accurate simulation. While the simulation of the NOx emission is mainly influenced by the quality of the burn rate model, the simulation of the soot formation and oxidation processes depends on significantly more parameters. Different models in 0D as well as in 3D simulation were investigated. In addition, optical measurements on the single-cylinder research engine are used to validate the soot models. Combustion and radiation modelling of laminar premixed flames using OpenFOAM: A numerical investigation of radiative heat transfer in the RADIADE project Sajjad Haider, Technical University of Denmark, Denmark Kar Mun Pang, Technical University of Denmark, Denmark Anders Ivarsson, Technical University of Denmark, Denmark Jesper Schramm, Technical University of Denmark, Denmark The RADIADE project is initiated at TES-DTU in collaboration with MAN Diesel & Turbo AS. The aim of the RADIADE project is to enhance capabilities of computational models to understand the complex coupling between the radiant heat transfer, rate of combustion progress and formation of harmful products in combustion processes. The interest in radiation comes from the large dimensions of marine diesel engines, where radiation as a consequence is expected to be more influential on heat transfer than heat convection. The model results will be validated by conducting detailed experimental measurements. In parallel with the various experimental works in the RADIADE project, multidimensional computational fluid dynamics (CFD) modelling is meanwhile carried out to study the radiative heat transfer under diesel-like combustion. In this reported work, the open source CFD software OpenFOAM is employed to simulate the combustion and radiation processes in laminar premixed flames. This flame type offers the highest level of flame control. The stability and uniformity of the flame achieved in this setup facilitate the 54 SPECIAL Schiff&Hafen | Ship&Offshore | May 2013
Monday, May 13th Tuesday, May 14th Wednesday, May 15th Thursday, May 16th optical line of sight diagnostics and hence the in-situ measurements of temperature and soot concentrations. Effects of diffusion and turbulence are minimised here and efforts are therefore paid on the modelling of combustion chemistry, radiation and soot formation. For improved computational runtime, a two-step chemical reaction scheme proposed by Westbrook and Dryer is used together with a steady-state solver. The steady-state solver is developed by modifying an existing solver, Local Time Stepping (LTS) ReactingParcelFoam. Akin to reactingFoam, which has been widely used in combustion simulations, LTSReactingParcelFoam is also applicable for laminar and turbulent reacting flow but it is a local time stepping solver for steady-state simulations. The modified version is henceforth addressed as radiationReactingLTSFoam (rareLTSFoam). In order to simulate the radiative heat loss, P1 radiation model is used. The model validation uses two test cases of laminar premixed flames with different equivalence ratios. In the first case, a stoichiometric flame is produced in which soot radiation process can be omitted; while in the second case, a rich flame with equivalence ratio of 2.15 is used. The results generated by the integrated CFD chemistry model are validated against temperature measurements at different heights along the axial direction. For the radiative heat transfer, a parametric study is conducted using P1 model. The absorption coefficients are modeled using RADCAL and WSGGM models. Implementation of the steady-state solver has been proved to simulate the stabilised, laminar premixed flame accurately with an expedited calculation. This serves as a useful platform when comprehensive radiation model such as inite Volume Discrete Ordinate Method (fvDOM) radiation model is implemented. Understanding and further improvements on the robustness of numerical models achieved at this phase are critical prior to computationally investigating the radiative heat transfer process in turbulent diffusion flame and diesel engine combustion that have higher levels of complexity. Flow and pressure simulation of cooling water, lubricating oil and fuel supply systems Andreas Hjort, Wärtsilä, Finland Juhani Ervasti, Wärtsilä, Finland Jaakko Koivula, Wärtsilä, Finland Lars Ola Liavag, Wärtsilä, Finland Alexandre Pereira, Wärtsilä, Finland Antonino Di Miceli, Wärtsilä, Finland When designing fluid systems for four-stroke medium-speed diesel engines, it is beneficial to use modern simulation tools to achieve an optimised design in an early phase. Today’s engines have become very compact and typically have a high degree of integration of fluid channels into castings. Therefore, changes to address flow problems after design is complete will require big re-design efforts and should be avoided. The heat balance of the engine determines the needed cooling water flow to achieve sufficient cooling without excessive temperature increase in the water. As the pumps used are of centrifugal type the flow in the system is determined by the system pressure drop. CFD simulation of complicated channelling as part of the design phase will ensure unnecessary pressure drop is avoided and thus the water flow through the system will be increased. A well-designed cooling system will have the majority of the pressure drop in coolers and as little as possible in the channels and piping. Oil pumps for four-stroke diesel engines must be dimensioned to ensure sufficient pressure is available in the critical components at all conditions. Over-dimensioning of the oil pump will lead to unnecessary oil flow wasted through the pressure control valve. To determine the exact oil flow through the engine in the design phase is difficult, as the oil system has many consumers with different characteristics. 1D flow simulation of a complete oil system gives a sufficiently accurate prediction of the needed flow to avoid over- or under-dimensioning of the oil pump and avoid excessive pressure drop in any part of the oil system. Pressure pulsation from mechanical fuel pumps to the fuel supply line can be a source for vibration both on the engine itself but also in the external fuel piping of the installation, e.g. ship. By 1D simulations of the fuel supply system, the pulsation can be predicted and the need for damping can be determined. This paper presents successful simulation projects of all the above mentioned systems. Turbulence during the compression stroke Eero Antila, VTT Technical Research Centre of Finland, Finland Mika Nuutinen, Aalto University, Finland Ossi Kaario, Aalto University, Finland Normally, diesel combustion simulations are started from bottom dead centre before combustion. Initial values of pressure and temperature are taken from experimental results or 1D-simulations. As initial turbulence values (k and ε), some correlation, intake flow simulation or just best practise values are used. All those values are initialised to be constant for whole simulation volume. In the previous study, intake channel simulations were done. Authors found that the level of turbulence values at TDC were different if the intake stroke was simulated or if average values were initialised at IVC. In this paper three different engines are simulated. For each engine intake and compression strokes are simulated to get the best possible knowledge about the real turbulence values. From those results the average values of p, T, k, ε and swirl number at IVC are captured and used as initial values of compression simulation. Finally, a better method to initialise turbulence values is described and tested. Wednesday May 15th / 13:30 – 15:00 Room B Environment, Fuel & Combustion Gas and Dual-Fuel Engines – Abnormal Combustion Understanding the influence of heat transfer and combustion behaviour on end gas knock in heavyduty lean burn engines Joel Hiltner, Hiltner Combustion Systems, USA The onset of end gas knock remains one of the primary factors limiting the thermal efficiency, fuel flexibility, specific power output, and transient capability of lean burn natural gas engines. In the past two decades, huge strides have been taken to improve the performance of these engines, based largely on a fundamental understanding of the impact of thermodynamic design and fuel properties on the resistance of a given combustion platform to engine knock. Simulation tools based on this knowledge have led to optimised designs as regards expansion ratio, Miller cycle utilisation, and other design approaches aimed at limiting end gas temperatures. Two basic engine phenomena whose impact on knock is less well understood are in-cylinder heat transfer and overall combustion rate, phasing, and stability. In-cylinder heat transfer has a profound impact on charge temperatures and can lead either to increased or decreased knock tolerance for a given design, depending on a number of factors. Combustion chamber surface temperatures are a function of detail design, engine load, and engine operating condition and have a direct impact on heat transfer rates during compression and the early part of combustion. Incylinder bulk flow and turbulence level induced, for example, by swirl and squish also impact the heat transfer rate and thus the unburned gas temperature. The influence of these heat transfer effects May 2013 | Schiff&Hafen | Ship&Offshore SPECIAL 55
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