【作者】

Marius Banica

【摘要】

该论文已在赫尔辛基举行的第28届CIMAC世界大会上发表，论文的版权归CIMAC所有。 The development of new combustion engine designs results in ever more demanding requirements on the supercharging system such as increasing pressure ratios and increasing specific volume flow rates. A major driver for these new developments are environmental aspects, such as increased fuel economy and reductions in exhaust gas emissions. At the same time, compactness of the supercharging system should further be maintained. As a result, the mechanical requirements on the turbochargers have increased considerably for new developments. In addition to these development trends on the engine and turbocharging side, vessel Occupational Health and Safety (OHS) regulations are constantly being tightened. Particularly relevant to turbocharger designers is resolution MSC.337 (91) of IMO. This regulation defines the “Code on Noise Level on Board Ships” to be mandatory under the SOLAS convention, thus leading to stricter requirements on the noise level on board ship for new vessels. A major part of the noise of modern 2- and 4-stroke engines is emitted from the supercharging system if no effective noise reduction measures are applied. To fulfil the requirements regarding noise emissions from engines in the future, a new approach to implement noise reduction measures on the engine side as well as on the turbocharging side is needed in many cases. On the supercharging side, the challenge is to develop solutions that constitute an optimum between noise reduction, compactness, weight, cost, and mechanical robustness. In the past, the development of new noise reduction measures has been a time consuming process that relied heavily on experimental methods. Given the tremendous increase in computational power over the past few decades, however, it is now becoming increasingly attractive for industry to optimize designs acoustically by means of modern CFD and FEM methods. This paper discusses current development trends in noise mitigation strategies for turbocharger systems and their pertinence to regulatory frameworks. Particular emphasis is placed on the application of state-of-the-art commercial CFD methods to the prediction of noise emitted by maritime radial compressors in the nominal operating range. Here, the compressor constitutes the main source of noise, which is emitted through both the inflow and the outflow. The former is linked to rotor locked shock fronts, which are a result of the transonic flow on the blade suction surfaces. Their strength, and hence the noise levels, are determined by the machine operating point. In the outlet, noise is generated by two mechanisms, unsteady pressure field of the rotor exit flow and rotor-stator interactions. Surface integral methods are not applicable and the noise needs to be propagated numerically. This places high demands on the numerical method. Therefore, a brief overview of issues such as numerical damping, dissipation, and required temporal and spatial resolution is provided. Computed sound pressure fields in compressor inflows and outflows are presented and compared to experimental data where available. The continuous assessment of noise by ABB Turbo Systems Ltd. over decades secured for all product platforms noise levels going below the respective limits. Based on this fundament and by applying and further developing the most recent methods also in the future a significant contribution to noise reduction on board ships will be made. This enables not at last the offering of solutions to the industry like the noise reduction package for the A100-L/A200-L turbocharger series comprising special features including an air outlet silencer as an answer to the challenge of advanced noise limits.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

返回