【作者】

Nikolaos Sakellaridis,Dimitrios Hountalas

【摘要】

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 Turbocharger condition is critical for the performance of turbocharged Diesel Engines and especially large scale 2-stroke ones. In this case, in addition to increasing power density, the turbocharger must also maintain a positive difference between exhaust and inlet pressure to facilitate cylinder scavenging. In large scale 2-Stroke Diesel engines the mass flow through the engine, and therefore A/F ratio, is greatly influenced by turbocharger performance. In the present paper it is presented a theoretical investigation to determine and quantify the effect of turbocharger performance degradation on the performance characteristics of a slow speed 2-stroke marine Diesel engine. The closed cycle is modelled using a multi-zone phenomenological combustion model. For the gas exchange, the filling and emptying method is applied. The model has been extensively validated for cases of Heavy Duty four stroke Diesel Engines, and has been modified to capture special characteristics of large 2-Stroke Diesel Engines operating on HFO. The T/C turbine and compressor are simulated using newly developed physically based quasi-dimensional models. Flow is solved at key stations along the T/Components, while flow losses and angles are derived from semi-empirical correlations. For the turbine a modified version of the Ainley and Mathieson axial turbine performance prediction technique is applied. The compressor is modelled using a mean line model of ra-dial compressor performance. For the turbomachinery models calibration, data from the Engine NO, Technical file are used (where air and exhaust gas flow data are provided). Thus, it is resolved the problem of limited availability of turbomachinery maps, which is very common for field applications. The complete engine model is validated through the comparison of predicted performance data against the corresponding values of the shop tests. Using the model, various scenarios of turbocharger performance degradation are investigated. The effect of turbine efficiency reduction, compressor efficiency reduction saw as their simultaneous reduction are investigated with respect to their impact on engine performance. The effect of turbine nozzle ring fouling on engine operation is also investigated since this is a common problem for two-stroke marine diesel engines. From the analysis of generated results, it is possible to develop a methodology for turbocharger condition monitoring that will allow safe detection of the actual component fault.

【会议名称】

第27届CIMAC会议

【会议地点】

上海

【下载次数】

1

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