A turbocharger retrofitting platform utilizing one-dimensional (1D) models for calculating turbomachinery components map and a fully coupled process for integration with the turbomachinery components and the diesel engine, is presented. The platform has been developed with two modes of operation, allowing the retrofitting process to become fully automatic. In the first mode, available turbocomponents are examined, in order to select the one that best matches the entire engine system, aiming to retain or improve the diesel engine efficiency. In the second mode, an optimization procedure is employed, in order to redesign the compressor to match the entire system in an optimum way. Dimensionless parameters are used as optimization variables, for a given compressor mass flow and power. A retrofitting case study is presented, where three retrofitting options are analyzed (compressor retrofit, turbocharger retrofit, and compressor redesign). In the first and second option, turbocharger retrofitting is carried out, using available turbocomponents. It is shown that initial performance cannot be reconstituted using off-the-self-solutions. In the third option, compressor designing is performed, using the optimization mode, in order to provide an improved retrofitting solution, aiming to at least reconstituting the original diesel engine performance. Finally, a CFD analysis is carried out, in order to validate the compressor optimization tool capability to capture the performance trends, based on geometry variation.

A marine turbocharger 3D compressor design tool, implemented on an existing marine turbocharger retrofit platform is presented. It produces 3D centrifugal compressor geometry for optimal compressor retrofit. It encompasses two modules, allowing the design process to become fully automatic. First, a 1D compressor multi-point design optimization process is carried out, aiming to provide a fast and reliable solution based on Turbocharged diesel Engine range of operation. Structural integrity is ensured by using simplified structural analysis. Dimensionless parameters are used as optimization variables, for a given nominal compressor mass flow and power. Then a CFD compressor multi-point design optimization process is carried out, producing optimized 3D compressor geometry. It complies with the Turbocharged diesel Engine range of operation, while structural integrity is ensured by using Finite Element analysis. A turbocharger compressor design case study is presented. First, a turbocharger 1D compressor design is carried out, aiming to at least reconstituting the original diesel engine performance. This first module provides a reliable compressor initial geometry for the 3D design module. A fully 3D compressor design is then performed, using a CFD-FEA optimization process, in order to provide an improved retrofitting solution. Comparison between the multi-point and the traditional one-point design method, shows that the multi-point method provides a wider SFC reduction in the range that the Diesel engine normally operates.

Turbocharged diesel engines are extensively used in marine vessels, both as propulsion engines and as generator sets. The engines operation in the hostile marine environment results to performance degradation having a negative effect on the economics of the marine vessel's operation both in terms of fuel consumption and maintenance. This paper presents a turbocharged 4-stroke diesel engine simulation framework based on one-dimensional calculations and analysis. The framework is suitable for turbomachinery and heat exchanger components fault simulation predicting both turbocharger and diesel engine performance and operability. Meanline models were used in conjunction with beta lines method for generating accurate and detailed compressor and turbine performance maps, coupled with a single zone closed-cycle diesel engine model for generating engine performance characteristics. The simulation framework modules are adjusted and validated against measured data. Following specific faults are simulated utilizing physical consistent parameters such as blade friction and thickness based on relevant literature data. Overall system simulation and operation analysis is carried out assessing operability and performance parameters. Analysis results show a significant reduction in engine performance, especially in case of both turbo-components being fouled (22% power reduction), in contrast with the heat exchanger fouling where the power reduction is about 1%.

A turbocharger retrofitting platform utilizing 1D models for calculating turbomachinery components maps and a fully coupled process for integration with the turbomachinery components and the diesel engine, is presented. The platform has been developed with two modes of operation, allowing the retrofitting process to become fully automatic. In the first mode, available turbo-components are examined, in order to select the one that best matches the entire engine system, aiming to retain or improve the diesel engine efficiency. In the second mode, an optimization procedure is employed, in order to redesign the compressor to match the entire system in an optimum way. Dimensionless parameters are used as optimization variables, for a given compressor mass flow and power. A retrofitting case study is presented, where three retrofitting options are analyzed (compressor retrofit, turbocharger retrofit and compressor redesign). In the first and second option, turbocharger retrofitting is carried out, using available turbo-components. It is shown that initial performance cannot be reconstituted using off-the-self solutions. In the third option, compressor designing is performed, using the optimization mode, in order to provide an improved retrofitting solution, aiming to at least reconstituting the original diesel engine performance. Finally, a CFD analysis is carried out, in order to validate the compressor optimization tool capability to capture the performance trends, based on geometry variation.

An integrated turbocharger 1D design tool, allowing retrofit of both compressor and turbine is presented. An optimization procedure is employed, to design both compressor and turbine to match the entire turbocharged system in an optimal way. The optimization process focuses on engine specific fuel consumption reduction in the engine range of operation, while ensuring appropriate matching between turbomachinery components and the diesel engine. Structural integrity of both turbo-components is ensured by using simplified structural and modal analysis. Dimensionless parameters are used as optimization variables, for both compressor and turbine, allowing the design process to become fully automatic. The platform produces four optimal 1D geometries, of different possible centrifugal compressor diffuser and turbine combinations. The combination that gives the best improvement to the diesel engine operation is identified. A case study is presented, where all four turbocharger configurations are designed and analyzed aiming to at least recover the original diesel engine performance. The platform then sorts all four optimized turbocharger geometries based on annual fuel cost reduction. The best configuration achieves the largest fuel consumption reduction (0.4% for the case presented), while stable operation and structural integrity are ensured. Additionally, a study of how the new machine learning volute loss models affect the designed geometry is performed. Finally, a techno-economical assessment is performed in order to identify the most profitable retrofit option, turbocharger redesign being one of four possible turbocharger options considered by the authors. Redesigning the entire turbocharger is shown to provide the largest long term profit.