MAN B&W Turbocharger Technology Unveiled
This past May marked the unveiling of an ocean-going product deep in the heart of Bavaria, specifically at the lake at Ammersee near Munich, where MAN B&W presented its newest engine series – the TCA (Turbocharger Axial). Encompassing two years of research and development, the first production turbocharger, the TCA77, has entered into service with an MAN B&W 7S50MC-C two-stroke diesel engine.
With the TCA77 being first production turbocharger form this series, the new turbocharger development combines a radial-flow compressor wheel with axial-flow turbine blading. In addition, frame sizes ranging from the TCA33 – all the way up to the TCA99 – are currently in development. So this broad range can be covered, the new turbocharger is of modular design – meaning that air is sucked in either via an air intake silencer, a 90-degree intake casing or an intake manifold. The exhaust gas from the combustion process then flows into the turbine via either an axial- or a radial flow casing. The new TCA series also features the proven separate-casing-base concept from the NA series, thus making it adaptable to the turbocharging requirements of the application in question.
The intake air is compressed by the compressor wheel, which is driven by the turbine. Both the compressor wheel and the turbine can then be adjusted to engine requirements by selecting from a range of meridians and blading configurations. Diffusers and nozzle rings, which are finely-shaped in their mass-flow areas allow the turbochargers to be fine-tuned to the engine. To achieve maximum variability, an optional nozzle ring capable of adjustment during operation will be available in the near future.
All TCA turbochargers also come equipped with a minimum of external connections. On the engine side and in the plant system itself the only additional connections – apart from the air and exhaust-gas connections – is an oil inlet and drain pipe, together with a breather connection for the bracket.
The TCAs are also equipped with hot casing components with a new temperature and noise-reducing casing with a sturdy sheet-metal cover. This casing significantly lowers the risk of engine-room personnel becoming injured by coming into contact with excessively hot surfaces in installations where the turbocharger is accessible.
None of the TCA turbocharger bearing casings is water-cooled – not even in the largest frame sizes – the TCA88 and TCA99. The heat brought in by the compressor and the turbine is dissipated in the luboil flung off the shaft of the rotating assembly. The oil mist thus generated can drop down the walls of the generously-dimensioned interior of the bearing casing, thereby evenly absorbing the heat, which is to be dissipated.