August 6, 2004
MAN B&W launches new radial turbocharger
Following the successful introduction of the TCA axial turbocharger two years ago, MAN B&W Diesel Group has now announce a completely new radial turbocharger.
The TCR turbocharger will replace the current NR series, which has been in production for nearly 50 years culminating in the current NR/S design.
The new TCR series has a compressor pressure ratio of 4.7 and is capable of up to a 5.2 ratio when built as a special version.
Aimed specifically at the medium and high-speed diesel and gas markets, six different models are able to cover a wide range of outputs from 400 kW to almost 6,000 kW.
Introduction of a new turbocharger series always attracts attention in the medium speed engine world. Usually the market behaves with caution. This was not, however, the case when the axial TCA turbocharger was launched. Since delivery of the first unit in May 2002 over 350 have now been ordered. MAN B&W Diesel is quite confident it will be able to repeat this success with the TCR series.
The TCA and TCR are the first MAN B&W Diesel turbochargers to be completely designed using a 3D-CAD system.
This simplifies and reduces development work by integrating innovative software tools during the CFD (flow) and FEA (strength) analysis. These findings allow the optimization of the material used for the turbocharger to combine maximum strength with the lowest possible weight and a compact design.
The flow and strength analyses resulted in a completely new design of compressor wheel, which permits higher efficiency, quicker response behavior during acceleration and, therefore, minimal emissions from the complete system.
The compressor wheel is screwed onto the shaft via a special retainer, which ensures precise centering. This design permits, among other things, a reduction of the hub and, therefore, an increase in the airflow rate.
For the rotor support, the MAN B&W engineers came up with "something special." The axial bearing was located between the two radial bearings which permitted minimization of the bearing space requirements. The sealing system was also designed to be as compact as possible and without any additional sealing air requirement. The piston ring gasket, combined with a labyrinth seal, was thoroughly tested and proved to provide optimum sealing capacity both in operation and at standstill.
Flow calculations played a major part in the development of the new turbine in order to create a shape offering both high efficiency and a wide application range on the other. Consequently, says MAN B&W, the new turbine provides optimum values in part load and full load operation and is equally suitable for constant and pulse pressure turbocharging.
Optimization is not restricted to the turbine rotor but covers the complete system from the gas inlet casing, via the nozzle ring to the turbine outlet casing, which can be obtained in various mounting variants. An optional variable nozzle ring permits turbocharger adaptation to most load conditions.
Development work also concentrated on the noise level. A completely new intake silencer, not only reduces the turbocharger noise but is very easy to install. With regard to weight, the one piece casing in aluminium cast design benefits once again from FEA optimization, while an integrated washing system permits compressor wheel cleaning during operation.
Good design takes the working life of the product into consideration. During TCR turbocharger development, great importance was attached to an extended service life of the wear parts, which is to the operator's benefit with extended service work intervals and the possibility to carry out maintenance work with other services to be done on the engine. Many design details contribute to simplifying and reducing maintenance. For example, an opening in the turbine outlet casing permits inspection of the turbine wheel without having to remove the casing.