Study of the functional parameters of main engine turbocharger for a tanker ship

Abstract

To correctly understand the requirements of a system, we must first study its schematics. In the case of energy systems, they require a detailed diagram of energy performance. Heat losses can be classified into high-temperature losses, medium-temperature and low-temperature losses. On board ships with low-speed propulsion engines, heat recovery systems operate in the range of 100-400 °C. Many residual energy recovery systems from internal combustion engines are under development: for example the MAN WHR development program for Tier III technologies. In this paper, I will treat both theoretical calculation elements and real elements of the operation of the turbocharging system, for the main reference engine. I chose to treat this system because it is a main subassembly for the engine, in terms of operation and thus its efficiency. In the theoretical calculation, I will start from the initial calculation data and I will expose the geometric and functional parameters of the turbocharger. The exhaust gases up to a temperature of 650 °C passes continuously through the turbine and heat its components, without its system of contraction cooling. In particular, the shaft bearing must withstand high operating temperatures without ever breaking the lubrication device. On the compressor side, the air is heated to over 200 °C. High temperatures lead to extreme thermal loads of the material in many locations. Speeds are extremely high: METxxSE turbochargers, as in figure 1, run at speeds between 10000 and 35000 rpm, depending on size. In this respect, the tangential speeds of 560 m / s and even more are reached at the compressor turbine, which rises to 1.7 times the speed of sound or 2000 km / h. The efficiency of the operation of the turbocharger system related to the main propulsion engine depends on the internal processes that take place in its operation, and also on the environmental conditions. In this way, the direction of processing on the installation is dictated by the engine load, taking into account the extreme situations, corresponding to the operation of the ship in special conditions (overload, tropical temperature, arctic temperature etc.).