Expansion of the range of permissible loads of a marine four-stroke diesel engine when using an adjustable turbocharger nozzle apparatus

Abstract

The paper analyses the influence of the adjustable turbocharger nozzle apparatus on the parameters and criteria determining the thermal and mechanical stress of the main marine four-stroke diesel engine. The methodology of construction of limiting characteristics of mechanical and thermal stress using approximation dependences of parameters and criteria obtained by calculation-theoretical method is developed. The main parameters limiting the range of maximum permissible diesel engine loads on mechanical and thermal stress in the initial variant and in the variant with adjustable nozzle apparatus are revealed. It is established that the increase in the angle of rotation of blades of the adjustable nozzle apparatus up to the maximum permissible value causes a decrease in the parameters of thermal stress, as a result of which the zone of maximum permissible modes of operation of the diesel engine expands. At the same time, the parameters and criteria determining the mechanical stress of the diesel engine increase, but the reduction of the zone of maximum permissible loads on mechanical stress does not reduce the range of maximum permissible loads established by changing the thermal stress parameters.