Increasing the Economic Efficiency of Marine Power Plants Using Waste Heat Boilers with Controlled Flow Separation

Abstract Heat recovery of exhaust gases from main and auxiliary marine diesel engines is an effective way to improve the technical and economic parameters of marine power plants. Improvements in engine efficiency necessitate an increase in the weight-size parameters of the waste heat boilers, which makes it difficult to recover heat. Intensification of the heat transfer process is considered to be an effective way to reduce these indicators. By utilising mathematical modelling, this paper shows the effectiveness of using profiled heating surfaces of waste heat boilers for this purpose. The use of elliptical heating surfaces with a mechanism of controlled flow separation, in the form of a triangular notch, is proposed. This will reduce surface drag and increase the overall thermal-hydraulic efficiency of the heat transfer processes. It is shown that the use of such surfaces in waste heat boilers makes it possible to increase the efficiency of marine power plants in tankers with a deadweight of about 45,500 tons up to 1.5% absolute and container ships with a deadweight of about 122,000 tons up to 2.5% absolute.