The pursuit of realism in the ERS environment is progressing with ICT development. On the other hand, there is no discussion focused on reproducibility that includes comprehensive load side characteristics, such as propeller characteristics through the shaft system and hull resistance characteristics, which is one of important knowledge requirements specified in IMO Model Course 2.07. In this report, the author focuses on load side characteristics in ERS performance in order to make clear typical challenges facing ERS, advance marine engineer training and promote research and development related to ship engine operation management, all of which are rarely considered in the current general ERS.

  In this report, the author introduces the results of an experiment based on actual ship measurements and numerical simulations regarding the reproducibility of the power load characteristics while promoting greater awareness of the issue raised in this paper. The author hopes for wider use and development of ERS that considers the importance of power load characteristics and more robust discussions on improving the ERS environment.

  The numerical simulation of turbulent heat transfer for helium gas flowing in a horizontal small-diameter tube was performed. The numerical simulation conditions were 0.8 mm and 1.8 mm for inner diameters, and 102-128 m/s and 87-241 m/s for velocities at the inlet of the tube, respectively. The numerical solution was carried out by applying ANSYS FLUENT software. The standard k-ε model and a user-defined wall function were used for the analysis. The thickness of the conductive sublayer, which is the region where heat transfer by conduction is dominant, was estimated. As a result of the numerical simulation, it was found that the thickness of the conductive sublayer becomes thinner as the flow velocity increases and the inner diameter decreases. Moreover, the heat transfer coefficients of the simulation data were compared with the previous experimental data, and they were in good agreement with the experimental data.

In the marine engineering field, research has been conducted to reduce fuel consumption and emissions of harmful exhaust gases from medium- and low-speed diesel engines by improving supercharging performance, scavenging efficiency, and introducing electronic control technology, etc., and these technologies have been put to practical use. However, most of these technologies have been applied to newly constructed vessels, and oxygen-containing fuels such as water-emulsion fuel and DME fuel have not yet been put to practical use. In this study, the effects of heating high viscosity residual oil and mixing air into the fuel as fine bubbles on the combustion and exhaust characteristics of the fuel were investigated using a practical medium-speed marine diesel engine. As a result, the fuel consumption reduction effect was confirmed when fine air bubbles were mixed in heated residual oil, as is the case with them being blended into marine diesel oil. In particular, the maximum reduction was 7% at 75% load and 0.2L/min air volume, and the average reduction was 3.2% at 75% load. In terms of the exhaust gas characteristics of the fuel, no significant reduction in NOx was observed when microbubbles were mixed, but smoke values were reduced by up to 33%.