The digital twin (DT) approach has risen in popularity for applications in many industrial process managements. By applying the “Shipyard 4.0” digital transformation trend, the ship industry is developing techniques able to reduce risks by improving operation process management. This study proposes a combination of a DT approach and practical experiment as part of a five-tier framework for DT-driven process management in the ship industry. This study focuses on the characteristic scenarios and crucial parameters within the ship engine system and shipping cargo container in operation procedures. DT-based models and platforms are established in this study based on the basic modeling of Maya and scene rendering of Unity 3D. To address the fusion issue of multi-source heterogeneous data in the ship operation process, a Bayesian neural network (BNN) method is introduced into DT’s virtual model layer and data support layer. By integrating an improved BNN-based algorithm into DT-based models, the collected data can be extracted and aggregated accordingly. In the ship engine room, the operating temperature is selected as a critical parameter, with the best mean percentage deviation (MPD) between DT-driven predictions and test value of 3.18%. During the shipping cargo container process, the results indicate that DT-based models have acceptable performances under different conditions, with optimal MPDs of 5.22%.

The flame behavior of engine fires, such as those caused by leaked fuel coming into contact with an ignition source, is significant in practical applications, where flame detection is used to minimize the damage of the attendant ship fire safety problem. In this work, the flame behavior of hot-surface ignition (HSI) under crossflow was studied, with a particular focus on the difference in lateral airflow velocities for HSI-driven flame deviations at the windward and leeward sides of a ship engine room; a problem such as this has not previously been quantified. Full-scale experiments were conducted in a ship engine room using marine diesel and hydraulic oil as the fuel, and by adopting lateral airflow with the velocities of 0 m/s, 1.0 m/s, 3.0 m/s, and 5.0 m/s, together with an HSI mechanism consisting of marine diesel and hydraulic oil coming into contact with elevated hot-surface temperatures. The results show that the effects of disturbing the combustible gaseous mixture for marine fuel HSI, at both the windward and leeward sides, strengthened as the airflow velocity increased. The HSI position of the leaked marine fuel in the engine room was strongly dependent on ventilation, while that under the airflow condition decreased with the increase in the hot-surface temperature. A model was proposed to characterize this difference on the basis of the HSI height, which was defined as the ratio of the height during the initial HSI to the stationary period. The results indicate that the scale of the flame gradually increased in the horizontal direction, which was significantly different from the result in the scenario without mechanical ventilation. The results also revealed that the fluctuation of hydraulic oil through the temperature field was significant and lasted for a long time under a low HSI temperature.

Gas extraction quantity from coal seam is the key index to evaluating the effect of eliminating coal and gas outbursts. The prerequisite for increasing the gas extraction quantity and improving the effect of gas control is to make clear the influencing factors of gas extraction. The main factors affecting gas extraction are permeability, gas pressure, and buried depth of coal seam in this paper. The qualitative and quantitative analyses of gas extraction quantity by three factors are carried out according to the test data. The research results show that: (1) In the areas with high permeability and gas pressure, the gas extraction volume shows random characteristics, indicating clear regional differences. (2) The increase of buried depth of coal seam will reduce the fluctuation of gas extraction quantity, resulting in a lower extreme value of gas extraction quantity. The possibility of gas extraction at a lower level will be significantly increased. (3) The correlation analysis shows the change law of the positive correlation coefficient between gas extraction quantity, gas pressure, and permeability, and shows the opposite trend with the increase of the buried depth of coal seam. The results show an important guiding significance for improving the efficiency of gas control.