# Bulk Grain Cargo Hold Condensation Based on Computational Fluid Dynamics
## 1 Introduction
Over the past decade, the research work concerning condensation in bulk grain piles has been conducted to a more detailed degree, and achievement has further increased. In 2021, [PERSON] et al. [17] proposed that, when the temperature difference between the grain pile and the external air is between 5 and 6 \({}^{\circ}\)C, condensation may occur in the grain pile. In the same year, [PERSON] [18] developed a multi-field coupled mathematical model to simulate the process of grain pile dew condensation changes under a specific temperature difference. More recently, [PERSON] [19] established a condensation experiment simulation platform to explore the occurrence and development of different types of soybean condensation during storage, and found the critical parameters of soybean condensation. With the increase in bulk grain maritime trade, cargo damage has occurred in the bulk grain cargo hold, and the safe storage of bulk grain during transportation has gradually attracted attention. In 1976, [PERSON] [20] described the various factors affecting the safe transportation of grain by sea and pointed out that the soybean's own moisture content, breakage, and impurities can affect the grain's safe storage. In 1988, [PERSON] et al. [21] explained the formation of ship sweat and cargo sweat during the transport of grain by ships, reporting that it is the transport of moisture from the inside out that leads to the generation of condensation in the area of contact between liquid water and the cold ship hull. The Transport and Loss Prevention Department of the German Insurance Association [22] reported in 1998 that temperature and moisture content are the two most significant factors affecting the secure transport of soybean by sea, but the degree of influence of each factor was not analyzed in depth. In the 21 st century, [PERSON] [23] examined the temperature and humidity fields of sea-transported coffee seeds, noting that condensation is most likely to occur because of the high humidity in the headspace, and this report offers recommendations for preventing condensation during the transport of coffee beans. In 2018, [PERSON] et al. [24] conducted a risk assessment of the soybean meal transport process, observing that the humidity of the ambient air during transport and the size of the bean balancing particles also have a significant impact on the quality characteristics of the cargo. In recent years, [PERSON] et al. [25] described the risk of transporting cocoa beans by ship in terms of five aspects: humidity, moisture content, condensation, post-fermentation, insect damage and mold, and simulated these with software. In 2020, [PERSON] et al. [26] explained the properties of the self-nature of different types of grain during maritime transport, and presented the corresponding theoretical basis. In the same year, [PERSON] [27] provided evidence of the negative effects of high grain moisture content during ventilation. In 2021, [PERSON] et al. [28] explored the container condensation mechanism and developed a statistical model to estimate the condensation probability by considering external weather. Subsequently, [PERSON] et al. [29] explored the phenomenon of moisture absorption and desorption of hygroscopic goods when transported by sea, and summarized the moisture content range to prevent condensation of cargo. At the same time, [PERSON] et al. [30] conducted an experimental study of the sensitivity of different types of grain to the marine transportation environment, and pointed out that the best grain to prevent condensation is rye. In summary, the research work on safe storage of bulk grain on land is more developed than that onboard ships. Only a few studies have been conducted on the issue of condensation in the ship's cargo. Therefore, this paper has carried out innovative work from the following aspects:  
1. A model is developed after giving consideration to the dynamic fluctuations in sea temperature and sun radiation within the cargo hold;2. The condensation of grain near the side of the cargo hold is explored;
3.