Transmission mechanics of infectious pathogen in various environments are of great complexity and has always been attracting many researchers' attention. As a cost-effective and powerful method, Computational Fluid Dynamics (CFD) plays an important role in numerically solving environmental fluid mechanics. Besides, with the development of computer science, an increasing number of researchers start to analyze pathogen transmission by using CFD methods. Inspired by the impact of COVID-19, this review summarizes research works of pathogen transmission based on CFD methods with different models and algorithms. Defining the pathogen as the particle or gaseous in CFD simulation is a common method and epidemic models are used in some investigations to rise the authenticity of calculation. Although it is not so difficult to describe the physical characteristics of pathogens, how to describe the biological characteristics of it is still a big challenge in the CFD simulation. A series of investigations which analyzed pathogen transmission in different environments (hospital, teaching building, etc) demonstrated the effect of airflow on pathogen transmission and emphasized the importance of reasonable ventilation. Finally, this review presented three advanced methods: LBM method, Porous Media method, and Web-based forecasting method. Although CFD methods mentioned in this review may not alleviate the current pandemic situation, it helps researchers realize the transmission mechanisms of pathogens like viruses and bacteria and provides guidelines for reducing infection risk in epidemic or pandemic situations.

Much less attention has been focused on the particle deposition in rectifying plate though it is a common problem in shale gas pipe systems. The effects of particle parameter and flow field on the deposition and distribution of particle in a new‐type rectifying plate system are investigated. Both the computational fluid dynamics (CFD) method and the experiment method are used in order to analyze the particle deposition under various conditions. The accuracy of simulation model is verified with measurements in the experiment and from analyzing, and it is found that the Boltzmann equation can well describe the relationship between gas Reynolds number and particle deposition in the rectifying plate system. It is also found from investigation that the particle deposition is greatly affected by the particle parameter. Deposition rate rises with the increase of the particle diameter; however, it reduces gradually with the decrease of particle shape factor. Moreover, the particle mass concentration is an essential dimension that can give a prediction of where the particle may deposit.

The abnormal vibration of natural gas station pipelines seriously threatens the safety of pipeline transportation, and improper handling will cause huge economic losses. For the abnormal vibration of the pipeline, reasonable treatment must be carried out. The Yongchang gas station belongs to the west–east gas pipeline system in China. Since its production, abnormal vibration has often occurred in the west-third outbound pipeline of the Yongchang gas station, and the vibration changes according to the different gas transport volumes. In this paper, the outbound pipeline of the Yongchang pressure station is taken as the research object, and the vibration analysis of the station yard pipeline is carried out. The numerical model of the station yard pipeline is established, and the correctness of the model is verified by the field vibration test. The fluid–solid coupling method is used to analyze pipeline vibration under different working conditions. Then, three kinds of vibration reduction schemes are proposed and verified by simulation. The main conclusions are as follows: (1) The fluid pressure fluctuation in the pipeline is the root cause of abnormal vibration in the station. (2) When the gas transmission volume is large, the vibration of the pipeline system will become more severe. (3) The scheme of increasing pipe diameter and adding appropriate constraints has the best vibration reduction effect.

Erosion caused by sand particles in the pipe system is a major concern in the shale gas industry. In the rectifying plate system, the fluid with high Reynolds number is assumed to be the fully turbulent flow. To investigate particle erosion under the complex flow in the rectifying plate system, various erosion simulations are conducted in this study. Because the gas velocity, sand input, particles size, and particles shape can affect the erosion in rectifying system, the effect of gas velocities (5‐30 m/s), sand inputs (50‐400 kg/d), and particle parameters (various particle sizes and various particle shapes) on erosion is simulated. Moreover, the erosion experiment conducted in Tulsa University is used to verify the accuracy of simulation model. Through the calculation and analysis, it is obtained that different gas velocities will change the position where the max erosion rate appears. Various sand inputs lead to different max erosion rates. In addition, the effect of sand input on the distribution of erosion scars on rectifying plate is more obvious than that of on elbows. Finally, the effect of size and shape of particles on erosion is investigated. It is found that with the increase in particle diameter, the shape of erosion scar on elbow 1 changes gradually from an ellipse to the V‐shape.

In late December 2019, a new type of coronavirus was discovered, which was later named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2). Since its discovery, the virus has spread globally, with 2,975,875 deaths as of 15 April 2021, and has had a huge impact on our health systems and economy. How to suppress the continued spread of new coronary pneumonia is the main task of many scientists and researchers. The introduction of artificial intelligence technology has provided a huge contribution to the suppression of the new coronavirus. This article discusses the main application of artificial intelligence technology in the suppression of coronavirus from three major aspects of identification, prediction, and development through a large amount of literature research, and puts forward the current main challenges and possible development directions. The results show that it is an effective measure to combine artificial intelligence technology with a variety of new technologies to predict and identify COVID-19 patients.

In a shale gas gathering and transportation station, the sand particles that are not separated by the upstream desander will cause erosion damage to the vertical separator. In response to this problem, based on the field data of a production well in the Changning area, the corresponding mathematical model and vertical separator geometric model were established. On the basis of the software FLUENT, the effects of different gas velocity, particle size, and sand mass flow on the erosion of the separator and the motion of particles were simulated. The corresponding results show that the erosion scar of the inlet baffle presents a ring shape, and the maximum erosion position on the wall changes with the increase of gas velocity. The erosion rate of the inlet baffle is proportional to the sand flow rate and geometrically related to the gas velocity; the maximum erosion rate of the vertical separator is 520 μm/a under the conditions of 6 kg/d sand input; the separation efficiency decreases with the increase of particle size and speed.

As an important medium transmission element, the pipeline has a very important application in the chemical industry, electric power industry, and petroleum industry. However, the pipeline vibration problem has seriously restricted the large-scale development of equipment, reduced the reliability of equipment operation, and even caused serious accidents. Therefore, it is very important to analyze the dynamic characteristics of these vibrations and to reduce the impact of vibrations within pipelines. We focus on the problem of abnormal vibrations within the JYG compressor station pipeline and use a 3D calculation model of the launcher pipeline of west−east gas pipeline III to perform simulation analysis using Fluent to find the cause of the abnormal vibrations. Our results show that the fluid pressure fluctuation in the pipeline is the main factor for the abnormal vibration of the launcher pipeline in the JYG compressor station. The main causes of the vibrations are excessive fluid flow and high flow velocity. Also, by comparing and analyzing the natural frequency of the pipeline system and the pressure fluctuation frequency of the vortex core in the pipeline, we found that the pressure fluctuation frequency is close to the low-order natural frequency of the pipeline system, which is prone to resonance. In this paper, three vibration reduction schemes of the JYG compressor station are suggested and verified. The efficiency of vibration reduction is 68−94%, which can be effectively applied to the outgoing pipeline of the west−east gas pipeline III to solve the abnormal vibration problem of the pipeline.

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