Modern Subsea Engineering and Technology最新文献

{"title":"Prediction of Conveying Resistance for a Novel Hydraulic-mechanical Hybrid Vertical Lifting System","authors":"Xiangwei Liu, Shuhao Yang","doi":"10.53964/mset.2024002","DOIUrl":"https://doi.org/10.53964/mset.2024002","url":null,"abstract":"Objective: Recently a novel hydraulic-mechanical hybrid vertical lifting system was proposed for deep-sea mining. Accurate prediction of conveying resistance is important for the engineering design of the system. Plug flow of coarse particles is the main flow regime in the system. So far rare attention has been paid to the pressure drop prediction of plug flow of coarse particles. This paper aims to investigate eight theoretical pressure drop models on the applicability to predict the pressure drop of plug flow. Methods: Eight theoretical pressure drop models were studied. In addition, a hydraulic-mechanical hybrid vertical lifting test setup was developed. The novelty of this experimental work is that plug flow of coarse particles is formed and the lifting force of the plug can be measured with the test setup. Tests were conducted with varying particle sizes, lifting speeds and plug weights. The particle size is varied among 13, 18, and 25mm. The lifting speed is varied from 0.02m/s to 0.1m/s. The plug weight varies from 5 to 10kg. The range of Reynolds number for the tested particles is between 208 and 2,000. Results: Prediction errors of eight pressure drop models are derived and compared with the experimental data collected during this study. It was found that similar prediction trends are observed for all pressure drop models under most test conditions. Except the Rose model, all models produce average prediction errors less than 15%. The average prediction error for the Rose model is 20.59%. The average prediction error for the Ergun model is 12.43%. Conclusion: From this study it can be seen that the Ergun model produces the smallest prediction error among the eight selected pressure drop models for the given experimental conditions. Therefore, the Ergun model is considered to be most applicable for the calculation of the conveying resistance for the proposed vertical lifting system.","PeriodicalId":133624,"journal":{"name":"Modern Subsea Engineering and Technology","volume":"121 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140708748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Reliability Analysis of a Jacket Platform under Ice Loads Based on Respond Surface Method","authors":"Jiayu Fang, Yu Zhang, F. Zhang, Hongxiang Xiong, Yi Wang","doi":"10.53964/mset.2023006","DOIUrl":"https://doi.org/10.53964/mset.2023006","url":null,"abstract":"Objective: The jacket platform is made of various types of steel pipes and beams welded, mainly used in shallow water areas, such as Bohai oilfield in China. In winter, the sea area where the platform is located will freeze, and the influence of ice load on the platform can not be ignored. So the influence of ice load on the reliability of jacket platform is studied in this paper. Methods: In this research, the finite element model of the jacket platform was established in the form of beam element, and the loads were applied from different directions to find the load direction with the greatest influence on the platform state. When calculating the ultimate load of the platform structure, it is necessary to carry out nonlinear analysis. Selecting the ice load condition, increasing the ice load step by step on the platform structure. As the applied load gradually increases, the platform will appear nonlinear, then the ultimate load of the jacket platform will be obtain. The pile radius and pile thickness are uncertain components in the reliability study of the jacket platform due to manufacture, processing, and other factors, therefore the values of the pile's parameters are all random. Consider the deviation of geometric parameters with the extreme value type I distribution of ice load, the limit state equation for the strength failure of the platform under ice loads is obtained using Response Surface Method, then the reliability of the platform is calculated by the Monte Carlo method and First Order Second Moment Reliability method. Results: By nonlinear analysis, the ultimate bearing capacity of the platform studied in this paper is about 8000kN. The reliability probability of the platform calculated by Monte Carlo method is 0.9999993, and the reliability index is 4.813. The reliability probability of the platform calculated by the first order second moment method is 0.9999994, and the reliability index is 4.852. Conclusion: The results obtained by the two methods are almost the same, and the reliability index is very large, indicating that the platform can operate safely and reliably under the ice load.","PeriodicalId":133624,"journal":{"name":"Modern Subsea Engineering and Technology","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123351157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Underwater Image Stitching Method Based on AUV-guided Light Source Optimization","authors":"Ruonan Deng, Wei Qu, Chengjun Qiu, Jiuqiang Luo, Jiaqi Gao, Yuxuan Wu, Jiaqi Yan","doi":"10.53964/mset.2023005","DOIUrl":"https://doi.org/10.53964/mset.2023005","url":null,"abstract":"Background: Image stitching is the procedure of combining two or more pictures having the same feature point location information into a panoramic image, which is useful in target discovery, seabed research, and military applications. Most of existing underwater picture stitching technology makes use of well-lit photos, however natural light gradually diminishes during propagation of underwater autonomous submersibles plunge further into the sea. When the image focuses on the regions of lighting concentration and the larger dark, image details are lost and feature points are not matched, the perspective transformation matrix obtained does not reflect the mapping relationship of the entire image, resulting in a poor stitching effect and making it difficult to meet practical application requirements. Objective: This study aims to obtain underwater images with a good enhancement effect and improve feature point matching image. Methods: An adaptive image enhancement method based on adaptive light source optimization is proposed in this paper, underwater photos are preprocessed to enhance images for the feature registration. Results: The experimental consequence indicate that the improvement algorithm can improve picture standard with better detail performance and color recovery by preprocessing submerged photographs. Conclusion: It is accomplished that high exactness for images stitching by adding the feature points of the enhanced image for feature alignment.","PeriodicalId":133624,"journal":{"name":"Modern Subsea Engineering and Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121836800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact Dynamic Analysis of Suspended Marine Cables","authors":"Dapeng Zhang, Jingfu Yan, K. Zhu","doi":"10.53964/mset.2023004","DOIUrl":"https://doi.org/10.53964/mset.2023004","url":null,"abstract":"Objective: It is often impossible to avoid collisions between marine cables, the impact dynamic response of the collisions between marine cable needs to be obtained. Methods: In this paper, we derive the lumped mass method based on the bending moment and torque; using the lumped parameter method, the suspended cable is discretized into lumped mass models, and the impact force of the suspended cable is considered in the dynamic analysis; the impact dynamics model of the suspension cable is developed by referring to the specific parameters of the suspension cable and combining them with offshore construction processes. Results: There is a relationship between the impact force and the tension of the cable. The tension and impact force are related in cable collisions. While the maximum effective tension occurs at the upper end of the vertical cable and at the collision point, the horizontal cable's tension at the collision position is minimal. The distribution of curvature mutates at the collision point, causing bending deformation. The horizontal cable experiences greater bending change at the collision position than the vertical cable. Conclusion: In summary, collision of different parts of vertical cable is not obvious, while horizontal cable is more prone to self-collision and collision with vertical cable. Collision impact on horizontal cable is greater, with minimum tension occurring at collision point. Maximum velocity for horizontal cable appears at collision position, and for vertical cable at bottom. Maximum acceleration for both cables occurs at collision zone.","PeriodicalId":133624,"journal":{"name":"Modern Subsea Engineering and Technology","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132233381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Analysis of Oscillating Water Column Wave Energy Converter Using Contra Rotary Self-rectifying Impulse Turbine","authors":"Raffay Hannan","doi":"10.53964/mset.2023003","DOIUrl":"https://doi.org/10.53964/mset.2023003","url":null,"abstract":"Background: The global energy demand is rising day to day. To cover the energy gap, governments around the world are pursuing a variety of strategies to meet energy demands. However, according to the long-term strategy, all nonrenewable energy plants must be replaced with renewable energy sources. Existing technologies are enhanced, and new sources are being investigated for this purpose. The ocean covers 70% of the planet so there is a huge potential to extract energy from this source. Objective: This research aims to optimize the design of an oscillating water column (OWC) wave energy converter to extract energy from ocean waves. Methods: The total efficiency of an OWC wave energy converter is determined by the turbine's design configuration and the chamber's partially submerged water column. The various designs of wave energy turbines were examined before simulating the contra rotary impulse turbine with middle vanes at specific angles. The efficiency of the turbine was determined using ANSYS FLUENT workbench simulations. Additionally, the design of an OWC was simulated to determine the optimal chamber slope. To conduct experiments, a 3D-printed contra rotary self-rectifying impulse turbine with middle vanes was generated as a demonstration model. Middle vanes used in contra-rotary turbines can assist in reducing turbulence between contra rotors. Results: The results demonstrate that the turbine with middle vanes has a higher torque coefficient Ct than the turbine without middle vanes. Similarly, the input coefficient Ca is higher for the turbine which has middle vanes. Therefore, the turbine with a middle vane shows better efficiency than the turbine without a middle vane in low flow coefficient as well as higher flow coefficient. Conclusion: The efficiency of the contra rotatory turbine is greater than the single rotatory turbine and the efficiency increases further when middle vanes are added.","PeriodicalId":133624,"journal":{"name":"Modern Subsea Engineering and Technology","volume":"577 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127069206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Flow-induced Vibration Based on Discharge Pipeline on Offshore Platform","authors":"Yanfei Chen, Zuming Wu, Fuheng Hou, Zhihao Wang, Yu Liu","doi":"10.53964/mset.2023002","DOIUrl":"https://doi.org/10.53964/mset.2023002","url":null,"abstract":"Objective: Because of the widespread use of offshore oil production platforms, there is a large amount of pipeline equipment on them. The excitation generated by fluid flow in the pipeline will cause flow-induced vibration of the pipeline and damage the pipeline structure. As a result, researching the flow-induced vibration of the pipeline is critical. Methods: In this paper, the pipeline on an offshore oil production platform in the South China Sea is taken as the research object, and the calculation and analysis of the pipeline section on the platform are focused on. The fluid-structure coupling method is used to calculate and analyze the pipeline section, and the flow-induced vibration of the pipeline is simulated. Results: Through calculation and analysis, the results show that the vibration speed of the pipeline in its original state exceeds the specified range. To reduce the degree of vibration, the pipeline constraint is redesigned and flow-induced vibration analysis is conducted. The results show that the vibration level meets the requirements. Conclusion: The flow-induced vibration of offshore pipelines is mainly caused by the uneven distribution of pressure in the pipelines caused by gas-liquid two-phase flow in the pipelines, and the reasonable setting of pipeline constraints can effectively reduce the degree of pipeline vibration.","PeriodicalId":133624,"journal":{"name":"Modern Subsea Engineering and Technology","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125982059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Analysis of Seakeeping of Offshore Photovoltaic Floating Unit","authors":"Yinfu Sai, Wenhua Wu, G. Huang","doi":"10.53964/mset.2023001","DOIUrl":"https://doi.org/10.53964/mset.2023001","url":null,"abstract":"Background: In recent years, offshore photovoltaic (PV) power systems have become an emerging hot issue. For offshore PV, the marine environmental loads are more complex, especially wave loads will put higher demands on the mooring system, and a failure of the mooring system will cause great harm. In order to ensure the safe operation of the system, the floating unit should be designed for high seakeeping. Objective: In this paper, six common configurations of floating units are selected, and the six configurations are divided into two experimental groups, one of which includes floating units with different shapes of holes, and mainly discusses the effects of different shapes of holes on the seakeeping of floating units, and the other experimental group includes common configurations of catamarans and trimarans in ships, and mainly discusses the effects of different bottom structures on the seakeeping of floating units. And after determining the better configuration, further shape optimization is performed. Methods: The problem described in this paper cannot ignore the change of the solid deformation on the flow field boundary, when both interaction processes between the two phases need to be calculated. Therefore, this paper discusses a bi-directional fluid-solid coupling process. For the six float units, a bi-directional fluid-structure coupling calculation analysis was carried out with high seakeeping as the research objective, and the effects of different float unit configurations on the seakeeping performance of floats were discussed. Results: Ultimately, the trimaran configuration is considered to have better seakeeping performance than the remaining configurations among the six configurations. On this basis, the bottom structure of the trimaran configuration was further optimized, and the cross-sectional shape of the bottom structure with better seakeeping performance was obtained. Conclusion: The wave resistance of the trimaran configuration was calculated to be superior compared with other configurations. The cross-sectional shape of the bottom structure of the trimaran was further analyzed. It is concluded that the trimaran structure with a bottom structure cross-section whose bottom edge is at an angle of 0° with the horizontal plane has the best wave resistance. It provides some guidance for the design of similar marine structures with high seakeeping.","PeriodicalId":133624,"journal":{"name":"Modern Subsea Engineering and Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117087060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}