Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100649
Rashed Kaiser , Chi-Yeong Ahn , So-Yeon Lee , Yun-Ho Kim , Jong-Chun Park
Polymer Electrolyte Membrane Fuel Cells (PEMFCs) represent a promising energy solution for the marine industry, facilitating a sustainable transition from fossil fuels to emission-free alternatives. Despite their high power density and efficiency, water management is an issue. The serpentine flow channel (SFC) design is known for its efficient reactant distribution and enhanced water removal due to high-pressure drops when certain design conditions are met. Regardless these channels exhibit drawbacks such as increased flow resistance due to extended lengths and sharp bends, alongside non-uniform reactant distribution near the channels. This study develops a multiphase three-dimensional model to simulate the transport of mass, species and water within a PEMFC equipped with a five-channel SFC. The simulation results are validated through experiments and compared with two novel convergent 5-channel serpentines. The newly proposed convergent five-channel SFCs demonstrated improved performance at high current densities, notably in power density, pressure drop, water distribution, and removal.
{"title":"Numerical analysis of water management and reactant distribution in PEM fuel cells with a convergent 5-channel serpentine flow field for emission-free ships","authors":"Rashed Kaiser , Chi-Yeong Ahn , So-Yeon Lee , Yun-Ho Kim , Jong-Chun Park","doi":"10.1016/j.ijnaoe.2025.100649","DOIUrl":"10.1016/j.ijnaoe.2025.100649","url":null,"abstract":"<div><div>Polymer Electrolyte Membrane Fuel Cells (PEMFCs) represent a promising energy solution for the marine industry, facilitating a sustainable transition from fossil fuels to emission-free alternatives. Despite their high power density and efficiency, water management is an issue. The serpentine flow channel (SFC) design is known for its efficient reactant distribution and enhanced water removal due to high-pressure drops when certain design conditions are met. Regardless these channels exhibit drawbacks such as increased flow resistance due to extended lengths and sharp bends, alongside non-uniform reactant distribution near the channels. This study develops a multiphase three-dimensional model to simulate the transport of mass, species and water within a PEMFC equipped with a five-channel SFC. The simulation results are validated through experiments and compared with two novel convergent 5-channel serpentines. The newly proposed convergent five-channel SFCs demonstrated improved performance at high current densities, notably in power density, pressure drop, water distribution, and removal.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100649"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100674
Je-In Kim , Bu-Geun Paik , Jong-Woo Ahn , Il-Ryong Park
This study presents a comprehensive estimation of full-scale self-propulsion performance for a high-speed, twin-screw, single-skeg surface vessel using Reynolds-averaged Navier–Stokes (RANS)-based computational fluid dynamics (CFD). Resistance, propeller open-water characteristics, and self-propulsion behavior were analyzed by incorporating recent benchmark data on surface roughness—identified as a critical factor in full-scale CFD analysis. The numerical predictions, including key self-propulsion parameters, were validated against full-scale performance data extrapolated from model tests conducted at KRISO. Additionally, ship speeds were estimated by simulating surge motion induced by thrust from specified propeller RPMs under wave conditions, replicating sea trial environments. Finally, ship speeds corresponding to the prescribed RPMs were compared across CFD simulations, model tests, and actual sea trial results.
{"title":"RANS analysis of the self-propulsion performance for a twin-screw ship","authors":"Je-In Kim , Bu-Geun Paik , Jong-Woo Ahn , Il-Ryong Park","doi":"10.1016/j.ijnaoe.2025.100674","DOIUrl":"10.1016/j.ijnaoe.2025.100674","url":null,"abstract":"<div><div>This study presents a comprehensive estimation of full-scale self-propulsion performance for a high-speed, twin-screw, single-skeg surface vessel using Reynolds-averaged Navier–Stokes (RANS)-based computational fluid dynamics (CFD). Resistance, propeller open-water characteristics, and self-propulsion behavior were analyzed by incorporating recent benchmark data on surface roughness—identified as a critical factor in full-scale CFD analysis. The numerical predictions, including key self-propulsion parameters, were validated against full-scale performance data extrapolated from model tests conducted at KRISO. Additionally, ship speeds were estimated by simulating surge motion induced by thrust from specified propeller RPMs under wave conditions, replicating sea trial environments. Finally, ship speeds corresponding to the prescribed RPMs were compared across CFD simulations, model tests, and actual sea trial results.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100674"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100688
Xu Geng , Dong Qin
Ships navigating in complex sea conditions typically do not experience catastrophic failure due to a single extreme load; rather, the primary structural components such as stiffened panels of the hull undergo plastic deformation under repeated cyclic loading and may develop cracks under low-cycle fatigue. This leads to a decrease in ultimate bearing capacity and eventual structural failure due to insufficient ultimate strength, resulting in hull buckling. Currently, methods for evaluating the ultimate strength of ship hull stiffened panels under cyclic extreme loading considering the coupling effects of accumulative plasticity and low-cycle fatigue are not well-developed. Therefore, there is a need for research into computational methods for assessing the ultimate strength of stiffened panels structures considering the coupling effects of these two factors. This paper investigates the ultimate load-bearing capacity of pre-cracked stiffened panels under the combined effects of accumulative plasticity and low-cycle fatigue. During the experiments, hysteresis curves of stress-strain relationships and relevant fracture parameters for stiffened panels were obtained under various crack positions and load conditions. Ultimately, the study provides the ultimate load-bearing capacity of stiffened panels considering low-cycle fatigue and accumulative plasticity interactions, offering a foundational calculation basis for designing vessels under severe sea conditions.
{"title":"Experimental study on ultimate bearing capacity of pre-cracked ship hull stiffened panel under low-cycle fatigue and accumulative plasticity coupling","authors":"Xu Geng , Dong Qin","doi":"10.1016/j.ijnaoe.2025.100688","DOIUrl":"10.1016/j.ijnaoe.2025.100688","url":null,"abstract":"<div><div>Ships navigating in complex sea conditions typically do not experience catastrophic failure due to a single extreme load; rather, the primary structural components such as stiffened panels of the hull undergo plastic deformation under repeated cyclic loading and may develop cracks under low-cycle fatigue. This leads to a decrease in ultimate bearing capacity and eventual structural failure due to insufficient ultimate strength, resulting in hull buckling. Currently, methods for evaluating the ultimate strength of ship hull stiffened panels under cyclic extreme loading considering the coupling effects of accumulative plasticity and low-cycle fatigue are not well-developed. Therefore, there is a need for research into computational methods for assessing the ultimate strength of stiffened panels structures considering the coupling effects of these two factors. This paper investigates the ultimate load-bearing capacity of pre-cracked stiffened panels under the combined effects of accumulative plasticity and low-cycle fatigue. During the experiments, hysteresis curves of stress-strain relationships and relevant fracture parameters for stiffened panels were obtained under various crack positions and load conditions. Ultimately, the study provides the ultimate load-bearing capacity of stiffened panels considering low-cycle fatigue and accumulative plasticity interactions, offering a foundational calculation basis for designing vessels under severe sea conditions.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100688"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100664
Martin Alexandersson , Wengang Mao , Jonas W. Ringsberg , Martin Kjellberg
Ships with wind-assisted propulsion systems (WAPS) are often equipped with large rudders to compensate for WAPS-induced drifting forces. The WAPS also significantly affects the effectiveness of mathematical models used to describe the ship’s maneuvering characteristics. In this study, a modular maneuvering model is proposed to enhance the original MMG model, with the aim of producing accurate maneuvering simulations for ships with WAPS. Methods of virtual captive tests (VCT) are proposed to recreate the forces acting on WAPS ships during free-running model tests (FRMT) in motor mode, identifying all the parameters in the modular model. The hydrodynamic damping coefficients within the model are determined through linear regression of the VCT data. The added masses are then determined from pure yaw and pure sway simulations using a fully nonlinear potential flow (FNPF) panel method. Two ships designed for WAPS, wPCC and Optiwise, are used to validate the proposed method based on the inverse dynamics of their experimental model tests. The wPCC is equipped with a semi-empirical rudder that has previously shown to work well for this twin-rudder ship. The Optiwise single rudder is modeled with a new quadratic version of the MMG rudder model, proposed in this paper. Inverse dynamics analysis, together with state VCTs, is concluded to be an efficient way to analyze the models, and the maneuvering model can be efficiently identified when the correct VCTs are used in the proposed method. However, the inverse dynamics analysis also revealed potential errors in the wPCC VCT data due to false assumptions about wave generation and roll motion. The Optiwise test case, where these assumptions should be more valid, showed much better agreement with the FRMT inverse dynamics.
{"title":"Identification of maneuvering models for wind-assisted ships with large rudders using virtual captive tests","authors":"Martin Alexandersson , Wengang Mao , Jonas W. Ringsberg , Martin Kjellberg","doi":"10.1016/j.ijnaoe.2025.100664","DOIUrl":"10.1016/j.ijnaoe.2025.100664","url":null,"abstract":"<div><div>Ships with wind-assisted propulsion systems (WAPS) are often equipped with large rudders to compensate for WAPS-induced drifting forces. The WAPS also significantly affects the effectiveness of mathematical models used to describe the ship’s maneuvering characteristics. In this study, a modular maneuvering model is proposed to enhance the original MMG model, with the aim of producing accurate maneuvering simulations for ships with WAPS. Methods of virtual captive tests (VCT) are proposed to recreate the forces acting on WAPS ships during free-running model tests (FRMT) in motor mode, identifying all the parameters in the modular model. The hydrodynamic damping coefficients within the model are determined through linear regression of the VCT data. The added masses are then determined from pure yaw and pure sway simulations using a fully nonlinear potential flow (FNPF) panel method. Two ships designed for WAPS, wPCC and Optiwise, are used to validate the proposed method based on the inverse dynamics of their experimental model tests. The wPCC is equipped with a semi-empirical rudder that has previously shown to work well for this twin-rudder ship. The Optiwise single rudder is modeled with a new quadratic version of the MMG rudder model, proposed in this paper. Inverse dynamics analysis, together with state VCTs, is concluded to be an efficient way to analyze the models, and the maneuvering model can be efficiently identified when the correct VCTs are used in the proposed method. However, the inverse dynamics analysis also revealed potential errors in the wPCC VCT data due to false assumptions about wave generation and roll motion. The Optiwise test case, where these assumptions should be more valid, showed much better agreement with the FRMT inverse dynamics.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100664"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号