考虑水介质作用的船冰碰撞解耦方法及载荷预报

考虑水介质在船冰碰撞过程中水压变化的影响,是模拟水介质中船-冰碰撞的关键.本文开展数值模拟的动网格技术研究,基于RANS方程和改进的双相流流体体积函数VOF,实时预报船冰靠拢全过程中船体表面、冰体表面的压力变化情况.得到船体表面、冰体表面的P(V)函数.进而将水介质对船冰碰撞载荷的影响简化为对船体、冰体碰撞面预加载荷来实现,达到解耦目的.     

船用食品保鲜技术发展研究

归纳了食品保鲜的涵义,概括了食品保鲜技术的发展,介绍了传统冷藏、气调贮藏和冰温贮藏三种食品保鲜技术.论述了国内船用食品保鲜技术的应用现状,针对这一现状以及前述三种保鲜技术的各自特点,提出了针对船舶的中、长期需求分别采用冰温冷藏＋真空保鲜、冰温冷藏＋气调贮藏的食品保鲜模式,并说明了今后在实践过程中需要进行研究的一些技术问题.     

Finite element based meta-modeling of ship-ice interaction at shoulder and midship areas for ship performance simulation

The climate change has made the transit through Arctic area more feasible, which demands reliable methods to evaluate ship performance. Ship performance in ice is a cross-scale problem, where the desired output such as ship speed lies in larger scale while the actual ship-ice interaction happens in smaller scale. Due to insufficient knowledge in ice mechanics and the demand for computational efficiency, existing approaches for modelling ship-ice interaction from ship performance perspective are mostly either (semi-) empirical, or simplified analytical, with reduced dimensions and extensively simplified mechanics. This paper presents a novel approach to model ship-ice interaction, which maintains the accuracy of the modelling with Finite Element Method (FEM) in ship-ice interaction scale, while being computationally very cheap, therefore is capable to be applied in ship scale simulations. The ice failure is firstly qualitatively investigated through full-scale and model-scale observations, as well as a numerical simulation with Extended Finite Element Method (XFEM). The model is then simplified and executed by Abaqus to automatically run a large database. A neural network is used to fit the results to get a simulation-free tool for ship-ice interaction calculation. Finally, the uncertainty in the results due to an important assumption is quantified. The results show that the obtained neural network fits the database with excellent performance. Therefore, it can be applied in ship scale simulations with improved accuracy compared to empirical or analytical approaches.     

Dilated-polyhedron-based DEM analysis of the ice resistance on ship hulls in escort operations in level ice

The ice resistance on ships in escort operations in level ice are investigated using the discrete element method (DEM). A dilated polyhedron—generated by the Minkowski sum of a sphere and a polyhedron—is employed in the DEM; this dilated polyhedron-based DEM (DPDEM) is adopted to simulate the ship–ice interaction, wherein the contact force and bond-failure criterion are considered for the collision and fracture of sea ice, respectively. A three-point bending test was simulated with DPDEM, and a field test was conducted in the Bohai Sea to validate the DEM results. Further, a parametric analysis of flexural strength was conducted to identify the parameters involved in the bond-failure criterion. The ice resistance on icebreakers and cargo ships in level ice are simulated using DPDEM. The simulated ice resistances are compared with the Lindqvist and Riska formulas and the model test, which proves the validity of the DEM simulation. The interaction between ships and level ice is simulated parametrically to investigate the ice resistance on cargo ships with and without the icebreaker escort. Influencing factors such as ship speed, ice thickness, and ship breadth were examined to investigate the ice resistance on the escorted cargo ship. Analysis and change rules of the ice resistance on cargos affected by those factors were given.     

A summary of the formation and seasonal progression of the Northeast Water Polynya

A summary of the seasonal development of the Northeast Water Polynya ice cover characteristics is presented. This is based primarily on satellite remote sensing observations, with some in situ measurements, including both new and published data.     

电动汽车空调系统解决方案

为了保持电动汽车的舒适性,本文探讨了电动汽车空调系统的几种解决方案,分别对电动空调系统、电驱动压缩机系统、座椅空调系统以及冰水冷媒制冷系统进行了介绍。对于电动空调系统,分别介绍了电动热泵式空调系统、电动压缩机制冷与电加热器制热混合调节空调系统。     

高寒地区公路工程施工中的“冰包”防治

针对高寒地区公路施工,阐述了“冰包”（涎流冰）形成的机理,并结合长期治理“冰包”的实践方法,提出了治理“冰包”的几种措施。     

冰雪道路表面的热量平衡研究

道路上存在的冰雪导致路面抗滑性能下降,并影响车辆的行车安全。冬季道路养护的关键是把握路面冰雪的状态,最重要的是预测路面冰雪的状态变化。文章根据观测结果将路面积雪分类,进行冰雪道路表面的热量平衡探索,为改善冰雪道路的路面安全性奠定一定的理论基础。     

冰雪条件下乌鲁木齐市平面交叉口交通特征分析

立足于乌鲁木齐市中心城区平面信号控制交叉口,以乌鲁木齐市西虹西路与南昌南路交叉口为例,调查不同天气条件下交叉口的交通流特性,研究冰雪条件下道路交叉口机动车的延误、车速及车头时距状况。分析冰雪条件下机动车存平面信号交叉口时的交通流特征,并与正常天气下进行对比。结果表明冰雪条件下机动车停驶延误增加4～8S,引道延误增加2～5S,车速降低约30％,车头时距增加10％～20％。研究成果为乌鲁木齐市在交通规划和设计中提供参考依据。     

海难再次提醒我们注意冰区航行

结合“埃德蒙顿”号在白令海冰困遇难的教训,建议船舶应谨慎进入冰区;同时对从事冰区航行的船舶应做的准备、冰区航行的方法以及冰困后的救助措施进行了论述。