重型清障车液压油泵配置方案探讨

针对目前国内重型清障车存在吊臂旋转回路压力损失过大和绞盘回路速度过慢的缺点,提出了改变液压系统油泵配置的改进方法,不但能够减小液压系统的压力损失,也降低了系统发热,而且在不增加损失发动机功率的情况下使绞盘的收放绳速度提高了50%,降低了用户的使用成本。     

宽体矿用自卸车液压系统油压特性分析与结构优化

通过模拟宽体矿用自卸车卸货模式,建立了举升模型和计算模型,计算出多级缸各临界工作位置的系统油压,并绘制了油压特性曲线,分析了系统最大油压出现的位置点,为液压系统与货箱结构的合理匹配提供了一种设计方法。     

穿越输油管道腐蚀评价模型

随着运行时间的增加,穿越输油管道必然受到不同程度的腐蚀,如果不及时维修或更换,可发生泄漏或爆裂。为了确定管道的腐蚀情况,提出了一种模糊评判法。根据引起穿越输油管道腐蚀失效的各个因素,建立穿越输油管道腐蚀评价体系,对穿越输油管道进行腐蚀因素的模糊综合评判,通过实例分析,验证了该评价方法的实用性。     

1 000 t供油船货油系统改建设计

本文就1 000 t供油船货油系统部分的改建设计进行简要的介绍。     

船舶重油动态乳化过程智能控制系统设计

根据船舶重油动态乳化过程的特点,分析了其实际应用存在的困难,采用基于PLC的智能自动化方法对重油动态乳化的过程控制系统进行了设计;对此系统的工作流程、功能特点以及系统硬件和软件设计进行了介绍,并给出了部分实验核心程序.实验结果表明,该系统对掺水率的控制精度可达1%以上,燃油消耗率平均降低7.8%.具有明显的实用性和经济性.     

大型耐压壳环焊缝焊接残余应力实验研究

采用盲孔法对某大型耐压壳废弃壳圈环焊缝及两个模拟模型进行焊接残余应力测试,结果表明,焊接残余应力普遍较大,mises应力超过0.5σs的测点约占2/3左右,另有10%~20%的测点mises应力超过0.8σs,接近屈服极限.     

5 500 t成品油船设计特点

主要介绍5500t成品油船作为一新型中小型液货船,在满足国际公约、世界主要石油组织和船东特殊要求上的一些设计特点。     

Prediction of residual stresses induced by low transformation temperature weld wires and its validation using the contour method

Welding residual stresses are one of the main factors influencing the engineering properties of welded structures, and should be taken into account during designing and manufacturing products such as ships, bridges, etc. Recently, both computational and experimental methods play a significant role for providing residual stresses. The contour method (CM) became one of the most powerful techniques that can provide measurement of residual stresses normal to a plane of interest. In this method a component is cut at any plane of interest. Displacements normal to the cut surface are measured and then processed. Using the Thermal–Elastic–Plastic Finite Element Method (TEP-FEM), residual stresses after welding can be predicted. As well as, the elastic FEM can be used to reproduce residual stresses from measured longitudinal displacements in the CM.The main objective of this paper is to evaluate the effectiveness of different low transformation temperature (LTT) weld wires using TEP-FEM and the CM. In the simulation part, a computational approach is developed to numerically simulate both of welding and the CM. In the TEP-FEM, phase transformation is considered for LTT welds, additionally volume change and variation of mechanical properties with temperature are considered. In the simulated CM, welded specimens to be measured are replaced by TEP-FE models. Then the procedure of the CM is examined before applying it to real measurements. The simulated CM successfully predicted how the CM would reconstruct the residual stresses if applied experimentally. In the experimental part, welding is conducted using conventional and various LTT weld wires. Longitudinal residual stresses produced due to welding are measured using the CM. The results of TEP-FE simulation and the CM show the effectiveness of the different LTT weld wires in introducing compressive stresses in the weld. It is also observed that the applied LTT weld wires, which have almost the same martensitic transformation start temperatures, do not show big difference in the induced compressive residual stresses in the weld metal.     

The role of nano additives for biodiesel and diesel blended transportation fuels

The energy crisis is due to two reasons, one is the rapid increase in worldwide population and the other is changing living style of human beings. The fossil fuel is also a major contributor to add the harmful pollutants into the atmosphere. Fuel modifications play a major role in increasing engine efficiency and reducing emissions. In the present investigation focused on fuel modifications in diesel engine. Initially the single cylinder diesel engine was operated with 20MEOM, 40MEOM, 60MEOM, 8MEOM and 100MEOM without additives with diesel at different loads at constant rated speed. From the experimental study proved that 20MEOM is the best fuel ratio compared to other blends. In second phase based upon first phase results the engine was operated 20MEOM blended fuel with adding 50 ppm copper oxide nano additives with diesel using solgel process. From the results, the brake thermal efficiency was 2.19% improved compared than 20MEOM blend without additive at full load condition. Emissions of HC, CO and smoke were considerably reduced. The present analysis reveals that the biofuel from mahua oil with nano additives is quite suitable as an alternate fuel for diesel engine.     

基于CFD的高速排水型圆舭折角船型剩余阻力系数分析研究

基于CFD对某圆舭折角高速船进行阻力数值仿真,并将仿真结果与该船的船模试验值进行比较分析,寻求利用FINE/Marine软件进行船舶阻力数值仿真的适用方法。同时根据此方法分别对NAPA所建立的系列圆舭折角船模进行阻力数值仿真,并将计算结果归纳分析,从而生成剩余阻力系数对排水量长度系数和傅汝德数的关系图谱,以便为圆舭折角船型阻力估算提供快捷途径。