RHIC中Au-Au碰撞末态带电粒子快度分布的研究

通过研究高能碰撞中产生的带电粒子的快度分布有助于人们研究和理解粒子的产生及相互作用的物理机制、宇宙形成时早期物质的性质、微观世界中的物理规律和物质的本性。研究Khalatnikov势相关的1+1维流体动力学中金-金碰撞带电粒子的快度分布。理论结果与实验数据符合得很好。     

细胞剪切耐受性检测装置的设计、模拟及验证

针对动物细胞培养过程中流场作用力对其的制约作用,文中借助计算流体力学的方法设计了一种新型的微流道装置。在该装置内可以产生分布均一而恒定的流场剪切力,并且大小与装置内液体的流速密切相关;同时本次研究采用了微尺度的粒子图像测速技术(PIV)对实验结果进行了验证。结果表明数值模拟得到的流场结构与PIV拍摄得到的流场非常接近,具有很好的吻合性,建模及计算结果是准确可信的。     

连续推钢式轧钢加热炉的数值模拟

运用流体动力学计算软件（CFD）FLUENT,对湘潭钢铁公司第二高速线材厂轧钢加热炉的三维流场进行了数值模拟,获得该轧钢加热炉内的气体流动、流速和压力的分布规律.通过与加热炉内的结构特点和实际操作状况对照分析,表明该加热炉的局部结构与操作不相适应,尤其是压力分布不适应加热炉的操作要求,造成炉内供热调节的灵活性降低,从而影响到加热质量.分析结果与加热炉的实际运行状况相符,为加热炉的进一步结构改造提供依据.     

Numerical Study of Forced Convection Lid-Driven Cavity Flows Using LES （Large Eddy Simulation）

This study presents the LES （large eddy simulation） of forced convection in laminar and two dimensional turbulent flows when the flow reaches the steady state. The main purpose is the evaluation of a developed numerical methodology for the simulation of forced convection flows at various Reynolds numbers （100 _〈 Rex 〈_ 10,000） and for a fixed Prandtl number （Pr = 1.0）. The hexahedral eight-node FEM （finite element method） with an explicit Taylor-Galerkin scheme is used to obtain the numerical solutions of the conservation equations of mass, momentum and energy. The Smagorinsky model is employed for the sub-grid treatment. The time-averaged velocity and temperature profiles are compared with results of literature and a CFD （computational fluid dynamics） package based on finite volume method, leading to a highest deviation of nearly 6%. Moreover, characteristics of the forced convection flows are properly obtained, e.g., the effect of the Reynolds number over the multiplicity of scales.     

基于Kriging代理模型液压锥阀抗空化结构优化研究

空化是液压锥阀运行时造成振动及噪声的重要因素，其影响原因颇为复杂。针对水液压锥阀内空化问题，利用Fluent中混合模型(Mixture)及标准k-ε湍流模型，对不同阀芯锥角的锥阀进行计算流体动力学(CFD)分析，发现锥角和开度对锥阀内的空化程度有直接影响。将阀芯锥面改为2个不同锥角的锥面，对阀芯结构参数作5水平全因子实验设计，分析出125个模型的气体体积分数，以平均气体体积分数为空化优化设计目标，建立平均气体体积分数与阀芯结构参数之间的Kriging模型，然后采用遗传算法对此模型进行寻优，得到最优的锥阀结构。优化后的锥阀结构对空化有一定抑制效果。     

计算流体力学仿真在引信外露机构分析中的应用

由于冲塞动能作用下的质量-弹簧系统动力学分析不符合实际情况,提出采用计算流体动力学仿真软件计算引信外露机构的运动,建立触发开关碰击所受的最大迎面空气压力、碰击雨滴的作用力和碰击水面时的作用力仿真模型,得到在碰击不同目标情况下引信头部开关所受压力值.通过试验,初步验证了方法的合理性和正确性,可供引信头部外露机构优化设计参考.     

滑动阀片笼罩式喷射浮阀塔板的性能

报道一种新型浮阀——滑动阀片笼罩式喷射浮阀。应用空气-水系统,在600mm×250mm矩形塔内,对阀片厚度3mm的滑动阀片笼罩式喷射浮阀塔板的流体力学进行了试验研究,给出了冷模试验结果、与通常使用的F1浮阀塔板性能的对比和塔板流体力学性能的计算关联式。试验结果表明滑动阀片笼罩式喷射浮阀塔板的各项流体力学性能均优于F1型浮阀塔板。操作弹性大,是特别适合低气速下的一种塔板。     

SIMULATIONS OF THE THREE-DIMENSIONAL TOTAL DISSOLVED GAS SATURATION DOWNSTREAM OF SPILLWAYS UNDER UNSTEADY CONDITIONS

Dams are often operated in a way to discharge over the spillways, which would cause a high dissolved concentration of air and be harmful to fish. The bubble transfer and the water surface transfer play an important role in affecting the concentration of the Total Dissolved Gas (TDG). Based on recent numerical simulations of the total dissolved gas saturation, in this article, a two-phase TDG transport equation is adopted to develop an unsteady three-dimensional (3-D) two-phase flow Computational Fluid Dynamics (CFD) model, including a number of parameters such as water depth, pressure and air volume entrained. This model is used to predict the hydrodynamics and the TDG distribution under unsteady discharge conditions. Good agreement between measured and numerical results is obtained for a case study.     

沉淀池数值模拟技术的研究进展与评论

在水处理应用当中的沉淀池数值模拟研究近些年取得了很大的进展.自20世纪70年代,国外的研究人员开始进行许多沉淀池场方面的试验研究与数值模拟工作,在试验测量方面进行了原型池与模型池的测量,包括对速度场与浓度场都进行了许多的测量工作.国内于近几年也开始开展一些数值模拟研究工作,但试验测量方面的工作几乎没有.数值模拟技术尚未能很好地发展到实际工程应用的阶段.对模型的最新进展、所需解决的关键性问题进行了总结.     

Influence of high-porosity mesh stent on hemodynamics of intracranial aneu- rysm： A computational study

This paper studies the influence of a High-Porosity Mesh （HPM） stent on the hemodynamic characteristics in the intracranial aneurysm based on the Computational Fluid Dynamics （CFD）. An idealized basilar tip aneurysm model and a HPM stent model are built. The pulsating blood flow in a cardiac cycle is computationally simulated for non-stented and stented models, to provide a wealth of information of the spatio-temporally varying blood flow field. The influence of the stent placement on the hemodynamic characteristics is analyzed in terms of distributions of velocity, pressure, Wall Shear Stress （WSS） and Energy Loss （EL）, which are believed to play an important role in the development and rupture of the aneurysm. The numerical results clearly show that the velocity, pressure, WSS and EL of the blood flow in the aneurysm are reduced by 30%-40% when the HPM stent is implanted. These computational results may provide valuable hemodynamic information for clinical neurosurgeon.