变截面微管道的制作与气体流动特性分析

为提高硅微无阀泵和空间微推进器的性能，采用微电子机械工艺在硅片上加工出不同长度，不同喉部宽度、断面形状为矩形的变截面微管道，实验测量微管道内氮气的流量特性，分析不同因素对流动特性的影响，研究发现，相同变截面微管道，扩张方向的性能好于收缩方向，不同变截面微管道，随着扩张角，等直段长度，宽度的不断增加，流动性能逐渐提高。     

陶瓷喷砂嘴应力的有限元分析

根据喷砂工作情况和一种具体陶瓷喷砂嘴结构,建立了单粒子冲蚀模型,利用有限元软件模拟陶瓷喷砂嘴冲蚀过程,研究了喷砂嘴材料在冲蚀过程中的破坏状态以及不同时刻的应力、能量分布情况,为进一步研究陶瓷喷砂嘴冲蚀磨损的动态过程及冲蚀磨损机理提供了有力依据.     

汽轮机性能试验ASME流量喷嘴及GB/T2624-93喷嘴校验

研究汽轮机试验ASME流量喷嘴检定的数据处理方法,就3组检定数据进行了计算处理,指出了数据分析的难点.讨论了用GB/T2624-93与ASME流量喷嘴检定方法与的异同,给出了由GB/T2624-93检定结果向ASME喷嘴检定结果转换方法.     

重油催化裂化装置油浆泵进出口泄漏原因分析

由于分馏塔底油浆泵口经常泄漏,对泄露的原因进行了分析。运用应力分析软件,模拟了冷态和热态时管系对泵口的受力状况。结果表明:配管不当是造成泵口泄露的主要原因。采用以下方式可很好的降低泵口的受力及力矩:进口管道采用泵侧边布管并且采用T型过滤器加弯头与泵口连接,在过滤器处设弹簧支架;出口管道采用回型弯的方式,在弯头的地面支撑处设支架。最终的泵口受力值还必须得到泵厂家确认合格。     

Aero-thermo-chemical characterization of ultra-high-temperature ceramics for aerospace applications

Ultra-High-Temperature Ceramic (UHTC) materials, because of their high temperature resistance, are suitable as thermal protection systems for re-entry vehicles or components for space propulsion. Massive UHTC materials are characterized by poor thermal shock resistance, which may be overcome using C or SiC fibers in a UHTC matrix (UHTCMC).The University of Naples “Federico II” has a proven experience in the field of material characterization in high-enthalpy environments. A hypersonic arc-jet facility allows performing tests in simulated atmospheric re-entry conditions. The Aerospace Propulsion Laboratory is employed for testing rocket components in a representative combustion environment. Ad-hoc computational models are developed to characterize the flow field in both facilities and perform thermal analysis of solid samples.Current research programs are related to a new-class of UHTCMC materials, for rocket nozzles and thermal protection systems. The activities include design of the prototypes for the test campaign, numerical simulations and materials characterizations.     

1069 t／h 锅炉布风板风帽数值模拟及试验研究

某热电厂2号锅炉系东方锅炉（集团）股份有限公司生产的DG1069／17.4-Ⅱ1型锅炉。该锅炉为单汽包、自然循环、循环流化床锅炉。该厂两台锅炉在运行过程中,中部床温与左右两侧床温偏差达55～110℃,给运行人员优化调整带来困难。结合流化床锅炉的结构尺寸与运行特性,采用计算流体力学软件Fluent对锅炉布风板风帽开展了数值模拟研究,分析在不同风帽芯管速度下,风帽阻力系数的变化。同时实施了水冷风室静压分布的现场试验,对试验数据进行了全面分析,计算出该厂风帽实际阻力系数,验证了数据模拟的结论。结果表明,随着风帽芯管速度的提升,风帽阻力系数逐渐趋于不变;对风帽进行数值模拟计算得到的阻力系数值,与工程计算的阻力系数值的偏差均非常小,仅为2％左右,模拟结论与试验结果相互印证。     

Comparison of PIV and PDA droplet velocity measurement techniques on two high-pressure water mist nozzles

The need for reliable measurement of droplet velocities and droplet size has increased with the more widespread use of water mist systems. Two optical measuring techniques have been investigated, Particle Image Velocimetry (PIV) and phase Doppler anemometry (PDA). Measurements have been performed on two high-pressure nozzles, a hollow cone nozzle and a full cone nozzle. Both methods performed well close to the nozzle and further away from the nozzle. In the intermediate region the results obtained with PIV are biased against the larger droplets. The two methods complement each other, PIV giving the instantaneous velocity field and PDA giving both the droplet velocity and droplet size at a point. The measurement indicates that higher throw length can be archived with a full cone nozzle compared to the hollow cone nozzle, if both nozzles have the same cone angle and flow rate.     

辅助喷嘴间距变化对纬纱飞行状况的影响

为更好了解喷气引纬时纬纱运动状态,减小纬纱波动程度,采用由喷气引纬系统主要构件和高速摄像系统组成的气流指数测试仪.对喷气引纬时纬纱在异型筘槽内实际飞行状态进行拍摄记录,并用专业图像分析软件进行分析,测试在不同辅助喷嘴间距时筘槽内纬纱实际飞行运动速度变化情况,以及纬纱在筘槽中飞行运动的波动幅度,得出在辅助喷嘴间距为65 mm时纬纱飞行运动的速度波动变化.相对75 mm和85 mm间距时,纬纱头端速度波动变化要小,头端飞行运动更加平稳.     

筒体接管的力学分析

在压水堆核电设备的强度计算校核中,经常需要对圆筒型容器上的接管进行评估。本研究分别采用有限元壳体单元和实体单元模型以及公式法预估对筒体的接管进行单变量作用下的应力分析。结果表明运用有限元壳体模型得到的结果是保守的,典型载荷下内压对接管最大应力强度的影响是最为显著的。公式法预估最大应力强度应在使用厚壁壳体公式基础上乘以一定的应力集中系数。这些结果将为以后涉及设备接管应力强度的估计及评定提供参考。     

Numerical simulation of vortical flows in the near field of jets from notched circular nozzles

The vortex dominated flows in the near field of jets from notched circular nozzles are investigated using direct numerical simulation. The nozzles studied include a normal circular nozzle, a V-shaped notched nozzle, and an A-shaped notched nozzle, all with the same circular cross-section. The vortical structures resulting from these different circular nozzles are visualized by using a numerical dye visualization technique. Results for the V-shaped notched nozzle are compared with available experimental measurements using laser-induced fluorescence techniques. In addition to azimuthal vortex rings created because of the shear-layer between the jet and the ambient fluid, the computations also reveal streamwise vortex pairs both inside and outside the vortex rings that spread outward as the vortex rings move downstream. Comparisons of the three different nozzles show that, unlike in the case of the circular nozzle where the streamwise vortex pairs emerge evenly along the nozzle lip, streamwise vortex pairs for the notched circular nozzles are produced only at peak and trough locations. Analysis of the mixing characteristics of the three types of nozzles shows that the notches in the nozzle exit significantly enhance jet mixing.