Intensification of convective heat transfer in a stator–rotor–stator spinning disc reactor

A stator–rotor–stator spinning disc reactor is presented, which aims at intensification of convective heat‐transfer rates for chemical conversion processes. Single phase fluid‐rotor heat‐transfer coefficients h_r are presented for rotor angular velocities rad s^?1 and volumetric throughflow rates m³s^?1. The values of h_r are independent of and increase from 0.95 kWm^?2K^?1 at ω = 0 rad s^?1 to 34 kWm^?2K^?1 at ω = 157 rad s^?1. This is a factor 2–3 higher than values achievable in passively enhanced reactor‐heat exchangers, due to the 1–2 orders of magnitude larger specific energy input achievable in the stator–rotor–stator spinning disc reactor. Moreover, as h_r is independent of , the heat‐transfer rates are independent of residence time. Together with the high mass‐transfer rates reported for rotor–stator spinning disc reactors, this makes the stator–rotor–stator spinning disc reactor a promising tool to intensify heat‐transfer rates for highly exothermal chemical reactions. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2307–2318, 2015     

矩形型腔熔体充填规律的可视化实验

通过精密注射成型可视化实验系统,直观地研究3种典型矩形型腔内高温熔体在型腔中的流动行为,研究得到矩形型腔内制品熔接痕和喷射缺陷形成机理.通过分析模具结构设计、成型工艺参数与熔体宏观流动行为及制品宏观缺陷之间的内在联系,提出解决熔接痕和喷射缺陷的具体措施.     

四板式电位器盒注塑模设计

分析了电位器盒塑件的工艺特性,介绍了电位器盒注塑模具的结构特点和工作原理。该模具采用四板式,一模一腔二,次分型中,心点浇口进料,推件板推件。模具结构紧凑工,作可靠,可实现全自动操作。     

高压轴向柱塞泵缸体抗空化结构分析

针对高压轴向柱塞泵缸体内油液空化现象,分析缸体倾斜式柱塞腔和腰形孔抗空化结构对空化的抑制情况。基于Pumplinx仿真分析平台,对柱塞泵工作过程中缸体柱塞腔内气体体积分数进行仿真分析,分别探究缸体柱塞腔倾斜角度和腰形孔倾斜角度对空化的抑制情况;通过Kriging插值预测已知参数邻近未知参数,解析抗空化最优结构参数。结果表明：缸体腰形孔和柱塞腔倾斜最优角度分别为75.3°和9°,柱塞腔内气体体积分数分别降低了1.2%和1.7%。     

等通道球形转角膨胀挤压工业纯铝的组织与性能

采用新型等通道球形转角膨胀挤压(equal channel angular expansion extrusion with spherical cavity,ECAEE-SC)工艺,对工业纯铝进行室温1道次挤压变形。借助光学显微镜(OM)、电子背散射衍射(EBSD)研究变形过程中工业纯铝显微组织的变化规律,并进行了硬度测试和拉伸试验。结果表明:ECAEE-SC工艺具有复合成形效果和较高的挤压效率,坯料成功实现了单道次连续变形。工业纯铝经1道次ECAEE-SC变形后,在机械剪切、应变累积和静水压力的共同作用下,晶粒显著破碎和细化,内部形成了大量细小、均匀的等轴亚晶,平均晶粒尺寸约为4.6mm;材料表现出优良的综合力学性能,HV显微硬度由未变形时的366 MPa增加至702 MPa,增幅为91.8%,且分布趋于均匀;抗拉强度高达183.8 MPa,而伸长率降低至12.7%,拉伸断口表现出明显的韧性断裂特征。     

An investigation into the influence of microwave treatment on mineral ore comminution

The influence of microwave pre-treatment on mineral ore breakage has been investigated. Samples of lead-zinc ore were microwave pre-treated prior to strength testing and change in strength with microwave exposure time determined. Comparisons of change in strength were made between microwave-treated and -untreated material. Using a multimode microwave cavity, it was found that strength could be significantly reduced in 0.5 s when using 15 kW of microwave power. Lower powers in this type of cavity were found to be less effective. Drop weight tests were used to quantify the change in strength in terms of reduction in required comminution energy. Reductions of up to 40% were achieved for particles of mean size 14.53 mm. Preliminary tests in a single-mode microwave cavity gave strength reductions of 50% at 10 kW of microwave power with a residence time of only 0.1 s, indicating that high electric field strength is important in the failure of ore. A preliminary energy balance indicating the benefits of single-mode heating is presented.     

基于CAE技术的自行车座同模异穴型腔熔料流动平衡设计

利用CAE技术对2种尺寸的自行车座在同一副注射模中成型时熔料的流动平衡状态进行分析,提出对原浇口结构进行改进的方案,并对改进的方案进行模拟分析。根据分析的结果,对原浇注系统尺寸进行改进。结果表明:CAE技术在熔料填充模具型腔的流动平衡设计过程中,具有快速、准确、高效等优势,可以缩短模具制造周期,降低制造成本,提高生产效率。     

基于加工中心的大尺寸深腔之精加工方法

对于尺寸较大的配合型腔的精加工,可先加工出四周内壁之间的圆弧过渡部分,再分别对内壁和底面进行粗加工和精加工,最后加工底面圆角。具体分析了每一环节可能出现的问题,并提出切实可行的加工办法和操作技巧。     

插装阀先导控制级的集成设计

对具有换向动作要求的插装阀先导控制级集成设计进行了研究。以单容腔执行元件和双容腔执行元件为基础研究了先导控制级的集成设计过程,并通过在注塑机液压系统中的应用完整演示了集成设计的应用方法。结果表明:经过插装阀先导控制级的集成可以节省液压系统成本,降低系统控制的复杂程度,该方法可以进一步推广到具有比例方向、流量和压力控制功能的其他系统中,可为液压系统智能设计工具的开发提供参考。     

套筒热挤压工艺与模具设计

给出了套筒零件实用的热挤压工艺和模具结构,论述了模具的工作过程及凹模与凸模设计。该模具通过更换凸、凹模,便可生产不同规格的反挤压杯形挤压件,提高了模具利用率,降低了生产成本。