BBD 磨煤机气相流场的数值试验研究

基于４０．５３型直燃式双进双出（ＢＢＤ）磨煤机实际工况条件,首次对ＢＢＤ磨煤机流场进行了热态数值试验研究。通过研究磨煤机的填充率和进出口管道口径的大小,对其内部气相流场的运动规律有一定认识。文中总结出磨煤机内气相流场随磨煤机填充率和进出口管道口径变化的规律,为磨煤机的结构优化设计和实际生产中对磨煤机内部流场进行控制提供了有益的参考。     

Influence of spinning parameters on milkweed/cotton DREF-3 yarn properties

In this study, Pergularia milkweed fibre (70%), cotton fibre (30%) core and 100% cotton fibre sheath DREF-3 core yarns of 74?tex were produced using different spinning parameters in order to understand their effect on yarn properties. Box–Behnken design was used for the optimization of core ratio, drum speed and suction pressure, and to evaluate the effects and interactions of the process variables on the yarn properties at a constant opening roller speed of 12,000?rpm and production speed of 100?m/min. The effects of the core/sheath ratio on all the yarn properties are significant. With an increase in the core/sheath ratio, yarn tenacity and elongation decrease due to insufficient wrapper fibres in the yarn and yarn unevenness; imperfection increases due to higher feed rate and draft at higher core ratio. The yarn hairiness increases at higher core ratio due to higher number of short fibres in milkweed and lesser sheath fibres to cover the core fibres effectively. An increase in the spinning drum speed damages fibre in the sheath and increases the number of hooks at the end of fibres, as a result of which the core yarn tenacity decreases at higher drum speed. At a higher air suction pressure, yarn tenacity and the elongation at break increases. The drum speed and suction pressure have no significant effect on yarn unevenness and imperfections. The yarn hairiness decreases slightly with increase in drum speed and suction pressure but is insignificant.     

基于RSM-BBD的拜耳法赤泥胶结充填配比优化

针对拜耳法赤泥难以规模化利用的问题,开发拜耳法赤泥作为矿山胶结充填骨料.基于配方探索试验结果,运用BBD方法设计9组试验,以响应面优化法探究料浆浓度和拜耳法赤泥C料质量比与充填体抗压强度、坍落度和C料单耗3个响应量的相关关系及最佳配比.结果表明:在拜耳法赤泥C料质量比为6.88、料浆浓度为58.69％时满意度值达到最大...     

基于响应面优化法的某矿山充填配比优化

为得到某矿山充填最佳配比方案,在实验的基础上利用BBD 响应面设计法确定充填配比的最佳条件.通过实验得到影响充填体强度因素的排序,并得到最佳配比实验方案,即灰砂比（质量比）1∶4,养护时间为28 d,浓度为75%,按照此方案得到的充填体强度为5.48 MPa,与理论值5.71 MPa的误差为4.2%,利用响应面法优化得到充填体的配比方案真实可靠,能够为矿山充填配比的应用提供理论依据,在实践中具有指导意义.而真实值比理论值偏低,可能是试验过程中仍存在干扰因素,建议在后续深入研究过程中考虑的因素要更彻底、更全面.     

响应面分析优化新橙皮苷二氢查尔酮合成工艺条件研究

以20g新橙皮苷为原料,催化加氢合成新橙皮苷二氢查尔酮（NHDC）。通过单因素实验,确定响应面实验因素与中心水平。根据Box—BehnkenDesign（BBD）实验设计原理,采用3因素3水平的响应面法,以合成收率为响应值,分析各因素的显著性和交互作用。结果表明：最佳合成条件为反应时问10．38h,NaOH浓度1．14mol／L,Pd／C催化剂用量2．29g,此时NHDC的产率可达71．2％。     

基于响应曲面法的自动铺放工艺参数分析与优化

通过对自动铺带(Automated tape laying,ATL)成型工艺的分析,提出了一种新的铺放质量评分标准。采用响应曲面法(Response surface methodology,RSM)设计了铺放工艺参数优化实验,分析了热风温度、铺放压力和铺放速度各工艺参数及其交互作用对铺放质量的影响,建立了各工艺参数与铺放质量的二次多项式回归方程的预测模型。根据回归方程求得了最佳铺放质量下的工艺参数,以及可接受铺放质量下的最大铺放速度时的工艺条件,为自动铺带工艺参数的控制提供了参考。     

双进双出磨煤机干燥能力的确定

本文对双进双出钢球磨煤机干燥系统进行了热力学分析，导出了系统在稳定工作时，干燥能力的数学计算公式，并在进口设备上得到了实测验证。     

火电站中磨煤机的运行机理

介绍了火电站的制粉系统中所采用的磨煤机的历史,解释了磨煤机的研磨理论,并从理论和实践上着重介绍了双进双出钢球磨的工作特点。     

柴油喷雾蒸发仿真中KH-RT模型的数值试验研究

在柴油喷雾蒸发混合过程仿真中,基于Box-Behnken design(BBD)方法对KH-RT模型参数进行数值试验研究。采用高速阴影法对定容弹内环境温度900K、密度15kg/m3、喷射压力120MPa条件下柴油喷雾蒸发混合过程进行记录。将喷束气液两相贯穿距的仿真计算结果与试验数据对比。根据相对误差,采用响应曲面法分析Kelvin-HelmholtzRayleighTaylor(KH-RT)模型的各参数在柴油喷雾蒸发混合发展中的影响。结果表明破碎时间常数是主要影响因素。进一步得出优化的模型参数组合,经验证明其具有良好的预测性。     

Optimization of the Strength Properties of Waste Oil Palm (Elaeis Guineensis) Fronds Fiber

In this study, Box-Behnken design (BBD) and response surface methodology (RSM) was applied to study the effects of alkaline peroxide treatment variables (cooking time, sodium hydroxide concentrations, and hydrogen peroxide concentrations) on the pulp and paper strength properties (screened pulp yield, kappa number, tensile index, tear index, burst index), which are considered dependent variables or response variable of the extracted cellulose from oil palm (Elaeisguineensis) fronds (OPF) vascular bundle fibers. The results indicated that at the optimum operating conditions of 2.35% NaOH, 5.00% H₂O₂ and a 53.41 min cooking time, resulting maximum strength properties (tensile index, burst index, tear index,) gave 9.92 Nm/g, 6.55 KPam²/g, 6.22 mNm²/g, respectively. The study revealed that alkaline peroxide pulped fibers of oil palm frond vascular bundles could be considered a suitable alternative for paper qualities with moderate strength requirements.