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本文介绍风量差压变送器仪表量程更改和温度补偿在风量测量上的应用,计算出更改仪表量程和增加温度补偿的实际运算结果,证明仪表量程和温度变化对流量影响很大。 相似文献
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利用CFD流体计算软件建立了炉内传热模型,并耦合氧化铁皮计算程序计算钢坯氧化烧损率,流动模型采用k-ε湍流模型,燃烧采用PDF燃烧模型,辐射换热模型采用离散坐标(DO)辐射模型。模拟常规工况与试验工况下的炉内气氛,结果表明,常规工况下加热制度不合理,高温区氧的体积分数高达8%,而试验工况下可使高温区氧的体积分数降低为1.2%;氧化烧损的计算表明,试验工况下可使钢坯氧化烧损率由0.895 1%降低至0.51%;试验工况的现场应用测试表明:试验工况下可使钢坯氧化烧损率降低47%。 相似文献
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分析过孔板式差压流量计量程比受到限制的原因,以及现阶段随着微电子技术、传感器技术的发展和计算机技术对仪表的渗透,孔板式差压流量测量技术获得了一次飞跃,使测量的量程比达到10:1.同时指出三种扩展量程比的方法,以及这些方法在上海梅山钢铁股份有限公司运用的具体实例. 相似文献
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采用GEO-SLOPE公司开发的二维饱和-非饱和渗流有限元程序计算地下水位,运用传递系数法对张家湾滑坡进行了稳定性计算.结果表明,滑坡最危险的工况为库水位下降工况,计算结果与目前检测情况相符. 相似文献
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为了研究运转工况下风电塔的地震响应及倒塔模式,使用风电塔设计软件FAST建立风电塔模型,比较停机和运转不同工况下的结构响应,并在运转工况下通过改变地震动输入方向研究不同风震组合角对结构响应的影响,得到最不利工况;使用ABAQUS建立风电塔的精细化有限元模型,将FAST计算的塔顶风荷载导入ABAQUS开展分析计算.将基于叶素理论计算的塔顶荷载与FAST计算结果进行对比,并进一步将弹性阶段ABAQUS与FAST模拟的塔顶位移进行对比,校验分析方法的合理性.利用ABAQUS模型将地震动调幅,开展倒塔模拟.研究结果表明运转工况下最不利风震组合角是90°,强震下塑性铰在塔身下部出现并向中上部发展,最终该风电塔在中上部发生破坏. 相似文献
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盘锦乙烯厂对于进厂乙烷的计量采用的是差压流量计 ,原设计的量程为0~15t/h ,正常流量为7 32t/h ,但由于油气田的变化 ,乙烷量的供应量减少 ,实际的流量最小时为3t/h ,最大时为7t/h。在流量测量中 ,国家标准规定 :节流装置适用的流量比为30 % ,即最小流量∶最大流量=1∶3。如果流量比小于30 %时 ,雷诺数往往低于临界值 ,流量系数发生变化 ,造成测量不准。实际上 ,该厂乙烷计量值比供方计量值要少得多 ,无法作为乙烷结算的参考计量。为此 ,必须对流量计的量程进行修改 ,以提高计量的准确性。量程改变的计算方法… 相似文献
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介绍了一种用于测试电热法制取铝硅合金用团块气孔率的新方法,并在此基础上考察了压力、烧结条件、粒度对气孔率的影响。结果表明,团块气孔率随着压力的增大和物料粒度的减小而减小,而随烧结温度的升高及烧结时间的延长而增大。在压力、烧结条件、物料粒度三者之中,烧结条件对团块气孔率的影响最为明显。 相似文献
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研究了三轴条件下饱和砂土在排水与不排水冲击时的动力响应和冲击后再固结性状.结果说明,不排水冲击时的孔隙水压力在跳跃中不断累积上升后渐趋平稳,冲击时轴向应变随冲击击数、能量的增大呈近线性增长,最大轴向冲击压缩量与能量呈近线性增长,体变产生于冲击后的再固结;排水条件下冲击的孔隙水压力虽会产生跳跃、但不产生累积,轴向应变与冲击击数、最大轴向冲击压缩量与冲击能量的关系近于双曲线,体变量基本产生于冲击阶段.对比发现,同能量、同冲击击数时,不排水条件下冲击的轴向压缩量大于排水冲击的,而排水冲击的总体变要大于不排水冲击的总体变. 相似文献
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提高设备单机可靠性乃至整条生产线的可靠性是设备运行管理所追求的目标.文章以皮带机为例,通过对实现目标的两个条件的措施、做法的阐述,说明了实现目标的可行性与现实意义. 相似文献
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化学镀Ni-B合金的工艺条件研究 总被引:7,自引:0,他引:7
研究了镀液成分和工艺条件对Ni—B合金沉积速度的影响,确定了合适的化学镀N—B合金的工艺条件,按此条件获得了含硼量为4.508%的非晶态Ni—B合金层,并具有较好的耐蚀性。 相似文献
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The effects of chemico-physical growth conditions such as pH, temperature and water activity (aw) on lethal high homogenization pressure effects on Listeria monocytogenes, Staphylococcus aureus, Escherichia coli and Yarrowia lipolytica were investigated. The results, though based on standard media, emphasize the importance of food system composition and its thermal history on the high pressure tolerance of the microbial population. 相似文献
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Solutions for the borehole problem based on Biot’s poroelasticity theory have shown that drilling through fluid saturated formations, gives rise to time-dependent stress and pore pressure fields in the vicinity of the borehole. As a natural consequence, borehole stability in such formations is of a time-dependent nature. However, existing analyses are based on two limiting cases viz., constant pore pressure and/or no flux boundary conditions at the borehole wall. Adding time dependency to the pore fluid boundary conditions can simulate realistic field conditions such as those observed during hydraulic fracturing, fluid injection or development of filter cake. Analytical solutions for inclined boreholes with time-dependent pore pressure and flux boundary conditions at the borehole wall are presented in this paper. Analysis is carried out for two special cases of the ramp-type pore pressure and linearly reducing flux boundary conditions. Analytical solutions are supplemented with asymptotic solutions for small and large time analysis. The effects of these conditions on stress concentrations near the borehole wall and their implications on borehole stability are examined in detail. 相似文献
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本文就山东省冶金工业总公司1993年底的主要生产设备现状,在调查的基础上,指出了存在的主要问题。并就进一步提高设备装备技术水平、正确计提折旧等提出了建议。 相似文献
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Theories on the evaporation of pure substances are reviewed and applied to study vacuum evaporation of pure metals. It is shown that there is good agreement between different theories for weak evaporation, whereas there are differences under intensive evaporation conditions. For weak evaporation, the evaporation coefficient in Hertz-Knudsen equation is 1.66. Vapor velocity as a function of the pressure is calculated applying several theories. If a condensing surface is less than one collision length from the evaporating surface, the Hertz-Knudsen equation applies. For a case where the condensing surface is not close to the evaporating surface, a pressure criterion for intensive evaporation is introduced, called the effective vacuum pressure, p eff. It is a fraction of the vapor pressure of the pure metal. The vacuum evaporation rate should not be affected by pressure changes below p eff, so that in lower pressures below p eff, the evaporation flux is constant and equal to a fraction of the maximum evaporation flux given by Hertz-Knudsen equation as 0.844 $ \dot{n}_{\hbox{Max} } $ . Experimental data on the evaporation of liquid and solid metals are included. 相似文献