排序方式: 共有69条查询结果,搜索用时 15 毫秒
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考虑包括热辐射在内的质量传递、动量传递、热量传递三维模型,利用流体力学计算软件,对18对棒西门子多晶硅CVD还原炉实际情况进行数值模拟.考察了两种进气方式下还原炉内的流场和温度场分布.计算结果表明,为了实现硅棒均匀沉积,与底盘上分散进气、中心集中出气的还原炉结构相比,中心集中进气、中环与外环之间分散出气的流场及温度场分布更为合理.后者可能有效避免气体在进出口间的“短路”现象,又使炉内各处温度分布更为均匀,减小硅棒不均匀生长现象.模拟结果还表明,采用典型工况的数据,还原炉中总能量损失占能量输入的78.9;,辐射热损失占总能量损失的70.9;,产品单位质量能耗为72.8 kWh/·kg-1,与很多其他研究结果及实际相一致. 相似文献
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WolfgangKlose Amdt-PeterSchinkel 《中国颗粒学报》2004,2(3):107-112
The transport mechanisms of momentum,mass,species,and energy are invertigated in detail for the ro-tary kiln process.The residence time prediction of the granular bed is well improved by considerng differet flow patterns in the drum.Introducing a mixed flow pattern of the basic slipping and slumping behaviour has the most important effect on the improvement of the residence time prediction.The granular bed is assumed to hehave as a Bingham fluid in the active layer of the bed.The transport mechanisms of momentum,species,and energy are modelled on the basis of this assumption and using the kinetic gas theory.Additionally,a mathematical transformation is presented to save comput a-tional time.The model results of the temperature field are in very good agreement with experimental data. 相似文献
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Reynolds stress component due to magnetic turbulence was first measured in the plasma edge region of the HT-7 superconducting tokamak using an insertable magnetic probe. A radial gradient of magnetic Reynolds stress was observed to be close to the velocity shear layer location; however, in this experiment its contribution to driving the poloidal flows is small compared to the electrostatic component. The electron heat transport driven by magnetic turbulence is quite small and cannot account for the total energy transport at the plasma edge. 相似文献
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相变材料微胶囊流体相变过程对储热蓄热影响 总被引:1,自引:0,他引:1
用石蜡混合物(以C_(19)H_(40)为主体,相变温度:25~38℃,比热容极大值出现在31.5℃左右)作芯材,树脂材料作囊壁,与水混合制备成微纳米胶囊流体,将其填充在矩形密闭容器内,在下表面加热,其余各表面绝热条件下,对相变材料相变化过程的储热蓄热特性进行分析。结果表明,相变材料相变化过程提前了自然对流的启动时间,加强了换热强度;在蓄热温度超过35℃之前,相变化的促进作用随温度增加而逐渐增强,超过35℃以后,相变化的促进作用开始减弱. 相似文献
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Heat transfer analysis in the flow of Waiters' B fluid with a convective boundary condition 下载免费PDF全文
Radiative heat transfer in the steady two-dimensional flow of Walters' B fluid with a non-uniform heat source/sink is investigated. An incompressible fluid is bounded by a stretching porous surface. The convective boundary condition is used for the thermal boundary layer problem. The relevant equations are first simplified under usual boundary layer assumptions and then transformed into a similar form by suitable transformations. Explicit series solutions of velocity and temperature are derived by the homotopy analysis method (HAM). The dimensionless velocity and temperature gradients at the wall are calculated and discussed. 相似文献
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