共查询到20条相似文献,搜索用时 31 毫秒
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为了探讨旋流腔结构对涡流二极管正向流动和反向流动的影响,分别采用RNG κ-ε湍流模型和κ-ε湍流模型进行了数值模拟,模拟结果与实验数据吻合良好。在此基础上,计算分析了旋流腔结构型式及几何尺寸对正向流动和反向流动的影响,并得到了旋流腔的优化结构。结果表明:渐缩型旋流腔反向阻力系数最大;薄板型正向阻力系数最小;渐缩型综合性能最佳,可以在原型基础上提高30%。渐缩型旋流腔中心高度应根据等流速设计原则,其最佳值略小于轴向出口管直径的1/4。 相似文献
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基于壳程周期性单元流道模型;采用数值模拟方法分析了一种新型的传热强化元件——旋流片作为管间支撑物的湍流流动与传热特性。数值模拟采用重整化(RNG)κ ε双方程湍流模型;SIMPLEC算法进行压力和速度的耦合;壁面处理采用强化壁面处理法。分析了单元流道横截面流场和湍流强度的周期性变化;以及截面上流场和温度场的协同关系。比较了截面平均Nusselt数和平均协同角的对应变化趋势。结果表明;旋流片使流体在管束间做三维螺旋运动;破坏了流体流动的连续性和稳定性;增强湍流强度从而强化传热;同时改变了管束间流体的速度场与温度场分布;旋流片强化传热的根本机理是改善了两场的协同关系。 相似文献
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刘学 《中国石油和化工标准与质量》2013,(8):56
旋流分离器是一种利用相间的密度差产生不同的离心力,进而完成气-液、液-液、气-固等分离的设备,具有结构紧凑、分离效率高、环境适应性强等优点,在石油、化工、矿山、煤炭等行业应用广泛。旋流分离器的流动机理研究在整个旋流分离器的研究过程中占据重要地位,其内部流场属于三维强旋湍流,流动复杂,对分离器流场进行充分的研究是指导分离器设计、提高分离性能的前提。本文将对旋流分离器的流场结构进行详细介绍,并就国内外学者关于分离器结构变化对流场分布的影响关系进行总结概括。这对加深对旋流分离器的认识,指导其优化设计具有重要的辅助作用。 相似文献
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为优化聚结器结构,应用计算流体力学(CFD)方法,选用RNG k-ε模型,以SIMPLE算法为基础,对旋流式和蛇形管式聚结器在湍流状态下的流体流动场进行数值模拟,得出该两种结构聚结器的油相浓度分布云图。数值模拟结果表明,蛇形管式聚结器对油滴的兼并和聚结效果优于旋流式聚结器。 相似文献
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J. B. LYON 《Journal of the American Ceramic Society》1927,10(3):185-204
Seventeen periodic kilns were studied for construction and design details, operation, and results. Eleven were round and six were rectangular. Alterations were made in grate area proportions, floor openings, flue design, and dimensions; the firing conditions and quality of ware obtained with each were recorded. The data obtained show effect on heat distribution and on time and fuel expenditures. Detail designs of flues are shown and the data are in tables and graphs. Detail specification and bill of materials are given for the 30-foot round kiln which was found to give best results in ware and costs. 相似文献
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Edward Schramm 《Journal of the American Ceramic Society》1944,27(9):282-284
Saggers for glost placing must give good life and avoid harmful secondary effects on the ware. Low thermal expansion is the most necessary property but, if carried too far, may cause the fault known as pin chipping. This defect, however, is compensated by low expansion in the pin itself. The system sagger-pin-ware should be adjusted to minimize tensile stresses in cooling. 相似文献
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W. E. Cramer 《Journal of the American Ceramic Society》1922,5(8):492-499
The successful application of the car tunnel kiln to the firing of electrical porcelains is described. This kiln is 321 feet long, 54 1/2 inches wide inside, and has a placing height of approximately 60 inches. The ware is placed in saggers as formerly. Ware has been fired through this kiln in 48 hours-total time for heating up, soaking, and cooling. The kiln operates at cones 10, 11, and 12, depending upon the ware being fired. Natural gas is used as fuel and is supplied to the kiln through Maxon Premix burners. Auxiliary fuel oil equipment is also installed. 相似文献
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窑法磷酸生产的旋窑制气试验研究 总被引:7,自引:0,他引:7
以清平和中低品位金河磷矿为原料,研究了窑法制磷酸磷矿炭热还原过程的规律。在小型旋窑内进行了旋窑制气试验,弄清了在同一旋窑内磷矿还原与磷蒸气氧化时,分别要求还原和氧化气 氛的矛盾,以及型料熔结产生窑圈的实质。找到了解决的途径和方法,考查了旋窑制气工艺,测定了有关工艺和设备设计参数。 相似文献
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James Fuller 《Drying Technology》2000,18(6):1349-1359
The origin of material response (changing shrinkage rates) during drying is changing stress levels within the lumber as was determined in a previous paper. The object of this research was to demonstrate that a kiln control system based on material response parameters can reduce the drying time while incurring no additional drying defects. One control run and two pilot runs were performed. The results showed that it is possible to advance the kiln schedule using only material response as the controlling parameter and maintain or improve the quality of the lumber. Accelerating the drying substantially reduced the residual stress levels in the final product. 相似文献
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H. B. Henderson 《Journal of the American Ceramic Society》1930,13(7):458-460
A heavy, white, fuzzy coating on brick developed in the firing. The coating consisted entirely of silica, produced from the reduction of silica and vaporized as silicon and reoxidized. 相似文献
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