共查询到20条相似文献,搜索用时 93 毫秒
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基于传热学理论,对挤出成型塑料管材的冷却过程进行了分析并建立了数学模型。引入聚合物的比热容和热导率对温度的依赖关系,运用有限差分数值方法,求解变物性参数条件下一维非稳态传热方程,模拟了塑料管材在定型冷却过程中的温度场,并由此确定冷却段的合理长度。 相似文献
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通过对PU(聚氨酯)轮胎作出合理的假设,建立轮胎滚动状态下的稳态温度场预测模型,应用ANSYS软件模拟规格为10.00R20的聚氨酯/橡胶复合轮胎在滚动状态下的温度场,同时针对聚氨酯/橡胶的接触层进行详细分析和实验数据对比,以便在设计之初对轮胎结构进行优化设计和配方设计,从而提高轮胎的安全性和使用寿命。 相似文献
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Freezing processes of several liquids under static magnetic field (SMF) less than 50 mT were investigated.Central temperature of liquid samples held in glass test tubes immersed in a liquid bath was measured and collected.Nucleation temperature and phase transition time were obtained from freezing curves.Normality tests were performed for nucleation temperature of these liquids with/without magnetic field and normality distributions were justified.Analysis of variances was carried out for nucleation temperature of these liquids with magnetic field flux density as the influencing factor.Results showed that no significant difference was found for deionized water with or without SMF.However,differences exist in 0.9% NaCl solution and 5% ethylene glycol solution with and without SMF.Nucleation temperature of 0.9% NaCl with SMF is lower than that without SMF,while its phase transition time is shorter than that without SMF.Nucleation temperature of 5% ethylene glycol with SMF is higher than that without SMF,while its phase transition time is not modified with SMF. 相似文献
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水冷壁气化炉温度分布及影响因素分析 总被引:1,自引:0,他引:1
对气流床水冷壁气化炉炉壁的温度分布及影响因素进行了计算和分析。建立了气流床水冷壁气化炉的三维传热数学模型,运用有限元方法,计算出水冷壁的温度分布,炉壁导热主要通过渣钉完成;探讨了水冷管内工质传热系数、炉内温度、渣钉间距、鳍片厚度、鳍片宽度及熔渣厚度对渣钉、水冷管、鳍片端部和根部等关键部位的最高温度点温度的影响;为了验证热分析的正确性,在实验室的小型气化炉上进行试验,鳍端背火侧温度计算值与实验测量值吻合良好,误差在5%之内;其计算模型和分析结果可为水冷壁气化炉的设计提供相应依据。 相似文献
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In the present work, the drying kinetics and evolution of sample's core temperature and moisture distribution of yam slices during convective hot-air-drying were investigated. In terms of drying kinetics, the effect of drying temperature (50, 55, 60, 65, 70°C), relative humidity (20, 30, 40, 50%), and sample thickness (5, 7, 9 mm) on drying characteristics of yam slices were studied. Results indicated that all the three factors had significant influence on the drying kinetics, whereas drying temperature gave the most significant effect, followed by relative humidity and sample thickness. Moisture-effective diffusivity and activation energy were calculated, and it was found that the diffusivity was in the range of 5.5454 × 10?10–1.0804 × 10?9 m2/s and the activation energy was 29.528 kJ/mol. Heat and mass transfer models were developed based on the finite element method to calculate the core temperature and moisture distribution of yam slices during drying. Model validation exhibited good agreement between predicted and experimental data, which illustrated that the developed models could precisely predict the core temperature profile and moisture distribution of the sample. The current work provides further insights to understand the characteristics and mechanism of drying process of yam slices. 相似文献
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针对兰新二线无砟轨道修建后道床板混凝土出现的早期开裂等耐久性问题,在室内进行1:1足尺模型试验,利用人工气候模拟箱模拟西北地区的大温差恶劣环境,从早期水化热温度场的分布及变化规律以及变形等方面研究无砟轨道道床板混凝土开裂机理,建立道床板混凝土水化温度场与西北地区大气温度环境的关系;同时,通过有限元软件模拟计算水化热温度场,计算结果与室内试验结果进行对比.研究结果表明:大温差恶劣环境是导致道床板开裂的主要原因,道床板温度场与环境温度呈周期变化,越靠近道床板表面温度梯度越大,越容易产生裂缝. 相似文献
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电动汽车锂离子电池温度过高会降低电池的放电效率,加速电池寿命的衰减。为了降低电池组温度,设计了热管内插于电池组的散热系统。以电动汽车实际行驶过程中的速度为依据,对不同放电电流下电池组的温度场分布进行了数值计算。结果表明:随着车速的提高,电池的放电电流、产热量急剧增加,当车速达到120 km·h-1时,放电电流高达143 A,电池放电截止时,电池组温度达到56℃;与自然对流冷却方式相比,热管冷却可以将电池组的平均温度降低4.6℃,电池组温差降低2.2℃;热管冷凝段长度的增长可以有效地降低电池组的温度,热管冷凝段长度为50 mm时,可以基本上满足电池组的散热需求。 相似文献