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对固体碱催化剂催化固定床法工业化生产生物柴油进行了模拟.顺利进行了小试实验,并建立了生物柴油合成的酯交换反应的动力学模型,该模型能较为准确地描述酯交换反应.通过对文献中的气液平衡数据的回归得到了生物柴油的安托因方程.选择NRTL模型对脂肪酸甲酯(FAME)-甲醇-甘油体系进行描述,得到了体系NRTL的二组分参数,利用Aspen Plus对该体系液液平衡数据(LLE)的回归得到了三组分相图.为了预测固定床工艺生产在工业规模放大1 000倍后的效果,Aspen Plus对2个流程进行了仿真模拟,预测物料和能量消耗.模拟结果表明,与先前文献报道的数据相比,每小时生产每吨生物柴油至少可以减少350.42 kW的能量消耗. 相似文献
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对弹性管束水-水换热器的传热与阻力特性进行了研究。主要分析了换热器在不同工况下的传热系数的变化规律;研究了弹性管束在管外流体和管内流体的共同诱导作用下,管外和管内对流换热的情况;并对管程和壳程的流动阻力损失进行了实验测量,得出了管程和壳程的阻力损失变化的规律,以及换热器管程阻力损失的计算方法。 相似文献
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尝试在工程流体力学实验中应用比较教学法,从实验工质的性质、局部阻力损失的计算、流量测量方法等方面进行比较式教学,从而进一步提高教学质量。 相似文献
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根据人为非定态操作技术和丁烷氧化制顺酐反应的特点,以CDS-804微反系统为基础,建立了一套用于丁烷氧化制顺酐固定床反应器浓度周期操作的实验装置,具有操作方便、运行可靠的特点。该装置也可用于其他烷烃选择氧化的人为非定态操作性能研究。 相似文献
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本文介绍了重金属废水处理新工艺——铁屑固定床法的原理和设计过程,并对其运行成本作了简单的核算.由核算结果看出该工艺具有省水、节电、运行费用低等特点,可以解决重金属废水治理难题. 相似文献
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《实验室研究与探索》2013,(12)
在分析大量实验数据的基础上,合理地简化了空气粘滞阻力与滑块运动速度的关系,建立了测定空气粘滞阻力的实用模型,并对此模型进行验证,提出了在气垫导轨实验中修正空气粘滞阻力对实验结果影响的方法。实践证明,该方法的应用对提高实验结果的精确度具有重要的理论价值和实践指导意义。 相似文献
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MA Gai-ling XU Hong CUI Wen-yong 《浙江大学学报(A卷英文版)》2007,8(5):778-785
Applying the results of stress and strain calculated by 3D finite element model of truck radial tire 11.00R20, a MATLAB program used to compute rolling resistance of the tire caused by hysteresis rolling resistance (HRR) is worked out. The HRR distribution on different part of tire section, and the effects of speed, load, internal pressure and the width of the rim on HRR are analyzed. The analysis results showed that energy loss produced by tread rubber contributes the most part to HRR of the whole tire, and that to decrease the HRR, the hysteresis factor of the tread rubber should be reduced, and the distribution of the stress and strain on the section be optimized. 相似文献
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电动截止阀是流体输送的重要元件.阀的传统设计方法很少从流体角度对其流道进行设计,其流阻系数比较大,容易造成局部压力损失.流体介质通过阀口时,流动方向发生变化,可能产生诸如局部涡流、空化、水锤和死水区等水流现象及湍流脉动噪声,对阀体有很强的破坏性,降低阀的使用寿命.基于RAN-S方程组和RNG k-ε湍流模型,利用CFD技术对全开启状态下的电动截止阀的内流道进行三维的湍流数值模拟,获得其总压图、速度矢量图、湍动能强度图.通过数值模拟,可以直观地显示阀的内流道中流体的流动过程.改变进出口段流道的长度、曲率以及阀杆在流道中的布局等,进出口的压力差相对于未改进前减少30%左右,速度突变区域明显缩小,局部涡流现象消失,湍动能强度也降低了15%左右. 相似文献
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1937年抗战爆发后,随着国民政府政治中心的转移,大后方人口急剧膨胀和高度集中,随之而来的便是消费需求爆炸性的增长,给后方资源形成了前所未有的压力。在此压力之下人们便毫无节制地掠取自然资源,使人类与自然环境的相互作用变得激烈起来,不可避免地催生了各种自然生态环境问题:森林和草地面积缩小,生物多样性减少、水土流失严重、自然灾害频仍等。 相似文献
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《International Journal of Educational Development》2000,20(3):177-188
The current supervisory system in Pakistan obviously does not contribute to teachers' professional development. An alternative model which combines supervisory pressure and support; where professional development is linked to school performance; and supervisory responsibilities are shared among external supervisors, heads and supervisory teachers in a network of schools is proposed. It is claimed that this model has the potential to create additional, more appropriate and more accessible resources for supervision. However, efforts to implement it will be met with some resistance. The sources of and reasons for this resistance are identified for further study. 相似文献
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Pressure pipes are widely used in modern industry with some in potentially dangerous situations of explosion and impact. The security problems of these pipes when subjected to impact have attracted a lot of attention. A non-linear numerical model has therefore been developed to investigate the dynamic behavior of pressure pipes subjected to high-velocity impact. A high strain rate effect on the pipe response is considered here and the fluid and pipe interaction is modeled to include the coupling effect between the deformation of the pipe and its internal pressure. Low-velocity and high-velocity impact experimental results are used to verify the numerical model, and a reasonable agreement between the numerical and experimental results has been achieved. The effects on the dynamic behavior of the pipes of the nose shape of the projectile, the diameter of the spherical projectile, and the pipe wall thickness and internal pressure, are investigated quantitatively. During high-velocity impacts, the increase of pressure in the pipes decreases their resistance to perforation. A rise in internal pressure increases the elastic resistance of the pipes toward impacts without crack formation. 相似文献
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杨惠山 《泉州师范学院学报》2002,20(4):22-25
建立一类不可逆斯特林制冷机模型,研究一般传热规律下斯特林制冷机的基本优化关系,并讨论热阻,回热损失对斯特林制冷机性能的影响,所得结论可为二热源机的研制和优化设计提供新的理论指导。 相似文献
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This paper emphases on analyzing and investigating the mechanical behavior of electro-rheological fluid (ERF) semi-active damper. Theoretical model was developed to describe the relationship between electric field and the resistance force of ERF flowing through two parallel plane electrodes. In the model, the pressure drop along electrodes was supposed to consist of two parts: one related with viscosity and the other related with dynamic yield shear stress. The concept of yield stress influence factor was developed in 相似文献
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杨惠山 《泉州师范学院学报》2003,21(2):23-27
应用有限时间热力学理论,建立一类较普遍的不可逆斯特林热机模型,研究存在热阻、热漏、回热损失斯特林热机的优化性能,导出了热漏损失服从一般传热规律时热机的功率与效率间的优化关系,讨论了不同情况下热漏和回热损失对热机性能的影响,从而可为二热源热机的研制和优化设计提供新的理论指导。 相似文献
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林智勇 《福建工程学院学报》2016,(4):318-323
利用数值分析方法建立了软土地基模型,采用比奥固结理论,计算分析了真空预压下的软土地基流固耦合作用;并进一步分析了真空度损耗率、密封墙、塑料排水板打设深度等因素对软基加固效果的影响。分析结果表明:在抽真空早期,地表沉降增长很快,达到一定天数后,沉降值逐渐趋于稳定;真空负压沿深度、水平方向上损耗,在加固软土外围形成一个零孔隙水压力面;真空度损耗率、塑料排水板打设深度对真空预压加固软土的效果影响很大;侧向密封墙对加固区内土体影响不大,但其限制了真空负压的侧向传递,使影响区的地基沉降大幅减小。 相似文献