多功能化工原理实验装置

本文介绍了对现有“传热膜系数的测定实验”装置进行适当改造后,可成为能进行五个化工原理实验的多功能实验装置 。     

填料吸收塔实验教学方法改革

实验教学在高等教育体系中占有举足轻重的地位,本实验对填料吸收塔实验提出了新的教学方法,通过正交实验法根据实验结果确定填料吸收塔最佳条件。通过正交表2可知:Kya值最大是试验号为7的一组,所以在此条件下填料塔吸收率最高。R1>R2>R3,因素一的R最大,为13.29,说明NaOH溶液的浓度对本实验影响最大,其次为碱液流量的影响,空气流量对结果的影响最小。这样既使学生掌握了传质总系数的测定方法,达到了传统填料吸收实验的教学目的,又掌握了一种实验设计理念,从而使实验教学适应教育发展的要求。     

化工原理吸收实验中气液两相流率对气相体积吸收系数的影响

吸收实验是重要的化工单元操作实验之一,通过吸收塔的流体力学性能及气相流量和液相流量参数变化得到不同的实验结果,联系传质双膜理论,使得学生通过吸收实验加深对相关理论的认识,获得较大的收获。     

新型多功能筛板塔拆装实训装置的开发

综合分析现有化工原理塔安装测试实验装置,设计出一种新型多功能筛板塔拆装实训装置。实训装置具有离心泵变频调速、流量测量、压力测量、筛板塔塔底液位变频控制等功能,可实现筛板塔拆卸安装、双塔串联和并联的冷模开停车调试等实验。实践表明,该装置使学生对筛板塔的结构、安装和操作方法的认识更加清晰,对筛板塔双塔串联和并联相关性能及其应用的理解更加深刻。     

新型饱和蒸汽压及传质系数测试装置

设计和搭建了一套新型饱和蒸汽压及传质系数测试装置,并介绍了该装置的结构及工作原理。通过静态法测定液体饱和蒸汽压实验测试去离子水在不同温度下的饱和蒸汽压,对该装置的准确性进行了验证。实验结果表明:测试结果与理论值相吻合,其测试误差在±10%以内。该装置基于气液平衡原理,实现了在同一装置中采用同一压力传感器对液体饱和蒸汽压和气液传质系数进行测试,成功消除了系统误差,对改善实验质量具有明显的效果。     

填料塔吸收实验设计改进和应用

依气液传质设备填料塔工艺参数为依据,对填料塔吸收实验的设计作了改进。     

化工原理实验装置的设计实践

通过自行设计建成先进、科学、实用的化工原理实验装置,既锻炼和培养了教师队伍又节约了建设经费,并使培养学生实践能力和创新能力的实验教学改革思路在实验装置中得到了充分的体现.     

化工原理实验装置的设计实践

通过自行设计建成先进、科学、实用的化工原理实验装置，既锻炼和培养了教师队伍又节约了建设经费，并使培养学生实践能力和创新能力的实验教学改革思路在实验装置中得到了充分的体现。     

关于工程研究型实验教学的思考与探索

工程研究型实验教学在培养优秀工程师方面发挥着重要作用.将工程实际问题融入实验教学过程,能使实验者在实验研究中掌握的实验方法、操作技能以及得到的实验结论有效地提高其日后处理工程实际问题的能力.以流体流动阻力测定实验、离心泵特性曲线测定实验、筛板塔精馏实验和填料塔吸收实验为案例,分别通过处理工程实际问题的方案研究、过程操作条件的优化研究、化工单元装置的操控研究、工程实验结果的分析研究得出:让学生带着研究任务参与实验,运用已有的专业知识解决几个简单的工程实际问题,从中树立一些工程观点,掌握几种处理工程问题的方法,必将大大激发学生的学习积极性,对开阔他们将来解决实际工程问题的思路具有很大帮助.     

化工原理实验多媒体教学的实践与体会

化工原理实验课作为化工原理课程的一个重要教学环节，目的是使学生加强理解和巩固化工原理课程中阐述的理论知识，通过对化工原理实验多媒体教学，可以更形象、生动地展示给学生解决工程问题的过程，培养学生解决问题的能力，从而让学生比较容易掌握实践操作技能。通过两年来的教学实践，起到了较好的效果，改变了学生认为化工原理学习困难、不感兴趣的观念。     

Numerical study of heat transfer characteristics of downward supercritical kerosene flow inside circular tubes

The heat transfer characteristics of China RP-3 aviation kerosene flowing in a vertical downward tube with an inner diameter of 4 mm under supercritical pressures are numerically studied. A ten-species surrogate model is used to calculate the thermophysical properties of kerosene and the re-normalization group (RNG) k-ε turbulent model with the enhanced wall treatment is adopted to consider the turbulent effect. The effects of mass flow rate, wall heat flux, inlet temperature, and pressure on heat transfer are investigated. The numerical results show that three types of heat transfer deterioration exist for the aviation kerosene flow. The first type of deterioration occurred at the tube inlet region and is caused by the development of the thermal boundary layer, while the other two types are observed when the inner wall temperature or the bulk fuel temperature approaches the pseudo-critical temperature. The heat transfer coefficient increases with the increasing mass flow rate and the decreasing wall heat flux, while the inlet bulk fluid temperature only influences the starting point of the heat transfer coefficient curve plotted against the bulk fluid temperature. The increase of inlet pressure can effectively eliminate the deterioration due to the small variations of properties near the pseudo-critical point at relatively high pressure. The numerical heat transfer coefficients fit well with the empirical correlations, especially at higher pressures (about 5 MPa).     

Modeling of mass transfer characteristics of bubble column reactor with surfactant present

Danckwert's method was used to determine the specific interfacial area, a, and the individual mass transfer coefficient, kL, during absorption of CO2 in a bubble column with an anionic surfactant in the carbonate-bicarbonate buffer solution and NaAsO2 as catalyst, the presence of which decreases the specific interfacial area and the individual mass transfer coefficient. The specific interfacial area and the individual mass transfer coefficient increase with increasing superficial gas velocity. The specific interfacial area decreases whereas the individual mass transfer coefficient increases with increasing temperature. The results of experiments were used to determine the dependence of a, kL, and kLa on the surface tension, the temperature of the absorption phase, and the superficial velocity of the gas. The calculated results from the correlation were found to be within 10% deviation from the actual experimental results.     

Enhancement of solubility and mass transfer coefficient of salicylic acid through hydrotropy

This study deals with the effect of hydrotropes on the solubility and mass transfer coefficient of salicylic acid. The solubility and mass transfer studies were performed using the hydrotropes, i.e., sodium acetate, sodium salicylate, citric acid, and urea at concentrations of 0-3.0 mol/L and system temperatures of 303-333 K. It was found that the solubility and mass transfer coefficient of salicylic acid increases with increase in hydrotrope concentration and also with system temperature. All hydrotropes used in this work showed an enhancement in solubility and mass transfer coefficient to different degrees. The maximum enhancement factor values were determined for all hydrotropes used in this study. The highest value was 28.08 for solubility studies and 10.42 for mass transfer studies. The performance of hydrotropes was measured in terms of the Setschenow constant （Ks）. The highest value observed was 0.696.     

扩散吸收式制冷系统中板式换热器综合传热性能分析

在一种太阳能驱动、采用喷雾吸收器并以板式换热器作为主要换热部件的LiNO3-NH3-He三工质扩散吸收式制冷系统中,根据试验测得的运行参数,以溶液的p-t-x西方程及物性方程、传热基础理论等为依据,提出了计算溶液换热器中溶液流量的方法,并利用综合传热系数k、传热单元数N_TU与换热器效率s研究了板式换热器作为LiN03-NH3-He扩散吸收式制冷系统发生器、冷凝器、溶液热交换器、溶液冷却器时的换热性能．试验与分析表明,板式换热器的换热面积及其内部流道中的流量（流速）对其综合传热性能具有较大影响;在介质流量一定时,板式换热器不宜考虑过大的面积预留量;板式溶液换热器内部流道宜采用多流程布置形式以强化传热、提高换热效率．     

多功能薄膜干涉实验装置的应用

在常规实验装置的基础上设计安装了一个光具架,由此制成了一种多功能薄膜干涉实验装置。在该装置上不仅可以完成常规的牛顿环实验,还可完成劈尖干涉实验和多种扩展实验,解决了在单一薄膜干涉实验装置上只能完成一种实验的弊端。     

水蒸气蒸馏提取植物精油的传质研究

建立水蒸气蒸馏分离植物挥发油传质过程数学模型．对常规蒸馏器进行改进，加入搅拌装置强化了传质．通过３种植物蒸馏的实验数据，求取了总传质系数值并验证了数学模型，并讨论了搅拌转速对传质系数的影响．     

超临界流体萃取过程的动力学问题

围绕超临界流体萃取过程中的传质、传质系数的计算,超临界流体萃取速率、传质阻力,超临界流体通过固定床的压降以及超临界流体萃取过程中的影响因素等动力学问题进行了探讨和阐述,对于超临界流体萃取技术的应用与过程操作具有参考价值。     

Science Letters:On the critical radius in generalized Ostwald ripening

INTRODUCTION A polydisperse precipitate produced by nuclea-tion in a metastable supersaturated solution is far from thermodynamic equilibrium, i.e. a state of minimal free energy. A decrease of free energy is accom-plished by a coarsening of the precipitate which es-sentially reduces the surface free energy with respect to the surrounding solution. The process is called Ostwald ripening and is a direct consequence of the Kelvin effect (Adamson and Gast, 1997), that is the higher solubi…     

Science Letters： On the critical radius in generalized Ostwald ripening

The relation between the critical radius and the particle size distribution for generalized Ostwald type ripening processes whereby the mass transfer coefficient is modelled by a power law was derived. The critical radius is determined by the growth rate, the mass transfer coefficient and the mass balance, and is independent of whether the limiting stationary growth regime has been obtained.