HEAT TRANSFER IN A THIN LIQUID FILM IN THE PRESENCE OF AN ELECTRIC FIELD

Heat transfer enhancement in an evaporating thin liquid film utilizing a electric field under isothermal interfacial condition is presented. A new mathematical model subjected to van der Waals attractive forces, capillary pressure, and an electric field is developed to describe the heat transfer enhancement in the evaporating thin liquid film. The effect of the electrostatic field on the curvature of the thin film, evaporative flux, pressure gradient distribution, heat flux, and heat transfer coefficient in the thin film is presented. The results show that applying an electric field can enhance heat transfer in a thin liquid film significantly. In addition, utilizing electric fields on the evaporating film will be a way to expand the extended meniscus region to attain high heat transfer coefficients and high rates of heat flux.     

红甜菜萃取液蒸发浓缩过程研究(I)红甜菜萃取液蒸发浓缩动力学

对红甜菜萃取液的蒸发浓缩动力学作了研究。表明甜菜红色素损失速率为表观二级反应,温度的影响遵循Arrhenius方程,建立了甜菜红色素降解速率与料液温度、料液相对密度、抗坏血酸浓度相关联的蒸发浓缩动力学模型。新型异形竖板降膜蒸发器中蒸发浓缩过程中甜菜红色素吸光度实测值与动力学理论模型的吸光度预测值吻合良好,表明动力学模型对预测工业蒸发器浓缩过程中甜菜红色素损失程度具有良好的准确性;可用于指导工业生产。     

铬酸钾-碳酸钾高效分离研究Ⅰ.相图分析与溶解度计算

铬酸钾-碳酸钾的高效分离是铬盐清洁工艺亚熔盐介质再生的重要环节.据K2CrO4-K2CO3-H2O体系溶解度分析,蒸发结晶是该分离过程控制的关键,对此进行了详细的相图分析.选用Pitzer模型的HW公式,以二元电解质溶液的Pitzer参数推算了100℃时K2CrO4-K2CO3-H2O体系相平衡情况,理论计算结果与实验结果吻合较好,最大相对误差为16.26%,平均相对误差为7.39%.     

硫磺汽化管失效原因及对策

通过对原高温硫磺汽化管失效原因的分析,提出了改进管子化学成分的方案,实践证明这一方案是有效的。     

Limitations on the use of the planar laser induced exciplex fluorescence technique in diesel sprays

The Planar Laser Induced Exciplex Fluorescence (PLIEF) technique is widely used to visualize and measure the fuel concentration fields in both liquid and vapor phases of DI Diesel sprays. However, the real limitations of the PLIEF technique in Diesel sprays and the accuracy of the results obtained are still a source of controversy. In this work, a complete methodology for maximum penetration and fuel concentration measurements in evaporating conditions in Diesel sprays has been developed and the reliability of the results obtained has been investigated. The methodology includes new procedures for measuring both liquid and vapor phases, adapting, when necessary, correlations available in the literature for calibration.

An experimental matrix of nine test points with different injection pressures and combustion chamber densities has been performed. A critical analysis of the different error sources for proper quantification is made. Results have shown that macroscopic features can be accurately determined using the PLIEF technique, but for fuel concentration measurements special considerations have to be taken into account, particularly in the regions where liquid and vapor coexist.     

Effects of wall slip and temperature jump on heat and mass transfer characteristics of an evaporating thin film

A new mathematical model is developed to predict heat and mass transport characteristics of the evaporating thin film. The model considers effects of velocity slip and temperature jump at the solid-liquid interface, disjoining pressure, and surface tension. Three-dimensional nonequilibrium molecular dynamics simulations for coupling between the momentum and heat transfer at the nanoscale solid-liquid interface are performed to obtain the slip length and interfacial thermal resistance length. It is found that both slip length and interfacial thermal resistance length decrease significantly with the decreasing interface wettability of the liquid to the wall. Velocity slip and temperature jump at the solid-liquid interface intend to reduce the superheat degree of the evaporating thin film, and thus result in a sharp decrease of the heat and mass transport characteristics of the evaporating thin film. It is also noted that velocity slip and temperature jump at the solid-liquid interface show a more pronounced effect as the superheat degree increases.     

乳化沥青残留物获取方法和技术要求试验研究

研制了乳化沥青蒸馏器，用蒸馏法和蒸发法分别提取乳化沥青残留物，对残留物性能进行了试验比较。对我国乳化沥青残留物获取方法及技术要求提出了修订建议。     

铜吹炼转炉余热汽化冷却汽包水位的自动控制

通过与其他工业锅炉汽包水位控制方法的比较，提出铜吹炼转炉余热汽化冷却汽包水位控制系统，介绍其实现方法。     

基于力控的管内蒸发、冷凝实验台测控系统开发

采用力控软件为开发平台,对单管管内蒸发、冷凝试验台的监控系统进行开发。介绍了实验台的原理及总体控制设计,并详细说明了软件各部分的功能。     

汽车空调蒸发风机与专用逆变器系统的研制

汽车空调蒸发风机与专用逆变器系统是机电一体化产品.其逆变器依据正弦波脉宽调制(SPWM)技术,主电路采用三相双极性逆变桥式电路,逆变管采用电力场效应晶体管.控制电路采用了数字集成电路.实现将汽车内的直流电压变换为电压、频率可调的三相正弦交流电压,带动三相异步电动机.