氟聚合物加工助剂在HDPE挤出中的应用初探

通过毛细管转矩流变仪对氟聚合物加工助剂在HDPE挤出中的研究试验发现,在HDPE挤出中加入含氟聚合物加工助剂(PPA),可以极大地降低体系的出口压力;同时使体系的粘度也有所降低,提高挤出效率。试验还发现,含氟聚合物加工助剂PPA与分散剂共用,有利于建立平衡时间的缩短,对加工转矩和体系粘度的影响不明显。     

高流动PVC树脂的结构性能研究

通过对高流动PVC树脂的微观结构、流变性能和力学性能的研究，确定了高流动PVC树脂的结构特点、加工范围。加工应用试验结果表明该树脂既有较高的流动性又有良好的力学性能。     

工业陶瓷超声辅助加工技术研究

陶瓷材料具有耐高温、硬度高、绝缘性好的优良性能,在航空航天、军事医疗、电子信息等领域具有广泛的应用。旋转超声辅助加工的刀具磨损小、材料去除率高、加工精度高,在工业陶瓷精密加工领域取得了较好的运用。本文以常用的石英陶瓷和氮化硅陶瓷为加工对象,进行了表面磨削及钻孔试验研究,通过宏观形貌观察、测量表面粗糙度值、工件及刀具微观形貌分析,确定了PCD砂轮结合超声辅助磨削加工,可以得到较好的表面加工质量。开展了石英陶瓷凹槽面、平面及过渡面的磨削加工试验,取得了较好的表面形貌;利用不同类型的砂轮加工氮化硅陶瓷孔,从而确定高强度的金刚石磨头是加工硬性材料的最优砂轮。     

陶瓷结合剂金刚石砂轮在加工PCD刀具中的优越性

通过陶瓷结合剂、树脂结合剂、金属结合剂金刚石砂轮在磨削加工PCD77具中的应用，获得了一些具有对比性的试验结果。通过对试验结果的分析，发现陶瓷结合剂金刚石砂轮在加工PCD刀具上同树脂结合剂和金属结合剂相比具有：磨削效率高、耐用度高、加工成本低的特点。     

矿用载重子午线轮胎胎面胶配方优化

对矿用载重子午线轮胎胎面胶配方进行优化。结果表明：通过调整配方体系中炭黑的种类和用量以及硫化体系和活化体系对胎面胶配方进行优化,胶料的加工安全性大幅提高,拉伸强度、拉断伸长率、撕裂强度、抗切割性能和耐磨性能明显提高,压缩疲劳温升降低;采用优化试验配方制备的成品轮胎耐久性能大幅提高,与生产轮胎相比较使用寿命提升,经过6个月的实际道路测试,试验轮胎胎面光滑平整,割口明显减少。     

用氢化丁腈橡胶制作橡胶密封制品

阐述了氢化丁腈橡胶的基本性能;通过对硫化体系、碳黑补强剂、防老剂等进行选择性试验,确定了橡胶配方;通过工艺试验,确定了产品加工工艺条件;产品性能试验及应用结果表明氢化丁腈橡胶具有良好的耐热、耐油、耐臭氧性能和低压缩永久变形性,其性能与氟橡胶相近;用氢化丁腈橡胶可替代氟橡胶制作汽车发动机曲轴油封.     

高粘着性薄膜的生产工艺

本文概述了用分散粒子改性的高粘着性薄膜的加工方法及加工设备,并通过试验说明该种薄膜的粘着强度及其应用。     

全钢子午线轮胎上三角胶配方设计研究

从硫化体系、增塑体系、加工助剂三方面对全钢子午线轮胎上三角胶配方进行优化设计研究,通过小配合试验、大配合试验、试制胎机床试验,对优化后的配方进行全面性能测试,结果表明：调整硫化体系,提升多硫键含量,在不影响工艺操作性能的前提下,减少芳烃油用量,减少增粘树脂的用量,能显著提升上三角填充胶料的耐疲劳性,轮胎的胎圈耐久性能得到提升。     

国内外高透明聚乙烯薄膜专用料生产技术现状

论述了聚乙烯薄膜雾度产生的机理和影响因素,综述了国内外聚乙烯生产企业和研究单位通过改变共聚单体类型、改变催化剂体系、优化助剂配方、优化加工工艺生产高透明聚乙烯薄膜专用料的方法,通过对比发现,优化助剂配方和优化加工条件生产高透明聚乙烯薄膜专用料,操作简单灵活,不需要对工业化生产装置做大的改动,是高透明聚乙烯薄膜专用料最容易工业化推广的方法,为高透明线性低密度聚乙烯(LLDPE)薄膜专用料的开发提供技术参考。     

三螺杆挤出机中剪切-拉伸交变流场对PP/PE-HD体系增韧效果的影响

利用倒三角形排列三螺杆挤出机与传统双螺杆挤出机对不同黏度比的聚丙烯/高密度聚乙烯(PP/PE-HD)体系进行混炼加工,研究了三螺杆挤出机中剪切拉伸交变流场对于高黏度比聚合物两相体系的分散混合及分布混合效果的影响;并通过高黏度比体系的混合效果证明三螺杆挤出机中剪切拉伸交变流场的作用效果及机理。结果表明,在高黏度比体系的加工中,倒三角形排列三螺杆挤出机分散与分布混合效果明显优于双螺杆挤出机,且三螺杆挤出机的增韧效果随着体系黏度比的增大而提升。     

隔热、防腐蚀、装饰涂层体系在车载式安全检查设备上的应用研究

通过太阳光照射试验和碘钨灯模拟太阳光照射试验,获得了“环氧底漆＋环氧中间漆＋太阳热反射辐射双组分丙烯酸涂料”和“环氧底漆＋环氧中间漆＋阻隔型水性隔热涂料”所形成的复合隔热涂层试验数据;设备外表面的隔热涂层通过了耐盐雾、耐酸碱、耐湿热、光泽等性能检测,可以实现产品对涂层体系隔热、防腐蚀、装饰的技术要求。探索出实施复合隔热涂层的工艺过程和操作方法,为车载式安检设备的生产积累了经验。     

基于LabVIEW的风洞试验控制系统设计

按照风洞试验系统的试验要求,使用LabVIEW作为开发工具,将虚拟仪器技术与测试技术结合起来,建立了集试验系统、数据采集、存储与分析为一体的紧凑式换热嚣性能测试系统.     

基于FPGA的高温热流传感器信号采集系统设计

介绍了基于FPGA的高温热流传感器信号采集存储系统.系统使用XC2S50作为主控制芯片,实现了对高温热流传感器测量信号和温度信号两路模拟量数据的采集,并将获得的数据混合编帧存储.实验证明,该系统能够完整获得热流传感器的测试信号及其温度信号,具有电路简单、采集精度高、稳定性高等特点.     

Improving the performance of a thermoelectric power system using a flat-plate heat pipe

A gravitational flat-plate heat pipe is designed and fabricated in this paper to serve as a heat spreader to diffuse the local heat source to the hot side of the thermoelectric power module. Based on this, an experimental test for the thermoelectric power generation system is conducted to study the influences of the heat spreader on the temperature uniformity and power generation performance when exposing to a local heat source. In addition, the effects of the heating power, inclination angle, and local heat source size on the power generation performance of the thermoelectric power module using a flat-plate heat pipe as a heat spreader are examined and compared with that using a metal plate. The results indicate that the gravitational flat-plate heat pipe has considerable advantages over the metal plate in the temperature uniformity. The superiority of temperature uniformity in the improvement of power generation performance for the thermoelectric power system using a heat pipe is demonstrated. Particularly, the heat pipe shows good adaptability to placement mode and the local heat source size, which is beneficial to the application in the thermoelectric power generation.     

低粘度高耐热环氧树脂组成物研究

在改性酸酐固化的环氧树脂体系中,加入非环氧类低粘度活性交联剂,得到了室温下粘度仅为80mPa·s的酸酐 环氧树脂体系。利用正交试验优选了树脂配方,该树脂体系在有效降低粘度的同时,还提高了耐热性,优选配方树脂体系的热变形温度达到265℃。该树脂体系适用于RTM(ResinTransferMolding)成型工艺制备高性能复合材料及电器设备的灌封。     

密闭式纯水循环冷却系统热负荷试验方法的探讨

以空气散热器热平衡试验为基准,来验证密闭式纯水冷却系统的散热性能是否满足设计及使用要求。在密闭式纯水循环冷却系统出厂前,应用热负荷试验装置模拟换流阀冷却过程,并通过多方位的数据采集及处理,以达到提前把握产品实际散热功率、预防散热能力不足并及时进行有针对性改善的目的。同时也为设计人员提供了一定设计参考,可以更高效地完成设计工作。     

板式换热器热工测试板片微变形问题的探讨及应对措施

通过对板式换热器流体阻力特性试验研究,探讨了由于板片微变形引起的压降检测结果的差异性。并针对该问题提出处理对策,推出一种新型板式换热器液相介质压降测试系统,为压降检测工作提供借鉴。     

Investigation of flow boiling in circulating three-phase fluidised bed: Part I: Experiments and results

In flow boiling apparatus, fouling is frequently a problem. Mechanical methods to mitigate fouling include the impact of solids on the deposit to remove it. Solid particles fluidised by the two-phase boiling mixture may accomplish sufficient deposit removal to keep boiling surfaces clean. This results in a self-cleaning fluidised bed boiling heat exchanger. The particles additionally enhance the heat transfer. In this paper, a comprehensive investigation of three-phase fluidised flow boiling in a circulating system is presented. A test apparatus which is a three-phase circulating fluidised bed was built with glass construction to visualise boiling phenomena in a water system. It could also be operated as a two-phase system and this was investigated to provide the basis for comparison and also to verify reproducibility and confirm well-established flow boiling results. For the three-phase system (where steel particles were added), a range of liquid flowrates and heat fluxes was used and three different particle sizes were investigated. Three-phase results were compared with two-phase results. This work is primarily a study of boiling heat transfer enhancement as a result of addition of particles, but the effect of the particles creating a self-cleaning heat exchanger is a significant operational advantage for industrial application.As expected, heat transfer coefficients were higher overall for the three-phase system than for the two-phase system. The onset of nucleate boiling was independent of heat flux and the heat transfer coefficient initially increased with increasing Reynolds number whereafter there was some deterioration of heat transfer. Visualisation of boiling heat transfer phenomena for the three-phase system is also provided which allows mechanistic explanations of the measured phenomena.In Part II of this paper, a correlation is developed, based on boiling heat transfer modelling, to describe heat transfer during boiling in a three-phase circulating fluidised bed. A flow-dependent function is added as is a boiling heat transfer enhancement factor. This correlation is validated against this experimental data and found to show agreement within about 20% and better agreement with the data than an existing correlation.     

Prediction of heat release in the single burning item test

This paper presents a modification of an existing mathematical model that uses cone calorimeter test results to predict heat release rate in the single burning item (SBI) test. A method for classification of cases based on multivariate statistical analysis is incorporated in the modified model. This makes it possible to determine the development of the heat release curve in the SBI test with better precision than the original version was able to. The model has been applied to 100 cases of cone calorimeter test results from 33 different products. For most of the products the predicted shape and level of the heat release curves are close to measurements in the SBI test. Using the predicted heat release results as input to calculation of FIGRA_0.2MJ and THR_600s within the new European system for reaction‐to‐fire classification, we were able to predict membership of the correct class in 90% of the analysed cases. Copyright © 2002 John Wiley & Sons, Ltd.     

EXPERIMENTAL STUDIES ON A NOVEL CHEMICAL HEAT PUMP DRYER USING A GAS–SOLID REACTION

The authors have been studying Chemical Heat Pumps (CHP) from the viewpoints of energy saving and environmental impact. The CHP can store thermal energy in the form of chemical energy by an endothermic reaction, and release it at various temperature levels during heat demand periods by exo/endothermic reactions. The authors have proposed in an earlier study a novel chemical heat pump (CHP) system for environmentally-friendly effective utilization of thermal energy in drying as a chemical heat pump dryer (CHPD). In this exploratory study, we test the effectiveness of operating the proposed CHPDs experimentally. Basic experiments on the CHPDs such as hot dry air production for convective drying are performed on lab-scale CHPD apparatuses using gas–solid reactions in calcium oxide/calcium hydroxide reactant beds. The proposed CHPDs are found to produce hot air by CHP operation for drying. The temperature levels of the produced hot air and the reaction rates/conversions are as good as in the case of hot water supply system using basically same CHP operation. The cold heat for air dehumidification is also found to be generated/recovered by the same CHPD system. The generated heat amounts can be increased by changing the operating conditions although the heat recovery must be enhanced for practical application of CHPDs.