节点文献
材料冻粘特性及矿车冻粘规律试验研究
Experimental Research on Material Freezing Adhesive Characteristic and Tramcar Freezing Adhesive Law
【作者】 金敬福;
【导师】 丛茜;
【作者基本信息】 吉林大学 , 农业机械化工程, 2004, 硕士
【摘要】 早在 20 世纪 30 年代,随着飞机技术的快速发展,冻粘现象就成为制约飞机技术发展的严重阻碍。以此为契机很多行业和领域开始关注冻粘现象,并进行了大量的冻粘机理及其防冻粘技术的研究。冻粘作为低温下普遍存在的现象,给我们的生活与生产活动带来了诸多不便。据观察由于冻粘现象而引起的各种消耗、事故远远高于一般情况。如有关资料显示,在煤矿行业中由于在冬季煤矿中矿车以及煤本身冻结等缘故,其工作效率与正常情况下相比明显降低,造成煤炭产业虚实比达 20-40%。再如冬季路面积雪结冰现象是交通部门面临的急需解决的问题,冬季路面结冰使事故增加,交通堵塞,造成运输效率严重下降。由于冬季路面打滑而造成的交通事故,每年损失高达十几亿元人民币。此外机械机构由于冻粘而引起的工作阻力变大,机械故障、事故也常有发生。因此,冻粘现象及其防治技术的研究尤为重要。揭示冻粘机理,探求有效、实用的冻粘防治技术是冻粘理论研究的最终目的。本文以常用工程材料冻粘特性研究入手分析冻粘形成规律及特点,通过对矿山行业的冻粘现象与规律研究,分析矿车冻粘机理并对铝质材料的冻粘特性进行应用试验研究。二、冻粘理论一种现象的研究离不开相关理论分析。我们对冻粘现象的观察发现,冻粘现象主要以结霜、固体表面结冰积雪、物料冻结以及材料之间的冻粘粘接形式存在。其中固体表面上的冰粘附(结冰)现象作为最为典型的冻粘现象,冻粘的研究主要以此为对象进行。冻粘是一种特殊环境下的粘附现象。温度与水份是冻粘形成最主要的因素,其中温度条件是区别于一般粘附的因素,是形成冻粘的根源。冻粘形成过程是系统从一个不稳定状态进入稳定状态的过程。分析表明材料的表面特性及热特性对冻粘效应有影响。 -60 -<WP=65>吉林大学硕士学位论文冻粘界面层由界面粘结层和粘附冰层组成,二者中强度较低的一层决定冻粘强度。多数的冻粘试验表明,界面粘结层的强度远远高于粘附冰层的强度,并且冰的强度决定于内部结晶状态及结构。而冰的结晶形态及结构,主要受到冻结方式及杂质因素的影响。三、材料冻粘特性试验研究材料的一些重要的物理、化学性能参数对表征不同材料各种性能差异、指导工程设计与制造具有重要意义。但是到目前为止,工程中尚没有对材料的抗冻粘能力进行评价,也没有定义相关表征系数,提供相关测试仪器。基于上述原因,本文就工程中常用材料提出了材料冻粘系数 (用 C 表示)的概念,研制了冻粘力测试仪。并对几种工程材料进行了试验研究,分析了材料特性对冻粘效应的影响。定义的材料冻粘系数测定公式如下: 法向冻粘系数 cσ = σ = F1 / S (1) 切向冻粘系数 cτ = τ = F2 / S (2)式中: F1- 法向拉脱力,单位为kg ; F2- 切向拉脱力,单位为kg ; S - 冻结界面的面积,单位为cm2。图 1 是冻粘力测试仪结构图。测试仪可以通过不同的夹具完成 螺旋操纵杆 仪器框架法向、切向冻粘强度测试。 纵向定位板(1)图 2 是测试所得的 6 种材料的 纵向定位板(2) 换向板冻粘系数对比图。从材料冻粘系数 联结器(1)柱状对比图中可知,铝合金材料具 横向定位板有很好的防冻粘特性,非金属柔性 拉力传感器 联结器(2)材料橡胶及一定粗糙度的毛化玻 试样容器璃也表现出很好的防冻粘特性。金 试样固定板 仪表箱属材料的 Q235 和光滑硬基底材料 调平螺栓 试样材料馈线如光滑玻璃有很高的冻粘粘附系 图 1 试验仪器结构图数,作为低能表面材料的 PTFE 材 - 61 -<WP=66>摘 要料也有较高的冻粘系数。 3.5 3 法向 ) 2 2.5 2 切向 kg/cm 1.5 1 强度( 0.5 0 PTFE Q235 铝合金 光滑玻璃 毛化玻璃 橡胶 图 2 几种材料冻粘系数对比柱状图 试验中对冻粘破坏界面形态的观察分析证实了冻粘破裂形态决定冻粘强度的理论。大部分材料的冻粘破裂发生在粘结冰层内部,从破裂形态对比中发现,破裂形态与冻粘强度有关。如铝合金(切向冻粘强度 0.07kg/cm2),毛玻璃(切向冻粘强度 0.69kg/cm2),Q235(切向冻粘强度 2.20kg/cm2)破坏界面形态分别为材料表面光滑脱离,粘附冰层内部颗粒状破裂脱离,粘附冰层内部凸包状破裂脱离。四、矿山冻粘现象与规律及防治技术研究 矿山中的冻粘现象影响矿山生产效率。根据在冬季对矿山的实地考察发现,由于产生冻粘使矿山的工作效率下降 60%,能源消耗增加 30%以上。矿山中的冻粘问题主要表现在运煤矿车与煤冻粘。因此对矿车冻粘现象及规律的研究就成为矿山中防冻粘问题的重点。 铝内衬矿车
【Abstract】 Introduction Freezing adhesive has been a serious restriction to the airplane from 20century 30s, so there are many scholars attend this problem and study itsmechanism and prevention skills. Freezing adhesive, which is a common phenomenon, brings muchinconvenience. According to observing, all kinds of consuming andaccidents brought by freezing adhesive are very serious. For example, workefficiency is obviously lower because of freezing adhesive of tramcar andcoal in winter, and the ratio between false and true is 20-40%. Take anotherexample, in winter, ice freezing on road, which is seriously unresolvedproblem faced by ministry of communications, causes increasing accident,traffic jam and low transport efficiency. Traffic accidents caused by roadsurface skid in winter cost ten hundred millions every year. In addition,because of freezing adhesion, machine resistance caused by becomes big,at the same time, troubles and accidents constantly happen. So studying thefreezing phenomenon and preventing skills is very important. The objectiveis discovering freezing mechanism and searching efficient and appliedpreventing skills. According to analyzing the forming law and characteristic of freezingadhesive, tramcar freezing adhesive law can be discovered in this paperincluding Experimental research on aluminum material freezing adhesivecharacteristic.Freezing adhesive theory According to studying freezing adhesive phenomenon, we can know itexists as frost, icing snow on solid surface, materiel freeze and freeingconnecting. The main study objective is icing on solid surface that is most - 64-<WP=69>吉林大学硕士学位论文typical freezing adhesive phenomena. Freezing adhesive whose two main forming factors are temperature andwater content is an adhesive phenomena. And temperature plays a vital rolein its forming. The course of forming freezing adhesive is changing coursefrom the astaticism to the stabilization. The freezing adhesive domino effectcan be influenced by material surface characteristic and heat characteristic. Freezing adhesive interface layer is composed of interface adhesivelayer and adhesive ice layer, which lower intention decides its intention. Asfreezing adhesive examinations show, interface adhesive intention is higherthan adhesive ice layer intention that is decided by interior crystal state andconfiguration affected by freezing manner and impurity factor.Experimental research on material freezing characteristic Some physical and chemical function parameters of material haveimportant meanings for characterizing function difference of differentmaterial, guiding engineering design and manufacture. However, there areno evaluations for anti-freezing capability, defining pertinent characteristicparameters and pertinent testing instrument. Because of above all, thisarticle puts forward concept of material freezing adhesive coefficient(denoted by C) for some common material in engineering and explodesfreezing adhesive test. According to analysis of material character andfreezing adhesive affection the definition of material freezing adhesivecoefficient is as follow: Normal freezing adhesive coefficient cσ = σ = F1 / S (1) Tangent freezing adhesive coefficient cτ = τ = F2 / S (2) Annotate: F1—Normal dragging and doffing force ,unit kg; F2—Tangent dragging and doffing force, unit kg; S—Area of freezing interface, unit cm2 . Fig.1 is the layout of the test principle. It is able to test normal andtangent freezing adhesive with different clamp. - 65 -<WP=70>Abstract 1 2 3 4 5 6
【Key words】 Freezing adhesive; Material; Freezing adhesive coefficient; Adhesive force; Tramcar;
- 【网络出版投稿人】 吉林大学 【网络出版年期】2004年 04期
- 【分类号】TD52
- 【被引频次】39
- 【下载频次】479