人人文库网 > 图纸下载 > 毕业设计 > CA10B解放牌汽车调整臂外壳工艺规程及专用夹具设计【车φ60孔及端面】【钻φ13.8和φ16沉孔】【说明书+CAD+3D】
CA10B解放牌汽车调整臂外壳工艺规程及专用夹具设计【车φ60孔及端面】【钻φ13.8和φ16沉孔】【说明书+CAD+3D】
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车φ60孔及端面
钻φ13.8和φ16沉孔
说明书+CAD+3D
CA10B
解放
汽车
调整
外壳
工艺
规程
专用
夹具
设计
60
端面
13.8
16
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说明书
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CA10B解放牌汽车调整臂外壳工艺规程及专用夹具设计【车φ60孔及端面】【钻φ13.8和φ16沉孔】【说明书+CAD+3D】,车φ60孔及端面,钻φ13.8和φ16沉孔,说明书+CAD+3D,CA10B,解放,汽车,调整,外壳,工艺,规程,专用,夹具,设计,60,端面,13.8,16,沉孔,说明书,CAD
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青岛理工大学机械加工工序卡产品型号产品名称 解放牌汽车车间金工毛坯种类铸造设备名称卧式车床夹具编号专用夹具JJ-C01工位器编号工步号工步名称工艺装备描图1粗车大端两端面至厚34mm端面车刀2半精车大端端面至厚度32mm端面车刀3粗车50至57外圆车刀4半精车57至60外圆车刀描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK02零件名称前刹车调整臂外壳共 页第 1 页工序号工序名称材料牌号1车削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数C620-1CM-011夹具名称切削液车床夹具工位器具名称工序工时准件单件127.5主轴转速/(rmin-1)切削速度/(mmin-1)进给量/（mmr-1）背吃刀量/mm进给次数工时/s机动单件/s18537.750.5125718537.750.5125715025.910.713.519.615025.910.711.513.9设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-C01工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式铣床夹具编号专用夹具JJ-X01工位器编号工步号工步名称工艺装备描图1铣小端面直柄铣刀描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK03零件名称前刹车调整臂外壳共 页第 2 页工序号工序名称材料牌号2铣削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数X5012XM-011夹具名称切削液 铣床夹具工位器具名称工序工时准件单件49.2主轴转速/(rmin-1)切削速度/(mmin-1)进给量/（mmmin-1)背吃刀量/mm进给次数工时机动单件/s13016.20.152249.2设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-X01工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式钻床夹具编号专用夹具JJ-Z01工位器编号工步号工步名称工艺装备描图1钻11麻花钻112扩12扩孔钻12铰12高速钢铰刀描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK04零件名称前刹车调整臂外壳共 页第 3 页工序号工序名称材料牌号3钻削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数Z535ZM-011夹具名称切削液钻床夹具工位器具名称工序工时准件单件12.9主轴转速/(rmin-1)切削速度/(mmin-1)进给量/(mm/r)切削深度/mm进给次数工时机动单件/s96033.160.321214.6853019.970.51214.510021213.6设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-Z01工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式铣床夹具编号专用夹具JJ-X01工位器编号工步号工步名称工艺装备描图1铣方槽至宽26mm圆柱铣刀2铣方槽至宽26mm圆柱铣刀描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK05零件名称前刹车调整臂外壳共 页第 5 页工序号工序名称材料牌号4铣削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数X5012XM-011夹具名称切削液铣床夹具工位器具名称工序工时准件单件46.3主轴转速/(rmin-1)切削速度/(mmin-1)工作台进给量/mmin-1)背吃刀量/mm进给次数工时机动单件/s3553.91652132.733553.94000.5113.5设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-X01工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式铣床夹具编号专用夹具JJ-X02工位器编号工步号工步名称工艺装备描图1铣凸台1直柄铣刀2铣凸台2直柄铣刀3铣凸台3直柄铣刀描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK06零件名称前刹车调整臂外壳共 页第 6 页工序号工序名称材料牌号5铣削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数X5012XM-011夹具名称切削液铣床夹具工位器具名称工序工时准件单件122.4主轴转速/(rmin-1)切削速度/(mmin-1)进给量/(mm/r)背吃刀量/mm进给次数工时机动单件/s13016.20.152240.813016.20.152240.813016.20.152240.8设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-X02工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式钻床夹具编号专用夹具JJ-Z02工位器编号工步号工步名称工艺装备描图1钻13孔至12麻花钻2扩13孔至13扩孔钻3铰13孔高速钢铰刀4钻13.8孔至13麻花钻5扩13.8孔至13.8扩孔钻描校6铰13.8孔高速钢铰刀7钻16至15麻花钻底图号8扩16至16扩孔钻9装订号101112标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK07零件名称前刹车调整臂外壳共 页第 7 页工序号工序名称材料牌号6钻削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数Z535ZM-011夹具名称切削液钻床夹具工位器具名称工序工时准件单件55.9主轴转速/(r/min-1)切削速度/(m/min-1)进给量/(mm/r)切削深度/mm进给次数工时机动单件/s75033.160.3224110.2553019.970.524110.21022411075033.160.323417.7553019.970.53417.0110023417.275033.160.32211.7553019.970.5212.48设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-Z02工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式钻床夹具编号专用夹具JJ-Z02工位器编号工步号工步名称工艺装备描图1钻孔9麻花钻2攻M10螺纹丝锥描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK08零件名称前刹车调整臂外壳共 页第 8 页工序号工序名称材料牌号7钻削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数Z535ZM-011夹具名称切削液钻床夹具工位器具名称工序工时准件单件31.9主轴转速/(rmin-1)切削速度/(mmin-1)进给量/mm切削深度/mm进给次数工时机动单件/s96033.160.322415.4739212.30.310226.4设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-Z02工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式钻床夹具编号专用夹具JJ-Z01工位器编号工步号工步名称工艺装备描图1钻54麻花钻2扩54.3扩孔钻铰54.3高速钢铰刀描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK09零件名称前刹车调整臂外壳共 页第 9 页工序号工序名称材料牌号8钻削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数Z535ZM-011夹具名称切削液钻床夹具工位器具名称工序工时准件单件178.4主轴转速/(rmin-1)切削速度/(mmin-1)进给量/(mm/r)切削深度/mm进给次数工时机动单件/s110013.80.11121109110014.850.512121.27100112148设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-Z01工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称立式钻床夹具编号专用夹具JJ-Z03工位器编号工步号工步名称工艺装备描图1钻Rc1/8 锥孔锥形钻2攻螺纹丝锥描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK10零件名称前刹车调整臂外壳共 页第 10 页工序号工序名称材料牌号9钻削KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数Z535ZM-011夹具名称切削液钻床夹具工位器具名称工序工时准件单件49.4主轴转速/(rmin-1)切削速度/(mmin-1)进给量/（mmr-1）切削深度/mm进给次数工时机动单件/s19560.2522244.339212.30.52215.1设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号专用夹具JJ-Z03工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称锉刀夹具编号工位器编号工步号工步名称工艺装备描图1去毛刺锉刀描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK11零件名称前刹车调整臂外壳共 页第 11 页工序号工序名称材料牌号10去毛刺KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数CD-011夹具名称切削液工位器具名称工序工时准件单件120主轴转速/(rmin-1)切削速度/(mmin-1)进给量/mm背吃刀量/mm进给次数工时机动单件/S120设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号工位器编号青岛理工大学机械加工工序卡产品型号CA10B产品名称解放牌汽车车间金工毛坯种类铸造设备名称夹具编号工位器编号工步号工步名称工艺装备描图1检查游标卡尺等描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK12零件名称前刹车调整臂外壳共 页第 11 页工序号工序名称材料牌号11检验KT350毛坯外形尺寸每毛坯可制件数每台件数159883611设备型号设备编号同时加工件数1夹具名称切削液工位器具名称工序工时准件单件60主轴转速/(rmin-1)切削速度/(mmin-1)进给量/mm背吃刀量/mm进给次数工时机动单件/S60设计（日期）审核（日期）标准化（日期）会签（日期）签字日期夹具编号工位器编号青岛理工大学工艺加工工艺过程卡产品型号CA10B产品名称解放汽车材料牌号KT350毛坯种类 铸件毛坯外形尺寸1598836每毛坯可制件数工序号工序名称工序内容车间1铸造铸造毛坯铸造车间2车削车大端端面，60孔金工3铣削铣小端端面金工4钻削钻扩铰12孔金工5铣削以60孔，12孔和端面，一面两销铣方槽金工6铣削以60孔，12孔和端面，铣三个凸台金工7钻削钻扩铰13孔，13.8孔，16孔金工8钻削钻攻M10螺纹金工9钻削钻扩铰54.3金工10钻削攻Rc1/8锥孔金工11钳工去毛刺金工描图12检验终检金工描校底图号装订号标记处数更改文件号签字日期标记处数更改文件号零件图号831012TZBWK01零件名称汽车前调整臂外壳共 1 页第 1 页1每台件数1备注工段设备工艺装备工时准终单件/sC620-1专用夹具JJ-C01C620-1专用夹具JJ-C01127.5X5012专用夹具JJ-X0149.2Z535专用夹具JJ-Z0112.8X5012专用夹具JJ-X0146.3X5012专用夹具JJ-X02122.4Z535专用夹具JJ-Z0255.9Z535专用夹具JJ-Z0231.9Z535专用夹具JJ-Z01178.4Z535专用夹具JJ-Z0349.412060设计（日期）审核（日期）标准化（日期）会签（日期）签字日期 夏亮亮20100501附件1用于金属切削的空冷技术-布赖恩博斯韦尔和蒂拉克机械工程学系，科廷科技大学，邮政总局信箱U1987，西澳大利亚珀斯6845摘要：空气冷却干燥加工都是切割金属行业为处理长期运行时为延长刀具寿命，降低机床故障和尽量减少在刀尖产生的热量等问题进行试验所获得的可能的解决方案。迄今为止，这个行业仍不得不使用大量昂贵的会造成环境破坏和健康危害的冷却剂。如今，干加工引入金属切削行业的目的是不懈地努力减少加工费用和化学物质对环境的影响。现代加工工具已经有能力维持其刀刃在较高温度下切割，然而即使有了这种改善，切削刃最终也会损坏。应用冷空气吹入这些现代工具的结合面也将有助于延长工具寿命，减少切削损失。空气干燥加工被用于到工具界面在这篇文章中认为有可能替代有害液基冷却。然而，低对流散热率与传统空冷相关方法一般是不足以及时散掉激烈的切割产生的热量，适当的能够提高冷却的过程方法，还没有建立起来。引言 本研究旨在探讨一种被称作朗克，希尔施涡旋管的，在加工过程中用于冷却的有效设备。该朗克- 希尔施涡旋管的影响是在30年代初，它的发明引起了很大轰动，因为它表明，通过压缩空气一管有可能产生热冷空气。起初 人们很难相信，这种装置可以产生热空气和冷空气并且达到有用的流量。涡旋管一个没有移动部件，简单的装置同时生产冷，热空气流。但是，到目前为止，很少有确定利用冷却工具涡流管的效率的研究。因此，为确定在刀刃上的热效率转移过程的一系列实验调查已经开始进行了。这些试验将确定最合适的参数使用，如冷和热空气的质量流量，冷热管直径、长度，和可实现的冷空气最低气温。风冷从未被制造业采用是由于这样一个事实，多年来，传统的切削液已被证明是在机械加工冷却过程中有效的方法。这项研究结果将证明，在很多加工设备中，空气冷却都可以取代传统的切削液，不会减少刀具寿命或也不会造成工作质量的下降或是影响工件表面的完成。给工件表面提供冷空气的朗克，希尔施涡旋管的使用说明表明提高空冷性能的重要。刀具结合界面的温度记录清楚地表明，刀刃的温度有显著的减少。用显微镜观察可发现，这种温度减缓降低了机械齿面的磨损。因此，当刀面用风冷时，监测后刀面磨损的发展情况，显示着被延长了的刀具寿命。该朗克，希尔施涡管1是一个了不起的设备，它能够同时独立为两个不同的气流，一股比进来的空气热和另一股比进来的空气冷，其间没有任何移动部分参与。该设备分离产生的冷空气和热空气穿过涡流管时的温度是尚未完全清楚。这是一个被称为麦克斯韦妖怪，一个幻想不经任何工作就能分离热量的装置。这种涡管基本上包括三个管和一个使压缩空气在冷管处的温度较低的供应装置。朗克2试图利用这种无运动部件就能产生热空气和冷空气的奇怪设备的商业潜力。不幸的是，这家合资公司失败了，涡流管也因此变得无人问津。该装置把冷传到热所依据的能量转移原理仍然很难理解。然而，对于这个基本物理现象有一场辩论，尽管大多数研究者认为该设备是基于互动动荡，可是由压缩和剪切的工作过程，却表现出浦大卫的戴斯勒和3分析。最近，研究分为两类。第一 类称为外部研究关注与该管的性能。它是发现 Gulyaev 4，该比例最低的长度管的直径是13。其他的研究建议40比50为最佳运作。至于隔膜，最适尺寸是2:3的比例膜片直径管的直径。涡流管由三个重要部分组成，空气进入到旋涡发电机（这增加了空气的速度）的中间部分，冷轧管，热管，如图1所示。通常热管是约350毫米长，并在底部有一个锥形阀控制流出的热空气量。涡流发生器的右侧是冷轧管出口。涡流发生器和冷轧管之间有个中心带有可以很容易改变大小的孔的隔膜，。带有可大可小孔的隔膜还可以增加或减少在寒冷的出口所得的温度。考虑到上述涡管，压缩空气以声波速度供应到圆形管，并产生一个每分钟1万转气旋（涡流）。空气是被迫自旋进入中心，在那里它然后沿着热管当前最不抵抗气流的道路逃离。旋转的空气，因为它继续沿管前行，直到它达到了锥形阀的地方变成了旋转的空气柱（涡部分内部本身）。较慢的内空气柱的旋转流动的空气放弃了它的热量，让其更快的旋转到空气柱外。寒冷的空气撞倒正奉命出的涡流发生器的旋转空气并且冷端的热空气耗尽流出的涡流管的另一端。调整锥形阀将内置闷热的空气排出可以改变这两个温度，空气流低至-55 C的由图所示。涡流理论 目前没有人能确切地解释为什么涡管会如此运作：这个过程本身正如莱温和Bejan 6所述的那么简单。切向进气喷嘴对涡流发生器，因此可以提供一个高速旋转产生的气流旋涡。后来，有一径向温度梯度由管芯到管外壁增加。这是主要是因为空气的压缩势能转换为动能，由于附近空气中的外切向力矩进口形成的强迫涡。因此，高速旋转内流管，远离墙壁产生。涡旋内的热管现有的空气，通常与大气温度相等，当旋转气流的涡管流进它就扩大了，但其温度下降到比环境温度低。两气温的区别将导致温度梯度沿管生产比周围空气的核心更冷的空气。因此，中央空气分子将失去热将到达外部区域，如图所示3。值得注意的是，该系统是一个动态的系统由于对管内气流的性质，因此将无法达到平衡。因此，周边的空气有较高的动能（温度超过内空气（冷）。一个主要的压力梯度由于在径向方向被迫涡将提供一个圆形旋转的向心力，因此这将导致高压的在管壁上，并低压在中心处。当空气进入到周边地区（A），随着它的膨胀，由于它的扩张外部空气得以冷却。因此，内核的空气（B）会得到温暖，因为它是由压缩周边膨胀的空气。然后转热从内核（B）到外核心（A）。由于内部空气被压缩，自然会尝试推着向周边膨胀。因此，处理外核的空气，然后加热，由于膨胀和压力的不同，这会导致对工作要做周围的空气得到不同结果收缩的空气。因此，热量转移径向向外图所示4。当空气继续沿管旋进产生的更多的分离能量将发生轴向对流，而使空气向热端移动。在这个进程中，将热量从核心转的空气移到外部空气。随着气流到达最热时，一小部分的空气将通过位于热端的锥形阀门排出，依靠临近中心的不良压力梯度，剩下的空气将在冷端旋转，如图所示5。其余部分的温暖的空气保持垂直流动，其运动方向要么是沿管道顺时针要么是逆时针。此外，这种气流 在管内核心的空气产生的气流的压力也较低。如果两空气流的角速度保持，这意味着任何两个取自图 4的粒子：示意图阵地周边和内部核心空气 图5：在涡管气流模式图无论是空气流将采取同样的时间才能完成围绕管周长一次循环。从角动量守恒原理，它似乎是在内核分子角速度将增加，见EQ： 公式表明，在内部的核心中，RA的值（径向距离测量中心在管中特别关注分子）很小，应该有一个相应的增加分子的角速度，以便让总的角动量守恒系统。此假设是微不足道，在管道内两任何空气分子的质量差异。然而，某一角速度在内部核心分子保持不变。这也就是说，在涡流管内的核心，角动量实际上已经失去了。由于热量转移到外的核心，对内核的角动量不保留或有更具体的跌幅，这将导致核心能量从内到外转移。内核的热能损失事外核心范围内的空气分子升温。因此，外核变热和内核变凉。 当达到热极限，通过热锥形阀和管壁（热插座）之间的小开口将周围的空气逸出。不过，中央的空气较冷，是由锥形阀轴偏转，并继续对从热端流向冷管。只有最里面的空气分子通过隔膜和从收集冷空气的出口溢出。因此，空气分子被分为冷流和热流通过涡流管的冷热两端。该图 6很好的绘出了涡流管。重要的是要注意，特别是在热端管发生分离。该锥形主轴（锥形阀），的目的是将一个寒冷的空气逆流到管轴向地区。该隔膜（孔另一方面）是用来挡周围的空气，使中央流会通过冷端溢出。涡管部件的缺少可能会造成这种错误的假设，这种现象是违反热力学规律的。事实上，如果没有在室温下做任何工作，空气流可以分为两个不同的蒸汽，这一冷一热划分工作，似乎违背了热力学第二定律。不过，关键是要提的是，尽管有这个误导的观念，可是物理保持不变。虽然，该涡管物理学是复杂的，但作为热力学的基本原理研究，可以帮助加深对涡流管内发生了什么进行更深入的了解。热力学第一定律是关于节约能源。根据这项规律，在系统之间的反应，它的环境，能源可以使从周围接收到该系统与从系统中传给周围的能量值相等。这种能量可以由两个不同状态显现：热和功。因此，对于每一个具体的控制体积热力学系统：图7：一涡管控制体积示意图制冷实际情况对于确定该冷却装置的性能系数是如此的重要。因此，确定性能系数的旋涡管和比较与传统制冷性能系数在使用它来确定它的效率，似乎合乎逻辑。涡流管可以用作制冷设备在寒冷的管壁是用来降低温度或作为加热装置，当热管墙是用来增加外壳温度。应该指出的是，对面是什么通常在热力学看，在这种情况下涡管是一个开放的控制储存装置。如果系统认为是稳定的状态，然后从第一定律热力学：其中，DH_是系统焓的变化和平行的演算法之间的系统及其周围环境的热量交换。让我们假定平行的演算法近似为零，即使冷轧管上可能有霜冻，热管是很温暖。如果是这种情况则：在那里，_Hc是冷流焓变化和_HH是热焓变流。假设为理想气体，总焓变的空气可以写为：其中，mc，在冷管的质量流量，氢是热管的质量流量，Tc是冷空气的温度，Ti是进风温度，Th是热空气的温度和Cp为空气比热在不断的压力和承担可逆的绝热过程。通过应用热力学第二定律上述： 其中，_S是总熵变，q是传热和T为绝对温度。在实际的稳态控制体积熵的变化是：熵变化的实际控制数量， 稳定状态是： 其中，_Sc和_Sh是从入口到出口的熵变的部分进入寒冷的空气管留下了，一部分是进入热管。对于理想气体（空气）比热，熵变化可以在那里我的下标，C和H分别进流，冷流和热流，R是理想气体（空气）保持不变。 自冷（或热外观）的影响时无运动部件将尝试管壁考虑为冰箱（或竞争此设备热泵），估计其系数性能（COP）是有效的。围绕冷却效果可以通过放置一个寒冷的管外壳，性能系数，可计算方法是：冷流通过冷管壁像热（换热器）由一些喜欢在一冷箱源（冰箱）和W在本案中是工作压缩完成从大气压力和空气温度对管的入口条件。 其中，T2是压缩机出口温度和T1是压缩机进气温度（可逆的，多方过程;空气量：N = 1.4）。如果我们考虑一个完整的系统，P1和T1的是大气压力和温度， P2和T2的是压缩机出口条件， 空气被压缩后，它在保持在高压状态，在当时它冷却大气温度，使音速喷嘴的入口温度T1，相当于T1的温度： 方程（23）可从T2的计算式。 （24）这是一个理想的工作值，它比所需的驱动器的实际工作较少于压缩机。通过考虑上述方程和使用的EQ（21），对涡流管性能系数可以决定的。 实验分析涡管设计为了帮助比较的涡管数参数是非常有用的使用质量分数为冷这是可以对比以上的涡管范围测试。此参数是简单的空气质量流量比率在管冷端进口处的压缩空气的平均流速，。重要的是要注意气团在管热端流率各不相同，从它的最高值（即等于质量流量的压缩空气）到最低值（这是等于零），并显示在横向轴的图表。在冷端质量流量等于质量差的进气流量和质量流量率的冷端。因此，通过改变质量在热端流率，有效地控制你在制冷结束时，其最低流量的大规模最大的价值。 其中： mc =空气质量在冷端流率 mh=空气质量流率在热端 mh=压缩空气的质量流率在进 寒冷空气的质量分数为输入压缩空气通过冷端释放管的百分比。一般来说，稍稍寒冷的空气被释放后，就会变得更寒冷。调节控制阀旋钮将改变不同寒冷度的质量分数。将给予质量分数高的寒冷更大的气流，但并没有给尽可能低的温度。高质量分数寒气流与冷温度组合，产生最大低温冷藏能力。另一方面低质量分数气流是指一股出来时体积较小且非常冷的空气。总之，较少的空气被释放，空气变得更冷。在最冷的那头，速度对温度下降的影响很有效，因为如果产生最低气温的速度是已知的，那么，压缩空气的压力和冷喷嘴直径可以达到最优化。喷嘴直径的减少也将迫使空气向热端流动，并会导致对涡管效率的提高有一定影响。估计的性能系数可以用来给出了该冷却系统的制冷性能，这是一个能够确定涡流管的性能。这对涡流管性能系数计算用到公式（21），并发现了1.38的价值。与传统制冷系统通常约为3.5的值相比，1.38这个值较低。即使这表明，涡流管是不是空调系统的理想器件，它仍然合适现场冷却。对涡流管显示设计的测试，寒冷气流的温度下降的寒冷的质量分数由、是涡流管的一个功能，如式（27）所示。从这些实验情况表明，喷嘴使之产生一个最大降温如图9所示。这已是最小光圈喷嘴直径（直径3毫米之间的发电机和冷涡管）。可以从这些测试得出结论，冷涡发生器出口直径越小，温度下降越大。检查（图8 - 11B条）显示的趋势，最低气温伴随低的寒质量分数发生。不幸的是，该流量计没有测量接近零的寒冷质量分数的能力。因此，它无法找到确切的最低气温出现时的寒冷的质量分数。虽然，从图就可以假设这个值将介于0和0.1。在冷空气出口产生最大的温降，同时在热空气出口产生最大的温升，这个结果显示在用喷嘴 1时寒冷质量分数在0.6和0.7之间，如图8所示。 此图形9显示了不同喷嘴直径图的趋势，从0都开始增加至最高点，然后有一个温度下降趋势。这种方式是可以预见的，因为它是已知的，寒冷的质量分数低，一内旋转气流有很高的比例加入在出口外流动的热空气，因此，热气流的温度下降。由于锥形阀逐渐打开，一场更高的比例热空气逃脱出口，而其余部分则返回混入涡旋空气中通过冷端回来。这让热气流温度增加至其最高点以及生成最冷空气。继续打开超出其最佳位置锥形阀可以通过额外的空气逸出，使热空气出口温度降低。该热管的长度对能源上的涡管分离有重要的影响，可以由（图10A条，二）证明。例如，通过增加热管长度，温度下降的快。这是由于空气内流有更多的时间将能量转移到外部气流。但是，对大于对360毫米的涡流管进行测试显示：一旦超出了热管的最佳长度，温度下降速度开始下跌。这种温度的下降减少所造成的能量，使得外热流量开始让内流升温，当内流时到达锥形阀，它返回到更冷的温度冷端。从图中可以得出结论说，所有的长度，最高温度可以通过增加0.4和0.7之间的寒冷质量分数进行测试。另外一个重要参数，对涡流管影响较大的是压力，因为所示（图11A条，乙），这表明一般通过增加更大的压力，您会获得一个温度下降。萨迪和亚兹迪7从他们的研究还发现，通过增加管长，温差增大，对能源的损失减少了。斯蒂芬7在他的实验得到那些类似的趋势，在米= 0.8米= 0.95间得到最高温升。为此涡管的最高值被发现是在m= 0.5和m = 0.7间，如图11 b所示：作者与斯蒂芬的涡管比较这些寒冷分数的测试，存在几何上的不同。风冷金属切削在刀尖嵌入的热电偶的位置图12上显示，最接近被测量工具接口由13个频道（Ch13热电偶）。图13显示了涡管，产生的冷空气正在走上工具界面直接在金属切削试验。这一过程的空气冷却性能可以进行评估，确定了此加工条件对刀具寿命等的影响。如图14所示的在测量工具提示之前加工与记录-5的温度热电偶2，如通道热电偶（Ch13）和（Ch15）表示当空气涡流出口已达到-30左右，加工开始。正如在刀尖温度升高的现象9，该工具上升到了60摄氏度的温度稳定状态，如图15所示。在最后一点温度下降时，表示已停止进料，没有更多的铁削正在生成。这使冷却空气流过该工具时提供一个从减少工具的温度，加快工具更快的散热，如图16所示。 在切削实验的过程中涡流管的霜凝可以清楚地看到确认，涡流管是提供极冷的空气。空气冷却对刀具寿命的影响 据了解，所有的磨损机制都会减少高温下刀具寿命10。 在寒冷的空气中，应用工具显示会避免长时间在尖端的温度下使用工具能够让刀具有一个较长的寿命11。空气冷却系统的效率可以显示，磨损为干切一1分钟，7分钟的加工风冷削减之间的比较。图第17A - D显示的后刀面磨损下一个具有63光学显微镜的放大倍率设定时间。后刀面磨损的发展证明需要更长的时间，发展空气冷却时，应用到切削区，如图17d所示。经过七年的干式加工分钟前刀面的月牙洼磨损开始发展，在0.5毫米的侧面，如图18a所示。干式加工将进一步加快这一磨损率。在这个阶段，刀具半径没有显示出磨损迹象和顶部侧面边缘没有明显的缺口。空气冷却工具显示在顶部前刀面和后刀面磨损没有明显的迹象是刀具磨损也大大减少。在干燥和空气的冷却表示，该芯片产生的热量多，正在切削区慢慢消退。图19显示了在干燥和空气冷却刀尖试验产生的铁屑。左侧是干燥刀尖试验和右侧是空气冷却产生的铁屑。总结先前的研究，如刘等人。12证明，压缩空气没有像油水乳液或水蒸汽达到工具的界面，使之良好散热。然而，结果得到利用压缩空气与涡管结合表明，这种冷却工具接口方法是有效的，与传统的冷却方法相比,格外好。在图20中可以看出，此种方法的温度记录是60，比传统的湿加工降低40，比干加工低了210。这些温度距工具界面1毫米开始测量，所以其在这个位置产生的温度记录要比工具表面的低一些。但是，必须假定该工具界面以及工具的测点的温度将减少。因为我们知道，刀具寿命和磨损机制之间的关系将由切削温度升高显示出来，所以是检测空气冷却效率的最便捷的方法就是通过检测刀具寿命。该工具的使用在显微镜的尖端检测证实，该工具被空气冷却时磨损减少，具有更长的刀具寿命。涡管空气冷却系统证明能够使刀尖有效散热，证明空气冷却是一个冷却刀具尖端的有效方法。因此，干加工进行金属切削时，空气冷却的首选方法应纳入，因为它没有相关的环境问题，并延长了刀具寿命。American Journal of Applied Sciences 6 (2): 251-262, 2009 ISSN 1546-9239 2009 Science Publications Corresponding Author: Brian Boswell, Department of Mechanical Engineering, Curtin University of Technology, GPO Box U1987, Perth Western Australia 6845 Tel: (08) 9266 3803 Fax (08) 9266 2681 251 Air-Cooling Used For Metal Cutting Brian Boswell and Tilak T Chandratilleke Department of Mechanical Engineering, Curtin University of Technology, GPO Box U1987, Perth Western Australia 6845 Abstract: Air-cooling and dry machining are both being trialled as possible solutions to the metal cutting industrys long running problems of extending tool life, reducing tool failure and minimising the heat generation at the tool tip. To date, large amounts of expensive coolant which cause both environmental damage and health hazards have had to be used. The introduction of dry machining is the goal of todays metal cutting industry that tirelessly endeavours to reduce machining costs and impact from chemicals in the environment. Modern tool tips are already capable of maintaining their cutting edge at higher temperatures, but even with these improvements in tool materials, the cutting edge will eventually break down. Applying cold air to the tool interface of these modern tool tips will also help prolong their tool life reducing the cost of metal cutting. Dry machining incorporating air being directed on to the tool interface is considered in this paper as a possible alternative for harmful liquid-based cooling. However, low convective heat removal rates associated with conventional air-cooling methods are generally inadequate for dissipating intense heat generation in the cutting processes and suitable improved cooling methodologies have yet to be established. Key words: Vortex tube, tool life, flank wear, cold fraction, coefficient of performance, air-cooled, environmentally friendly INTRODUCTION In this research examines the operational effectiveness of a Ranque-Hilsch vortex tube being used to cool tool tip during machining. The Ranque-Hilsch vortex effect was discovered in the early 1930s when it caused considerable excitement, as it demonstrated that it was possible to produce hot and cold air by supplying compressed air to a tube. At first it is hard to believe that such a device can produce hot and cold air and at a useful flow rate. The vortex tube is a simple device with no moving parts, which simultaneously produces cold and hot air streams. However, to date, there is little research in determining the efficiency of using a vortex tube in cooling tool tips. Therefore, to establish the effectiveness of the heat transfer process on the tool tip a series of experimental investigations has been carried out. These tests will determined the most suitable parameters to use, like mass flow rate of cold and hot air, cold and hot tube diameter with respect to tube length, to achievable minimum cold air temperatures. Air-cooling has never been taken seriously by the manufacturing industry due to the fact that for many years traditional cutting fluid has been shown to be effective in cooling tool tips during the machining processes. The outcome of this research will prove that air-cooling can replace traditional cutting fluid for many machining applications, without any reduction in tool life or reduction in quality of work piece surface finish. The introduction of using a Ranque-Hilsch Vortex Tube to provide cold air to the tool interface is shown to significantly improve the performance of air-cooling. Recorded tool tip interface temperatures clearly indicate that there is a highly significant reduction in tool tip temperature. This reduction in temperature slows the wear mechanisms as shown by the reduced flank wear when examined under a microscope. Therefore, monitoring the growth of the flank wear indicates the increased tool life when being air-cooled. The Ranque-Hilsch vortex tube1 is a remarkable device that is able to separate airflow into two different streams simultaneously, one hotter than the inlet air and the other cooler, without any moving parts being involved. The mechanism producing the temperature separation of cold air and hot air when passing through the vortex tube is not yet fully understood. This device has been described as Maxwells demon, a fanciful means of separating heat from cold without work. The Am. J. Applied Sci., 6 (2): 251-262, 2009 252 vortex tube basically consists of three pipes and a supply of compressed air to achieve a moderately low temperature at the cold outlet. Ranque2 attempted to exploit the commercial potential for this strange device that produced hot and cold air with no moving parts. Unfortunately, this venture failed and the vortex tube slipped into obscurity. The mechanism underlying the energy transfer from the cold to the hot flow remains elusive. However, there is debate even as to the basic physics of the phenomenon, while the majority of researchers suggest the mechanism is based on the interactions of turbulence, compressibility and shear work as shown by the analysis of Deissler and Perlmutter3. Recent research has been divided into two categories. The first category termed as external studies were concerned with the performance of the tubes. It was found by Gulyaev4 that the minimum ratio of the length of the tube to that of its diameter was thirteen. Other research suggested a ratio of forty to fifty for optimum operation. As for the diaphragm, the optimum dimension is a ratio of 2:3 for the diaphragm diameter to tube diameter. The vortex tube consists of three important parts the mid-section where the air enters into the vortex generator (which increases the speed of the air), the cold tube and the hot tube as shown in Fig. 1. Normally the hot tube is about 350 mm long and at the end there is a conical valve which controls the amount of hot air escaping. On the right side of the vortex generator is the cold tube exit. Between the vortex generator and the cold tube there is a diaphragm, with a central hole that can be easily changed. Diaphragms with large or small holes can also increase or decrease the temperature obtained at the cold exit. Considering the above vortex tube, the compressed air is supplied circumferentially into the tube at sonic speed and creates a cyclone (vortex) spinning at a million revolutions per minute. The air is forced to spin inward to the centre where it then escapes up along the hot tube as this path presents the least resistance to the airflow. The air continues to spin as it travels along the tube until it meets the conical valve where it turns part of the spinning air column (vortex) inside itself. The slower moving air inside column of the spinning air gives up its heat to the faster spinning outside column of air. The cold air travelling down the spinning air is now directed out the cold end of the vortex generator and the hot air is exhausted out of the other end of the vortex tube. Adjusting the conical valve built into the hot air exhaust can change the temperature of these two air streams to as low as 55C as shown by Fig. 2. Fig. 1: Diagram of the Hilsch Vortex Tube5 -60-50-40-30-20-10010050100150Time (s)Nozzle exit temperature (C) Fig. 2: Temperature recoded at cold nozzle exit having an inlet pressure of 1Mpa VORTEX THEORY Currently no one can definitively explain why the vortex tube operates as it does: the process itself is straightforward as outlined by Lewins and Bejan6. The inlet nozzle is tangential to the vortex generator and therefore can provide a high speed rotating airflow inside the vortex generator. Subsequently, there is a radial temperature gradient increasing from the inner core of the tube to the outside wall of the tube. This is primarily because of the potential energy of compressed air converting to kinetic energy due to the forced vortex caused by the external torque near the tangential air inlet. Therefore the high-speed swirling flow inside the tube and away from the walls is created. The existing air inside the vortex hot tube is normally at the atmospheric temperature and so, when the rotating flow enters the vortex tube it expands and its temperature drops to a temperature lower than the ambient temperature. The difference between these two temperatures will lead to a temperature gradient along the tube producing colder peripheral air than the core air. As a result, the central air molecules will lose heat to those in the outer region as shown in Fig. 3. It is notable that this system is a dynamic system due to the nature of the airflow in the tube and so will not reach equilibrium. Hence the peripheral air has a higher kinetic energy (hotter) than the inner air (colder). Am. J. Applied Sci., 6 (2): 251-262, 2009 253 Fig. 3: Radial heat convection in vortex tube due to the expansion of the compressed air The existence of a major pressure gradient due to the forced vortex in the radial direction will provide a centripetal force for circular swirling and therefore it will lead to a high pressure at the tube wall and low pressure at the centre. When the air enters to peripheral region (A), as it expands, the outer air will be cooled due to its expansion. Consequently, the inner core air (B) will get warm because it is compressed by the expansion of the peripheral air. Heat is then transferred from the inner core (B) to the outer core (A). As the inner air is being compressed, it naturally tries to push against the periphery by expanding. Work is therefore done on the outer core air, which then gets heated and the difference in pressures results in the expansion and contraction of the air, which causes work to be done on the peripheral air. Therefore, heat is transferred radially outward as shown in Fig. 4. When the air continues to swirl along the tube the more energy separation will occur by axial convection while it moves towards the hot end. During this progression, the heat will be transferred from the core air to the outer air. As the airflow reaches the hot end a fraction of the air will exhaust through the conical valve, which is located at the hot end and the remaining air flow will spin back towards the cold end due to the adverse pressure gradient near the centre as shown in Fig. 5. The remaining portion of the warm air preserves its direction of motion in the vertical flow that is either in a clockwise or anticlockwise manner around the circumference of the tube. Furthermore, this air stream resides at the inner core of the tube where the air pressure there is lower. If the angular velocities of both the air streams are preserved, it means that any two particles taken from Fig. 4: Schematic positions of the peripheral and inner core air Fig. 5: A diagram of the airflow pattern in vortex tube both the air streams will take the same time to complete a revolution around the circumference of the tube. From the principle of conservation of angular momentum, it seems that the angular velocity of the inner core molecules would increase, by the Eq: 2a aaam rconstant = (1) The equation implies that in the inner core, where the value of ra (radial distance measured from the centre of the tube to the particular molecule in concern) is small, there should be a corresponding increase in the molecules angular velocity, wa, to allow for the conservation of the total angular momentum in the system. This is assuming that there is negligible mass difference, ma, between any two-air molecules in the tube. However, the angular velocity of a particular molecule in the inner core remains unchanged. This means that angular momentum has actually been lost from the inner core of the vortex tube. Angular momentum of the inner core is not preserved or more specifically decreases, due to heat transferred to the outer core. This results in the transfer of energy from the inner core to the outer core. The loss in heat energy Am. J. Applied Sci., 6 (2): 251-262, 2009 254 Fig. 6: Schematic vortex tube diagram showing tangential air inlet from the inner core goes into heating up of the air molecules in the outer core. Hence, the outer core becomes hotter and the inner core becomes cooler. Upon reaching the hot end, the hotter peripheral air escapes through the small openings between the conical valve and the tube wall (hot outlet). However, the central air that is cooler is deflected by the tapered valve spindle and continues its travel from the hot end towards the cold tube. Only the innermost air molecules pass through the diaphragm and exit through the cold end where it is collected. As a result, the air molecules are separated into a hot stream and cold stream through the hot and cold ends of the vortex tube respectively. The Fig. 6 shows a good view of the vortex tube. It is important to note that separation takes place specifically at the hot end tube. The purpose of the tapered spindle (conical valve) is to direct the cold air to the axial region of the tube in a counter flow. The diaphragm (orifice) on the other hand is used to block the peripheral air, so that the central flow will escape through the cold end. The absence of moving parts in the vortex tube may create this wrong supposition that this phenomenon is violating thermodynamics law. The fact that without doing any work at room temperature, a stream of air can be divided into two different steams, one cooler and one hotter, seems to contradict the second law of thermodynamics. However, it is important to mention that despite this misleading belief the physics remains intact. Although, the physics of the vortex tube is complicated, the study of the basic principles of thermodynamics can help to gain a better understanding of what is happening inside a vortex tube. The first law of thermodynamics is about the conservation of energy. According to this law, during a reaction between a system and its ambient, the energy that can be received from the ambient to the system is exactly equal to the energy that is lost from the system to the ambient. This energy can be seen in two different states: Heat and Work. Hence, for every thermodynamics system with a specific control volume: Fig. 7: Schematic control volume of a vortex tube 2iC.Viii2eeeec.vvQm (hgz )2vm (hgz )W2+=+? (2) where cvQ?is the rate of heat flow, which transfers through the control volume boundary and cvW?is the work that can be done by the system on its ambient, m ? is the mass flow rate, h is the enthalpy of the air stream, v is the air stream velocity, z is the distance between the air stream and a source point and the subscripts i and e refer to inlet and outlet streams. Assuming that the vortex tube is well insulated, then the heat transfer between the system and the ambient can be taken as cvQ?equal to zero, with vi and ve also equal to zero, as can the work W. Considering the control volume as shown in Fig. 7 for the vortex tube then Eq. (2) can be simplified as: iieem hm h=? (3) The expanding air can be treated as ideal gas and hence with no Joule-Thomson heating or cooling effect. Also, assuming air obeys the ideal gas laws and having constant specific heat capacity Cp, you can write: ipihC T= (4) ipicpchphm C Tm C Tm C T=+? (5) Am. J. Applied Sci., 6 (2): 251-262, 2009 255 by defining cf as the cold fraction: ccfimm=? (6) from the continuityEq: chimmm+=? (7) Combining Eq. 5, 6 and 7 gives the relationship between inlet stream temperature and cold stream temperature, (hot stream temperature and cold fraction). Hence Eq: ()icfchTT1T= + (8) by assuming, hcTTT= (9) cicTTT= (10) hhiTTT= (11) where, ?T is the difference between the hot and the cold air stream temperatures, ?Tc is the temperature difference between the inlet and cold air streams and finally ?Th is the temperature difference between the inlet and hot air streams. The equation can be written as: hcTTT= (12) Combining E q. 8 and 12 allows you to determine ?Tc and ?Th theoretically by measuring the cold fraction, cf and total temperature difference, ?T. Therefore: ()ccfT1T= (13) hcfTT= (14) Equation 13 and 14 can be used to show the consistency of the first law of thermodynamics for test carried out on the vortex tube. VORTEX TUBE EFFICIENCY In practical cases of refrigeration it is so important to determine the coefficient of performance of the cooling device. Hence, it seems only logical to determine the coefficient of performance of the vortex tube and compare it with the conventional refrigeration coefficient of performance to determine its efficiency in use. The vortex tube can be used as a refrigeration device when the cold pipe wall is used to reduce the temperature or as a heating device when the hot pipe wall is used to increase the temperature of an enclosure. It should be noted that opposite to what is normally viewed in thermodynamics, the vortex tube in this case is an open control volume device. If the system was assumed to be steady state, then from the first law of thermodynamics: HQ=? (15) where, H? is the system enthalpy change and Q? is the heat exchanged between the system and its surroundings. Lets assume that Q? is approximately zero even though the cold tube may have frost on it and the hot tube is very warm. If this is the case then: cHHHH0= + = (16) where, ?Hc is the enthalpy change of cold stream and ?HH is the enthalpy change of hot stream. Assuming the air as an ideal gas, the total enthalpy change can be written as: ()()cpcihphiHm C(TTm CTT0=+= (17) where, mc is mass flow rate at cold tube, mh is mass flow rate at hot tube, Tc is cold air temperature, Ti is inlet air temperature, Th is hot air temperature and Cp is specific heat of air at constant pressure and assumes the process as reversible and adiabatic. By applying the second law of thermodynamics to the above: 1Sdq0T =? (18) where, ?S is total entropy change, q is heat transfer and T is absolute temperature. The actual entropy change of the control volume at steady state is: chSSS = + (19) where, ?Sc and ?Sh are the entropy change from entrance to exit of the portion of entering air which leaves the cold tube and the portion of entering are Am. J. Applied Sci., 6 (2): 251-262, 2009 256 which leaves the hot tube, respectively. For an ideal gas (air) with constant specific heat, the entropy change can be written as: ccihhippiiciihmTPmTPSC lnRlnC lnRlnmTPmTP? =+?(20) where the subscripts i, c and h are respectively inlet stream, cold stream and hot stream and R is the ideal gas (air) constant. Since the appearance of a cold (or hot) effect upon the pipe wall without moving parts would attempt to consider this device as competition for a refrigerator (or heat pump), it is useful to estimate its coefficient of performance (COP). Focusing on the cooling effect that can be achieved by placing the cold pipe within an enclosure, the coefficient of performance can be calculated by: cHCOPW=? (21) Where cH? is obtained from: ()ccicHmTT=? (22) cH? is equal to the heat that is transferred to the cold stream through the cold pipe wall (like a heat exchanger) from some source (like the cold box in a refrigerator) and W? in the present case is the work done to compress the air from atmospheric pressure and temperature to the inlet conditions of the tube. Assuming reversible compression (isentropic, minimum work), W?is then obtained from: ()21mR TT nWn1=? (23) where, T2 is the compressor exit temperature and T1 is the compressor inlet temperature (reversible, polytropic process; air: n = 1.4). If we consider a complete system, P1 and T1 are the atmospheric pressure and temperature, P2 and T2 are the compressor exit conditions, 2211n1PTnPT= (24) After the air is compressed, it is kept in the high-pressure tank where then it cools down to the atmosphere temperature, T1 so the inlet temperature of the sonic nozzle Ti, is equal to T1 noting that: pRnCn1= (25) Equation (23) can be simplified to: ()ip21Wm CTT=?(26) with T2 calculated from Eq. (24). This is an ideal work value so it is less than the actual work needed to drive the compressor. By considering the above equations and using the Eq. (21), the coefficient of performance of the vortex tube can be determined. EXPERIMENTAL ANALYSIS OF VORTEX TUBE DESIGN To help compare a number of the vortex tube parameters it is useful to use the cold mass fraction as this can be contrasted over the range of vortex tube tests. This parameter is simply the ratio of air mass flow rate at the cold end of the tube to the mass flow rate of the compressed air at inlet. It is important to note that the air mass flow rate at the hot end of the tube is varied from its maximum value (which is equal to the mass flow rate of the compressed air) to its minimum value (which is equal to zero) and is shown on the horizontal axis on the graphs. By the law of the conservation of mass, the mass flow rate at the cold end is equal to the difference of the inlet mass flow rate and the mass flow rate at the cold end. Therefore, by varying the mass flow rate at the hot end, you effectively control the mass flow rate at the cold end from its minimum to its maximum value. cinhininmmmCold Mass Fractionmm=? (27) Where: cm?= Air mass flow rate at cold end hm?= Air mass flow rate at hot end hm?= Mass flow rate of compressed air at inlet Cold mass fraction is the percentage of input compressed air that is released through the cold end of the tube. Generally, the less cold air being released, the colder the air will be. Adjusting the control valve knob will vary the cold mass fraction. High cold mass fraction would give a greater airflow, but does not give Am. J. Applied Sci., 6 (2): 251-262, 2009 257 the lowest possible temperature. The high cold mass fraction combination of airflow and cold temperature produces the maximum refrigeration capacity. A low cold mass fraction on the other hand means a smaller volume of air coming out that is very cold. In short, the less air to be released, the colder the air becomes. The effect of velocity on the temperature drop at the cold end is important since if the velocity that produces the lowest temperature drop is known, then the compressed air pressure and the cold nozzle diameter could be optimised. A decrease in the nozzle diameter would also force the air to flow towards the direction of the hot end and would lead to an improvement in the vortex tube efficiency to some extent. ALm.Avt= ? (28) mvA=? (29) Where: m ?= Mass flow rate, kg s1 ? = Density, kg m3 v = Velocity, m s1 The coefficient of performance estimation can be used to give a good measure of the refrigeration performance of the cooling system, which can be used in determining the performance of the vortex tube. The coefficient of performance for this vortex tube was calculated by using Eq. (21) and was found to give a value of 1.38. This value is low when compared with a conventional refrigeration system, which are normally around 3.5. However, even though this shows that a vortex tube is not an ideal device for an air conditioning system, it is still suitable for spot cooling. Tests on the design of the vortex tube show that the temperature drop at the cold stream is a function of cold mass fraction as shown by Eq. (27). From these tests it is shown that nozzle one produces the biggest temperature drop as shown by Fig. 9. This nozzle had the smallest diaphragm diameter (3 mm diameter) between the vortex generator and the cold tube. It can be concluded from these tests the smaller the diameter at the cold exit of the vortex generator, the bigger the temperature drop. Examination of (Fig. 8-11b) shows the trend that the lowest temperatures occur at the low cold mass fraction. Unfortunately, the flowmeter was not capable of measuring the cold mass fraction near zero. Therefore it was not possible to find the exact cold Fig. 8: Nozzle temperature drop with respect to cold fraction Fig. 9: Nozzle diameter effects on temperature mass fraction where the lowest temperature occurs. Although, from the graphs it is possible to assume that this value will be between 0 and 0.1. The biggest temperature drop at the cold air outlet with highest air hot outlet temperature increase was shown to have cold mass fraction between 0.6 and 0.7 when using nozzle 1, as shown on Fig. 8. The trend shown for the different nozzle diameter all graphs in Fig. 9 show that from 0 = all graphs start increasing to a highest point and then there is a decline in temperature. This manner was predictable as it is known that at low cold mass fraction, a high fraction of inner swirling air flow joins the outer air flow at the hot outlet and therefore the temperature of the hot air stream decreases. As the conical valve gradually opens, a higher portion of the air escapes out the hot exit, while the rest of the air is returned back towards the cold end through the middle of the vortex air. This allows the temperature of the hot air stream to increase to its optimum point as well as generating the optimum cold air. Continuing to open the conical valve beyond its optimum position allows additional air to escape through the hot exit with a reduced temperature. Am. J. Applied Sci., 6 (2): 251-262, 2009 258 Fig. 10a: Temperature drop at cold exit with respect to tube length Fig. 10b: Temperature rise at hot exit with respect to tube length The length of the hot tube has an important effect on the energy separation in the vortex tube, as can be shown in (Fig. 10a, b). For example, by increasing the length of the hot tube, the temperature drop increases. This is due to the air inner flow having more time to transfer energy to the outer airflow. However, beyond the optimum length of the hot tube the temperature drop starts to decrease as shown by tests carried out on a vortex tube larger than 360 mm. This reduction in temperature drop was caused by the energy transfer becoming inversed as the outer hot flow starts warming up the inner flow and when the inner flow reaches the conical valve, it returns back towards the cold end at a higher temperature. From the tests it can be concluded that the maximum temperature increase for all lengths can be achieved by the cold mass fraction between 0.4 and 0.7. Another important parameter that has great effect on the vortex tube is pressure, as shown in (Fig. 11a, b), which shows that generally by increasing the pressure you get a larger temperature drop. Sadi and Yazdi7 also found from their research that by increasing the tube length the temperature difference increases and energy destruction decreases. Fig. 11a: Temperature drop with respect to pressure Fig. 11b: Temperature increase with respect to pressure The trends obtained are similar to those that Stephan7 obtained in his experiments that is, the temperature increased between = 0.8 and = 0.95. For this vortex tube the maximum values was found to be between = 0.5 and = 0.7, as shown in Fig. 11b. The reduction of the cold fraction for these tests compared with Stephan being accounted to the geometrical differences of the vortex tube tested. AIR-COOLED METAL CUTTING The positions of the thermocouples imbedded in the tool tip are shown on Fig. 12, with the temperature closest to the tool interface being measured by thermocouple on channel 13 (Ch13). Figure 13 shows the vortex tube, generated cold air being directed onto the tool interface during the metal cutting tests. The air-cooling performance of this process can now be evaluated by determining the effect on tool life Ay et al.8 for this machining condition. The temperatures shown in Fig. 14 were measured at the tool tip prior to machining, with two of the thermocouples recording temperatures of 5C, as indicated by thermocouples on channel (Ch13) and (Ch15). Am. J. Applied Sci., 6 (2): 251-262, 2009 259 Fig. 12: Position of thermocouples in tool tip Fig. 13: Vortex tube being used to cool tool tip -40-30-20-100102030010203040Time (s)Tool tip temperature ( oC)Ch13Ch14Ch15Cold nozzle teemp. Fig. 14: Tool tip temperatures before machining has commenced. The vortex tube used a 3 mm diameter orifice plate at a pressure of 0.8 MPa When the vortex exit air has reached approximately 30C, machining is commenced. As indicated by the rise in the tool tip temperatures9, the tool tip rises to a steady state temperature of 60C as shown in Fig. 15. The temperature drop at the end indicates the point when the feed is stopped and no more chips are being generated. This allows the cooling air to flow unimpeded across the tool tip giving a better heat Fig. 15: The graph shows the tool tip temperatures during machining, and after the tool feed has stopped cutting Fig. 16: Picture showing frost on the outside of the cold tube dissipation from the tool reducing the temperature of the tool rapidly Fig. 16. The build up of frost on the vortex tube during the cutting tests can be clearly seen confirming that the vortex tube is delivering very cold air. EFFECT OF AIR-COOLING ON TOOL LIFE It is known that all the wear mechanisms increased at elevated temperatures reducing the tool life10. The application of cold air to the tool tip is shown to reduce the temperature at the tool tip enabling the tool tip to have a longer tool life11. The effectiveness of the air-cooled system can be shown when a comparison is made between the wear for a dry cut and an air-cooled cut for one minute and seven minutes of machining. Figure 17a-d shows the flank wear as seen under a microscope with a 63 optical magnification setting. Am. J. Applied Sci., 6 (2): 251-262, 2009 260 Fig. 17a: Picture showing flank wear for a dry cut after 1 minute of machining at a cutting speed of 190 m min1 and feed rate of 0.23 mm/rev with a 2 mm depth of cut Fig. 17b: Picture showing flank wear for a air-cooled cut after 1 minute of machining at a cutting speed of 190 m min1 and feed rate of 0.23 mm/rev with a 2 mm depth of cut Fig. 17c: Picture showing flank wear for a dry cut after 7 minute of machining at a cutting speed of 190 m min1 and feed rate of 0.23 mm/rev with a 2 mm depth of cut Fig. 17d: Picture showing flank wear for a air-cooled cut after 7 minutes of machining at a cutting speed of 190 m min1, and feed rate of 0.23 mm/rev with a 2 mm depth of cut Fig. 18a: Picture showing top rake face w
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