压缩空气基本知识参考资料课件.ppt
ATLAS COPCO-2003,ATLAS COPCO,空气理论,基础知识培训,2003,ATLAS COPCO-2003,?,压缩空气理论,?,压缩机基本类型及工作原理,?,自由空气流量,概念,参考工况和实际工况,测量,FAD,的新标准,主要内容,:,COMPRESSOR TYPES,空气理论,ATLAS COPCO-2003,空气,什麽是空气,?,空气是无色,无臭,无味的,.,空气是一种机械混合物,主要成份,是,:,氮气,(N2,78%),氧气,(O2,20.9%),氩气,(0.9%),和其它气体,.,氧气,20.9%,氮气,78%,水,空气中总是包含一定数量的水分,ATLAS COPCO-2003,?,压力,温度和容积是息息相关的,.,它们之间的关系可以用下式,来表示,:,?,在此,:,P=,压力,V=,容积,T=,温度,(,凯氏,),w=Avogadro number,R=,常数,空,气,wRT,PV,?,ATLAS COPCO-2003,绝对压力和相对压力,?,绝对压力考虑了大气压力,?,相对压力就是我们通常用压力表或压力计所测量到的压力,相对压力也被称作“工作压力”,或,“表压”,或,“有效,压力”,?,P,绝对压力,=P,相对压力,+P,大气压力,ATLAS COPCO-2003,压比,?,压比,P,r,是进气侧与排气侧绝对压力的比值,?,压缩机工作的海拔高度对压比有直接的影响,P,r,=P,出口绝压,/P,入口绝压,ATLAS COPCO-2003,压比,:,举例,假设一台压缩机在海拔,2000,米的高度运行,.P,大气,=0.776 bar.,压缩机工作压力为,7 bar(e),P,r,=(0.776+7)/0.776=10.02,这台压缩机的压比为,10.02,但是,压缩机的不同压比相对应它所能工作的环境有一定的限制,.,请参考,高度性能曲线图,P,r,=(P,at,+7)/P,at,ATLAS COPCO-2003,空,气,?,空气中总是包含一定数量的水蒸气,空气的整个压力可视为干,空气和水蒸气压力的总和,(,道尔顿分压定律,).,?,在一定温度下,当水蒸气分压力等同与饱和水蒸气压力,说明此,时空气是饱和的,.,?,饱和压力只与温度有关,.,ATLAS COPCO-2003,空,气,空气在常压下冷却,当分压力,等同与饱和压力,此时的温度,即为露点温度,.,大气的露点就是在大气压力,下水蒸气开始冷凝时的温度,.,任何进一步的冷却,便有冷凝,水析出,.,含水量,常压露点,有,效,压,力,压,力,露,点,自由空气流量,FAD,ATLAS COPCO-2003,自由空气流量,F.A.D.,自由空气流量,:,将压缩机的排出空气量换算到标准的进,气条件时的流量,.,表示将气体重新膨胀到环境条件时,将会有,多少升的空气,.,F.A.D.,可以用,l/s,m3,/min,或,cfm,表示,.,ATLAS COPCO-2003,实际上,:,Atlas Copco,用,F.A.D.,来标定容积式压缩机,-,压缩机的排放流量测定按照,ISO 1217,annex C.,标准,(,后冷却器,止回阀和水分离器的下方,),-,当地环境温度,-,AML,中的参考工况,用,ISO 1217,标准,环境温度,:,压力,:,相对湿度,冷却水,/,空气,温度,:,20,C,1 bar(a),0%,20,C,68,F,14.5 psia,0%,68,C,F.A.D,ATLAS COPCO-2003,螺杆压缩机常用流量,自由空气排量,FAD,进口实际流量,Acfm,由于空气滤清器阻力损失,:0.03bar,所以,FAD=(1-0.03)Acfm,外部泄露,外部泄露,ATLAS COPCO-2003,离心压缩机常用流量,进口流量,Icfm,标准流量,ATLAS COPCO-2003,参考工况,设计工况,实际工况,ISO1217,基准,1 bar(a),20,0%,ZR630-7.5:103.m3/min,563 kw,工况,1,1.033 bar(a),30,75%,ZR630-7.5:104.1 m3/min,562 kw,螺杆压缩机不同工况时的性能参数,ATLAS COPCO-2003,FAD,的计算举例,客户,A,位于,2000,米海拔高度,需要一台无油机,流量为,190,SCFM,工作压力为,7 bar(e),环境温度,=20 C,RH=60%,你会推荐什麽机型,?,FAD,ATLAS COPCO-2003,V,2,=P,1,X T,2,X V,1,P,2,T,1,V,2,=1.013/0.776 X 293/288.56 X 89,V,2,=1.31 X 1.02 X V,1,V2=118.9 l/s,基本公式,:,P,1,V,1,=P2V2,T,2,T1,标准工况,T1=15.56,C=288.56,K,P1=1.013 bar,V1=190 CFM=89 l/s,当地环境条件,T2=20,C=293,K,P2=O.776bar,V2=?,压力影响系数,温度影响系数,ZT55,F.A.D.,ZT45,ATLAS COPCO-2003,水蒸气在,20,C,时的饱和压力,PVS=23.7 mbar,相对湿度,60%,意味水蒸气的压力为,:Pv=0.6 X 23.7=14.22 mbar,PV/P2=14.22/776=0.0183,空气中含有高达,1.83%,的水分,那麽就需要更多的,FAD,V2=1.0183 X 118.9=121.1 l/s,ZT55?,F.A.D,压比,=10-,核对,AML,中,9 Bare(1 Bar,进气压力,),主轴输入功率,(,和冷却水流量,),修正系数为,0.87,电机必须适合高海拔地区运行,.,相对湿度是,60%,对,FAD,有何影响,?,ATLAS COPCO-2003,?,第一阶段,:,没有任何标准,?,第二阶段,:ISO 1217,版本,2(,复杂难解,),?,第三阶段,:CAGI-PNEUROP PN2 CPT-1/-2/-3,?,第四阶段,:ASME PTC 9,PTC 10,?,第五阶段,:ISO 1217,版本,3,附录,A,B,C,D,(,压缩机制造商一致协商采用此标准,),最终目的,:,测量,FAD,标准的变迁历程,客,户,的,安,全,ATLAS COPCO-2003,ISO 1217,第,3,版,附录,C,3.,所有,功率输入,1.,整个,压比,2.,出口处流量,过滤,器,阀,主机,后冷,止回,阀,油分离器,入口,出口,电机,齿轮箱,风扇,ATLAS COPCO-2003,附表,:,饱和水蒸气压力和密度,t,C,Ps,mbar,Pw,g/m,3,-40,0.128,0.119,-38,0.161,0.146,-36,0.200,0.183,-34,0.249,0.225,-32,0.308,0.277,-30,0.380,0.339,-29,0.421,0.374,-28,0.467,0.413,-27,0.517,0.455,-26,0.572,0.502,-25,0.632,0.552,-24,0.689,0.608,-23,0.771,0.668,-22,0.850,0.734,-21,0.937,0.805,-20,1.03,0.884,-19,1.14,0.968,-18,1.25,1.06,-17,1.37,1.16,-16,1.51,1.27,t,C,Ps,mbar,Pw,g/m,3,-15,1.65,1.39,-14,1.81,1.52,-13,1.98,1.65,-12,2.17,1.80,-11,2.38,1.96,-10,2.60,2.14,-9,2.84,2.33,-8,3.10,2.53,-7,3.38,2.75,-6,3.69,2.99,-5,4.02,3.25,-4,4.37,3.52,-3,4.76,3.82,-2,5.17,4.14,-1,5.62,4.48,0,6.11,4.85,1,6.57,5.19,2,7.06,5.56,3,7.58,5.95,4,8.13,6.36,t,C,Ps,mbar,Pw,g/m,3,5,8.72,6.80,6,9.35,7.26,7,10.01,7.75,8,10.72,8.27,9,11.47,8.82,10,12.27,9.40,11,13.12,10.01,12,14.02,10.66,13,14.97,11.35,14,15.98,12.07,15,17.04,12.63,16,18.17,13.63,17,19.37,14.48,18,20.63,15.37,19,21.96,16.31,20,23.37,17.30,21,24.86,18.34,22,26.43,19.43,23,28.09,20.58,24,29.83,21.78,t,C,Ps,mbar,Pw,g/m,3,25,31.67,23.05,26,33.61,24.38,27,35.65,25.78,28,37.80,27.24,29,40.06,28.78,30,42.43,30.38,31,44.93,32.07,32,47.55,33.83,33,50.31,35.68,34,53.20,37.61,35,56.24,39.63,36,59.42,41.75,37,62.76,43.96,38,66.28,46.26,39,69.93,48.67,40,73.78,51.19,41,77.80,53.82,42,82.02,58.56,43,86.42,59.41,44,91.03,62.39,ATLAS COPCO-2003,谢,谢,
