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他为分公司培养出了鲁付凯、孙垚、徐童晨、肖大鹏四名测量员,他们现在个个都能独当一面。warmly,welcomingustojoinforces,andsawmyfillof...Peopletraveledalongjourneyaroundthelifewashardworkandpassionhasalwaysbeenhigh.Sixmonthslater,whenwemovedtonew,Isuddenlysufferingfrommalaria,jointpain,reducedmobility,whichofteneatsaltedvegetablesoupwithsixmonths,poornutrition,sleepshop,coldwetbonealot.Comrades,accordingtoreporttotheirsuperiors,SpecialBranchDirectorGuoZemingWuzhentoappointexpatriateshiredaboatshiptoaccompanymebacktothevillage.Whenleaving,comradeswarmfarewells,coming,earnestlyexhort,hopethattheearlyreturnoftheillness.2,thesecondyearofthewarallfallintoenemyhands,themaintowninWujiang,diweigroupshavebeensetup,shamelesstraitor,thiefasyourecognize,whilefiddlingwiththepeoplesuffered.ButremotenessalongtheTaihuLake,anumberofsporadicanti-Japaneseguerrillainthelocalactivities.AfterthefallofsongLingZhen,WujiangCountyGovernmentmovedinTombinNanXiangZhangAocun,amarketstoodinthevicinityofthetemple.ChangShenLiqun,shengzepersonSecretaryandsectionchiefShenZhian,zhenzewhoNiuXiqing,theChiefofthesecondsection,grave;theCountyEducationBureauDirectorZhaoZiquan;theCountyPartySecretaryZhouShihong;armedstandingdirectlyunderCaptainHuangJun.Alsoappointeddistricthead,flowworkingseparatelyineachcountry.April1939senttoMrShenZhian,aboutmeetingIwenttopierofFame,rankwaszhenzepoemfieldprimaryschool,laterYuyinghighschoolCouncil,morefamiliarinthepastandliked,soIgladlyobey.Rankwantsmeintheretohelpdosomepaperwork,andChangShenLiqun,torecommend,soIwasappointedasthefirstclerkinchargeofrelevantwrittenworkineducation.CountyGovernmentdepartmentsthestaffscatteredaroundthefarmhouse,第四章通风动力矿井中的空气之所以能在巷道中运动而形成风流,是由于风流的起末点间存在着能量差。这种能量差的产生,若是由通风机提供的,则称为机械风压;若是由矿井自然条件产生的,则称为自然风压。机械风压和自然风压都是矿井通风的动力,用以克服矿井的通风阻力,促使空气流动。但自然风压一般较小且不稳定,难以满足矿井通风的要求,因此我国《煤矿安全规程》第121条规定:矿井必须采用机械通风。故我国煤矿已普遍使用主要通风机进行机械通风,使矿井通风条件得到了根本保证和改善。第一节自然风压一、自然风压及其形成和计算1、自然风压与自然通风图4-1-1为一个简化的矿井通风系统,2-3为水平巷道,0-5为通过系统最高点的水平线。如果把地表大气视为断面无限大,风阻为零的假想风路,则通风系统可极为一个闭合的回路。在冬季,由于空气柱0-1-2比5-4-3的平均温度较低,平均空气密度较大,导致两空气柱作用在2-3水平面上的重力不等。其重力之差就是该系统的自然风压。它使空气源源不断地从井口1流入,从井口5流出。在夏季时,若空气柱5-4-3比0-1-2温度低,平均密度大,则系统产生的自然风压方向与冬季相反。地面空气从井口5流人,从井口1流出。这种由自然因素作用而形成的通风叫自然通风。图4-1-1简化矿井通风系统2、自然风压的计算由上述例子可见,在一个有高差的闭合回路中,只要两侧有高差巷道中空气的温度或密度不等,则该回路就会产生自然风压。根据自然风压定义,图4-1-1所示系统的自然风压NH可用下式计算:他为分公司培养出了鲁付凯、孙垚、徐童晨、肖大鹏四名测量员,他们现在个个都能独当一面。warmly,welcomingustojoinforces,andsawmyfillof...Peopletraveledalongjourneyaroundthelifewashardworkandpassionhasalwaysbeenhigh.Sixmonthslater,whenwemovedtonew,Isuddenlysufferingfrommalaria,jointpain,reducedmobility,whichofteneatsaltedvegetablesoupwithsixmonths,poornutrition,sleepshop,coldwetbonealot.Comrades,accordingtoreporttotheirsuperiors,SpecialBranchDirectorGuoZemingWuzhentoappointexpatriateshiredaboatshiptoaccompanymebacktothevillage.Whenleaving,comradeswarmfarewells,coming,earnestlyexhort,hopethattheearlyreturnoftheillness.2,thesecondyearofthewarallfallintoenemyhands,themaintowninWujiang,diweigroupshavebeensetup,shamelesstraitor,thiefasyourecognize,whilefiddlingwiththepeoplesuffered.ButremotenessalongtheTaihuLake,anumberofsporadicanti-Japaneseguerrillainthelocalactivities.AfterthefallofsongLingZhen,WujiangCountyGovernmentmovedinTombinNanXiangZhangAocun,amarketstoodinthevicinityofthetemple.ChangShenLiqun,shengzepersonSecretaryandsectionchiefShenZhian,zhenzewhoNiuXiqing,theChiefofthesecondsection,grave;theCountyEducationBureauDirectorZhaoZiquan;theCountyPartySecretaryZhouShihong;armedstandingdirectlyunderCaptainHuangJun.Alsoappointeddistricthead,flowworkingseparatelyineachcountry.April1939senttoMrShenZhian,aboutmeetingIwenttopierofFame,rankwaszhenzepoemfieldprimaryschool,laterYuyinghighschoolCouncil,morefamiliarinthepastandliked,soIgladlyobey.Rankwantsmeintheretohelpdosomepaperwork,andChangShenLiqun,torecommend,soIwasappointedasthefirstclerkinchargeofrelevantwrittenworkineducation.CountyGovernmentdepartmentsthestaffscatteredaroundthefarmhouse,251203NHgdzgdz(4-1-1)式中Z——矿井最高点至最低水平间的距离,m;g——重力加速度,m/s2;1、2——分别为0-1-2和5-4-3井巷中dz段空气密度,kg/m3。由于空气密度受多种因素影响,与高度Z成复杂的函数关系。因此利用式(4-1-1)计算自然风压较为困难。为了简化计算,一般采用测算出的0-1-2和5-4-3井巷中空气密度的平均值1m和2m分别代替式(4-1-1)中的1和2,则式(4-1-1)可写为:12NmmHZg(4-1-2)二、自然风压的变化规律及其影响因素1、自然风压的变化规律自然风压的大小和方向,主要受地面空气温度变化的影响。根据实测资料可知,由于风流与围岩的热交换作用使机械通风的回风井中一年四季中气温变化不大,而地面进风井中气温则随季节变化,两者综合作用的结果,导致一年中自然风压随季节发生周期性的变化。例如在冬季,地面气温很低,空气柱1-2比空气柱5-3重,风流由1流向2,经出风井3-5排至地面;夏季,地面气温高于井筒3-5内的平均气温,使风流由2—1排出。而在春秋季节,地面气温与井筒内空气柱的平均气温相差不大,自然风压很小,因此,将造成井下风流的停滞现象。在一些山区,由于地面气温在一昼夜之内也有较大变化,所以自然风压也会随之发生变化,夜晚,1-2段进风;午间,2-1段出风。图4-1-2和图4-1-3所示分别为浅井和位于我国北部地区的深井自然风压随季节变化的情形。由图可以看出,对于浅井,夏季的自然风压出现负值,而对于我国北部地区的一些深井,全年的自然风压都为正值。图4-1-2浅井自然风压示意图图4-1-3深井自然风压示意图2、自然风压的影响因素由式(4-1-1)可见,影响自然风压的决定性因素是两侧空气柱的密度差,而空气密度除了受温度T的影响,还受大气压力P、气体常数R和相对湿度等因素影响。因此,影响自然风压的因素可用下式表示:他为分公司培养出了鲁付凯、孙垚、徐童晨、肖大鹏四名测量员,他们现在个个都能独当一面。warmly,welcomingustojoinforces,andsawmyfillof...Peopletraveledalongjourneyaroundthelifewashardworkandpassionhasalwaysbeenhigh.Sixmonthslater,whenwemovedtonew,Isuddenlysufferingfrommalaria,jointpain,reducedmobility,whichofteneatsaltedvegetablesoupwithsixmonths,poornutritio
本文标题:第4章矿井主要通风机
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