综掘巷道大风量双压风筒下长压短抽除尘效果的模拟研究

煤矿井下大风量双压风筒综掘巷道具有产尘强度大、粉尘分散度高、巷道风速大等特点,严重威胁作业人员身心健康和矿井安全生产。为降低大风量综掘巷道粉尘浓度,基于CFD数值模拟软件建立了双压风筒综掘巷道物理结构,采用DPM模型,重点研究了单抽双压式通风下抽风筒入风口与巷道迎头之间的距离对掘进工作面粉尘运移规律的影响,分析了大风量双压风筒下长压短抽通风方式对司机位置作业环境的影响。结果表明：保持双压风筒出口距巷道迎头为4、5 m,压入风量为1 200 m³/min条件下,当抽风筒入口与巷道迎头之间的距离为8 m时,司机位置粉尘浓度为30～90 mg/m³,作业环境最佳。     

综掘工作面通风控尘参数匹配关系研究及应用

针对综掘工作面产尘量大,降尘效率不佳等问题,基于气固两相流原理、流体力学,研究长压短抽分流压风除尘系统的最佳匹配参数。以羊场湾Ⅱ020605综掘面为研究背景,采用FLUENT数值模拟软件,研究长压短抽分流控尘时巷道内部粉尘分布和运移规律,对比分析了轴径向压风比、附壁风筒位置、整流风筒位置对粉尘运移规律的影响。研究发现:羊场湾Ⅱ020605综掘面,在轴径向压风比为1∶3,附壁风筒距迎头11~13 m,整流风筒距迎头6~8 m时,能够有效地控制粉尘扩散,极大降低巷道粉尘质量浓度,综合降尘效率超过92%,保证了作业人员的工作环境质量。     

抽出式通风综掘工作面粉尘分布规律的数值模拟研究

根据煤矿综掘工作面生产过程中粉尘污染严重的实际情况,利用数值模拟方法对抽出式通风综掘工作面进行了数值模型。通过对抽出式通风综掘工作面掘进机截割生产时产尘的模拟分析,得出了抽出式通风综掘工作面粉尘沿巷道通风风流的分布规律以及粉尘分布规律受风筒入风口位置、抽风量大小影响的变化规律。     

综掘巷道抽、压组合的通风系统布置参数及效果研究

为了解决恒源煤业151303综掘巷道原通风方式下掘进迎头粉尘浓度过高的问题,拟采用抽、压组合的通风系统来降低迎头煤尘浓度,并进对风筒的布置参数进行研究。通过研究发现:压风筒筒口距离掘进迎头13m时,抽风筒固定于综掘机距迎头4m的位置处的除尘效果最佳。现场实测发现在采取了合理的综合降尘措施后,掘进工作面煤尘浓度下降了约89%,可以满足正常安全的掘进此巷道。     

综掘工作面长压短抽通风风筒合理位置选择

基于FLUENT数值模拟软件与现场试验,确定合适的压入风筒和抽出风筒距综掘工作面作业面的距离,以期达到提高风机效率和工作面降尘的目的。结果表明,压风口距离掘进面过近,二次扬尘扬起的大量粉尘扩散到射流区的后面,抽风筒不能将射流区后的粉尘吸入,降尘效果不好;吸风口位于射流影响区域范围内,压、抽风流能在工作面形成良好的控制流场,使工作面粉尘被控制在掘进面处,继而被抽风筒吸走,达到最佳通风降尘效果。     

附壁风筒条缝参数对综掘工作面控尘效果的影响

为明确附壁风筒条缝位置、宽度和压抽比对综掘面控尘效果的影响,运用FLUENT软件对建立的长压短抽式通风综掘巷道模型进行数值模拟。结果表明:随着附壁风筒条缝与迎头距离增大,巷道空间粉尘浓度先减小后增大,当条缝距迎头13 m时,旋流风幕将粉尘集中控制在迎头6 m范围内,综掘机司机处粉尘浓度下降到120 mg/m~3,风幕控尘起效;条缝宽度会影响旋流分风的风速,条缝越宽,旋流风速越大,但条缝宽度超过0.1 m时,反而会抑制旋流风幕控尘作用,当条缝宽度为0.05 m时,抽风筒口积聚的大量粉尘被抽离巷道,综掘机司机不受粉尘干扰;随着压抽比变大,巷道内粉尘浓度先减后增,压抽比为1.0时,压风筒高速射流被抽风筒全部吸收,粉尘被有效控制在迎头,巷道无粉尘扩散,控尘效果最佳。     

综掘工作面旋流气幕抽吸控尘流场的数值模拟

针对配有附壁风筒综掘工作面旋流气幕抽吸控尘流场的特点,分别采用k-ε和k-ε-Θ-k_p数学模型建立了该流场单相风流流动和气体-粉尘颗粒两相流动的数学模型,基于同位网格的SIMPLE算法,利用Fluent软件对该流场风流及粉尘的扩散进行了数值模拟。模拟结果显示,综掘工作面旋流气幕抽吸控尘系统可在掘进机司机的前方形成基本封闭整个巷道断面的旋流气幕,能有效地将粉尘封闭在掘进头至掘进机司机前方0.5 m的空间内,防止粉尘向其它区域扩散。依据模拟结果和工作面现场的实际条件,设计了由附壁风筒和抽尘净化装置构成的综掘工作面旋流气幕抽吸控尘系统,该系统在综掘工作面应用后,有效地降低了工作面现场各作业地点的粉尘浓度,取得了较好的降尘效果。     

综掘面压抽组合式通风参数优化研究

为改善煤矿综掘面粉尘问题,根据气固两相流理论,建立综掘面两相流瞬态模型,对压抽组合式通风方式下综掘面粉尘扩散过程进行分析,研究了压抽风口安装位置、压抽比对综掘面粉尘分布规律的影响。研究结果表明:当压风口距工作面距离为14 m、抽风口距工作面为5 m、压抽比为1.15时,粉尘扩散距离最短,巷道后方粉尘浓度明显降低,实验与仿真均表明,在该最佳参数运行的压抽组合式通风相较优化前能显著降低回风侧和司机位置粉尘浓度及粉尘扩散距离。     

附壁风筒出风口参数对掘进工作面控尘效果的影响北大核心

为明确径向出风式附壁风筒出风口宽度、径轴向出风比对综掘工作面控尘效果的影响,以冯家塔煤矿某综掘工作面为原型,运用FLUENT软件,对建立的长压短抽式通风综掘巷道模型进行数值模拟,并对模拟结果进行现场验证。结果表明:保持压抽比为1.3,径向出风口长为0.8 m时,随着出风口宽度增加,巷道空间内的粉尘浓度先减小随后增大,改变出风口宽度,当出风口宽度为0.05 m时,司机处粉尘浓度降至100 mg/m^(3),距掘进工作面20 m巷道内基本无粉尘,控尘效果最佳;保持最佳出风口宽度为0.05 m,随着径轴向出风比变小,巷道内粉尘浓度先减小后增大,当径向轴向出风比为1:2时,粉尘被集中控制在负压抽吸区,掘锚机司机位置处粉尘浓度降至1.2 mg/m^(3),此时径向出风式附壁风筒控尘效果最佳。     

基于ANASYS的综掘工作面通风参数优化

为了解决综掘工作面粉尘浓度过高工人作业环境差的问题,以某矿综掘工作面为参照建立物理模型,导入ANSYS并对该巷道模型在使用长压短抽式通风除尘时进行优化模拟,通过比较不同高度时压入式通风的粉尘分布情况确立了压入式风筒距离底板的合适高度。在此基础上优化长压短抽通风系统,通过比较发现当压入式风筒距离底板高度为2/3L(L为巷道高度),抽出式风筒距离底板高度为0.7L,压入式风筒距离综掘面距离为(3.5~4.5)S~(1/2)(S为巷道断面面积)、抽出式风筒距离综掘面距离小于S~(1/2)时除尘效果较好。     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

2014 second batch of rare earth quota released

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China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.     

Rare Earth Application in Steel in China

<正>China has rich rare earth resources.Output of rare earth and steel in China ranks the top first in the world.However,there is still certain distance between the steel produced in China and developed countries from the point of varieties and quality.China still has to import some types of steel.Improving the quality should be emphasiZed in future development of steel industry in China.Rare earth can be used to upgrade traditional steel     

Current situation and future trend of China rare earth luminescent materialindustry(continued)

<正>Developing ecological lighting source The world is facing the big problem of energy shortage today and the contradiction between economy development and environmental protection is worsened.Therefore,people are more likely to choose an ecological light source that is more energy efficient and environmental friendly.The choice provides great opportunity for the development of rare earth optical material industry in China.The concept of green lighting positions rare earth luminescent material as a leading player in illumination market.The light source of both rare earth luminescent lamp and LED lamp is ecological and energy saving.This is why     

稀散金属产业的观察与思考

分析了近年来国内外稀散金属产业的生产、应用、资源与市场状况.铟锡氧化物靶材、砷化镓晶片、锗红外材料、铼高温合金和硒在电解锰及玻璃的应用等已成为稀散金属的主要应用领域.稀散金属的产量快速增长达到历史高位而导致了市场的失衡.以GaInP_2/GaAs/Ge,CIGS和CdTe为代表的非硅系太阳能电池是稀散金属的新兴应用领域,将给稀散金属带来日益增长的需求.