Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,Jiangxi University of Science and Technology,Jiangxi University of Science and Technology第二级,第三级,第四级,第五级,*,School of Resources and Environmental Engineering,*,2024/11/17,1,2024/11/17,1,5,井巷通风阻力,Mine Ventilation Resistance,5.1,概述,5.2,摩擦阻力,5.3,局部阻力和正面阻力,5.4,井巷通风阻力小结,5.5,降低井巷通风阻力的方法,5.6,等积孔与井巷风阻特性曲线,2023/10/712023/10/715 井巷通风阻力,2024/11/17,2,2024/11/17,2,5.1,概 述,General Introduction,在通风工程中，空气沿井巷流动时，井巷对风流所呈现的阻力，统称,井巷的通风阻力,，而单位体积风流的能量损失简称为,风压降,或者,风压损失,。,井巷通风阻力是引起风压损失的原因，而风压损失则是通风阻力的量度。二者在数量上是相等的。,按风流边界状态的不同，通常将,通风阻力,分成三类：,第一类：,摩擦阻力,：,第二类：,局部阻力,;,第三类：,正面阻力,。,2023/10/722023/10/725.1 概 述,2024/11/17,3,2024/11/17,3,通 风 阻 力,Ventilation Resistance,第一类：,摩擦阻力,:,风流沿井巷流动时在全流程上的摩擦阻力（水力上称沿程阻力），克服摩擦阻力而造成的风流能量的损失，称为摩擦损失。,第二类：,局部阻力,:,由风流边界的急剧改变（突然扩大或者突然缩小等），所引起的阻力，克服局部阻力而造成的风流能量损失称为是局部损失。,第三类：,正面阻力,:,由于风流绕过固定边界的四周（如风流绕过电机车等）所引起的阻力，克服正面阻力而造成的风流能量损失是正面损失。,2023/10/732023/10/73通 风 阻 力 V,2024/11/17,4,2024/11/17,4,5.2,摩擦阻力,Friction Resistance,5.2.1,概述,5.2.2,层流的摩擦阻力,5.2.3,紊流的摩擦阻力,5.2.4,摩擦阻力系数的分析,5.2.5,摩擦阻力系数的确定,2023/10/742023/10/745.2 摩擦阻力,2024/11/17,5,2024/11/17,5,5.2.1,概述,General Introduction,在矿井通风中，摩擦阻力无论在层流或在紊流都可以用下式来计算。（达西公式，水力学）（式,5.1,）,(,Pa,),式中,h,f,摩擦阻力（,Pa,）,;,达西系数，是由管道的粗糙度与流体的运动状态所决定的常数，无因次；,d,管道直径或者巷道的等效直径（与断面相等的圆的直径,m,）；,L,巷道长度（,m,）；,V,巷道断面的平均风速（,m/s,）。,2023/10/752023/10/755.2.1 概述,2024/11/17,6,2024/11/17,6,5.2.2,层流的摩擦阻力,Friction Resistance of Laminar Flow,对于层流运动，流体的粘滞力起主导作用。实验和理论都得出 的结果。因此，层流状态的摩擦阻,力计算式为（式,5.2,）：,（,Pa,）,式中,为空气的粘性动力系数。上式表明，,层流状态下，摩擦阻力与平均风速的一次方成正比,。,2023/10/762023/10/765.2.2 层流的,2024/11/17,7,2024/11/17,7,5.2.3,紊流的摩擦阻力（,1,）,Friction Resistance of Turbulent Flow,在 中，,d,是非圆形巷道的等效直径，,根据水力半径的概念，即,或：,式中：,s,巷道断面；,p,巷道的周长。将上式代入阻力公式可以得式（,5.3,）：,（,Pa,）,2023/10/772023/10/775.2.3 紊流的摩,2024/11/17,8,2024/11/17,8,5.2.3,紊流的摩擦阻力（,2,）,Friction Resistance of Turbulent Flow,在式（,5.3,）中，对具体条件，是个常数，令,称为,摩擦阻力系数,，则有：,式（,5.4,）：,或 （,Pa,）,从上式可以看出，,P,L,S,Q,在,具体条件都是已知的，所以只要确定了摩擦阻力系数,，井巷,摩擦阻力,h,f,就可以求出。,2023/10/782023/10/785.2.3 紊流的摩,2024/11/17,9,2024/11/17,9,5.2.4,摩擦阻力系数的分析,(1),Analysis of Friction Resistance Coefficient,由 可知，,，,是影响,系数的因素。,1,空气密度的影响,与,成正比，所以若,随温度、湿度和气压变化，则,也将发生与,成正比的变化。,2,达西系数的影响,与,成正比，而,又是井巷的粗糙度和雷诺数所决定，所以井巷的粗糙度和雷诺数也就是摩擦阻力系数的影响因素。在水力学中，管道的粗糙度、雷诺数与,系数之间的关系，已由前人的实验（,尼古拉兹试验,）作了回答。,2023/10/792023/10/795.2.4 摩擦阻,2024/11/17,10,2024/11/17,10,5.2.4,摩擦阻力系数的分析,(1),Analysis of Friction Resistance Coefficient,在讨论这些关系之前，先介绍管道,粗糙度,的表示方法。水力学中管道的粗糙度是用,相对粗糙度,或者,相对光滑度,来表示的。,相对粗糙度,n,是管道内壁上凸起的平均高度（绝对粗糙度）,K,（,m,）与管道直径,d,（,m,）的比值，即,相对光滑度是指相对粗糙度的倒数，即,2023/10/7102023/10/7105.2.4 摩,2024/11/17,11,2024/11/17,11,5.2.4,摩擦阻力系数的分析,(1),Analysis of Friction Resistance Coefficient,在矿井通风中，用,混凝土砌碹支护,的一类巷道，其相对粗糙度与相对光滑度的概念和上述相同，但用,支柱支护,的一类巷道，其粗糙度则采用所谓,纵口径,和,横口径,来表示。,纵口径,是相邻两支架中心线的距离,l,（,m,）与支柱直径或厚度,d,（,m,）之比，即,横口径,的关系式为：,对于圆形巷道,对于非