摘要
热害矿井中,热因素的存在会引起井巷各断面气体参数的差异,产生风流流动的热阻力,阻力的变化将导致通风网络风量的变化,影响矿井通风安全。由于热阻力难以用1个参数表征,在通风网络解算中,一般只考虑巷道风阻力,忽略热阻力的存在,即忽略热因素的影响。将有稳定热因素影响的井巷视为壁面粗糙、无热因素和有热因素、无黏性的两个巷道的叠合,分别分析井巷的摩擦阻力和热阻力,对比摩擦阻力与热阻力计算公式,提出类似于风阻的稳定热因素影响下风流流动的热阻概念,并推导其计算公式。结果表明,热阻与初始停滞焓、热源绝对放热量、两断面空气密度以及井巷断面面积等物理参数有关,与风量无关,与风阻量纲一致。最后以常用的通风网络解算方法为基础,对风量修正公式进行修正,提出嵌入热阻后新的风网解算方法。对比热阻融入经验公式前后的结果,证明热因素的存在对网络风量调节有较大影响。
This paper takes it as its target to study the relation of the thermal elements and the successful interior ventilation net of the mine. As is known, in the heat harmful mine, thermal elements tend to lead to the difference of the gas standard between sections, which may cause thermal drag and impede the air flow. The variation of re- sistance of the thermal elements is likely to affect the regular ventila- tion rate change in the mining ventilation network and in turn may cause ventilation resistance and even breakdown of the ventilation network. Since it is not easy to define and describe the actual picture of the thermal drag, it is usually believed that it is merely a kind of roadway＇s friction drag and therefore can be neglected in the ventila- tion network calculation. However, the thermal element should not be ignored. This paper would like to break the roadway thermal elements into two parts, one being unstable thermal element with its wall roughness, the other being stable and coherent. On this ground, the thermal elements can be analyzed as the frictional resistance and the thermal drag respectively. It is on this basis, we have found the rela- tionship between the friction drag and thermal drag design formulas. In proceeding with our study, we have proposed the concept and de- sign formulas of the thermal resistance, which is a parameter, repre- senting the impact given by the thermal drag. Thermal elements can be embedded in ventilation network through the thermal resistance, which should be taken into account its impact on the ventilation net- work calculation. Thus, the thermal resistance can be defined as the initial stagnation enthalpy, the absolute heat output of heat sources, air density of two cross sections, acreage of the roadways, but nothing to do with the air quantity. The thermal resistance can be taken as the same dimension with the friction resistance, which can be plugged into the classical revise formula and can be used to revise the air quantity. Here is just an example to show that the results of mine ventilation network calculation should be greatly different from what we understand before and after embedding the thermal resistance. It has profound implications for the ventilation network calculation in the heat-detested mine with thermal elements.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2013年第5期175-178,共4页
Journal of Safety and Environment
关键词
安全工程
矿井通风
网络解算
热阻
降温
热因素
safety engineering
mine ventilation
network calcula- tion
thermal resistance
temperature reduction
ther- mal element
