带式输送机模拟摩擦因数的研究

为了提高带式输送机主要阻力的计算准确性,提出了一种模拟摩擦因数的量化分析方法。研究了主要阻力的组成部分,通过对各部分阻力的量化计算,确定了各部分阻力在模拟摩擦因数中的比例。针对不同工况进行计算,定量分析了对模拟摩擦因数的影响。研究表明:压陷阻力占主要阻力的一半以上;托辊组槽角对主要阻力的影响与角度成正比;托辊直径越大对主要阻力影响越小。在托辊更换的实践中,验证了该计算方法的有效性。

长距离带式输送机主要阻力计算分析

托辊的转动阻力和输送带的压陷阻力是长距离带式输送机的主要运行阻力。运用适当的方法对其进行计算分析,对带式输送机的整机系统模型的深入研究具有重要的意义。从静态和动态两方面分别讨论了计算主要阻力的方法,计算实例表明,提出的动态设计方法可以利用带式输送机特征参数进行计算,符合输送机实际运行工况,动态设计比静态设计更加准确。

“V”形临界状态复杂工况下带式输送机的分析与应用

虎龙沟煤业井下带式输送机纵向“V”形布置进行了设计,对基于“V”形临界状态的带式输送机在不同工况下运行的受力进行了计算,并进行了部件选型。实践应用表明,新设计的带式输送机实际运行效果理想,设计合理。

Heat transfer and friction factor of Therminol liquid phase heat transfer fluid in a ribbed tube

Experiments and simulations on flow and heat transfer behavior of Therminol-55 liquid phase heat transfer fluid have been conducted in a ribbed tube with the outer diameter and inner diameter 25.0 and 20.0 mm,pitch and rib height of 4.5 and 1.0 mm.respectively.Experimental results show that the heat transfer and thermal performance of Therminol-55 liquid phase heat transfer fluid in the ribbed tube are considerably improved compared to those of the smooth tube.The Nusselt number increase with the increase of Reynolds number.The increase in heat transfer rate of the ribbed tube has a mean value of 2.24 times.Also,the pressure drop results reveal that the average friction factor of the ribbed tube is in a range of 2.4 and 2.8 times over the smooth tube.Numerical simulations of three-dimensional flow behavior of Therminol-55 liquid phase heat transfer fluid are carried out using three different turbulence models in the ribbed tube.The numerical results show that the heat transfer of ribbed tube is improved because vortices are generated behind ribs,which produce some disruptions to fluid flow and enhance heat transfer compared with smooth tube.The numerical results prove that the ribbed tube can improve heat transfer and fluid flow performances of Therminol liquid phase heat transfer fluid.