熵产方法在旋风分离器内部能耗分析中的应用

Application of entropy generation method for analyzing energy loss of cyclone separator

应用雷诺应力模型对壁面绝热的旋风分离器的流场进行数值分析,对模拟结果采用熵产分析法和■分析法计算分离器的■损,证实了热力学第二定律研究旋风分离器能量损失的可行性。分别计算了旋风分离器内湍流熵产、黏性熵产、壁面熵产和温差传热熵产。结果表明,壁面熵产和湍流熵产占总熵产的比例分别大于56%和38%,是影响旋风分离器能耗的主要因素。分析了旋风分离器内局部熵产,结果表明,芯管附近体积占旋风分离器体积的10%,其熵产占分离器总熵产的比例高于14%,灰斗入口附近体积仅为旋风分离器体积的5.8%,其熵产占总熵产的比例高于16%,因此芯管附近和排尘口附近是旋风分离器能耗的主要区域。

In this paper, entropy generation analysis is applied to investigate cyclone separator. The Reynolds stress model is used to simulate the flow field in a cyclone separator with adiabatic wall. The energy loss predicted by pressure drop and exergy loss predicted by entropy generation analysis method and exergy analysis method for calculation results of computational fluid dynamics indicate the availability of the second law of thermodynamics for investigating the energy consumption in cyclone separator. The entropy generation due to turbulent dissipation, viscosity in turbulent core flows, fluid friction near the wall, and heat transfer are calculated with the computation of turbulent kinetic dissipation rate, velocity, wall shear stress and temperature. It is found that the fluid friction near the wall and turbulent dissipation are the main factors for energy loss of cyclone separator. The percent of entropy generation in the vicinity of finder vortex and dust exit with the volume ratio of 10% and 5.8% in the cyclone separator is over 14%and 16%, respectively. The result can serve as a direction to decrease energy loss of cyclone separator.