液-液循环流化床制冰过程的(火用)分析

采用水与另一种非相溶载冷流体直接接触换热结冰的液液循环流化床是一种新型动态制取流体冰方法.针对该方法建立了研究床内多相流动与传热过程的数值模拟平台,以热力学第二定律为基础提出了液液循环流化床制冰过程的火用损失计算模型.采用数值试验方法探讨了水滴直径、载冷液体入口温度和速度对系统的制冰能力和火用损失的影响.研究结果发现,减小水滴直径和入口温度可以不断提高循环流化床的制冰能力,但减小入口速度的作用有限,而减小水滴直径是兼顾制冰能力和过程火用损失的最有利途径.

Exergy analysis of ice-making process for liquid-liquid circulating fluidized bed

Liquid-liquid circulating fluidized bed,which can be used as a novel method of dynamic ice forming,was studied using direct contact heat transfer between droplets and the coolant for ice storage system.A numerical model for modeling multiphase flows and heat transfer in circulating fluidized bed is developed.Exergy is discussed for liquid-liquid circulating fluidized bed based on the second law of thermodynamics.The numerical method is used to study the influence of operating parameters(such as the droplet diameter and the inlet temperature or velocity average of liquid phase) on ice-making performance and exergy in the dynamic ice-making process.The research results indicate that ice-making performance always increases with decreasing droplet diameter and the inlet temperature of liquid phase and not so much with decreasing the inlet temperature of liquid phase.Moreover,to decrease the droplet diameter is considered to be the best way with consideration of the contradiction of ice-making performance and exergy.