Abstract: By adding particles into a gas flow, a gas-solid flow is formed. As the gas velocity increases, the gas-solid flow shows different patterns as bubbling fluidization, circulating fluidization and pneumatic conveying, in which the concentration of particles and the motion of gas-solid mixture are different, influencing the heat transfer between the gas-solid flow and immersed surface. In this paper, the heat transfer characters of the three flow patterns are reviewed, and the influencing factors, heat transfer mechanism and models are summarized. The concentration of particles and their movement play a decisive role on the heat transfer, and the operating parameters (gas velocity, bed pressure, bed temperature, etc) influence the heat transfer through changing the particle concentration and movement. A case of heat transfer enhancement, the heat exchange between gas-solid mixture and fixed bed, is analyzed. In addition, the future research area and the difficulty are presented.

Key words: heat transfer, two-phase flow, fluidization, conduction, gas-solid mixture

摘要： 在气流中加入颗粒，形成气固两相流。根据气流速度的不同，气固两相流分为鼓泡流态化、快速流态化、气力输送等形式。不同的流动形态，两相流内颗粒浓度及颗粒的运动规律不同，其传热特点也存在差异。通过回顾几种多相流流态的传热特点，总结了多相流与传热面换热的影响因素、气固两相流的传热机理与模型。气固两相流中颗粒浓度、颗粒运动对其传热起决定性作用，而操作参数（气流速度、床层压力、床层温度等）则主要通过改变颗粒浓度和颗粒运动影响传热。此外，通过气固两相流强化传热的应用实例——气固两相流与填充床的热交换，分析了颗粒在对流换热中所起的作用，并进一步提出了今后研究方向和难点所在。

关键词: 传热, 两相流, 流态化, 对流, 气固混合物