Investigation on heat transfer behavior of particles flowing around side wall tube for sustainable development

The efficient conversion and utilization of energy is an effective way to achieve sustainable development. Utilizing moving bed heat exchanger for waste heat recovery of high temperature particles is an effective method. At present, there is still potential for improving the heat transfer efficiency of moving bed heat exchanger. In this study, a moving bed heat exchanger model with a side wall heat exchange tube was established by Discrete Element Method (DEM). The effect of particle size, rest friction factor and density on heat transfer behavior of particles flow around side wall tube was investigated. The results showed that the particle size has a marked influence on the heat transfer behavior, with the increase of particle size from 3 mm to 19 mm, the effective heat transfer coefficient decreases by 99.36 W/(m2·K), the heat transfer rate decreases by 66.73 %, the number of contacts reduces by 97.26 %, and the small particles exhibit better temperature uniformity. As the rest friction factor increases from 0.3 to 0.7, the effective heat transfer coefficient reduces by 80.89 W/(m2·K), the heat transfer rate and number of contacts have a decrease of 2.29 % and 10.40 %. When the particle density increases from 1476 kg/m3 to 4200 kg/m3, the effective heat transfer coefficient increases by 74.76 W/(m2·K), the heat transfer rate has a growth of 20.89 %. The correlation formula of Nu and h is established for the prediction of heat transfer behavior in engineering application.