Thermal Characteristics Research Of Regenerative Heat Exchanger Based On Hybrid Packing

The process of industrial exhaust emissions was associated with a large amount of energy release which were not fully used and caused serious waste problem. In order to solve this problem, it was necessary to develop waste heat recovery technology. Regenerative heat exchanger which had an advantage of high thermal efficiency, low cost, compact structure was one of waste heat recovery equipment and widely used in the field of industrial heat utilization. This article made a research on this important regenerative heat exchanger, especially deepening the study on regenerative medium improvement, in order to make the regenerative heat exchange technology more perfect.This paper proposed a regenerative heat exchanger with hybrid packing. On the basis of previous research, the experimental and numerical simulation study on this heat exchanger were carried out. The performance of hybrid packing and other two traditional single packing were tested on self-built heat transfer experiment platform. Experimental research was focused on the performance comparison of the three types of regenerative packing; Simulation study was to deeply analysis the heat transfer dynamic process and discuss related impact factors of regenerative heat exchanger with hybrid packing. Through above research, some important conclusions were obtained, detailed summary as follows:(1) Based on regenerative heat transfer experiment platform, an experimental research was carried out in cold and hot conditions, which was related to the performance of honeycomb, ring packing and hybrid packing. The influence of inlet temperature and velocity on packing’s heat transfer effect was studied in hot test. The relationship between three packing’s thermal parameters and two factors was obtained, and it was found that the heat transfer effect of ring packing was better than honeycomb’s in low-speed area(less than 6.34 m/s). Honeycomb’s heat transfer effect was the best of three in more than 8 m/s high speed area. Hybrid packing’s heat transfer effect was better than the other two single packing’s within the speed range of 5.84 ~ 8 m/s, only 1% lower than honeycomb’s at a speed of more than 8 m/s. Similarly the influence of inlet velocity and packing height on packing’s resistance performance was studied in cold test, and the experimental resistance loss correlations of three packing was summarized. It was also found that the resistance loss of hybrid packing was 16% lower than ring packing’s, but 11.25% higher than honeycomb’s, which was more close to the honeycomb’s.(2) Regenerative heat exchanger’s heat transfer process was analyzed by simulation software. The influence of five structure and operation factors on hybrid packing were discussed. The results showed that it were good for hybrid packing’s heat transfer to appropriate increase cold air inlet velocity and shorten the reversing time. 13.4m/s best inlet velocity and 65 s optimal reversing time were obtained by analysis. Meanwhile increasing hybrid packing’s volume ratio and height were beneficial to thermal efficiency improvement, and taking height as 900 mm and volume ratio as 3 were more properly.