Experimental Study On Enhancing Heat Transfer Characteristics Of Flue Gas Heat Recovery Exchanger

Flue gas exchanger is important equipment in the process of the heat recovery, the heat transfer performance have a profound effect on the entire heat recovery system. Dimpled structure is a double strengthen heat transfer tube, while it used in the heat exchanger rarely reported. In order to evaluate the heat transfer performance, this article independently design and built the test bench, and research for the heat recovery exchanger boiling heat transfer characteristics. The research provide basis theoretical for the process of the same heat transfer equipment design, it has an important academic significance and engineering value.First of all, Micro turbine generate flue gas as heat source, water as the work fluid, research the boiling heat transfer characteristics of three types tube include plain tube, vortex tube, dimpled tube. Within the range of experiment parameters, the experiment result show that vortex tube overall heat transfer coefficient 1.3~1.6 times of plain tube, tube boiling heat transfer coefficient is about 1.6~2.1times of plain tube, external surface heat transfer coefficient is about 1.3~1.5 times of the plain tube. Dimpled tube overall heat transfer coefficient can reach 1.8~2.3 times compare with the plain tube, tube boiling heat transfer coefficient was about 2.03~2.5 times compare with the plain tube, external surface transfer coefficient was about 1.8~2 times compare with the plain tube. Dimple structural tube has a markedly advancement in heat transfer.Next, introduce some important tube boiling heat transfer empirical formula; analyze the heat transfer enhancement mechanism of dimpled structure tube, using the experimental data and physical properties, through linear regression establish vortex and dimpled tube boiling heat transfer correlation.Finally, take Paper Co., Ltd., Sichuan 10t/h boiler optimization flue gas heat recovery system project as an example. After install flue gas heat recovery exchanger in the rear of the boiler, assess the effect of economic and environmental benefits comprehensively; relate methods and conclusions of this project can provided a reference for other heat recovery project.