Spirally Corrugated Tube Heat Transfer Enhancement And Application

Heat exchangers are widely used in chemical, petroleum, power, metallurgy, and energy fields, and it is very important to country economy. So heat transfer enhancement is the inevitable trend of heat exchanger development.The technology of heat transfer enhancement is a new energy conversation technology that can improve heat transfer performance. It is to increase heat transfer efficiency by improving heat exchanger's structure with enhanced heat-transfer element to get the minimum equipment investment and run cost. Nowadays, the latest development is simulation, visual research, nanometer fluid research and field synergistic effect research. Although many methods of heat transfer enhancement have been put forward, in fact, little has been used in heat exchanger. So, it is not only a subject to be figured out in modern industry but also an urgent task in new energy exploration and energy conversation to design new high-efficiency heat exchangers by researching all kinds of heat transfer enhancement.This paper carried out a theoretical analysis on enhancement mechanism of spirally corrugated tube and gave the best parameter range by alyzing the in-tube reynolds number, groove depth and pitch's effect in-tube resistance and heat transfer . In addition, it has put ward the analysis research on in-tube heat transfer and flow resistance characteristic and correlations of heat transfer and resistance with and without phase-change combining with domestic and foreign scholars' opinions. It has also presented the comprehensive estimation analysis on spirally corrugated tube's good anti-pollution.Spirally corrugated tube can evidently increase in-tube and out-tube heat transfer coefficient with and without phase-change heat transfer. Thein-tube heat transfer coefficient of spirally corrugated tube is 1.5-2.0 times than the one of smooth tube and out-tube heat transfer coefficient is 1.5 times. So the whole heat transfer performance is 2-4 times than smooth tube. Now the spirally corrugated tube can be widely used in convective, boiling and condensation heat transfer between liquid and gas and the enhancement is very evident especially in condensation of in-tube gas or liquid and out-tube steam.Double-cut tube heat exchanger is a high-efficiency equipment with spirally corrugated tube as the heat transfer element, and it has the advantage of high heat-transfer efficiency, little flow resistance, simple and compact structure, convenient manufacture, little and easily-cleaned fouling, small volume, little weight and steel conservation, so it is applicable in the reconstruction of heat transfer places, and provides new way for energy and investment conversation ,and as a result, it has been popular at present.In this paper, to the heating application of double-cut tube gas-water heat exchanger in zouping electric power company, a detailed contrastive calculation has been done with the identical size smooth heat exchanger compared. Besides, an estimation on the spirally corrugated tube's thermal performance has been given by calculating heat transfer coefficient K and resistance. Finally, the result has been obtained, i.e. the use of spirally corrugated tube not only can improve heat transfer performance by 60% but also can save equipment investment and bring enormous economic benefit.