| Vortex generator is a kind of element for passive heat transfer enhancement, usually on the heat transfer surface of heat exchange in the form of array layout, to produce the induced eddy to thinning or destroy the wall boundary layer and implementation to strengthen heat transfer.To install with the same cross-section of incident flow round going a while, rectangle and triangle stare blankly five kinds of vortex generator of rectangular channel has carried on the research of heat transfer and flow resistance characteristics. Through comprehensive comparison, can be assumed that a circular vortex generator is a kind of low flow resistance and high efficient new vortex generator. And further to install a circular stare blankly vortex generator of rectangular channel has carried on the research of heat transfer and flow resistance characteristics. Analyzed under different number Re, flute length, arrangement, size and arrangement of geometric parameters such as pitch radius of the circular stare blankly vortex generator effect on the heat transfer and flow resistance characteristics of rectangular channel. The results show that, the best integrated heat transfer in a circular stare blankly vortex generator geometric parameters as follows: pull over with in-line arrangement, stare blankly is 4/8H long, radius of 2.5mm, the spacing between 30-40 mm. At the same time, here is using the field synergy theory analysis, collaborative number Fc rectangle smooth passage and four different flute length of the horizontal semi-cylindrical vortex generators are decreased with the increase of Reynolds number Re, and the change tendency is becoming more and more gentle, eventually gradually tend to be constant value. The changing trends and strengthen the overall heat transfer calculation results reflect the rule is consistent.To study of circular stare blankly vortex generator operation condition and the influence of structure parameters of the heat exchange surface fouling. Firstly analyzed the concentration of a solution of CaSO4, wall temperature and inlet velocity on the fouling deposition rate and denudation rate and the influence of fouling resistance. The results showed that with the increase of inlet velocity deposition rates and denudation rate increases, while reducing the thermal resistance of fouling. As the wall temperature increases the deposition rate, denudation rate and fouling resistance are increased. With increasing concentration of the working fluid deposition rate, denudation and fouling resistance rates were also increased. Then analyzed the long circular going a while at the vortex generator, arrangement, the size of the radius and the longitudinal spacing between the geometry factors affect the surface fouling deposition. The results showed that, the fouling resistance after decreased and then increased with the length of the vortex generator increased and appear minimum at 4/8H shocked strengths; And increased with increasing the spacing of vortex generator, when the spacing more than 55 mm fouling resistance will gradually tend to the light path of fouling resistance; And increased with increasing the radius of vortex generator; The same spacing, radius and long stare blankly of 4/8H, pull over arrangement of fouling resistance is minimal.Finally, based on the different structure of circular stare blankly vortex generator heat transfer surface dirt and comprehensive analysis of heat transfer. It can be considered, When long stare blankly is 4/8H, spacing in 35-50 mm and radius in 4-5mm, round stare blankly vortex generator can keep a good scale inhibition and the comprehensive heat transfer effect. |
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