The Research Of Heat Exchange Performance Effect On Twisted Tube Vortex Effect In Liquid-solid Two Phase Flow

Twisted tube is mainly used in the heat exchange equipment in the field ofenergy and chemical industry, it has advantages like higher heat transfer performance,turbulence intensity and higher comprehensive performance comparing with ordinarycircular tube. In order to develop its heat transfer performance and enhance the abilityof heat transfer, we collect the result of research on fluidized bed and spiral flow fieldin recent years, considering adding solid particles into twisted tubes, then comparingwith normal circular tubes for analysis.Through the analysis of the heat transfer mechanism of twisted tube, knowingthat the main factors of influencing the twisted tube fluid turbulent intensity includeslong-short diameter ratio A/B and twist ratio S/De, adding solid particlesin twistedtube can achieve a better disturb effect. At this moment we have analyzed theenhanced heat transfer mechanism of liquid-solid two phase flow, which offeredtheoretical foundation for numerical simulation, at this moment wecome up with anappropriate relevance for the way to evaluate combination property.Base on the theoretical analysis of twisted tube and liquid-solid two phase flowtaking numerical simulation for two phase flow in tube, investigating the heat transferperformance, resistance performance and combination property of twisted tube indifferent Re and particle concentration. The result shows the heat transferperformance and resistance performance increasing with the degree of distortion andflattening increasing, enhancing39.7~48.1%and70%~136.3%comparing withnormal tube. At this moment the heat transfer performance of twisted tube slightlydecreases when the particle concentration is lower than5%and gradually increaseswhen the particle concentration is greater than5%. Considering the allowing pressuredrop range in engineering, the particle concentration couldn’t beyond10%.Furthermore we also take twisted tubes with different degree of distortion andflattening for contrastive analysis, then working out the optimizing results and theway of developing in the future.Constructing the experimental platform of twisted tube heat exchangersindependently, we take the experimental3kinds of twisted tube for liquid-solidtwo-phase-flow heat transfer enhancement experiments, also we have tested the heatexchanger performance and pressure drop of the different kinds of Re, particle sizeand particle concentration, at this moment twisted tube cross section ovality and distortion ratio of tube mixed fluid heat transfer performance and resistanceperformance influence have been investigated. Within the scope of the experimentresearch, with the improvement of twisted tube ovality and distortion ratio decreasedthe tube of the heat transfer performance increasing while fluid pressure drop in tubeincreasing. The heat exchanger performance of3kinds of twisted tube with particlesenhanced13.2%,13.4%and15.5%averagely comparing with the tubes withoutparticles, the pressure drop of them enhance61.2%,68.2%and74.1%. Basing on theanalyzing data ensuring Better heat transfer performance of the particle size2-5mmand particle volume concentration range of5%After the experiment the appropriaterange of particle size and particle concentration as the twisted tube can achieve thebetter heat exchange performance. The error between the value of experiment andnumerical simulation is11.2%, which demonstrating the reliability of numericalsimulation.