Elliptical Tube Inserted To Strengthen The Sphere Circulating Particle Heat Transfer Performance Impact Study

The fouling phenomenon in the heat exchange tube has great impact on the heat transfer performance of the heat exchanger. The liquid-solid two phase flow has strong effect on the fouling scale removal and prevention and the function of strengthening heat transfer. On the basis of comprehensive analysis of existing multiphase flow application technology, the technique of tube inserted ellipsoid to strengthen the liquid-solid two phase flow is proposed. This article analyzes the influence of tube inserted ellipsoid on the liquid-solid two phase flow and the fouling scale removal and prevention from the theoretical analysis, numerical simulation and the experimental study and application of several aspects. This thesis mainly consists of the following aspects.First of all, by analyzing the research and application status of the heat transfer enhancement and scale removal technology, this article summarizes the research and application status at home and abroad, numerical simulation and experimental test methods of the heat transfer enhancement of multiphase flow technology, then proposes this topic and research methods.Secondly, the paper introduces the basic theory of phase fluids, the calculation model and control equation of the continuous phase and the discrete phase in liquid-solid two-phase flow. And the solving process, the equation of motion, turbulent diffusion model and wear model of the discrete phase are introduced.Thirdly, this thesis makes stimulation of the tube inserted ellipsoid in tube flow field, heat transfer performance, resistance performance, wear volume and wear uniformity by using Fluent software. According to the simulation parameters specified in the previous work, this paper calculates three factors(fluid velocity, ratio of ellipsoid axle, the space of ellipsoid installation) and three levels and makes a comprehensive analysis on flow field, resistance performance, wear volume and wear uniformity. And the spiral structure parameters are analyzed and optimized by using orthogonal factor method, a better group is obtained through comprehensive performance evaluation.Fourth, through the experimental platform of the circulating fluidized exchanger and the interpolation ellipsoid and particles that are purchased according to the simulation parameters. Experiments study the influence of interpolation ellipsoid structure parameters, fluidized particle parameters and the process parameters on heat transfer performance of the heat exchanger and the effect of scale removal and prevention.According to comprehensive numerical simulation and experimental study: tube inserted ellipsoid scatters with spiral tube fluid flow which makes the fluid impact the surface of the tube wall directly. The solid phased particles along with the fluid shock the surface of the tube wall at the same time, which increases the collision probability of the particles and wall greatly, destroying the boundary layer of the flow and the temperature and increasing the turbulence intensity which enhances the heat transfer coefficient of large scale. Therefore, the heat transfer enhancement tube inserted ellipsoid and scale removal and prevention technology has broad application prospects.