The Numerical Simulation And Flow Analysis Of Tumble Steam Dryer And Its Rotary Joint

The energy-saving and environmental protection has become the urgent requirement of today’s heavy-smelting industry, and heat recovery boilers generally to be used to recovery high temperature flue gas that produced during metallurgical process, but it will be accompanied by the formation of high temperature steam. While the tumble steam dryer is resolved utilization of high temperature steam that produced by heat recovery boiler. The tumble steam dryer is based on the rational rotary dryer, equipped with a heating pipe in the interior of the drum, so that the convection heat transfer mode converted directly into indirect heat conduction. Its application is very extensive for a series of advantages of higher quality of dry product, lower pollution, lower costs and higher thermal efficiency, but its heat and mass transfer mechanism is more complex. So, CAD/CAE software and related theory of fluid mechanics to be used to analyze the problem of the low drying efficiency, short life of rotary joint and other issues when the rotary steam dryer was in use, also we analyzed single-phase flow field of steam for the key vulnerability of the rotary joint. Specific work is as follows:1) The establishment of CAD three-dimensional model.According to the structural parameter produced by entity mapping, using UG and SOLIDWORKS software to build a three-dimensional model of steam dryers and rotary joints.2) Pre-processing. Analyzing the structural features and working principles of the dryer and rotary joint, simplifying the establishment of fluid calculating model, utilizing MESH of WORKBENCH to divide the grid and set the boundary.3) The establishment and simulation of CFD finite element model. Setting diverse solutions needed by fluid analysis, selecting the model, calculating the parameter. By using standard SIMPLE algorithm and pressure-based solver, the hybrid model is selected in multiphase flow model, the standard K-E model is selected in turbulent model. In the aspect of material transfer, the model of UDF water evaporating formation is used to establish the dried CFD model of the dryer., then proceeding simulation in FLUENT.4) Numerical simulation of gas-solid flow in the dryer.Analyzing the state of motion and temperature distribution of gas-solid materials towards the tumble steam dryer, verifying the correctness of the CFD model, reselecting the optimal rotary speed and proposing the structure-optimized solution according to the simulated result and verifying the rationality of optimization.5) Analysis of steam’s flow rotary joint. Conducting the single-phase heat transfer analysis of the rotary joint, comparing the different distribution of temperature, velocity and pressure field towards rotary drums of different structure, and then selecting the better structure.In summary, this study provides a reference for reasonable selection of operation parameters of steam rotary dryer and structure optimization of the dryer and rotary joint.