Analysis of cavitation problem of heated elastic composite ball

The cavitation problem of a composite ball under a uniform temperature is investigated, and the ball is composed of two elastic solid materials. The nonlinear mathematical model of the problem is established with the finite logarithmic strain measure for a large geometric deformation and by the Hooke law for elastic materials. The analytic solutions in a parametric form are derived for the thermal dilatation of the composite ball with a large elastic deformation. Solution curves are given to describe the variations of the critical temperature in the cavitation with the geometric and material parameters. The bifurcation curve is also given to reveal the cavity growth after void nucleation. The numerical results for a computational example indicate that the radius of the cavity will rapidly grow above the critical temperature, and the loop stress will become infinite when void nucleation. ＂This means that the materials near the cavity will produce a plastic deformation leading to local failure and fracture if the material of the internal ball is elastoplastic. In addition, the cavitation of the composite ball appears at a low temperature if the elastic property of the material of the internal ball is nearly uncompressible.

Reasonable Ball Size of Ball Mill for Preparing Coal Water Fuel and Forecasting Productive Capacity

By using the matrix theory, a 5 parameter grinding mathematical model is established. Based on the properties of feed coal and requirements for size distribution of final product, the model gives the required grinding probability for various particles and corresponding ball size distribution. By using this model, 3 different sizes of ball mill are designed and put into commercial use for coal water fuel. The forecasted ball mill capacity, the particle sizes and particle size distribution as well as the coal water fuel quality parameters are all in line with industrial operation results, which have proved the suitability of the model.

Novel Concept of Cleansing the Liquid Steel by the Fine In-Situ Phase Due to the Composite Ball Explosion Reaction in RH Ladle

The production of high purity steel is a major task for the iron and steel enterprises in the 21st century. To improve the quality of steel products and produce the cleanness steel, the key technique is to control inclusions in the molten steel. In the present investigation, a novel fine inclusion removal technology due to the dispersed in-situ phase induced by the composite ball explosion reaction was put forward. A composite ball with this function has been designed and the industrial experimental investigation was also carried out. The results indicate that feeding composite ball in RH ladle is a novel technology and the inclusion in the molten steel can be removed effectively. Compared with conventional inclusion removal technology, the number of the oxide inclusion can be decreased to a lower level and the inclusion size becomes much finer. Using this novel technology, the total oxygen in the as-cast slab can approach to 6ppm and the steel production cost for per ton can be reduced by 5 -12 RMB. This novel technology can be achieved without special facility and be realized in most steelmaking plant.