Papers by Author: Kai Wu

Abstract: Biomass is a kind of important renewable energy resource, while the solidification technology provides an effective way for its energy utilization. The current feeding device of the biomass briquetting machine in China is manual or semi-automated, with low production efficiency. A new kind of automatic feeding device has been designed to meet the continuous feed requirements of a production line with the production capacity of 10~12 T/h in this paper. The shaftless screw device can realize continuous material supply, and the batch hopper provide materials for different briquetting machine, at the same time the crank-rocker mechanism provides certain vibration to prevent material clogging. This device gives a uniform material supply with a high degree of automation, which can improve the biomass fuel production effectively proved by practice.

Abstract: According to the analyses on the forming principle of the pellet mill and the relative motion state between the roller and the die during the extrusion process, the mathematical models of the extruding height of material and the extruding velocity of the material were developed. Based on the models, the influences of the radius ratio λ of the roller and the die and the maximum seizing angle θ on the maximum extruding height of material hmax and the pellet quality were analyzed and calculated. The calculation results show that the increases of θ and λ in a certain range are beneficial to the production yield, increasing the effective work area, and improving the pellet quality. The results provide a theoretical basis for optimizing structural design of the pellet mill.

Abstract: In view of the difficult balance of inertia force for the slider-crank mechanism, on the basis of analyzing inertia force of the slider-crank mechanism, a new balancing method of inertia force was proposed for the slider-crank mechanism with small linkage ratio, the rotary mass and the moving mass had replaced the mechanism mass, the inertia force of rotary mass was balanced by rotary weight counterbalance, a spring was disposed by slider, it provided variable elastic force and balanced the inertia force of moving mass. Then the balancing method was analyzed deeply and the theoretical derivation was made, the results show that this balancing method would achieved approximately balance for inertia force of the slider-crank mechanism with small linkage ratio.

Abstract: First the extruding force model of isotropic powder material passing through the die hole in pelleting process was founded, then the pressure distribution model in the extruding areas was built. Based on the two models, the torque model in pelleting process of rotated roll forming was developed. The experiments were carried out on the special designed pellet mill and the wireless torque testing system was used to analysis the torque datum. It is shown the computing datum is very close to the experimental results. The researches are helpful to the optimal structural design, energy consume reduction and proper use of the pellet mill in practice.

Abstract: Pellet mill has been widely used in feed industry and biomass energy industry and ring die is its critical component. The structure of the ring die hole not only determines whether the feed can go through the hole smoothly, but also has a great effect on the abrasion of die hole. The finite element simulations that describe the feed extruding in different die-hole have been done and the axial nodal displacements as well as equivalent force along the die-hole internal surface are extracted. Then the feed extruding in different conicities of inlets are also analyzed. It is shown that the camber inlet is better than the conical inlet when taking the abrasion of die-hole into account. Furthermore, the smaller entrance angle of conical inlet is better.

Abstract: A new finite element analysis method of driver drum is introduced in this paper, conveyor belt is introduced in analysis model, and the effect that bearing imposed on drum is treated as spherical constraints. The drum is analyzed under the coalition of assembly load and ultimate torque load using the paper method as well as the traditional method, and the results between two methods are compared. The analysis results show that the danger points are on the hub inner and the weld seam between spoke and hub, the comparison shows that the analysis results by the paper described method are smaller than the traditional method results by 10%. The load imposing ways described in this paper are more consistent with the actual work process, and the analysis results are more accurate and reliable.

Abstract: The structural characteristics of a laminating press were analyzed, and the corresponding finite element model was built with some essential simplification. By structural analysis, the distributions of stress and strain were obtained, based on which the rationality of the frame design can be verified. According to the complex structure and loading conditions of the laminating press, four analytical schemes with different models and boundary conditions were adopted, then the results of different analytical schemes were compared, and the causes resulting in the calculation differences were analyzed. The result shows that in analyzing different parts of the laminating press frame, different models and boundary conditions were required.

Abstract: The existent studies on the machining technologies of the thin-webbed structure component were reviewed. Then the milling dynamics analysis model on the thin-webbed component was presented. Based on the model, FEM analyses on the machining dynamics of the thin-webbed structure component were carried out. At last, the analysis results were concluded. It is shown that there is an optimized rotation speed of the spindle to minimize the machining vibration.

Abstract: The existent studies on the milling of the thin-web components are reviewed first, then the cutter selection strategies are discussed theoretically based on the mechanistic model of the milling cutter, and several experiments are carried out to verify the theoretical analysis. At last, the conclusions are given on the cutter selection strategy in the milling of the thin-web components.