p. lin

This study proposes a new intermediate warehouse to prevent the problem that the ore in the vertical pipeline hydraulic lifting system blocks the nozzle during the process of being sucked into the lifting hard tube. A mathematical model and a finite element model of ore transport are established. Numerical simulation and experimental research are performed on the process of ore injection into the intermediate warehouse. Results show that the proposed intermediate warehouse has higher ore transmission efficiency, smaller pressure pulsation, and more stable transmission process compared with the traditional structure scheme. The larger the slurry conveying flow, the shorter the time required to convey the ore. In the process of slurry injection, the closer to the inlet, the more uneven the velocity distribution on the Z section, and the more concentrated the dynamic pressure. The closer to the lower end of the intermediate warehouse, the more dispersed the dynamic pressure, and the fluctuation of dynamic pressure in the intermediate warehouse is the main cause of unstable flow. The feed flow has a great influence on the stress state of the intermediate warehouse structure, the ore transfer time, and the stress decay period. The feed flow rate should be reasonably selected to meet the working requirements.

The gas-liquid two-phase flow with interfacial behaviors and bubble-liquid interactions is widely encountered in industrial processes such as that in gas-liquid reactors. The complicated phase structure makes it difficult to be modeled. The present work proposes a multi-scale mathematical model to simulate the bubbly flow in a square column. The volume of fluid (VOF) method is applied to treat the separated interface, and the discrete bubble model (DBM) is incorporated to handle the dynamics of dispersed bubbles. The hybrid model is validated against the benchmark experimental data to study the accuracy and suitability of the modeling framework for bubbly flows. And the influence of interphase forces on bubbly flow patterns and velocity profiles is investigated. It is found that the employment of both pressure gradient force and Ishii-Zuber drag model provides fairly good agreements with experimental data for velocity profiles.

Squirrel cage fans are commonly used in HVAC (heating, ventilation, and air conditioning) systems. The single arc blade model is commonly used in this type of fans since it can be shaped simply only by two parameters of inlet and outlet angle of blade. However, the efficiency of the fans is much lower than that we expected. In this paper, the single arc blade is replaced by double-arc blade in order to optimize the blade model and to improve the static pressure efficiency and total pressure efficiency of the fan. Numerical results show that the design with double arc blade is able to improve the internal flow, and to enhance the aerodynamic performance of squirrel cage fans.