The relationship between the grinding characteristics of polymetallic complex ore and its component minerals, pyrrhotite, sphalerite, and quartz, under the action of abrasion was studied, based on batch grinding experiments and theoretical analysis methods of selective grinding. The results show that when the polymetallic complex ore was subjected to the action of abrasion, the crushing effect of ore was enhanced by the existence of sphalerite, that is, sphalerite plays a positive role in the crushing effect of ore. The crushing effect of ore was reduced by the existence of pyrrhotite and quartz, that is, pyrrhotite and quartz plays a negative role in the crushing effect of ore. In addition, the sphalerite had a more prominent effect on the grinding characteristics of the ore. The grinding speed of ore and its component minerals decreased exponentially with the grinding time, and the instantaneous grinding speed of 0 min was negatively correlated with the feed sizes. The rapidly decreasing trend of the grinding speed reached the threshold when the grinding time reached 4 min. The results can provide some theoretical guidance for the study of grinding characteristics of multi-component complex ores in subsequent grinding process.
In order to guide the optimization design of the pipeline network of the aircraft-fixed gas fire extinguishing system and improve its fire extinguishing performance, FLUENT software was used to simulate the influence of pipeline parameters such as diameter, length, and roughness on the release characteristics of the fire extinguishing agent. It can be found that the extinguishing agent can be divided into liquid and vapor extinguishing agents in the fire extinguishing pipeline system during the release. The spatial distribution and proportion of the liquid and vapor extinguishing agents are asymmetric. Results show that the peak value of the pressure drop rate (dPmax) has a good quadratic function relationship with the pipeline diameter (D) and the functional relationship is dPmax=−22.224+2.782D+0.089D2, which means that the peak value increased significantly with the increase in the pipeline diameter. Moreover, when the pipeline diameter is 25 mm, the average pressure drop rate of the vessel is about 35.02 MPa/s, which is 5.97 times the value of the average pressure drop rate when the pipeline diameter is 10 mm. With the increase in the pipeline diameter, the release time decreases significantly, the mass flow rate increases obviously, while the gasification ratio decreases rapidly at first and then increases slightly. The pipeline length also has a significant influence on the release characteristics of the extinguishing agent. With the increase in the pipeline length, the release time and the gasification ratio increase linearly, while the mass flow rate decreases linearly. Compared with the pipeline diameter and pipeline length, the influence of the pipeline roughness on the release characteristics of the extinguishing agent is weak. With the increase in the pipeline roughness, the release time and the gasification ratio of the extinguishing agent increases slowly, while the mass flow rate decreases slowly.
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