Mechanical model of hollow-external-screw drill rod for lunar soil particle vertical conveying
This paper presents a mechanical model of drilling rod in lunar soil deep drilling process by expanding the theory of vertical screw conveyor. Space systems on lunar surface need to adapt to extremely bad environment and a drilling system would represent the fittest tool to collect soil sample to be analyzed in lunar exploration. Hollow-external-screw drill rod is a kind of most commonly used and reliable drill rod configuration which is one of the core executive components of lunar drilling- sampling mechanism. Drilling cuttings at the bottom of the hole are continuously sent to the lunar surface and the interaction between the drilling rod and the soil is difficult to model by numerical tools. Solid vertical transport theory in vertical screw conveyor and a soil-transporting mechanical model of long earth boring auger are applied to model the aforementioned interaction. In this force analysis of the mechanical model, not only the spiral angle variation is considered, but also the radial distribution and soil pressure in the particle vertical conveying. All these make the theoretical analysis more comprehensive than traditional methods. This paper also provides mathematical simulation of the soil-transporting process and the validation of the theoretical model mentioned above will be confirmed by the numerical and physical experiments.
The mathematical simulation of a new equipment for particle conveying
This article brings out a brand-new equipment-Screw-gas Bulk Sucking and Taking Equipment for the solution, which applies both the theory of vertical screw conveyor and the theory of pneumatic handling. It constitutes of 3 parts; respectively from bottom to above they are: Centrifugal force Separating Part, Screw Lifting Part and Pneumatic Conveying Part. Particle material is drawn into the equipment in the form of gas-solid two-phase flow by the Atmospheric pressure, and then helically rises in the Centrifugal Force Separating Part which is an inverted cone. The material would be separated from the two-phase flow by the effect of centrifugal force and then be lifted in the Screw Lifting Part. The gas flow with the very little remained material would be drawn into the blower. By thus Screw-gas Bulk Sucking and Taking Equipment could take the material and put it to the next conveying process conveniently and efficiently. The article provides the mathematical simulation of the characteristics of separating surfaces of the material during the conveying process. Four types of separating curves have been found with the decision of the corresponding required conditions. The calculation based on Matlab proves the correctness of the assumptions and analysis.
Actuating Principle of Online Automatic Balancer with Counter Weight Driven by Magnetic Force
Kinematic precept of mass block in automatic balancer is proposed following the principle of online automatic dynamic balancing.By combination of electromagnet and permanent magnet,the magnetic circuit of the balancer with ring coil and rare earth permanent magnet is designed.Actuating process of the balancer is discussed and then a step drive voltage waveform is defined.For the high-speed grinding motorized spindle 170MD12Y16,the mechanical structure and dimensions of the balancer are schemed out.The electromagnetic simulations for the designed balancer are conducted and the better coil ampere-turns and reluctance adjusting ring thickness are then determined.The validity of simulation results is verified by a balancer driving experiment and the desired voltage value and its duration time are also determined.the designed balancer has a stable operation process without out-of-step and fluctuation around balanced position when the ampere-turns are considered as 1 kA,the reluctance adjusting ring thickness 0.2 mm,the driving voltage 12.4 V and the voltage duration time 120 ms.