Designing nano-aluminum laden fuel pump for aviation applications

In view of the fact that traditional liquid propellants cannot meet the design requirements of large-thrust flight vehicle, it has become a new trend to add nano-metal powder to liquid propellants to greatly increase density and specific impulse. In order to achieve the variable flow-rate and variable-proportion transportation of aviation fuel with nano-aluminum, a new type of solid-liquid mixing pumping system is designed, including powder conveying device, stirring device, pump and corresponding drive and transmission system. For the purpose of avoiding the frictional contact between the rotors, which will bring potential hazard to nano-aluminum powder, a non-contact twin-screw pump with synchronous gears is designed. Among them, based on the considerations of flow pulsation, volumetric efficiency and manufacturing difficulty, cycloid profile is adopted for screw rotors. After completing the functional design, geometric parameter design, structural design, 3D modeling, prototype manufacturing and preliminary performance estimation of the mixing pumping system, the performance of the screw feeder, agitator, screw pump was tested through experiments to meet the expected design requirements. The designed agitator can achieve sufficient mixing at 500 rpm in less than 10 s. Even though 50-micron clearances are designed with a relatively small rotor diameter, the volumetric efficiency of screw pump can reach above 50% when the discharge pressure is below 450 kPa and the flow rate is set as 10 L/min, the power of the screw pump is less than 700 W. This design facilitates the rapid real-time preparation of metallized propellants and provides a reference for further improving the design and control methods of nanoparticle two-phase flow pumping

Investigation of beryllium diffusion in the supercooled liquid and glassy states of the amorphous alloy Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5) by high energy helium elastic backscattering

The elastic scattering cross section for ^9Be(α, α)^9Be has been measured in a strongly resonant region from 6.00 to 6.50 MeV at a laboratory angle of 177°. This reaction has been used to investigate Be diffusion in the bulk metallic amorphous alloy Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5) in the solid state (SS) as well as in the supercooled liquid state (SLS). Above the glass transition, i.e., in the SLS, a remarkable increase in the diffusivity of Be (about two orders of magnitude over a 40 K temperature interval) was observed, which can be explained with a modified Arrhenius fit, which takes into account the change in configurational entropy due to the glass transition