Development of High-Energy-Density Liquid Aerospace Fuel: A Perspective

Aerospace aircraft has significantly improved the life quality of human beings and extended the capability of space explosion since its appearance in 1903, in which liquid propellants or fuels provide the key power source. For jet fuels, its property of energy density plays an important role in determining the flight range, load, and performance of the aircraft. Therefore, the design and fabrication of high-energy-density (HED) fuels attract more and more attention from researchers all over the world. Herein, we briefly introduce the development of liquid jet fuels and HED fuels and demonstrate the future development of HED fuels. To further improve the energy density of fuel, the approaches of design and construction of multi-cyclic and stained molecule structures are proposed. To break through the density limit of hydrocarbon fuels, the addition of energetic nanoparticles in HED fuels to produce nanofluid or gelled fuels may provide a facile and effective method to significantly increase the energy density. This work provides the perspective for the development of HED fuels for advanced aircrafts.

Designing high-performance hypergolic propellants based on materials genome

A new generation of rocket propellants for deep space exploration, ionic liquid propellants, with long endurance and high stability, is attracting more and more attention. However, a major defect of ionic liquid propellants that restricts their application is the inadequate hypergolic reactivity between the fuel and the oxidant, and this defect results in local burnout and accidental explosions during the launch process. We propose a visualization model to show the features of structure, density, thermal stability, and hypergolic activity for estimating propellant performances and their application abilities. This propellant materials genome and visualization model greatly improves the efficiency and quality of developing high-performance propellants, which benefits the discovery of new advanced functional molecules in the field of energetic materials.

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.

Economic sectors of strategic importance to the national security. A case of Poland

The purpose of the paper is to properly define the economic sectors of strategic importance to the national security and to evaluate the state’s tools which protect this security. The paper’s methodology is based on two analyses; the former focusing on instruments which are applied by the state in order to control certain fields of the economy, and the latter investigating economic sectors in terms of concentration, impact on the state security and integration with other sectors. The paper also defines the criteria which helped to identify sectors which have strategic importance to the national security, i.e. production and supply of electric energy; extraction and supply of natural gas; extraction, distribution and storage of liquid propellants, telecommunications, banking industry; banknotes and documents’ production (together with related IT solutions) and military industry. The article leads to the conclusion that these sectors are strategically important to the national security. However, there is still a lack of coherent and complete legal regulations that would protect the national security interest related to the part of the economy represented by the analyzed sectors and companies.