The paper presents the results of an activity carried out on a three-bladed inducer and compares the experimental data from other similar inducers. All the inducers considered in the present study have been designed by means of the simplified analytical model recently developed by some of the authors. The main effects of different geometrical solutions on hydraulic performance and flow instabilities of the pumps under noncavitating and cavitating conditions are presented in the paper

The article recalls the recent development of a reduced order model for the preliminary design, geometric definition and noncavitating performance prediction of tapered-hub, variable-pitch, mixed-flow inducers, and illustrates its application to a typical three-bladed, high-head inducer for liquid propellant rocket engines. The mean axisymmetric flow field at the trailing edge of the inducer blades and the noncavitating head coefficient at both design and off-design conditions are then compared with those obtained from the numerical flow simulations generated by a commercial CFD code. Together with earlier experimental validations, the results dramatically confirm the capability of the proposed model to generate interpretative and useful engineering solutions of the inducer preliminary design problem at a negligible fraction of the computational cost required by 3D numerical simulations.

Current research trends have advanced the use of “green propellants” on a wide scale for spacecraft in various space missions; mainly for environmental sustainability and safety concerns. Small satellites, particularly micro and nanosatellites, evolved from passive planetary-orbiting to being able to perform active orbital operations that may require high-thrust impulsive capabilities. Thus, onboard primary and auxiliary propulsion systems capable of performing such orbital operations are required. Novelty in primary propulsion systems design calls for specific attention to miniaturization, which can be achieved, along the above-mentioned orbital transfer capabilities, by utilizing green monopropellants due to their relative high performance together with simplicity, and better storability when compared to gaseous and bi-propellants, especially for miniaturized systems. Owing to the ongoing rapid research activities in the green-propulsion field, it was necessary to extensively study and collect various data of green monopropellants properties and performance that would further assist analysts and designers in the research and development of liquid propulsion systems. This review traces the history and origins of green monopropellants and after intensive study of physicochemical properties of such propellants it was possible to classify green monopropellants to three main classes: Energetic Ionic Liquids (EILs), Liquid NOx Monopropellants, and Hydrogen Peroxide Aqueous Solutions (HPAS). Further, the tabulated data and performance comparisons will provide substantial assistance in using analysis tools—such as: Rocket Propulsion Analysis (RPA) and NASA CEA—for engineers and scientists dealing with chemical propulsion systems analysis and design. Some applications of green monopropellants were discussed through different propulsion systems configurations such as: multi-mode, dual mode, and combined chemical–electric propulsion. Although the in-space demonstrated EILs (i.e., AF-M315E and LMP-103S) are widely proposed and utilized in many space applications, the investigation transpired that NOx fuel blends possess the highest performance, while HPAS yield the lowest performance even compared to hydrazine.

The present paper illustrates the firing tests recently carried out at Alta S.p.A., Pisa, Italy, on advanced catalytic beds for hydrogen peroxide (HP) decomposition in a new monopropellant thruster prototype designed for easier adjustment and control of the main operational and propulsive parameters. The tests refer to the comparison between a Pt/αAl 2 O 3 catalyst (named FC-LR-87) developed in collaboration with the Chemistry and

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