Numerical study of continuously rotating detonation in two-fuel gaseous mixture

Numerical simulation of continuously rotating detonations of stoichiometric two-fuel mixture with air has been carried out for the cylindrical annular detonation chamber (DC) of the rocket-type engine. The syngas (1-α)СO+αH2, a binary mixture of hydrogen H2 and carbon monoxide CO, is taken. We studied the global flow structure in DC, and the detailed structure of the transverse wave (TW) front in the continuous rotating regime. Integral characteristics of the detonation process − the distribution of average values of static and total pressure along the length of the DC, and the value of specific impulse have been obtained. The region of existence of stable continuous detonation regime in coordinates of the stagnation pressure - temperature in injection manifold (receiver) and the geometric limit of stable TW have been determined.

A novel hybrid aircraft propulsion based on the DEA compressor—part B: Performance

This two-parts article introduces a novel hybrid propulsion system based on the DEA compressor. The system encompasses a Pulse Detonation TurboDEA as the master engine that supplies several full-electric ancillary thrusters called DEAThruster. The system, called the propulsion set, can be categorized as a distributed propulsion system based on the design mission and number of ancillary thrusters. Part B of this article explains the performance sizing of the propulsion set designed in part A. Evaluating the performance of the propulsion, computer programs are written for all major components of the both master engine and ancillary thruster. The intake, compressor, detonation process, diffusers, axial turbine, and exit nozzle are modeled under certain flight conditions, and their performances are revealed and analyzed. The flight conditions are considered from the static condition at the sea level up to flight Mach number 5 at an altitude of 20,000 m. The performance of the propulsion set is also compared with some aircraft propulsions modeled by similar studies in all important aspects.

A novel hybrid aircraft propulsion based on the DEA compressor—Part A: Design

This two-part article introduces a novel hybrid propulsion system based on the DEA compressor. The system encompasses a Pulse Detonation TurboDEA as the master engine that supplies several full-electric ancillary thrusters called DEAThruster. The system, called the propulsion set, can be categorized as a distributed propulsion system based on the design mission and number of ancillary thrusters. Part A of this article explains the design process comprising intake, compressor, detonation process, diffuser, axial turbine, and the exit nozzle. The main target is to design a high-performance low emission propulsion system capable of serving in a wide range of altitudes and flight Mach numbers that covers altitudes up to 20,000 m and flight Mach number up to the hypersonic edge. Designing the propulsion set, the design point is considered at the static condition in the sea level. Design results show the propulsion set can satisfy all requirements necessary for its mission.

Synthesis of Oxide Ceramics in Detonating Atmosphere

A detonation process based on 2,4,6 trinitrotoluene (TNT), used as an energetic reagent, was successfully implemented in the synthesis of a series of metal oxide ceramics. TNT offers better physicochemical and mechanical properties than the energetic compounds traditionally used in such processes, thus offering safer handling and transport conditions. The experimental procedure, which consisted to of mixing the energetic molecule with a ceramic salt, was simple to perform. The detonation products were characterized by X-ray diffraction, scanning and transmission electron microscopies, energy dispersive X-ray spectroscopy and nitrogen physisorption. The as-synthesized ceramic powders (CeO2, HfO2, Nb2O5, and In2O3) were crystalline and made of nano-sized quasi-spherical particles. This investigation provides an enhanced detonation synthesis process for elaborating ceramics. The majority of the oxide materials mentioned in this study had never previously been prepared by the detonation process.

Strong-axis response of steel I-sections subjected to close-in detonations

The analysis of structural members subjected to close-in detonations involves a complicated dynamic scenario. Since the charge is very close to the structural member, the reflected pressure distribution on the member surface is highly non-uniform. In addition, the level of damage to the structural member may be high because of the large magnitude of the load. Due to these phenomena, the response of a structural member to close-in detonation cannot be accurately modelled by relatively simple methods like single-degree of freedom models, and more complicated models are required. Such models need to include numerical simulation of the detonation process, which produces a non-uniform pressure environment, allowing the pressure to reflect and flow around the member section. The local damage and flow around the section are especially of interest in I-shaped, or wide-flange-section members. Herein, the response of such sections is modelled by numerical simulations using a novel technique, which overcomes the difficulty of computation time, and is validated through various calculations. The model is used to perform a parametric study to investigate the response of I-sections subjected to close-in detonations, in terms of local damage and global behaviour, with scaled distances of 0.15–0.29 m/kg1/3 and loading causing flexure about the strong axis. Various aspects that affect the performance are studied, such as: the effect of scaled distance, the addition of welded stiffening plates between the flanges and web, the effect of boundary conditions and the effect of charge shape. Resulting local damage and residual deformations are assessed for the cases studied.

Influence of Gaseous Hydrogen Addition on Initiation of Rotating Detonation in Liquid Fuel–Air Mixtures

Hydrogen is the most common molecule in the universe. It is an excellent fuel for thermal engines: piston, turbojet, rocket, and, going forward, in thermonuclear power plants. Hydrogen is currently used across a range of industrial applications including propulsion systems, e.g., cars and rockets. One obstacle to expanding hydrogen use, especially in the transportation sector, is its low density. This paper explores hydrogen as an addition to liquid fuel in the detonation chamber to generate thermal energy for potential use in transportation and generation of electrical energy. Experiments with liquid kerosene, hexane, and ethanol with the addition of gaseous hydrogen were conducted in a modern rotating detonation chamber. Detonation combustion delivers greater thermal efficiency and reduced NOx emission. Since detonation propagates about three orders of magnitude faster than deflagration, the injection, evaporation, and mixing with air must be almost instantaneous. Hydrogen addition helps initiate the detonation process and sustain continuous work of the chamber. The presented work proves that the addition of gaseous hydrogen to a liquid fuel–air mixture is well suited to the rotating detonation process, making combustion more effective and environmentally friendly.