Detonation pulse engine is used in the production of propulsion power for aerospace applications. This engine works based on detonation and basically consists of a tube with a high ratio of length to internal diameter with an open end, ignition system, fuel supply system and control system. In this research, detonation pulse wave power generator has been designed and built. This generator uses compressed natural gas (CNG) with a purity of 88% methane as fuel and oxygen gas as oxidizer. In this pulse detonation generator, fuel and oxidizer are placed in two separate tanks, and for their proper combination, a suitable mixing system is placed on the way to enter the explosive tube. The performance of the engine was evaluated in the tests carried out. To investigate the effect of methane concentration on detonation combustion characteristics in the engine, the temperature and pressure of the exhaust gases of the engine have been measured. In the investigations, it was found that by increasing the equivalence ratio of fuel and oxidizer from 0.7 to 1.6, the pressure increases almost uniformly from 17 to 21 bar. Also, with the increase of the equivalence ratio to the stoichiometric equivalence ratio, the engine output temperature increases and then gradually decrease.

The practical and prolonged implementation of pulse detonation engines implies the control of temperature in detonation tubes. The nature of the detonation itself, plus the rapid repetition of different processes within the working cycle, are accompanied by variations of speed, temperature and pressure and create a heating environment which is different from conventional engines and difficult to specify and control. In this paper the various processes of the working cycle are studied and a template is proposed for the loading and thermal boundary conditions. In continuation, the analytical and thermal models have been developed based on the described assumptions and the thermal responses have been obtained for sequential loadings. The severe thermal gradients in the tube wall and the short duration of each detonation can cause high sensitivity of the response to solution parameters and affect the solution convergence. The validation and verification of the results have been carried out through comparisons of the analytical and numerical results with the experimental results reported in the literature. The obtained results not only provide the thermal condition for control design, but also give the required data for other related aspects of pulse detonation engine, like thermoelastic and thermal fatigue analyses.

Two-dimensional computational fluid dynamics (CFD) simulation with selected kinetics for H2– air mixture of a hydrogen-fuelled single-pulse detonation engine were performed through ANSYS FLUENT commercial software for diagnostic purposes. The results were compared with Chapman– Jouguet (CJ) values calculated by the CEA (Chemical Equilibrium with Applications) and ZND (Zel’ dovich– Neumann– Dö ring) codes. The CJ velocities and pressures, as the product velocities are in agreement, however, the CJ temperatures are too higher for 2-D simulations; as a consequence, the sound velocities were overpredicted. OH* kinetics added to the reaction set allowed visualization of the propagation front with several detonation cells showing a consistent multi-headed detonation propagating in the whole tube. The detonation front was slightly perturbed at the end of the tube with inclination of front edge and fewer cell numbers, and more significantly at the nozzle entrance with velocity reduction, resulting in a weak and unstable detonation. OH* images showed the detonation reaction zone decoupled from the shock front with disappearance of cellular structure. The inclusion of OH* reaction set for CFD simulation coupled to kinetics is demonstrated to be an excellent tool to follow the detonation propagation behaviour.

The present computational analysis reports the results of combustion phenomenon in 1200 mm long and 60 mm internal circular diameter (D) of three dimensional obstructed combustion chamber (combustor) of the pulse detonation engine (PDE). The simulation is carried out for stoichiometric mixture of two fuels Kerosene-air and Butane-air mixture at atmospheric pressure and temperature of 1 atm and 300 K respectively along with preheated air. The chemical species of Kerosene and Butane (C12H26 and C4H10) fuel are solved by species transport equation and irreversible one-step chemical kinetics model. The propagation speed of flame, detonation wave pressure and deflagration-to-detonation transition (DDT) run-up length are analyzed by three dimensional reactive Navier– Stokes algorithm along with realizable k-ɛ turbulence equation model. The obstacles are placed inside the combustor tube at spacing (s) of 60 mm (1D) and obstacles having blockage ratio (BR) 0. 5 for creating perturbation in propagating combustion flame. This resulted in increase of the surface area of propagating flame and reduces deflagration-to-detonation transition (DDT) run-up length.

Detonation combustion based engines are more efficient compared to conventional deflagration based engines. Pulse detonation engine is the new concept in propulsion technology for future propulsion system. In this contrast, an ejector was used to modify the detonation wave propagation structure in pulse detonation engine combustor. In this paper k-ε turbulence model was used for detonation wave shock pattern simulation in PDE with ejectors at Ansys 14 Fluent platform. The unsteady Euler equation was used to simulate the physics of detonation wave initiation in detonation tube. The computational simulations predicted the detonation wave flow field structure, combustion wave interactions and maximum thrust augmentation in supersonic condition with ejectors at time step of 0. 034s. The ejector enhances the detonation wave velocity which reaches up to 2226 m/s in detonation tube at same time step, which is near about C-J velocity. Further the time averaged detonation wave pressure, temperature, wave velocity and vortex characteristics interaction are obtained with short duration of 0. 023s and fully developed detonation wave structures are in good agreement with experimental shadowgraph, which are cited from previous experimental research work.

The objective of this paper is to experimentally investigate the effects of Shchelkin spiral geometry in the transition from deflagration to detonation on the quality of the produced detonation. Deflagration to detonation transition (DDT) is required in cases where ignition energy release is less than the critical ignition energy required for a direct detonation initiation. A stoichiometric mixture of hydrogen-oxygen has been used in a tube of 25 mm diameter and 700 mm length. Spiral coils have been mounted at the ignitionend of the tube to facilitate DDT. Keeping spiral coil diameter fixed at 22mm, the coil length, pitch and thickness were varied to produce desirable detonation waves. Spiral coil selection was based on several criteria including; the pressure and velocity jump across the wave at the beginning of the tube, and the percentage of successful tests in each batch. The results indicate that the spiral coil pitch has the greatest influence on minimizing the DDT length and obtaining a desirable detonation.

The use of explosion instead of combustion can lead to a significant reduction in the dimensions and mass of the propulsion chamber. Explosion releases significantly more energy compared to combustion, which causes more effective thrust and can create a new evolution in the aerospace industry. The purpose of this research is to develop the knowledge of enabling technologies in the field of space propulsion and to develop the concept and performance and to examine the status of scientific productions in the field of rotary explosive engine technology. The current research is of applied, data mining and scientometric type, and scientific database analysis techniques were used in its implementation. Data and keywords related to research between 2010 and 2024 were searched and evaluated using the Scopus database. Vosviewer software was used to analyze the data and visualize the obtained information. The statistical population of the research was 895 articles in the field of technology related and involved with the rotary explosive engine. The analyzes included the frequency of publication by year, the countries publishing the most documents, and the preparation of a map of technologies and a map of emerging technologies in this field. The results of the survey show that the main keywords include combustion chamber design, modeling and simulation, heat-resistant materials, and fuel injection systems and efficiency. The frequency and trend of publishing scientific documents in the field of rotary explosion engine is on the rise, China and the United States Muttahida has done the most research and support (scholarships, joint courses, equipping infrastructure and laboratories, etc.) in this field of technology.

Rotating detonation engines (RDEs) are an advanced propulsion technology utilizing detonation combustion. RDEs have shown significant potential for substantially enhancing the performance of conventional propulsion systems due to their inherent advantages such as rapid energy release, high thermal efficiency, and a compact reaction zone. Based on these strengths, we conducted experimental investigations of a disk-shaped rotating detonation engine to examine the influences of the oxygen content on the operation characteristics of the engine. The results demonstrate that oxygen enrichment significantly altered the evolution process of rotating detonation waves (RDWs), with dual-wave modes exhibiting higher initiation probability under oxygen-enriched conditions. The results of a quantitative analysis revealed that increasing oxygen content of 21% to 30% increased the velocity of the detonation wave by 11-17% for a single-wave mode and 5-7% for a dual-wave mode. The results of parametric studies demonstrate that increased mass flow rate enhanced the propagating stability of rotating detonation waves, which reduced fluctuations in their parameters. Increasing oxygen content conversely decreased the RDWs’ propagation stability, particularly at low flow rates in single-wave mode. Increasing the oxygen content facilitated the formation of multiple waves, which reduced critical mass flow rate as well as the lean limit of the equivalent ratio for multi-wave modes. Furthermore, oxygen enrichment markedly diminished the lean limit of engine’s operation equivalent ratio, which broadened the stable operating envelope. In contrast with pure air, the lean operation limit of equivalent ratio declined by roughly 25%-59% under oxygen-enriched air conditions. The results of this study demonstrate that oxygen content critically influences the RDWs’ propagation mode in disk-shaped structure as well as the parameters of the detonation waves and the engine’s operation envelope of the engine. These findings offer a deeper understanding of rotating detonation wave propagation and establish a foundation for advancing rotating detonation combustion applications.

Gaseous detonation in tubes produces moving pressure-thermal waves. A gaseous detonation consists of a shock wave and a reaction zone that are tightly coupled. The speed, pressure, and temperature of the products of detonation depend on the type and amount of the initial mixture. The maximum pressure of mechanical wave caused by detonation can be as high as 20-30 times the ambient pressure and temperature of gas in detonation may exceed 2000oC. The mechanical shock waves can cause oscillating strains in the tube wall, which can be several times higher than the equivalent static strains. On the other hand, the passage of the heat wave produces thermal stresses in the tube wall. In the current study the resulting mechanical and thermal stresses have been assessed using numerical simulations. In practice, the mechanical and thermal displacements have been computed separately. Finally, the combined effects of mechanical and thermal stresses caused by gaseous detonation have been simulated.