Detonation Technology Research Articles

An experimental study on gas-solid two-phase rotating detonation ramjet engine based on aluminum powder fuel

In order to explore the feasibility of solid powder detonation technology, the ground direct connection test of aluminum powder/hydrogen/air fuel detonation engine was carried out in this paper. The experimental results show that hydrogen is needed to achieve detonation combustion of aluminum powder with a diameter of 1 μm. A series of tests were carried out in the range of equivalence ratio of 0.8-1.2. With the increase of equivalence ratio, the mean value of steady pressure, average peak pressure, and average wave velocity of rotating detonation combustion increased first and then decreased gradually, and reached the maximum at the equivalence ratio of 0.9. The maximum propagation frequency of the detonation wave is 2653 Hz, and the average wave velocity is 1667 m/s.

Key technologies of two-phase pulse detonation combustor

The pulse detonation combustor is a new type of power device based on periodic high-temperature and high-pressure gas generated by detonation combustion as thrust. Due to its extremely fast heat release rate, detonation combustion has the characteristics of high thermal efficiency, low fuel consumption and low pollutant emissions. In recent years, relevant institutions have conducted extensive research on pulse detonation combustors. However, most research results focus on single studies where the fuel and oxidant are in the gas phase. Based on the vision of engineering application of pulse detonation combustors, the research progress of two key pulse detonation technologies, fuel atomization blending technology and rapid short-distance low-resistance detonation technology, as well as the research status of two-phase pulse detonation combustion based on kerosene are introduced. Regarding fuel atomization and blending technology, this paper mainly introduces the fuel atomization mechanism of two-phase detonation, fuel atomization technology and oil and gas blending technology. Regarding rapid short-distance low-resistance detonation technology, it mainly introduces obstacle-assisted detonation technology, spark plug ignition technology, hot jet ignition technology, pre-detonation tube ignition technology, shock wave focusing detonation technology and plasma ignition technology.

Detonation Technology in Producing Metal–Ceramic Powder Targets for Magnetron Sputtering

Detonation Technology in Producing Metal–Ceramic Powder Targets for Magnetron Sputtering

Dynamic Simulation of Micro-flyer Shocked Detonation

The shocked detonation technology of microflyer is safer and more stable via detonation. By using Ansys software to build a 3-D model of the flyer driven by explosive detonation, the mechanism of action, deformation and stress change were studied and analyzed. The shape and speed of the microflyer, when it strikes the main explosive, are controlled by the material, tilt-angle, and distance between the flyer and main explosive. The results showed that the microflyer needs 7.0 μs to reach 2490 m/s, which is its maximum speed. This study will provide a feasible method and reliable parameters for the safe and stable detonation of explosives.

Theoretical Analysis and Numerical Simulation of the Motion of RDX Deflagration-Driven Flyer Plate Based on Laser-Initiated Micro-Pyrotechnic Devices.

Miniaturized laser-initiated pyrotechnic devices have great application prospects in aerospace and modern weapon systems due to their excellent energy output performance and reliability. In order to develop a low-energy insensitive laser detonation technology based on a two-stage charge structure, it is important to deeply analyze the motion law of a titanium flyer plate driven by the deflagration of the first-stage charge (RDX). The effects of the charge mass of RDX, flyer plate mass, and barrel length on the motion law of flyer plates were studied through a numerical simulation method based on the Powder Burn deflagration model. The consistency between the numerical simulation and the experimental results was analyzed using the paired t confidence interval estimation method. The results show that the Powder Burn deflagration model can effectively describe the motion process of the RDX deflagration-driven flyer plate with a 90% confidence level, and its velocity error is ≤6.7%. The speed of the flyer plate is proportional to the mass of the RDX charge, inversely proportional to the mass of the flyer plate, and exponentially related to its moving distance. As the moving distance of the flyer plate increases, the RDX deflagration products and air in front of the flyer plate are compressed, which inhibits the motion of the flyer plate. In the optimum state (the mass of the RDX charge is 60 mg, the mass of the flyer is 85 mg, and the length of the barrel is 3 mm), the speed of the titanium flyer reaches 583 m/s, and the peak pressure of the RDX deflagration reaches 2182 MPa. This work will provide a theoretical basis for the refined design of a new generation of miniaturized high-performance laser-initiated pyrotechnic devices.

Experimental evaluation of aluminum powder fuel in a hydrogen/oxygen detonation tube

Solid powder detonation technology was investigated in this study. Several problems related to the controllable and uniform injection of solid powder fuels were examined. This study demonstrated the feasibility of solid powder detonation technology by designing fluidization devices and evaluating the solid powder supply system. A stable supply of powder was achieved, and ignition tests were conducted using Al/H2/O2 and H2/O2 fuels. The maximum detonation wave velocity obtained using Al/H2/O2 was 2950 m/s, which was 40% higher than that obtained using H2/O2. We observed a mixed two-phase double-front detonation structure, with hydrogen/oxygen being detonated in the first front and aluminum powder/oxygen being detonated in the second wave. At a relatively low equivalence ratio, the aluminum powder/oxygen wave surface pressure was higher, whereas the hydrogen/oxygen wave surface pressure was higher at a higher equivalence.

Rotating Detonation Combustion for Advanced Liquid Propellant Space Engines

Rotating (also termed continuous spin) detonation technology is gaining interest in the global research and development community due to the potential for increased performance. Potential performance benefits, thrust chamber design, and thrust chamber cooling loads are analyzed for propellant applications using liquid oxygen or high-concentration hydrogen peroxide oxidizers with kerosene, hydrogen, and methane fuels. Performance results based on a lumped parameter treatment show that theoretical specific impulse gains of 3–14% are achievable with the highest benefit coming from hydrogen-fueled systems. Assessment of thrust chamber designs for notional space missions shows that both thrust chamber length and diameter benefits are achievable given the tiny annular chamber volume associated with the rotating detonation combustion. While the passing detonation front drastically increases local heat fluxes, global energy balances can be achieved if operating pressures are limited to be comparable to existing or prior space engines.

Natural Gas Conversion and Liquid/Solid Organic Waste Gasification by Ultra-Superheated Steam

The technology of a pulsed detonation gun for gasification of organic waste with ultra-superheated steam has been experimentally demonstrated for the first time. Experiments were performed on natural gas conversion as well as on the gasification of liquid (waste machine oil) and solid (wood sawdust) waste by hot detonation products of natural gas–oxygen mixture at a frequency of detonation pulses f = 1 Hz. Periodic release of detonation products to a 100 L flow reactor provided a time-averaged mean temperature and pressure in the reactor at about 1200 K and 0.1 MPa. It is shown that the technology of a pulsed detonation gun can provide complete (100%) natural gas conversion to syngas containing H2 and CO with a H2/CO ratio of 1.25. During the gasification of liquid and solid wastes, the total volume fraction of combustible gases (H2, CO, and CH4) in the product syngas was 80 and 65% with H2/CO ratios of 0.8 and 0.5, respectively. Comparison of the experiments on natural gas conversion and liquid/solid organic waste gasification under the same conditions at f = 1 Hz showed that the composition of the product syngas in terms of H2 and CO content almost did not depend on the type of used feedstock. The estimated ideal energy gain defined as the ratio of the total energy of product syngas to the energy spent in its production from dry wood sawdust is about 4.6, i.e., the pulsed detonation technology of biomass gasification is economically very attractive.

Detonation Spraying of Composite Targets Based on Ni, Cr and B<sub>4</sub>C for Magnetron Multi-Functional Coating

The paper presents a method of producing a ceramic metal composite target by detonation gas-thermal spraying allowing spraying almost any powder compositions with high deposition efficiency of up to 90% and the possibility of spraying large areas at a relatively low cost, differentiation by coating thickness and size. The efficiency of detonation technology and related devices for the production of original composite cathodes for magnetron sputtering using the example of the powder composition Ni + Cr + B4C is justified. These materials make it possible to obtain composite coatings with a unique composition and characteristics using a magnetron. Magnetron sputtering is one of the most suitable methods for the industry. The influence of the process mode of metal ceramic powder application on copper substrate is considered. The structure of a metal-ceramic composite target was studied by scanning electron microscopy. It was shown that the target surface is dense without visible pores. The elemental composition of the powder is uniformly distributed over the target surface.

МОЛНИЕЗАЩИТНЫЕ ПОКРЫТИЯ МОТОГОНДОЛ АВИАЦИОННЫХ ДВИГАТЕЛЕЙ ИЗ ПОЛИМЕРНЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ. ЧАСТЬ 2. ПЕРСПЕКТИВНАЯ ДЕТОНАЦИОННАЯ ТЕХНОЛОГИЯ НАНЕСЕНИЯ МОЛНИЕЗАЩИТНОГО ПОКРЫТИЯ

The present paper contains results of trying the detonation technology of applying a lightning-protective coating and the results of testing the lightning resistance of samples of structurally similar elements of a nacelle made of polymer composite materials and coated using this technology. A lightning-protective coating was sprayed on samples of structurally similar elements of a nacelle made of carbon fiber prepreg VKU-25. The coating was applied using the CCDS2000 detonation computerized complex developed by the Lavrentyev Institute of Hydrodynamics of the Siberian Branch of the Russian Academy of Sciences. Copper, bronze and aluminum were used as materials for the lightning-protective coating. The thickness of the applied metallized layer was varied from 10 to 20 microns, this providing an extremely low specific gravity of lightning protection at the level of 0.087–0.178 kg/m2 for copper and bronze; 0.027–0.054 kg/m2 for aluminum. Samples with and without lightning-protective coating were tested with a simulated lightning discharge according to the requirements of aviation standards AP-25, including components related to lightning-hazardous zones 1A, 2A, 1B. The combi-nations of components complied with the qualification requirements of KT-160G. According to the results of tests on the lightning resistance of samples made of the VKU-25 carbon fiber prepreg, the functional operability of the detonation technology for any lightning-hazardous zone of the nacelle according to AP-25 has been demonstrated. No through destruction of carbon fiber was found in samples with detonation spraying. Samples without lightning-protective coating turned out to be non-resistant to the lightning current exposure. The tried detonation technology has the technical potential to reduce (up to 3 times) the specific gravity of the conduc-tive layer of the lightning-protective coating used in the engine polymer nacelles of commercially operated aircraft engines.

The effect of pulse plasma detonation post-processing on the oxidation of CoNiCrAlY coating

CoNiCrAlY coating is a traditional bond coating used in the thermal barrier coatings (TBCs) system. In this work, CoNiCrAlY coating was prepared on the surface of nickel-based superalloy by atmospheric plasma spraying. In addition, the pulsed plasma detonation(PPD) technology was used as a post-treatment. All samples were subjected to a static constant temperature at 1050 °C to investigate the oxidation behavior. A modified surface was achieved by using the PPD treatment, to effectively eliminate surface defects such as voids and porosities, and this dense layer can decrease the corrosive channel. In addition, Ta elements were deposited on the surface of the coating from the electrode , it can slow down the diffusion rate of the Al element and thus improve the oxidation resistance . • Pulsed plasma detonation (PPD) was used to re-melting the surface modification ofCoNiCrAlY coating. • Pulsed plasma detonation (PPD) treatment eliminated the surface defects, thus improving the oxidation resistance. • Ta were deposited on the surface, it can slow down the diffusion rate of the Al and improve the oxidation resistance.

Thermodynamic performance analysis of the rotating detonative airbreathing combined cycle engine

A configuration is presented for the rotating detonative airbreathing combined cycle engine with compatibility between the turbomachinery and rotating detonation combustor being realized. Two propulsion units are merged to achieve three different operating modes, which provides a favorable propulsion choice for advanced full range and trans-aerosphere vehicles. For the vehicle taking off from the ground, the engine operates at turbojet mode until the thrust demand could not be satisfied. Then the ramjet unit ignites and the operating mode turns into transition mode, during which the ratio of the thrust generated by ramjet unit to the total thrust increases with an increase in Ma0. When the ratio reaches 1.0, the engine transforms into the ramjet mode. Thereafter, a mode transition strategy with the thrust and freestream mass flowrate remaining constant is proposed for the combined cycle engine, based on the steady state characteristics of turbine and ramjet units. Furthermore, the parametric performance simulation model of the engine is developed to verify the potential performance improvements generated by the application of rotating detonation technology, and analyze the application characteristics of the mode transition strategy formulated in this study. It is shown the lower initial Mach numbers of mode transition result in higher values of equivalent specific thrust but lower values of equivalent specific impulse during the transition mode. For the detonative combined cycle engine, the minimum value of initial Mach number of mode transition is below 2.0, which is much lower than that of the conventional turbine based combined cycle engine. Therefore, the performance during transition mode is expected to be improved with the application of rotating detonation technology.

Microstructure and properties of GR2 titanium treated by plasma-pulsed detonation

Abstract The modified layers were prepared on the GR2 titanium by plasma-pulsed detonation technology (PPD) in the compressed air (Air), argon (Ar) and nitrogen (N2) atmospheres, respectively. We observed that the modified layer was composed of TiN, TiN0.3, TixOy and Ti phases. The second phase strengthening, the fine grain strengthening and the dislocations strengthening are the main reasons for the improvement of wear resistance. Compared with the substrate, all modified layers have lower friction coefficient and better wear resistance. The wear volumes of three kinds of modified layers decrease by about 97%, 72% and 95%, respectively.

地铁盾构孤石起爆技术数值模拟研究

地铁盾构孤石起爆技术数值模拟研究

Micro- and nanocomposite Ti-Al-N/Ni-Cr-B-Si-Fe-based protective coatings: Structure and properties

A new type of nanocomposite Ti-Al-N/Ni-Cr-B-Si-Fe-based coatings 70–90 μm thick produced by combined magnetron sputtering and a plasma detonation technology is created and studied. Phases Ti3AlN + Ti3Al2N2 and the phases caused by the interaction of plasma with a thick Al3Ti + Ni3Ti coating are detected in the coatings. The TiAlN phase has a grain size of 18–24 nm, and other phases has a grain size of 35–90 nm. The elastic modulus of the Ti-Al-N coating is E = 342 ± 1 GPa and its average hardness is H = 20.8 ± 1.8 GPa. The corrosion rate of this coating is very low, 4.8 μg/year, which is about three orders of magnitude lower than that of stainless steel (substrate). Wear tests performed according to the cylinder-surface scheme demonstrate high wear resistance and high adhesion between the thick and thin coatings.

BP neural network model on the forecast for blasting vibrating parameters in the course of hole-by-hole detonation

According to the neural network theory, combined with the technical characteristics of the hole-by-hole detonation technology, a BP network model on the forecast for blasting vibration parameters was built. Taking the deep hole stair demolition in a mine as an experimental object and using the raw information and the blasting vibration monitoring data collected in the process of the hole-by-hole detonation, carried out some training and application work on the established BP network model through the Matlab software, and achieved good effect. Also computed the vibration parameter with the empirical formula and the BP network model separately. After comparing with the actual value, it is discovered that the forecasting result by the BP network model is close to the actual value.

Application of pulse detonation technology for boiler slag removal

Pulse detonation technology for removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. This technology offers a potentially convenient, inexpensive, yet efficient way for on-line slag removal. This paper presents a feasibility study that includes both Computational Fluid Dynamics (CFD) simulations and laboratory experiments. CFD simulations provided visual and quantitative data to study the potential mechanisms for removal of slag. Mechanisms included direct impact, flow scrubbing, wave reflection and negative velocity impact on the back side of the tubes. Several experiments were carried out to verify the potential of the pulse detonation technology. Experiments were done using a pulse detonation engine and heat exchanger tubes with different types of slag placed in different orientations on the tubes. Tubes were placed at various distances from the detonation tube and in different configurations. The results present a strong case for the application of this technology for online slag removal. It is especially effective for removal of slag on the back sides of the tubes where other traditional methods are not very successful. A preliminary cost analysis indicated that the technology can be paid for within the first year itself and provide substantial savings in the subsequent years.

Structure and properties of Al 2O 3 and Al 2O 3+Cr 2O 3 coatings deposited to steel 3 (0.3 wt%C) substrate using pulsed detonation technology

Using the Rutherford back scattering method and elastic recoil detection analysis of protons, X-ray diffraction analysis, transmission electron microscopy as well as tests for hardness, adhesion and heat conductivity, coatings of Al 2O 3 and Al 2O 3+Cr 2O 3 deposited using a plasma-detonation technique, were investigated. The coating was deposited by means of a plasmotron, in which the jet velocity reached 8000 m/s and the temperature reached 4×10 4 K/s. Formation of α-Al 2O 3, β-Al 2O 3, γ-Al 2O 3; η-Al 2O 3 and FeAl with average crystal dimensions of 20–250 nm has been revealed in the coatings of Al 2O 3. In addition, the formation of such phases as α-Al 2O 3, β-Al 2O 3, γ-Al 2O 3 were detected; Cr 2O 3 and CrO with average dimensions of crystallites from 20 to 150 nm, and Cr 2O 3 crystallites of 500 nm were seen. Micro-hardness reached 1.95×10 −4 N/mm 2, the average density was ρ=3.90 g/cm 3 and the heat conductivity of Al 2O 3 was 38 W/m K.