Pulse Detonation Engine Performance Research Articles

Numerical Evaluation of Varying Combustion Chamber Length on the Performance of Pulse Detonation Engine Using DES Model

Numerical Evaluation of Varying Combustion Chamber Length on the Performance of Pulse Detonation Engine Using DES Model

Analytical Assessment of Blended Fuels for Pulse Detonation Engine Performance

A pulse detonation engine (PDE) is possible to be a next-generation high-performance propulsion system in aerospace-related applications. To generate power or thrust, PDE uses repeated detonations. The current study evaluates the PDE performance with alternative and blended fuels in the Zeldovich–von Neumann–Doring (ZND) model. Parameters such as temperature ratio, pressure ratio, detonation velocity, and specific impulse were determined analytically for the fuels. The computed detonation parameters and specific impulse were compared with those available in NASA’s open-source program, Chemical Equilibrium with Applications (CEA), to ensure the results' sufficient validity. It was found that the highest specific impulse was achieved with hydrogen at an equivalence ratio of 1. Analytical values of all the parameters were in an acceptable range as defined by NASA CEA. As compared to pure butane and propane, their blends yielded higher values (1 to 10 percent) of specific impulse. Propane and butane are safe, non-toxic, clean-burning fuels, great energy sources, and can be used as alternative fuels in PDE.

Research on Optical Diagnostic Method of PDE Working Status Based on Visible and Near-Infrared Radiation Characteristics

Fill fraction not only has a profound impact on the process of deflagration to detonation in pulsed detonation engine, but also affects the propulsion performance in both flight and ground tests. In this paper, a novel optical diagnostic method based on detonation exhaust radiation in visible and near-infrared region within 300–2600 nm is developed to determine the current working state in the gas–liquid two-phase pulsed detonation cycle. The results show that the radiation characteristic in each stage of detonation cycle is unique and can be a good indicator to infer the fill fraction. This is verified experimentally by comparison with the laser absorption spectroscopy method, which utilizes a DFB laser driven by ramp injection current to scan H2O transition of 1391.67 nm at a frequency of 20 kHz. Due to concentrated radiation intensity, time duration reaching accumulated radiant energy ratio of 50% in detonation status would be smaller than 1.2 ms, and detonation status would be easily distinguished from deflagration with this critical condition. In addition, the variation of important intermediates OH, CH, and C2 radicals during detonation combustion are obtained according to the analysis of detonation spectrum, which can also be proposed as a helpful optical diagnostics method for the combustion condition based on C radical concentration. The study demonstrates the feasibility of optical diagnostics based on radiation in visible and near-infrared regions, which could provide an alternative means to diagnose and improve pulsed detonation engine performance.

Internal flow dynamics and performance of pulse detonation engine with alternative fuels

In this study, analytical and computational analysis is performed to determine the effect of thermodynamic detonation parameters on the performance of the pulse detonation engine. For analytical study along with pure fuels blend of hydrogen (50 %) + kerosene (50 %), hydrogen (50 %) + methane (50 %) and methane (50 %) + kerosene (50 %) are considered. The ANSYS FLUENT program is utilized two-dimensional computational fluid dynamics (CFD) simulation using a stoichiometric mixture of three pure fuels: hydrogen-air, methane-air, and kerosene-air. Time-dependent numerical simulations are used to explore the flow condition inside the detonation tube. Excellent performance is observed for hydrogen-air fuel. Hydrogen shows the highest velocity of 2524.36 m/s and a specific impulse of 6842.16 s. The lowest velocity and specific impulse are produced by kerosene of 1520 m/s and 1473.6 s, respectively. It is shown that measured parameters could vary significantly depending on the choice of fuels used. The results infer that hydrogen blends of methane and kerosene fuels are also suitable for pulse detonation engine (PDE) application. Finally, these analytical and simulated results are validated with the previously published literature and NASA CEA (national aeronautics and space administration -chemical equilibrium with applications).

Oxygen concentration distribution in a pulse detonation engine with nozzle–ejector combinational structures

Pulse detonation engines (PDEs) with three different types of nozzle–straight ejector combinational structures at three different ejector positions were simulated by the unsteady 2-D axisymmetric method to understand the influence of nozzle–ejector combinational structures on the performance of PDEs. Three types of nozzles included the straight nozzle, convergent nozzle, and convergent–divergent (CD) nozzle. Three ejector positions were considered according to the ratio of the distance between the nozzle outlet and the ejector inlet to the diameter of PDEs (Δx/d). Propane was used as the fuel and air as the oxidizer. The simulation results indicated that for the PDE with the straight nozzle, it took the shortest time for high-temperature burnt gas to exhaust from the detonation tube. For the PDE with the CD nozzle, the time at which the ejector was filled with external air was the fastest. Within the time range of t = 0–10 ms, the ejected air was less than the original air in the ejector among all the nine combinational structures. The maximum ejected air was obtained with the convergent nozzle, followed by the CD nozzle, and the minimum with the straight nozzle. For certain nozzles, the maximum air was ejected at the ejector position of Δx/d = +1, followed by the ejector position of Δx/d = 0, and the minimum at the ejector position of Δx/d = −1. For the convergent nozzle–ejector combinational structure, the air ejection speed was the fastest. Oxygen concentration distribution in the PDE with the CD nozzle was more uniform along the axial direction than the other nozzles.

Experimental study of using biogas in Pulse Detonation Engine with hydrogen enrichment

Pulse Detonation Engine (PDE) is one of the pressure gain engines that provide prominent features over conventional engines such as higher thermodynamic efficiency, higher thrust, and less design complexity. Biogas is one of the promising alternative energy sources. The aim of this paper is to study the influence of hydrogen addition in biogas on detonation characteristics performance of PDE. The ideal detonation combustion characteristics of biogas are estimated using NASA Chemical Equilibrium with Applications (CEA). The equivalence ratio range is varied from 0.7 to 1.4. It was found that the higher the percentage of methane concentration in biogas increased the detonation characteristics of biogas such as pressure, temperature, and Mach number. However, a reduction in the flame speed, temperature, and pressure of biogas compared to pure methane was stipulated to be due to the presence of CO2 that acts as a dilutant in biogas. It was found also that, the optimal percentage of hydrogen addition into the biogas fuel mixture is 15%. At this percentage, the detonation pressure improved by 23%. The performance of PDE fuelled by biogas is presented experimentally at a frequency of 10 Hz. The results show a successful and stable detonation initiation in PDE by using biogas with 15% and 20% addition of hydrogen.

Propulsion Performance and Transportation Performance of Pulse Detonation Engine

Propulsion Performance and Transportation Performance of Pulse Detonation Engine

Numerical investigation of flame propagation in pulse detonation engine with variation of obstacle clearance

The objective of present research work is to investigate the combustion flame acceleration and performance of pulse detonation engine (PDE). The PDE tube consisting of obstacles of varying gap with fixed blockage ratio is analyzed in the current study. The three-dimensional reactive Navier–Stokes equation along with realizable k–e turbulence model is used to simulate the combustion phenomena of hydrogen–air mixture. The one-step irreversible chemical kinetics model analyzes detailed mechanism of exothermic reaction. The propagation of flame and deflagration-to-detonation transition (DDT) run-up length is based on normal propagating regime. As the gap between combustor inner surface and obstacle outer diameter increases, the propagating area near the combustor axis reduces. Therefore, loss of momentum of turbulence combustion particle and unburnt fuel particles (voids) are increased at the wake of obstacle due to the increase in gap (or reduction in obstacle outer diameter), which results reduction in detonation wave velocity and detonation total pressure. However, DDT flame run-up length increases with lower temperature along the axis of PDE combustor. The thrust force generated by PDE combustor also gets reduced as the obstacle diameter is reduced.

Effects of Various Compositions of the Fuel—Air Mixture on the Pulse Detonation Engine Performance

The objective of the present analysis is to investigate the effect of gaseous hydrocarbon fuels, such as Octane C8H18, Hexane C6H14, and Pentane C5H12 on the cyclic combustion process in an obstructed channel of the pulse detonation engine. Three-dimensional reactive Navier-Stokes equations are used to simulate the combustion mechanism of stoichiometric hydrocarbon fuels along with a one-step reaction model. The fuel is injected at atmospheric pressure and temperature and is ignited with pre-heated air. The investigation shows that initially a high-temperature combustion wave propagates with the local speed of sound; it creates turbulence after colliding with obstacles, resulting in an increase to supersonic flame speeds. Therefore, different values of the combustion flame propagation speed, combustion efficiency and impulse per unit area are obtained for these fuels. The detonation speed in the hexane-air mixture is about 5.8% lower than the detonation speed predicted by the NASA CEA400 code. However, it is observed that the octane fuel reduces the deflagration-to-detonation transition run-up distance as compared to other fuels.

Numerical Investigation of Detonation Wave Propagation in Pulse Detonation Engine with Obstacles

The numerical investigation of Detonation wave propagation and Deflagration-to-Detonation transition is done in straight long tube of 1200 mm length and 60 mm internal circular diameter with stoichiometric (ϕ=1) mixture of hydrogen-air at ambient pressure and temperature of 0.1 MPa and 293 K respectively. The detonation tube contains obstacles having blockage ratio (BR) 0.5, 0.6 and 0.7, and having 60 mm gap among them. The computation analysis is performed firstly on simple straight tube having no obstacle (BR=0.0) and then obstructed channel. The combustion phenomena of fuel-air mixture are modeled by one-step irreversible chemical reaction model. Three-dimensional Navier-Stokes equations along with realizable k-ɛ turbulence model are solved by the commercial computation fluid dynamics software ANSYS Fluent-14 code. The performance of pulse detonation engine (PDE) depends on blockage ratio (BR) of obstacles. The simulation results show that the initiation and propagation of flame is due to exothermic expansion of hot combustion gases. The obstacles generated turbulence at obstacle wakes, which caused to increase flame surface area. Therefore, obstacles reduced the Deflagration-to-Detonation transition (DDT) run-up length. The perturbation inside the combustor increases as increased the blockage ratio of obstacle. The PDE Simulation results of with and without obstacles were analyzed and compared with adiabatic flame temperature.

Thermodynamic Performance of Pulse Detonation Engine: A Technical Report

The pulse detonation engine (PDE) is a new concept that utilizes supersonic detonation waves in the propulsion or producing specific impulse. The performance of PDE has been analysed by experimental and analytical from the last decades. The number of researcher develops different theories, which is continuously increasing the PDE propulsive performance. The thermodynamic efficiency of the cyclic operation is discussed and compare to each other. In the present paper, five different analytical approaches such as ideal Brayton cycle, ideal Humphery Cycle, and ideal PDE cycle along with C-J model and ZND model have been studied. The consideration of assumptions and neglecting loses, the theoretical performance of the pulse detonation engine become higher than the experimental and computational predicted performance. The thermodynamic parameters such as pressure, temperature density, Mach number and detonation wave velocity are theoretically calculated inside the combustion chamber and exit of the tube.

Effects of Various Compositions of the Fuel-Air Mixture on the Pulse Detonation Engine Performance

Effects of Various Compositions of the Fuel-Air Mixture on the Pulse Detonation Engine Performance

The Experimental Study about the Effect of Operating Conditions on Multi-tube Pulse Detonation Engine Performance

This study examines a multi-tube pulse detonation engine (PDE) which has a type of constant volume combustion. We designed and made the multi-tube PDE and then conducted an experiment in various operating frequencies and equivalence ratios. First, experiments with operating frequencies of 40, 80, 120, 160, and 200 Hz resulted in an average thrust and specific impulse 23.14 N and 42.34 s. The next experiment resulted in the equivalence ratio varying from 0.81 to 1.38, which resulted in an average thrust and specific impulse 22.36 N and 40.11 s. The average detonation velocity was 8% lower than that calculated according to C–J theory. The incidence ratios of the detonation wave were stable with the exception of the operating frequency of 200 Hz. However, at 200 Hz, the incidence ratio was less than 50%. We assumed that a low fill fraction occurred for this problem. The thrust of the PDE increased with the operating frequency. However, the thrust increase was at a lower rate than in previous studies, because of a lost thrust output result from the slow response time of the load cell amplifier.

Parametric cycle analysis of an ideal pulse detonation engine – Supersonic branch

The purpose of this note is to present a mathematical description of an ideal pulse detonation engine (PDE) based on parametric cycle analysis for supersonic heat addition. The parametric cycle analysis is presented in terms of parameters similar to those for the well-known parametric cycle analyses for the ideal ramjet engine. The performance characteristics of specific thrust, thrust-specific fuel consumption, fuel-to-air ratio, thermal efficiency, propulsive efficiency, overall efficiency, and thrust flux are illustrated as functions of the two parameters: inlet/diffuser exit Mach number, M2 > 1, and freestream Mach number, Mo. This work provides algebraic equations which can be used quickly to investigate the ideal supersonic combustion PDE performance as a function of a variety of input parameters. It is hoped that this work will aid in exploring the performance of the ideal supersonic combustion PDE from a big picture perspective.

Intake Flow Analysis of a Pulsed Detonation Engine

Unsteady flow within the intake system of a hydrogen–air pulse detonation engine (PDE) has been analyzed using a quasi-one-dimensional (Q1D) computational fluid dynamic (CFD) code. The analysis provides insight into the unsteady nature of localized equivalence ratios and their effects on PDE performance. For this purpose, a code originally configured to model the PDE tube proper was modified to include a 6.1 m long intake with a single fuel injector located approximately 3.05 m upstream of the primary intake valve. The results show that constant fuel mass flow rate injection from the injector creates large local variations in equivalence ratio throughout the PDE within a cycle. The effect of fill fraction on the engine performance is better described with the presence of the inlet model. However, the effect of ignition delay is shown to be better predicted with a model without the inlet.

EFFECT OF DIFFERENT NOZZLES ON THE PERFORMANCE OF PULSE DETONATION ENGINE- A REVIEW

Pulse Detonation Engine (PDE) has recently got fancy of aero-propulsion community due to its simplicity and advantages over current propulsion systems. The PDE operates on the detonation of combustion products, which is produced by burning of a reactive gas mixture at normal pressure and temperature. The reactants are then at a high pressure and high temperature. The impulsive thrust is produced through rapid ignition and formation of detonation waves. The present paper is a review of various efforts made to enhance the Pulse detonation Engine performance by using different types of nozzle geometries.

Characteristics of pulse detonation engine versus ramjet characteristics

We discuss the method of comparing pulse detonation engines (PDE) and engines with combustion in subsonic flow (ramjet) by means of their specific impulse used by the “Center of Pulse-Detonation Combustion” (CPDC). We demonstrate that the method used by CPDC to calculate the performance of PDE overstates the value of specific impulse relative to its actual value by a factor of at least two. In contrast, the values of specific impulse for ramjet are understated. As a result, the specific impulse of PDE significantly exceeds that of ramjet or is close to it. We investigate these misleading conclusions, and demonstrate their complete failure.

Review on Recent Advances in Pulse Detonation Engines

Pulse detonation engines (PDEs) are new exciting propulsion technologies for future propulsion applications. The operating cycles of PDE consist of fuel-air mixture, combustion, blowdown, and purging. The combustion process in pulse detonation engine is the most important phenomenon as it produces reliable and repeatable detonation waves. The detonation wave initiation in detonation tube in practical system is a combination of multistage combustion phenomena. Detonation combustion causes rapid burning of fuel-air mixture, which is a thousand times faster than deflagration mode of combustion process. PDE utilizes repetitive detonation wave to produce propulsion thrust. In the present paper, detailed review of various experimental studies and computational analysis addressing the detonation mode of combustion in pulse detonation engines are discussed. The effect of different parameters on the improvement of propulsion performance of pulse detonation engine has been presented in detail in this research paper. It is observed that the design of detonation wave flow path in detonation tube, ejectors at exit section of detonation tube, and operating parameters such as Mach numbers are mainly responsible for improving the propulsion performance of PDE. In the present review work, further scope of research in this area has also been suggested.

Analysis of influence design parameters ejector pipe at the detonation specifications engine

The engines that use a detonation cycle have greater thermal efficiency than engines with constant-pressure combustion cycle. The mechanisms of ejector augmentation are evident in secondary air entrainment. The impulse characteristics of a pulse detonation engine (PDE) with ejector were investigated under different parameters. The propagation of a detonation wave in an ejector-augmented pulse detonation rocket engine fueled with a hydrogen-oxygen methane-oxygen and hydrocarbon-oxygen mixture is studied. The straight cylindrical ejector was coaxially installed at different axial locations relative to the exit of the detonation chamber. The use of a non-steady ejector is modeled for pulse detonation engine performance improvement. In this paper, a two-dimensional numerical model is developed to help design the basic geometry and operating parameters of the device. The unsteady flow processes are simulated and compared with a baseline PDE without ejector enhancement. Various features including detonation-shock interaction, detonation diffraction and vortex formation are observed. It is observed that the design of detonation wave flow path in detonation tube, ejector and operating parameters such as Mach numbers are mainly responsible for improving the propulsion performance of PDE.Object оf numerical simulation is the cylindrical detonation chamber with a diameter of Dc = 25 mm and a length of Lc = 100 mm. The cylindrical ejectors with a length of Le = 100 mm and diameters De = 35, 40, 45, 50 that 55 mm were attached to the chamber. Also ejectors with a diameter of De = 35 mm and lengths of Le = 50, 100, 150, 200 that a 250 mm respectively were attached to the chamber. The calculation was performed with a computer program that implements a numerical TVD-scheme. The results of calculations were presented as the dependence of specific thrust impulse Isp/Ispo ratio (Isp ­- specific thrust impulse with ejector nozzle; Ispo - specific thrust impulse of a chamber only) to the ejector-to-PDE diameter ratio (De/Dc), to the ejector-to-PDE length ratio (Le/Lc) and to the displacement of an ejector-to-PDE length ratio ((Ld +Lc)/Lc), where Ld – distance from the input section of the nozzle to the thrust wall of a detonation chamber. The method of a numerical simulation proved the possibility of a significant increase of pulse detonation engine performance through the use of ejector nozzle.

Parametric Cycle Analysis of an Ideal Pulse Detonation Engine

The purpose of this work is to present a mathematical description of an ideal pulse-detonation-engine-based on parametric cycle analysis. The parametric cycle analysis is presented in terms of parameters similar to those for the well-known parametric cycle analyses for the ideal turbojet engine and the ideal ramjet engine. The performance characteristics of specific thrust, thrust-specific fuel consumption, fuel-to-air ratio, thermal efficiency, propulsive efficiency, and overall efficiency are presented as functions of the two variables: compressor total pressure ratio and freestream flight Mach number . This work provides algebraic equations that can be used conveniently to investigate the ideal pulse detonation engine performance as a function of a variety of input parameters. It is hoped that this work will aid in exploring the performance of the ideal pulse detonation engine from a big-picture perspective.