Theoretical Assessment of Turbocharged Pulse Detonation Engine Performance at Various Flight Conditions

Author(s):  
Pereddy Nageswara Reddy

Abstract A typical Pulse Detonation Engine (PDE) cycle of operation includes three basic processes: initiation and propagation of detonation wave in the Detonation Chamber (DC); a quasi-steady exhaust of detonation products from the DC at varying pressure through the supersonic nozzle; and a steady exhaust of remained detonation products at constant pressure through the nozzle while filling the DC with fresh air. In the present work, a novel method of Turbo-charging is proposed to increase the inlet pressure/density of fresh air fed into the DC in each cycle so as to increase the thrust developed per unit area of DC. The thermodynamic cycle of operation of Turbocharged Pulse Detonation Engine (TPDE) is analyzed based on quasi-steady state one dimensional formulation, and a computer code is developed in MATLAB to simulate the cycle performance at different compressor pressure ratios. Thrust per unit area of DC, the specific thrust and the fuel-based specific impulse are estimated at various flight conditions at different pressure ratios by considering C2H4/air as the fuel-oxidizer. The net thrust developed per unit area of DC increases with an increase in compressor pressure ratio, up to the pressure ratio of 4.0, at all flight conditions. The compressor pressure ratio of about 2.0 is observed to be optimum pressure ratio as TPDE develops nearly the same air-based specific thrust at this pressure ratio irrespective of flight operating conditions.

Author(s):  
Hua Qiu ◽  
Cha Xiong ◽  
Wei Fan

A new design method for pulse detonation engines nozzle was developed theoretically. The effects of non-uniform exhaust on the performance of pulse detonation engine were analyzed by constant volume cycle model. The results showed thrust losses induced by the non-uniform exhaust could be decreased by increasing fill pressure ratio. If the fill pressure ratio was larger than 10, the performance losses with a fixed optimal nozzle could be controlled within 3%. The optimal area ratio of the nozzle was obtained when the time-averaged pressure at the nozzle exit equals the ambient pressure. This was also applicable to one-dimensional unsteady frictionless pulse detonation engine model. Thus an optimal area of the nozzle could be calculated by the time-averaged total pressure. Compared with the zero-dimensional results obtained by numerical search technique, the errors of predicted optimal area could be neglected if fill pressure ratio is too large to prevent shock from propagating back to the nozzle. And the errors of predicted optimal area are lower than 5% compared with the results of the one-dimensional unsteady pulse detonation engine model.


Shock Waves ◽  
2019 ◽  
Vol 29 (8) ◽  
pp. 1205-1225 ◽  
Author(s):  
V. B. Nguyen ◽  
C. J. Teo ◽  
P.-H. Chang ◽  
J. M. Li ◽  
B. C. Khoo

Author(s):  
Pinku Debnath ◽  
K. M. Pandey

Pulse detonation engines (PDEs) are new concept propulsion technologies and unsteady propulsion system that operates cyclically and typically consists of four stages, filling of fuel/air mixture, combustion, blow down and purging. Out of these four processes, combustion is the most crucial one since it produces reliable and repeatable detonation wave. Detonation is a supersonic combustion process which is essentially a shock front driven by the energy release from the reaction zone in the flow right behind it. It is based on supersonic mode of combustion and causes rapid burning of a fuel-air mixture, typically tens of thousands of times faster than in a flame, that utilize repetitive detonations to produce thrust or power. PDE offers the potential to provide increased performance while simultaneously reducing engine weight, cost, and complexity relative to conventional propulsion systems currently in service. It has the potential to drastically reduce the cost of orbit transfer vehicle system as well as space vehicle attitude control system and can be used for wide range of military, civil and commercial applications. Due to its obvious advantages, worldwide attention has been paid to the scientific and technical issues concerning PDE. The present study deals with the convergence and divergence nozzle effects on specific thrust and pressure of Pulse Detonation Engine (PDE) using computational fluid dynamics (CFD). Pulse Detonation Engine having 88.3cm length and 9.5cm diameter combustion chamber, convergence nozzle, detonation tube and divergence nozzle were design in Gambit 2.3.16. FLUENT 6.3 predict the flow physics of pressure and specific thrust (Fs), increase in divergence nozzle compared to convergence nozzle and specific thrust of detonation tube was changed with the change of flight Mach number. A three dimension computational unstructured grid was developed which gives the best meshing accuracy as well as computational results. RNG k-ε turbulence model was used for the mass flow rate, pressure and velocity contours analysis with standard wall function.


Author(s):  
Arun Prakash Raghupathy ◽  
Urmila Ghia ◽  
Karman Ghia

Pulse Detonation Engine (PDE) is considered to be the propulsion system of future air and space vehicles because of its low cost, light weight, and high performance. Hybrid PDE is a relatively new concept where a turbine is integrated with a PDE. This hybrid system is expected to operate under fuel-rich conditions during take-off (stoichiometric), and fuel-lean (φ = 0.44) conditions during cruise. Hence, the objective of the present study is to simulate the external flow field of a stand alone PDE system and study its variation during the above mentioned operating conditions. In order to study Hybrid PDE systems, the underlying concept of the working of a stand alone PDE, namely, detonation, has to be simulated first. For this purpose, the one-dimensional reactive Euler equations are solved. Since a propagating detonation wave is the result of chemical reactions in a very small region, flow adaptive grids are used for the one dimensional detonation simulations. The global chemical mechanisms employed predicted all the detonation quantities for both stoichiometric and lean mixture of hydrogen-air with the least error. The results from the global chemical mechanism for both mixtures are used in the two-dimensional PDE simulations. Analyses of the axial pressure and temperature distribution in the external flow field show the nature of the blowdown process and its variation for different operating conditions. Flow exergy analysis shows that there is 25% loss in available work when a turbine is placed at one tube length away from the exit of the PDE. One of the important outcomes of this study is the information that can guide in the placement of the turbine downstream of the PDE to achieve lower blowdown time.


Author(s):  
Hua Qiu ◽  
Cha Xiong ◽  
Chuan-jun Yan ◽  
Wei Fan

A novel two-mode propulsion system based on detonation combustion, known as a detonation turbine based combined cycle engine (DTBCC), was proposed and thermodynamically analyzed for potential application to aircrafts whose flight Mach number is from 0 to 5. The obvious advantage of the two-mode system is that both modes share the same multidetonation chambers. The quasi-stable total temperature and total pressure for inlet conditions of the turbine could be realized in this hybrid pulse detonation engine. A key parameter (drive area ratio) was defined as the ratio of the outflow area at the head to the cross-sectional area of the detonation chamber. The calculated results showed that the increase of the drive area ratio led to the increase in the mass flow entering the turbine; however, this led to the decrease of the total inlet temperature, the total inlet pressure, and the expansion-pressure ratio of the turbine. Compared with an ideal turbojet engine, the inlet temperature of the turbine in a preturbine hybrid pulse detonation engine with a drive area ratio of 1 was 80 K lower than the former under the same pressure ratio and the same fuel-air ratio. In other words, the increase of the drive area ratio may improve the performance of this hybrid pulse detonation engine. Variation of the pressure ratio was adapted to varied flight Mach numbers by a change of the drive area ratio, which induced the enlargement of the operating range. Finally, a performance model was established to research the components’ characteristics and the propulsive performance of the engine. Preliminary performance estimates suggested that thrust and specific fuel consumption of the two-mode propulsion system were superior to the existing turbine based combined cycle designs.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Gui-yang Xu ◽  
Chun-guang Wang ◽  
Yan-fang Zhu ◽  
Hong-yan Li ◽  
Lun-kun Gong ◽  
...  

AbstractThe experiment system of pulse detonation engine is set up to investigate on influence of diameter on detonation acoustic characteristic. The research of detonation acoustic characteristic of pulse detonation engine for four different diameters in different angles is carried out. Results from the test show that as the PDE diameter increasing, there are increases in amplitudes of impact noise in all angles, and the growth rate of amplitude of impact noise in the 90° direction is generally greater than that in the 0° direction. The smaller PDE diameter is, the distance of most obvious directivity at 0° turning to most obvious directivity at 30° is shorter. When the distance is shorter, such as 200 mm, the duration of detonation acoustic is increasing with the increase of PDE diameter, however, when the distance is longer, such as 3000 mm, it is just the opposite. The maximum duration of detonation acoustic is appeared in 3000 mm under 30 mm PDE diameter which reaches to 1.44 ms.


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