Numerical Studies of Multi-Cycle Detonation Induced by Shock Focusing

2016 ◽  
Author(s):  
Zhihong Zhang ◽  
Zhiqiang Li ◽  
Yunke Wu ◽  
Xingdong Bao
Keyword(s):  
High Temperature ◽  
Mach Number ◽  
Flow Field ◽  
Pulse Detonation Engine ◽  
Shock Focusing ◽  
Chemical Kinetic Model ◽  
Pulse Detonation ◽  
High Temperature And Pressure ◽  
Detonation Engine ◽  
Temperature And Pressure

Shock focusing ignition techniques can avoid deflagration-to-detonation transition (DDT), which make pulse detonation engine (PDE) more efficient. Numerical simulations of an idealized pulse detonation engine consisting of axial inlet and circumferential inlet are presented in this paper. Using detailed hydrogen-air mixture chemical kinetic model, investigation on detonation direct initiation by shock focusing is done. Studies indicate that in initial static flow field, the regions of high temperature and pressure created by shock focusing can produce detonation at the condition of circumferential inlet Mach 2.4. The temperature and pressure of the focusing region is nearly 3000K and 6.3MPa. But in dynamic flow field, the high temperature and pressure created by shock wave focusing for an incident Mach number of 2.4 decrease to 1027K and 4.5MPa which cannot produce detonation. When the incident Mach number increases to 3.5, the transient temperature and pressure of the focusing region is nearly 3000K and 30MPa, which capable of initiating a detonation wave.

Variations in the Flow Field of a Pulse Detonation Engine for Different Operating Conditions

2006 ◽  
Author(s):  
Arun Prakash Raghupathy ◽  
Urmila Ghia ◽  
Karman Ghia
Keyword(s):  
Flow Field ◽  
External Flow ◽  
Operating Conditions ◽  
Chemical Mechanism ◽  
Tube Length ◽  
Pulse Detonation Engine ◽  
One Dimensional ◽  
Pulse Detonation ◽  
Detonation Engine ◽  
The One

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.

scholarly journals Study on Influence of Diameter on Detonation Acoustic Characteristics of Pulse Detonation Engine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Gui-yang Xu ◽  
Chun-guang Wang ◽  
Yan-fang Zhu ◽  
Hong-yan Li ◽  
Lun-kun Gong ◽  
...  
Keyword(s):  
Acoustic Characteristic ◽  
Pulse Detonation Engine ◽  
Acoustic Characteristics ◽  
Experiment System ◽  
Pulse Detonation ◽  
Impact Noise ◽  
Maximum Duration ◽  
Detonation Engine ◽  
Set Up ◽  
Different Diameters

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.

scholarly journals Fatigue simulation of a short fiber re-inforced oil-filter under high temperature and pressure load

2018 ◽  
Vol 213 ◽  
pp. 207-214 ◽  
Author(s):  
Michael Hack ◽  
Wolfgang Korte ◽  
Stefan Sträßer ◽  
Matthias Teschner
Keyword(s):  
High Temperature ◽  
Short Fiber ◽  
Pressure Load ◽  
High Temperature And Pressure ◽  
Temperature And Pressure

Creep Modeling of Welded Joints Using the Theta Projection Concept and Finite Element Analysis

1999 ◽  
Vol 122 (1) ◽  
pp. 22-26 ◽  
Author(s):  
M. Law ◽  
W. Payten ◽  
K. Snowden
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Welded Joints ◽  
Creep Model ◽  
Projection Data ◽  
Predictive Capability ◽  
Element Analysis ◽  
High Temperature And Pressure ◽  
Temperature And Pressure

Modeling of welded joints under creep conditions with finite element analysis was undertaken using the theta projection method. The results were compared to modeling based on a simple Norton law. Theta projection data extends the accuracy and predictive capability of finite element modeling of critical structures operating at high temperature and pressure. In some cases analyzed, it was found that the results diverged from those gained using a Norton law creep model. [S0094-9930(00)00601-6]

High temperature and pressure rheological experiments on felsic granulite

2020 ◽  
Author(s):  
Dapeng Wen ◽  
Yongfeng Wang ◽  
Junfeng Zhang ◽  
Pengxiao Li ◽  
Zhen-Min Jin
Keyword(s):  
High Temperature ◽  
High Temperature And Pressure ◽  
Temperature And Pressure ◽  
Rheological Experiments

scholarly journals High temperature and pressure effects on the elastic properties of B2 intermetallics AgRE

Open Physics ◽  
2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Lili Liu ◽  
Xiaozhi Wu ◽  
Weiguo Li ◽  
Rui Wang ◽  
Qing Liu
Keyword(s):  
High Temperature ◽  
Intermetallic Compounds ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Second Order ◽  
Pressure Effects ◽  
High Temperature And Pressure ◽  
Normal Behavior ◽  
Temperature And Pressure ◽  
Temperature And Pressure Effects

AbstractThe high temperature and pressure effects on the elastic properties of the AgRE (RE=Sc, Tm, Er, Dy, Tb) intermetallic compounds with B2 structure have been performed from first principle calculations. For the temperature range 0-1000 K, the second order elastic constants for all the AgRE intermetallic compounds follow a normal behavior: they decrease with increasing temperature. The pressure dependence of the second order elastic constants has been investigated on the basis of the third order elastic constants. Temperature and pressure dependent elastic anisotropic parameters A have been calculated based on the temperature and pressure dependent elastic constants.

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