Transient pressure measurement at the end of a high-enthalpy reflected shock tube

1990 ◽  
Author(s):  
C. M. Gourlay ◽  
R. J. Stalker
2011 ◽  
Vol 83 ◽  
pp. 66-72 ◽  
Author(s):  
Vishakantaiah Jayaram ◽  
Singh Preetam ◽  
K. P. J. Reddy

Indigenously designed and fabricated free piston driven shock tube (FPST) was used to generate strong shock heated test gases for the study of aero-thermodynamic reactions on ceramic materials. The reflected shock wave at the end of the shock tube generates high pressure and temperature test gas (Argon, Ar) for short duration. Interaction of materials with shock heated Ar gas leads to formation of a new solid or stabilization of a material in new crystallographic phase. In this shock tube, the generated shock waves was utilized to heat Ar to a very high temperature (11760 K) at about 40-55 bar for 2-4 ms. We confirmed the phase transformation and electronic structure of the material after exposure to shock by XRD and XPS studies. This high enthalpy gas generated in the shock-tube was utilized to synthesize cubic perovskite CeCrO3from fluorite Ce0.5Cr0.5O2+δoxide. We were able to demonstrate that this ceramic materials undergoes phase transformations with the interaction of high enthalpy gas under shock dynamic loading.


2020 ◽  
Vol 234 (7-9) ◽  
pp. 1395-1426 ◽  
Author(s):  
Paul Sela ◽  
Sebastian Peukert ◽  
Jürgen Herzler ◽  
Christof Schulz ◽  
Mustapha Fikri

AbstractShock-tube experiments have been performed to investigate the thermal decomposition of octamethylcyclotetrasiloxane (D4, Si4O4C8H24) and hexamethylcyclotrisiloxane (D3, Si3O3C6H18) behind reflected shock waves by gas chromatography/mass spectrometry (GC/MS) and high-repetition-rate time-of-flight mass spectrometry (HRR-TOF-MS) in a temperature range of 1160–1600 K and a pressure range of 1.3–2.6 bar. The main observed stable products were methane (CH4), ethylene (C2H4), ethane (C2H6), acetylene (C2H2) and in the case of D4 pyrolysis, also D3 was measured as a product in high concentration. A kinetics sub-mechanism accounting for the D4 and D3 gas-phase chemistry was devised, which consists of 19 reactions and 15 Si-containing species. The D4/D3 submechanism was combined with the AramcoMech 2.0 (Li et al., Proc. Combust. Inst. 2017, 36, 403–411) to describe hydrocarbon chemistry. The unimolecular rate coefficients for D4 and D3 decomposition are represented by the Arrhenius expressions ktotal/D4(T) = 2.87 × 1013 exp(−273.2 kJ mol−1/RT) s−1 and ktotal/D3(T) = 9.19 × 1014 exp(−332.0 kJ mol−1/RT) s−1, respectively.


2021 ◽  
Author(s):  
Harmanjit Singh Chopra

A gasdynamic mechanism has been identified as a potential source of combustion instability in solid-propellant rocket motors (SRMs). This mechanism involves the reinforcement of a reflected shock wave in the nozzle convergence region of an SRM's exhaust nozzle. A shock tube apparatus was developed for the experimental component of this study. Various factors, such as the effect of different nozzle geometries and driven channel pressures, were examined. Also, a model of the shock tube was developed for computational fluid dynamics (CFD) simulations. These simulations were generated for comparison with the experimental results and to provide additional information regarding the nature of the flow behaviour. A gasdynamic mechanism has been identified as a potential source of combustion instability in solid-propellant rocket motors (SRMs). This mechanism involves the reinforcement of a reflected shock wave in the nozzle convergence region of an SRM's exhaust nozzle.A shock tube apparatus was developed for the experimental component of this study. Various factors, such as the effect of different nozzle geometries and driven channel pressures, were examined. Also, a model of the shock tube was developed for computational fluid dynamics (CFD) simulations. These simulations were generated for comparison with the experimental results and to provide additional information regarding the nature of the flow behaviour.Experimental and numerical pressure-time profiles confirm the appearance of transient radial wave activity following the initial incidence of the normal shock wave on the convergence region of the nozzle. The results establish that the strength of this activity is markedly dependent upon the nozzle convergence wall angle and the location within the shock tube


2004 ◽  
Vol 52 (603) ◽  
pp. 153-159 ◽  
Author(s):  
Munetsugu Kaneko ◽  
Igor Men’shov ◽  
Yoshiaki Nakamura

Author(s):  
Nick J. Parziale ◽  
Joseph S. Jewell ◽  
Ivett A. Leyva ◽  
Joseph Shepherd ◽  
Hans Hornung

2014 ◽  
Vol 752 ◽  
pp. 349-382 ◽  
Author(s):  
N. D. Sandham ◽  
E. Schülein ◽  
A. Wagner ◽  
S. Willems ◽  
J. Steelant

AbstractStrong interactions of shock waves with boundary layers lead to flow separations and enhanced heat transfer rates. When the approaching boundary layer is hypersonic and transitional the problem is particularly challenging and more reliable data is required in order to assess changes in the flow and the surface heat transfer, and to develop simplified models. The present contribution compares results for transitional interactions on a flat plate at Mach 6 from three different experimental facilities using the same instrumented plate insert. The facilities consist of a Ludwieg tube (RWG), an open-jet wind tunnel (H2K) and a high-enthalpy free-piston-driven reflected shock tunnel (HEG). The experimental measurements include shadowgraph and infrared thermography as well as heat transfer and pressure sensors. Direct numerical simulations (DNS) are carried out to compare with selected experimental flow conditions. The combined approach allows an assessment of the effects of unit Reynolds number, disturbance amplitude, shock impingement location and wall cooling. Measures of intermittency are proposed based on wall heat flux, allowing the peak Stanton number in the reattachment regime to be mapped over a range of intermittency states of the approaching boundary layer, with higher overshoots found for transitional interactions compared with fully turbulent interactions. The transition process is found to develop from second (Mack) mode instabilities superimposed on streamwise streaks.


1969 ◽  
Vol 22 (7) ◽  
pp. 1355 ◽  
Author(s):  
LJ Drummond ◽  
J Kikkert

Mixtures of ethylene oxide or cyclopropane with oxygen and argon were ignited with reflected shock waves In a shock tube. The temperature dependences of the ignition delay and the growth of light emitted during the induction period to explosion of C2H4O-O2 mixtures indicate that the rate-controlling reaction is that of formaldehyde oxidation. The temperature dependence of induction periods for C3H6-O2 mixtures suggests that a complicated but undetermined mechanism controls the delay to ignition.


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