ELECTRICAL CONDUCTIVITY OF INERT GASES – SEED COMBINATION IN SHOCK TUBES: II. REFLECTED SHOCK MEASUREMENTS IN ARGON

1965 ◽  
Vol 43 (7) ◽  
pp. 1334-1341 ◽  
Author(s):  
J. Lau ◽  
E. Mills
Keyword(s):  
Electrical Conductivity ◽  
Shock Waves ◽  
Shock Tube ◽  
Cesium Chloride ◽  
Incident Shock ◽  
Inert Gases ◽  
Shock Tubes ◽  
End Plate ◽  
Reflected Shock

The electrical conductivity of argon behind reflected shock waves in a shock tube was measured and compared with theory. The effect of seeding the argon with cesium chloride smoke was studied. The shock tube and seeding apparatus used was described by Lau (1964), except for a section added ahead of the dump tank where a gate can slide to form the end plate where the incident shock is reflected.

scholarly journals Experimental investigation of shock waves in liquid helium I and II

1976 ◽  
Vol 75 (2) ◽  
pp. 373-383 ◽  
Author(s):  
John C. Cummings
Keyword(s):  
Shock Wave ◽  
Experimental Investigation ◽  
Shock Waves ◽  
Shock Tube ◽  
Liquid Helium ◽  
Initial Conditions ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Liquid Interface ◽  
Reflected Shock

The flow field produced by a shock wave reflecting from a helium gas-liquid interface was investigated using a cryogenic shock tube. Incident and reflected shock waves were observed in the gas; transmitted first- and second-sound shocks were observed in the liquid. Wave diagrams are constructed to compare the data with theoretical wave trajectories. Qualitative agreement between data and theory is shown. Quantitative differences between data and theory indicate a need for further analysis of both the gas-liquid interface and the propagation of nonlinear waves in liquid helium.This work was a first step in the experimental investigation of a complex non-equilibrium state. The results demonstrate clearly the usefulness of the cryogenic shock tube as a research tool. The well-controlled jump in temperature and pressure across the incident shock wave provides unique initial conditions for the study of dynamic phenomena in superfluid helium.

ELECTRICAL CONDUCTIVITY OF INERT GASES—SEED COMBINATION IN SHOCK TUBES

1964 ◽  
Vol 42 (8) ◽  
pp. 1548-1563 ◽  
Author(s):  
J. Lau
Keyword(s):  
Shock Wave ◽  
Electrical Conductivity ◽  
Shock Waves ◽  
Alkali Metal ◽  
Shock Tube ◽  
Digital Computer ◽  
Theoretical Calculations ◽  
Inert Gases ◽  
Temperature Ratio ◽  
Seeding Material

The effect of seeding shock waves with alkali metal smoke is studied. The pressure, density, temperature ratio, electron density, and conductivity were calculated with a digital computer and tabulated for various combinations of gas and seeding material. A hydrogen-driven shock tube was constructed to measure the properties of the seeded gas behind the shock wave. The conductivity of argon seeded with cesium was measured with a conductivity probe and compared with theoretical calculations.

Shock-initiated exothermic reactions. VI. The oxidation of ethylene oxide and cyclopropane

1969 ◽  
Vol 22 (7) ◽  
pp. 1355 ◽  
Author(s):  
LJ Drummond ◽  
J Kikkert
Keyword(s):  
Shock Waves ◽  
Ethylene Oxide ◽  
Shock Tube ◽  
Induction Period ◽  
Ignition Delay ◽  
Exothermic Reactions ◽  
Induction Periods ◽  
Reflected Shock ◽  
Formaldehyde Oxidation ◽  
Temperature Dependences

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.

scholarly journals Shock Loading of Closed Cell Aluminum Foams in the Presence of an Air Cavity

2020 ◽  
Vol 10 (12) ◽  
pp. 4128
Author(s):  
Mahesh Thorat ◽  
Shiba Sahu ◽  
Viren Menezes ◽  
Amol Gokhale ◽  
Hamid Hosano
Keyword(s):  
Shock Waves ◽  
Shock Tube ◽  
Shock Loading ◽  
Pressure Rise ◽  
Incident Shock ◽  
Foam Density ◽  
Aluminum Foams ◽  
Closed Cell ◽  
Rigid Walls ◽  
End Wall

It is important to protect assets located within cavities vulnerable to incident shock waves generated by explosions. The aim of the present work is to explore if closed cell aluminum foams can mediate and attenuate incident shocks experienced by cavities. A small cavity of 9 mm diameter and 2 mm length was created within the steel end-wall of a shock tube and exposed to shocks, directly or after isolating by aluminum foam liners. Shock waves with incident pressure of 9–10 bar travelling at a velocity of 1000–1050 m/s were generated in the shock tube. Compared to the no-foam condition, the pressure induced in the cavity was either equal or lower, depending on whether the foam density was low (0.28 g/cc) or high (0.31 to 0.49 g/cc), respectively. Moreover, the rate of pressure rise, which was very high without and with the low density foam barrier, reduced substantially with increasing foam density. Foams deformed plastically under shock loading, with the extent of deformation decreasing with increasing foam density. Some interesting responses such as perforation of cell walls in the front side and densification in the far side of the foam were observed by a combination of scanning electron microscopy and X-ray microscopy. The present work conclusively shows that shocks in cavities within rigid walls can be attenuated by using foam liners of sufficiently high densities, which resist densification and extrusion into the cavities. Even such relatively high-density foams would be much lighter than fully dense materials capable of protecting cavities from shocks.

Paper 14: On the Reflection of Shock Waves from Deflector Plates

1965 ◽  
Vol 180 (10) ◽  
pp. 245-259
Author(s):  
W. A. Woods
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Reflected Shock Wave ◽  
Reflected Wave ◽  
Reflected Shock ◽  
Pressure Time ◽  
Wave Travel ◽  
Wave Region

The paper first explains the importance of the reflection of shock waves in the design of certain chemical plant. The theory of the reflection of shock waves is also discussed in the first part of the paper. It is shown that when a shock wave travelling along a pipe containing stationary gas reaches the outlet end of the pipe there may be ( a) a reflected expansion wave, ( b) a reflected shock wave, ( c) a reflected sound wave, ( d) no reflected wave at all, ( e) a standing shock wave situated at the end of the pipe, depending upon the strength of the incident shock wave and the amount of blockage present at the outlet end of the pipe. The conditions for each kind of reflection are determined, and in the case of the reflected shock wave region the strengths and speeds of the reflected shock waves are established throughout the region and the results are presented graphically. In the second part of the paper the results are given of experiments carried out on a shock tube fitted with various kinds of deflector plates. The experiments were performed to study the reflection of shock waves from the deflector plates by measuring pressure/time indicator diagrams near the outlet end of the pipe. The indicator diagrams revealed the approximate pressure amplitudes of the incident and reflected shock waves and also the wave travel times for the shock waves. This information was used in conjunction with the charts given in the first part of the paper to establish the deflector geometry and spacing needed in order to avoid the occurrence of a reflected shock wave.

Shock-Tube Study of Cr* Chemiluminescence During the Induction Period of the C2H2–O2 Reaction

1971 ◽  
Vol 49 (23) ◽  
pp. 3904-3907
Author(s):  
David Gutman ◽  
Shimpei Matsuda
Keyword(s):  
Shock Waves ◽  
Shock Tube ◽  
Induction Period ◽  
Emission Intensity ◽  
Gas Mixture ◽  
Chain Branching ◽  
Growth Constant ◽  
Reflected Shock ◽  
Tube Study

The Cr* (a7S–y7P) chemiluminescence at 360 nm during the induction period of the C2H2–O2 reaction was studied behind reflected shock waves. When the reaction gas mixture containing 10 p.p.m. Cr(CO)6, 0.5% C2H2, 1.0% O2, and 98.5% Ar was shock heated to 1650 °K, the emission intensity of Cr* grew exponentially with a growth constant equal to the chain branching constant. This observation indicates that reaction(s) leading to Cr* chemiluminescence involve only one chain carrier during the induction period of the C2H2–O2 reaction. The mechanism of the chemical excitation of Cr is discussed.

Nonideal effects behind reflected shock waves in a high-pressure shock tube

Shock Waves ◽  
2001 ◽  
Vol 10 (6) ◽  
pp. 405-420 ◽  
Author(s):  
Eric L. Petersen ◽  
Ronald K. Hanson
Keyword(s):  
High Pressure ◽  
Shock Waves ◽  
Shock Tube ◽  
Pressure Shock ◽  
Reflected Shock
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