Investigations of the Aerodynamic Characteristics of the Shock Tubes : (Part 1, The Effects of Tube Diameter on the Tube Performance)

Ikui, Takefumi; Matsuo, Kazuyasu

doi:10.1299/jsme1958.12.774

“…The finite opening time of the diaphragm can affect the shock formation distance and trajectory [21][22][23][24][25][26][27] and, in general, slow-opening diaphragms cause the peak in axial shock trajectory to occur further downstream [22]. The resulting slope of the attenuating shock downstream of the peak Mach number can be steeper than predicted assuming viscous effects alone [23].…”

Section: Shock Tube and Attenuationmentioning

confidence: 99%

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

Petersen

¹

,

Hanson

²

2001

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044REPORT Public reporting burden for this collection ot information is estimated to average 1 hour per response, including the time for review ng instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comment regarding this burden estimates or any aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and Shock tubes often experience temperature and pressure nonuniformities behind the reflected shock wave that cannot be neglected in chemical kinetics experiments. Because of increased viscous effects, smaller tube diameters, and nonideal shock formation, the reflected-shock nonidealities tend to be greater in higher-pressure shock tubes. Since the increase in test temperature (AT 5 ) is the most significant parameter for chemical kinetics, experiments were performed in the Stanford High Pressure Shock Tube using infrared emission from a known amount of CO in Argon. From the measured change in vibrationally equilibrated CO emission with time, the corresponding dT 5 /dt (or AT5 for a known time interval) of the mixture was inferred assuming an isentropic relationship between post-shock temperature and pressure changes. For a range of representative conditions in Argon (20-530 Atm, 1240-1900, the test temperature 2 cm from the endwall increased 3-8 K after 100 )J,s and 15-40 K after 500 u,s, depending on the initial conditions. Separate pressure measurements using a shielded piezoelectric transducer confirmed the isentropic assumption. An analytical model of the reflected-shock gas dynamics was also developed. The measured incident-shock axial velocity profile and a model of the boundary layer growth provide the upstream boundary conditions needed to define the properties behind the moving reflected shock. The calculated AT 5 's agree well with those obtained from experiment. The analytical model was used to estimate the effects of temperature and pressure nonuniformities on typical chemical kinetics measurements. When the kinetics are fast and occur in less than 300 |is, the temperature increase is typically negligible, although some correction is suggested for kinetics experiments lasting longer than 500 (xs. The temperature increase, however, has a negligible impact on the measured absorption profiles of OH and CH 3 when using laser absorption diagnostics at 306 and 216 nm, respectively, validating the use of a constant absorption coefficient. Infrared emission experiments are more sensitive to temperature and pressure changes, so T 5 nonuniformities should be taken into account when interpreting IR-emission data. NONIDEAL EFFECTS BEHIND REFLECTED SHOCK WAVES IN A HIGH-PRESSURE SHOCK TUBEEric L. Petersen f and Ronald K. Hanson AbstractShock tubes often experience temperature and pressure nonuniformities behind the reflecte...

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“…The resulting slope of the attenuating shock downstream of the peak Mach number can be steeper than predicted assuming viscous effects alone [23]. Opening time/formation distance has been found to vary inversely with driver-todriven pressure difference, P 41 (i.e, P 4 -P,), and directly with diaphragm density, diaphragm thickness, ultimate stress of the diaphragm material, and shock tube diameter [24]. For the HPST, the shock formation distance and diaphragm opening time are not routinely measured, but these cited trends qualitatively support the observed test-to-test variation in the incident-shock attenuation.…”

Section: Shock Tube and Attenuationmentioning

confidence: 99%

Nonideal Effects Behind Reflected Shock Waves in a High-Pressure Shock Tube

Mathieu¹,

Hanson²

1999

0

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044REPORT Public reporting burden for this collection ot information is estimated to average 1 hour per response, including the time for review ng instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comment regarding this burden estimates or any aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and Shock tubes often experience temperature and pressure nonuniformities behind the reflected shock wave that cannot be neglected in chemical kinetics experiments. Because of increased viscous effects, smaller tube diameters, and nonideal shock formation, the reflected-shock nonidealities tend to be greater in higher-pressure shock tubes. Since the increase in test temperature (AT 5 ) is the most significant parameter for chemical kinetics, experiments were performed in the Stanford High Pressure Shock Tube using infrared emission from a known amount of CO in Argon. From the measured change in vibrationally equilibrated CO emission with time, the corresponding dT 5 /dt (or AT5 for a known time interval) of the mixture was inferred assuming an isentropic relationship between post-shock temperature and pressure changes. For a range of representative conditions in Argon (20-530 Atm, 1240-1900, the test temperature 2 cm from the endwall increased 3-8 K after 100 )J,s and 15-40 K after 500 u,s, depending on the initial conditions. Separate pressure measurements using a shielded piezoelectric transducer confirmed the isentropic assumption. An analytical model of the reflected-shock gas dynamics was also developed. The measured incident-shock axial velocity profile and a model of the boundary layer growth provide the upstream boundary conditions needed to define the properties behind the moving reflected shock. The calculated AT 5 's agree well with those obtained from experiment. The analytical model was used to estimate the effects of temperature and pressure nonuniformities on typical chemical kinetics measurements. When the kinetics are fast and occur in less than 300 |is, the temperature increase is typically negligible, although some correction is suggested for kinetics experiments lasting longer than 500 (xs. The temperature increase, however, has a negligible impact on the measured absorption profiles of OH and CH 3 when using laser absorption diagnostics at 306 and 216 nm, respectively, validating the use of a constant absorption coefficient. Infrared emission experiments are more sensitive to temperature and pressure changes, so T 5 nonuniformities should be taken into account when interpreting IR-emission data. NONIDEAL EFFECTS BEHIND REFLECTED SHOCK WAVES IN A HIGH-PRESSURE SHOCK TUBEEric L. Petersen f and Ronald K. Hanson AbstractShock tubes often experience temperature and pressure nonuniformities behind the reflecte...

show abstract

“…Classical one-dimensional shock theory does not account for the effects of viscosity, heat conductivity, or diaphragm opening time when predicting shock wave strength and propagation speed in a shock tube [1]. As a result, it is insufficient to predict the acceleration and deceleration process that is observed experimentally in shock tubes [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…As a result, it is insufficient to predict the acceleration and deceleration process that is observed experimentally in shock tubes [1][2][3]. Shock wave velocity measurements in shock tube experiments have been found to deviate from the classical one-dimensional shock theory, especially at early times near the diaphragm rupture location [1,4].…”

Section: Introductionmentioning

confidence: 99%

“…As a result, it is insufficient to predict the acceleration and deceleration process that is observed experimentally in shock tubes [1][2][3]. Shock wave velocity measurements in shock tube experiments have been found to deviate from the classical one-dimensional shock theory, especially at early times near the diaphragm rupture location [1,4]. It has been observed that the actual bursting process of a diaphragm involves the formation of a small opening area close to the center of a diaphragm, which then grows as the diaphragm petals fold outward with time.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Diaphragm opening effects on shock wave formation and acceleration in a rectangular cross section channel

Pakdaman

¹

,

García

²

,

Teh

³

et al. 2016

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Shock wave formation and acceleration in a high-aspect ratio cross section shock tube were studied experimentally and numerically. The relative importance of geometric effects and diaphragm opening time on shock formation are assessed. The diaphragm opening time was controlled through the use of slit-type (fast opening time) and petal-type (slow opening time) diaphragms. A novel method of fabricating the petal-type diaphragms, which results in a consistent burst pressure and symmetric opening without fragmentation, is presented. High-speed schlieren photography was used to visualize the unsteady propagation of the lead shock wave and trailing gas dynamic structures. Surfacemounted pressure sensors were used to capture the spatial and temporal development of the pressure field. Unsteady Reynolds-Averaged Navier-Stokes simulation predictions using the shear-stress-transport turbulence model are compared to the experimental data. Simulation results are used to explain the presence of high-frequency pressure oscillations observed experimentally in the driver section as well as the cause of the initial acceleration and subsequent rapid decay of shock velocity measured along the top and bottom channel surfaces. A one-dimensional theoretical model predicting the effect of the finite opening time of the diaphragm on the rate of driver depressurization and shock acceleration is proposed. The model removes the large amount of empiricism that accompanies existing models published in the literature. Model accuracy is assessed through comparCommunicated by isons with experiments and simulations. Limitations of and potential improvements in the model are discussed.

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Investigations of the Aerodynamic Characteristics of the Shock Tubes : (Part 1, The Effects of Tube Diameter on the Tube Performance)

Cited by 35 publications

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

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

Nonideal Effects Behind Reflected Shock Waves in a High-Pressure Shock Tube

Diaphragm opening effects on shock wave formation and acceleration in a rectangular cross section channel

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